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1. SCLK 0123 45 6 7 8 9 1011121314 15 1617 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MODE 0 Smaple MOSI MISO OP CODE Field Write 0 x FO Address Field Data Field fai fol ofolohalahalalalalalalatalatalatalatalo o o olo o o o MOSI OP CODE Field Read 0 x OF Address Field Data Field EAEAN AAE eee eee eee eee wso oxo Y oom Y oe peameen Figure 8 16 Format of EtherX card SPI commands Courtesy of WiZnet Co Ltd 294 USING MULTICORE FOR NETWORKING APPLICATIONS ETHERX CARD APPLICATION PROGRAMMING INTERFACE Now that we understand electrically how the EtherX communicates with the HYDRA we should mention the driver that provides a clean interface for the code written on the Propeller The driver can be found in every example in the Chapter_08 Source directory It is also located on the Avery Digital website at www averydigital com products html Figure 8 17 shows the overall driver architecture and its relationship to the application and hardware As you can see from the figure between the application and the EtherX card there are three levels The bottommost layer is the hardware interface layer which is the physical interface that has been discussed already in the electrical interface section The next layer is the SPI assembly code layer which resides in a separate cog
2. C CH Channel 3 ID PAN ID 0 DH Destination Address High FF DL Destination Address Low 0 MY 16 bit Source Address 34200 SH Serial Number High 0021639 SL Serial Number Low 0 AR XBee Retries 0 AN Random Delay Slots 0 MM MAC Mode 9 NT Node Discover Time 0 CE Coordinator Enable 1FFE SC Scan Channels 4 SD Scan Duration 0 41 End Dev 0 A2 Coordinator Association 0 Al Association Indication 0 EE AES Encryption Enable i MJ KY AES Encryption Key COM6 96008 N 1 FLOW NONE B24 Ver 1045 Figure 5 7 X CTU software showing XBee configuration settings You should see the TX and RX lights flashing on both units if using the AppBee carrier and text in your Terminal window You should see two of each character what you typed in blue and what was echoed back and received in red as shown in Fig 5 9 Tip Having problems If you don t see any data returning be sure the remote XBee is connected properly If it is not a new XBee if may have been configured differently Turn off both units and swap the XBees After powering up Restore the XBee to default configuration using the X CTU button read the second XBee using the X CTU software and test again 200 WIRELESSLY NETWORKING PROPELLER CHIPS FCC ID OUR XREF IC ID 42 14A XBFE 3 ki a me ro bee tream net A Figure 5 8 Remote XBee connections for loop back
3. In line multi line document comment designators Code comment designator Document comment designator Categorical Listing of Propeller Assembly Language CPR S Elements marked with a superscript s are also available in Spin DIRECTIVES ORG Adjust compile time cog address pointer FIT Validate that previous instructions data fit entirely in cog RES Reserve next long s for symbol 450 APPENDIX A CONFIGURATION CLKSETS Set clock mode at run time COG CONTROL COGIDs Get current cog s ID COGINITS Start or restart a cog by ID COGSTOPS Stop a cog by ID PROCESS CONTROL LOCKNEWS Check out a new lock LOCKRETS Return a lock LOCKCLR Clear a lock by ID LOCKSETS Set a lock by ID WAITCNT Pause execution temporarily WAITPEQ gt Pause execution until pin s match designated state s WAITPNE S Pause execution until pin s do not match designated state s WAITVID Pause execution until Video Generator is available for pixel data CONDITIONS IF_ALWAYS Always IF_NEVER Never IF_E If equal Z 1 IF_NE If not equal Z 0 IF_A If above C amp Z 1 IF_B If below C 1 IF_AE If above or equal C 0 IF_BE If below or equal C Z 1 IF_C If C set IF_NC If C clear IF_Z If Z set PROPELLER LANGUAGE REFERENCE 451 IF_NZ IFC EQZ IFC NEZ IF_C_AND_Z IF_C_AND_NZ IF_NC_AND_Z IF_NC_AND_NZ IF_C_ORZ IF_C_OR_NZ IF_NC_OR Z IF_NC_OR_NZ IF_ZEQC IF Z NEC IF_Z_AND_C IF_Z_AND_NC
4. I quickly realized that while programming the DanceBot to move by itself was fun it would be much more fun if it could interact with others as well just by watching what they were doing Read the next chapter to find out how I added computer vision to my DanceBot Summary Although the DanceBot is quite complex the Propeller s multicog architecture makes it easy to understand build and debug each of the bot s subsystems one at a time In this chapter we ve integrated powerful sensors to the Propeller to measure the robot s position and orientation in the world Coupled with our control logic we were able to build a robot that balanced itself while we steered it like a normal RC car In the next chapter we ll add computer vision capabilities to the robot to make it interactive Exercises In this section we are going to explore a number of exercises with the Propeller powered balancing robot 1 Try changing the center of gravity of the robot What happens when the center of gravity is made higher for example by attaching a heavy weight to the top of the bot Does this make balancing easier or harder 2 Try using different wheels on different surfaces What happens when the robot s contact area with the ground gets smaller or larger 3 Try running the robot up and down inclined surfaces Does the robot stay balanced Why This page intentionally left blank CONTROLLING A ROBOT WITH COMPUTER VISION
5. Application Object Building Block Object Address Call Start Parameters Start Method lt Method Return Value Launch into 3 Other Cog Main Global RAM Variables N Method Cog Other Cog Figure 3 5 Cog information exchanges through mutually agreed upon memory addresses 58 DEBUGGING CODE FOR MULTIPLE CORES Common Multiprocessor Coding Mistakes Thanks to the Propeller microcontroller s architecture programming languages and object design conventions the list of common multiprocessor related coding mistakes is small This section explains each potential coding mistake its symptoms and how to correct it Missing call to a building block object s Start method Missing I O pin assignments in a new cog Incorrect timing interval Code that missed the waitcnt boat Only one cog is waiting while the other has moved on Memory collisions Wrong address passed to a method Forgotten literal indicator for assembly language code Method in a new cog outgrows stack space STUCK ON A BUG If you get stuck on a bug with test code using multiple processors go through this list because chances are the bug will be one of these items The community at http forums parallax com can also help with finding bugs and correcting misun derstandings about how a given piece of code works MISSING CALL TO A BUILDING BLOCK OBJECT S START METHOD A building block object that executes code in more than o
6. X CTU COM6 ol x About PC Settings Range Test Terminal Modem Configuration Line Status Assert Close Assemble Clear Show ore M RTS Break Ea Packet ES a I Figure 5 9 X CTU Terminal window Tip Beyond testing purposes the X CTU software is not essential and any terminal program or other serial software package may be used such as the PST Debug LITE software used in previous chapters Just ensure baud rates match between the software and the devices TESTING AND CONFIGURING THE XBee_ 201 As noted each character is transmitted as it is typed The XBee can actually send a string of characters at once up to 100 but it only waits so long before assembling a packet to be transmitted We type too slowly to get multiple characters quickly enough with the default configuration but we can assemble a packet of characters that will be kept together Y On the X CTU Terminal window click Clear screen and then click Assemble Packet v Type Hello World in the packet box and click Send Data You ll notice your text is returned as a single packet One last test is the range test This allows you to monitor the signal strength from 40 dBm to the XBee s sensitivity limit of around 100 dBm by having the software repeatedly send out a packet to be echoed V Check the check box below the vertical RSSI receiver signal strength indication v Click Start Y Monitor the number of good
7. Connection Disconnected Memory 00 01 02 Figure 7 8 Tracking an object at high speed Following a Line with a Camera In the previous section we controlled the behavior of the robot by shining a bright light at the camera This works in some environments where we can control the lighting and ensure that no other objects reflect or create light to the camera that s brighter than our flashlight It s also an active method where we have to power the flashlight We ll now look at a filter that is less restrictive and uses a passive method to steer a robot Traditional line following robots use two phototransistors to stay on a line One pos sible strategy works by ensuring that one detector is on the dark line while the other is on the lighter background More sophisticated robots use additional detectors to determine the robot s exact position on the line to look ahead or even to recognize junctions FOLLOWING A LINE WITHA CAMERA 271 Figure 7 9 DanceBot with camera configured to follow lines In this section we ll build a filter that uses our existing frame grabber to perform fol lowing a line with a camera Since our frame grabber gives us too much information we need to design a filter that will steer a robot in the middle of a line We start by mounting the robot s camera so that its field of view is from below the horizon to just in front of the robot see Fig 7 9 Now we can stream the video to ViewPort an
8. Figure 2 18 Building block objects used in a bike application VAR long Cog Holds ID of started cog long Stack 32 Stack workspace for cog PUB Start Pin Duration Count Start flashing led on Pin for Duration a total of Count times Stop Cog cognew LED_Flash Pin Duration Count Stack 1 PUB Stop Stop flashing led if Cog Did we start a cog cogstop Cog 1 If so stop it PRI LED Flash Pin Duration Count Flash led on PIN for Duration a total of Count times Duration is in 1 100th second units Duration clkfreq 100 Duration Calculate cycle duration diral16 23 Set pins to output 36 INTRODUCTION TO PROPELLER PROGRAMMING repeat Count 2 Loop Count 2 times outa lPin Toggle I O pin waitcnt Duration cnt Delay for some time Tip This source is from PCMProp Chapter_02 Source Flash spin Caution Don t run this yet Our application isn t ready until later in this exercise EXPLANATION The only change we made to LED_F lash is to declare it as PRI instead of PUB Do you recall how PUB declares a public method PRI declares a private method The differ ence is that while public methods can be called by other objects private methods cannot This feature helps an object maintain its integrity Generally most object methods are declared as public since they are meant to be called by other objects at any time Methods not designed for random calling f
9. T Untitled Wireshark He Edt View Go Capture Analyze Statistics Help ioj x SweeewiogGx s ai GBesvot2z SRiaaan Fiter v Borression Gear Apply Time 16 R 588484 164 8 589274 165 8 635683 167 8 635871 171 8 653272 172 8 708886 Destination 209 73 191 242 172 17 150 209 73 191 242 172 17 150 209 73 191 242 172 17 150 209 73 191 242 172 17 150 209 73 191 242 172 17 150 Nvidia_05 11 b5 Broadcast 209 73 191 242 172 17 150 Prtccal__ wo 58 TCP 58 TCP 58 TCP 58 HTTP 58 HTTP ARP 58 HTTP E A Ue TCP segment of a reassemn le PN TCP segment of a reassembled PDU TCP segment of a reassembled PDU HTTP 1 1 200 OK JPEG JFIF image HTTP 1 1 200 OK GPEG JFIF image Baa who has 172 17 150 1 Tell 172 1 HTTP 1 1 200 OK JPEG JFIF image E id Internet Protocol Frame 171 60 bytes on wire 60 bytes captured a a Ethernet II src Cisco_d6 0f 4a 00 0a 42 d6 0f 4a Dst Giga Byt_83 01 2f 00 16 e6 83 01 2f src 209 73 191 242 209 73 191 242 Dst 172 17 150 58 172 17 150 58 Dst Port 4429 4429 Seq 4470 Ack 437 Len 1 Transmission Control Protocol Src Port http 80 m Reassembled TCP Segments 4470 bytes 108 301 Hypertext Transfer Protocol JPEG File Interchange Format 110 1360 114 88 136 1360 138 1360 171 1 00 16 e6 83 01 2f 00 Oa 42 d6 OF 4a 08 00 45 00 00 29 e6 29 00 oe z 06 c2 1d di 49 bf f2 ac 11
10. When the top object is compiled all the objects referenced by it are included in the downloadable image called a Propeller Application Spin Code Each object has a specific talent that it performs when called upon by the object that references it Additional cogs may be started to assist with the performance if necessary as designed TV Object Graphics Object Mouse Object Spin Code Spin Code Spin Code a a 7 3 gt 2 Propeller Assembly Code Propeller Assembly Code Propeller Assembly Code Figure 1 3 A Propeller application s object hierarchy 6 _ THE PROPELLER CHIP MULTICORE MICROCONTROLLER An application is downloaded to the Propeller s RAM and optionally its external EEPROM Propeller Application f RAM only downloads are useful during development since they take less time EEPROM downloads are necessary if the application should be retained between resets or power cycles Download Main RAM Figure 1 4 Downloading to the Propeller Tip If the application was downloaded to EEPROM it will also start in the same way whenever a power up or reset event occurs Propeller applications may use multiple cogs all the time or just sometimes as the need requires Cogs may also be activated and then put to sleep consuming very little power so they may wake up instantly when needed Tip The next chapter will take you step by step through hardware connecti
11. Write data to the address specified in the arguments addQ a Set the arguments to the global addi al variables values dataout dout SPIRW SPI_WR Set SPIRW to the write value Wait until the driver clears SPIRW This indicates that it is done repeat until SPIRW SPI_DONE You can see that the write method has three input parameters a al and dout These represent the address you want to write to and the data to be written The write method will set the address parameters to the global variables add0 and add1 It will then set the dout parameter to the dataout global variable and will set the SPIRW global variable to 2 which is equal to the constant variable SPI_WR set in the CON section of the driver The write method then waits until the SPIRW global variable is set to 0 which is equal to the constant variable SPI_DONE set in the CON section of the driver Remember that the SPI layer will clear the SPIRW global variable to 0 when it is done with the SPI transaction Thus this method will block which means it will wait doing nothing until the SPI layer completes the transaction ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 299 That s it These methods are meant to be used by the application layer to read and write bytes to and from the W5 100 If you wanted to you could interface to the HY DRA EtherX card entirely just using these two methods In fact if you wanted to configure or use the W5100
12. damper flapper inspired thermostat design is now more than 100 years old the typical residential central air system controllers of today rely on essentially the same principles Though the modern thermostat may contain a microprocessor a real time clock timers and factory calibrated solid state temperature sensors the primary operating mode remains the same when the air temperature nears a preset point the thermostat simply turns an HVAC system off or on Though this method of temperature management is widely used it has observable issues regarding comfort and efficiency One problem with the binary nature of a thermostat is that the optimal temperature point is chased following a predictable sinusoidal path as it oscillates between too cold and too hot The reason for this cannot entirely be laid at the feet of the ther mostat module itself but instead may be attributed in part to the design of the heating and cooling portions of a typical central air system These systems are usually tuned to produce a specific amount of heated or cooled air usually in cfm or cubic feet per minute when activated This precludes providing a proportional response to temperature needs as fan speeds and heating cooling element temperatures are typically set at a fixed value though some newer HVAC fans do offer high low speed options in a rudimentary attempt to provide some proportionality As long as the thermostat is calli
13. 3 3V Ky Photoresistor P17 Fixed Resistor GND a P8 P23 a ee a Ba aro P22 o o o pyi m i y P21 ys es a P11 a eee ae pe Pt ya ee i P14 L P17 ese a P15 mie es eo ao cf Figure 4 10 Photoresisior as an on off circuit ON OFF SENSORS 133 Information The Cadmium Sulfide CdS cell or photoresistor was one of the most common ambient light sensors built into devices With the advent of the European Union s Restriction of use of certain Hazardous Substances ROHS directive cadmium sulfide photoresistors can no longer be built into devices imported into or manufactured in Europe This has given rise to a number of photoresistor replacement products including certain phototransistors and linear light sensors Many of these devices are designed to be drop in replacements for photoresistors making it possible for manufactures to comply with RoHS without redesigning all their circuit boards to accommodate new parts and circuits ON OFF SENSORS THAT DEPEND ON SIGNALING Some on off sensors require special signals to make them work properly One example is the Parallax CO sensor which has a control pin that requires a sequence of high low volt age levels for reliable readings from its alarm pin Another example shown in Fig 4 11 is an infrared object detection circuit The tube on the right houses an infrared light emitting diode IR LED like the ones found in common TV remotes and the sensor on the left is a PNA
14. 40 pit 2 PAN broadcast Up to 100 bytes per packet dBm 0 x 28 40 decimal is returned bits 3 7 reserved Figure 5 16 API packet for transmitting string using 16 bit address Reprinted by permission of Digi International 216 WIRELESSLY NETWORKING PROPELLER CHIPS values up to that point are summed together to create a checksum value The receiving unit will perform a summation itself verifying against this value before using the data If the packet is well formed the XBee will accept this frame and transmit it If not it will be discarded Simple huh Actually it s not all that bad but much more complex than just sending a string to be transmitted Let s look at the Spin code that forms a packet when we send a string such as XB API_Str String Hello From the XBee Object Pub API_Str addy16 stringptr Length chars csum ptr Transmit a string to a unit using API mode 16 bit addressing XB API_Str 2 string Hello number 2 Send data to address 16 TX response of acknowledgement will be returned if FrameID not 0 XB API_RX If XB Status Acc 1 No Ack ptr 0 dataSet ptrt 7E Length strsize stringptr 5 API Ident FrameID API TX cmd AddrHigh AddrLow Options dataSet ptr Length gt gt 8 Length MSB dataSet ptr Length Length LSB dataSet ptrt 01 API Ident for 16 bit TX dataSet ptrt _FrameID Frame ID dataSet p
15. If dataIn i i I O control IO XB rx Accept IO number as byte value value XB rx Accept state 1 0 as byte value dira 10 Set direction of pin outal1I0 value Set state of pin Using bytes instead the packet is always three bytes long To control P20 to turn on the structure would be li byte value 20 byte value 1 Instead of li string 20 2 bytes or characters string 1 By using bytes as values instead of decimal string the packet size can be com pressed For values greater than 255 maximum byte value two bytes can be used and combined Value bytel lt lt 8 byte2 220 WIRELESSLY NETWORKING PROPELLER CHIPS Where byte1 MSB is shifted over by eight bits and then added to byte2 LSB We used a similar technique in the RxPacketNow methods in the XBee Object to assemble the 16 bit address from two received bytes In the coordinator s code XB AT_Config string ATAP 1 shifts the XBee in API mode and the Propeller waits for an API packet to be received in ProcessFrame If the Identifier RxIdent is 81 the packet is of the message variety as opposed to a status or other type The source address is accessed and displayed XB API_Rx Wait for API data if XB RxIdent 81 If data identifier is a msg string Display source address PC Str string 13 Data Received from address PC DEC XB srcAddr Since the actual message contained values
16. Jeff Martin Introduction In the 1990s the term multicore had more to do with soldering equipment than it did with computer processors Though the concept was young and relatively nameless this was the time many silicon engineers began focusing their efforts on multiprocessor tech nology By the middle of the following decade multicore had become the industry buzzword and the first consumer accessible products arrived on the market The short years to follow would mark a time of extreme evolution innovation and adoption of multicore technology that is bound to continue at a fast pace So what exactly is multicore and why is it so important These are just two of the many questions we Il answer throughout this book with insightful examples and excit ing projects you can build yourself We ll reveal how this technology is changing the way problems are solved and systems are designed Most importantly we ll show just how accessible multicore technology is to you Caution This book is a collaboration of many enthusiastic authors who are eager to demonstrate incredible possibilities well within your reach Reading this material may leave you feeling inspired exhilarated and empowered to invent new products and explore new ideas prepare yourself In this chapter we ll do the following E Learn what multicore means and why it s important E Introduce the multicore Propeller microcontroller Explore Propeller
17. KBD KEY This command reads the keyboard connected to the Propeller Demo Board and echoes back the keys pressed continuously Give it a try with the following command Ready gt KBD KEY Try hitting keys on the keyboard plugged into the Propeller Demo Board and you will see them on the CCP To stop the loop hit a key on the PC s terminal keyboard TRYING NOT TO CONFUSE YOURSELF WITH THE LOCAL AND REMOTE KEYBOARDS OH MY One of the traps that is easy to fall into when using remote communications along with multiple keyboards is to forget what is talking to what I do this all the time so remember The keyboard connected to the Propeller Demo Board is the remote keyboard The PC s keyboard is connected only to the serial terminal program and you are typing to the CCP with it That completes our little demonstration of the CCP As you can see it s pretty cool and there are lots of possibilities with this technology You can more or less create a product right now that would allow users to throw commands via serial to a Propeller chip and render video audio and more And with a binary rather than ASCII protocol you could speed it up 10 tol100 fold and make a rather robust system But let s not get ahead of ourselves yet It s time now to look at the actual engineering of the whole system and all its pieces System Architecture and Constructing the Prototype As noted earlier in the chapter it was decided not to bui
18. Network Interface API Tl Enable API J Use escape characters ATAP 2 AT command Setup ASCII Hex Command Character cc 2 Guard Time Before BT 1000 Guard Time After AT 1000 m Modem Flash Update J7 No baud change Figure 5 6 X CTU software showing COM port selection The screen should have loaded with the configuration setting of the XBee as shown in Fig 5 7 Many of them will be explained shortly we re only going to use a handful of the settings available But for now let s test out some wireless communications TALKING XBee TO XBee USING LOOP BACK With a second XBee supply power and connect a jumper between DOUT and DIN or RX and TX on the carrier board as illustrated in Fig 5 8 using the AppBee SIP LV car rier board or similar Do not connect to any Propeller I O at this ttme we are simply using the board for power We used a second Demo Board for this test V Power up the remote XBee with loop back jumper in place Z Click the X CTU Terminal tab v Type Hello World TESTING AND CONFIGURING THE XBee 199 X CTu COM6 15 xj Remote Configuration PC Settings Range Test Terminal Modem Configuration Modem Parameters and Fi Parameter View r Profile Versions i Clear Screen Download new Always update firmware Show Defaults ical Modem XBEE Function Set Version xB24 z XBEE 802 15 4 fias z E Networking amp Security
19. Note Data is a ways sent in frames between XBees but when in AT mode transparent mode the only thing we deal with is the data or message itself First all frames start with a start delimiter so the receiving unit can locate where the start of a frame is as data pours in Next is a 16 bit length MSB and LSB which has to match the number of bytes from after the length through to the checksum but not including it This is followed by the API identifier a unique value telling the receiving unit what type of message it is Next is the identifier specific data consisting of the frame ID if set to 0 it will sup press acknowledgement packets back to the controller we will ignore these packets and then the 16 bit destination address as 2 bytes To send data to a unit at address 1 these would be values of 00 01 Options are set to disable acknowledgements or to send the data as a broadcast Next is the actual data up to 100 bytes And finally all the byte Start Delimiter Length Frame Data Checksum 0x7E MSB LSB 1 Byte API specific structure API Identifier identifier specific Data 0x81 cmdData Source Address Bytes 5 6 RSSI Byte 7 Options Byte 8 RF Data Byte s 9 n Received Signal Strength Indicator bit 0 reserved MSB most significant byte first Hexadecimal equivalent of dBm value bit 1 Address broadcast LSB least significant last For example If RX signal strength
20. Print a string VGA term_vga newline term_vga pstring vga_startup_string Initialize serial driver only works if nothing else is on serial port receive pin transmit pin baud rate serial start 31 30 0000 9600 baud rate Announce serial is good to go term_ntsc pstring serial_startup_string term_vga pstring serial_startup_string Start sound engine up on pin xx snd start 24 376 _ USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Announce sound is good to go term_ntsc pstring sound_startup_string term_vga pstring sound_startup_string Give everything a moment to initialize Delay 1_000_000 Play a little sound to let user know sound is good to go snd PlaySoundFM snd SHAPE_SQUARE snd NOTE_C4 lt Round Float snd SAMPLE_RATE 1 0 200 3579 _ADEF lt repeat 100 000 snd PlaySoundFM 1 snd SHAPE_SQUARE snd NOTE_C5 lt Round Float snd SAMPLE_RATE 1 0 200 3579 _ADEF lt repeat 100 000 snd PlaySoundFM 2 snd SHAPE_SQUARE snd NOTE_C6 lt Round Float snd SAMPLE_RATE 1 0 200 3579 _ADEF lt Start keyboard up 2 pin driver kbd start 26 27 Announce keyboard is good to go term_ntsc pstring keyboard_startup_string term_vga pstring keyboard_startup_string Final strings term_ntsc pstring ready_string term_vga pstring ready_string Initial splash text to terminal serial tx ASCII_CR serial tx ASCII
21. SENSOR BASICS AND MULTICORE SENSOR EXAMPLES three common resistive sensors are the photoresistor potentiometer and thermocouple The photoresistor s resistance varies with light level The potentiometer s resistance varies with the position of its adjusting knob or screw and the thermocouple s resistance varies with temperature You can find devices for many different physical properties including gas concentration force humidity temperature fluid level and salinity and that s still just a sampling of the myriad of resistive sensors available Examples of capacitive sensors include another type of humidity sensor as well as touchpad and displacement sensors Photodiodes and phototransistors are also compatible with this technique and tend to be selective for particular colors of light and some are available with optical filters to make them even more selective HOW RC DECAY MEASUREMENTS WORK RC decay circuits have resistive R and capacitive C elements connected in parallel to an I O pin If the R element is a variable sensor the C element has to be a fixed value Conversely if the C element is a variable sensor the R element has to be a fixed value The example in Fig 4 15 uses a variable resistor which means the resistive element is the sensor and the capacitor is a fixed value Figure 4 15 also shows the interaction between the Propeller I O pin and the RC circuit On the left the I O pin charges up the capacitor
22. Starts the SPI layer assembly code in a new cog stop Stops and frees the cog containing the SPI layer assembly code READ AND WRITE FUNCTIONS read a0 a1 Reads a byte from address a0 a1 from the W5100 via SPI write a0 a1 dout Writes byte dout at address a0 a1 to the W5100 via SPI APPLICATION FUNCTIONS init gway subnet ip mac Initializes the W5100 s gateway subnet IP and MAC open type source_port dest_port dest_ip Opens the socket close Closes the socket listen Used when TCP server should listen for connection from client connect Used when TCP client should establish a connection with server con_est Used to determine if a TCP connection has been established TX dataptr size Transmits size bytes from main memory pointed to by dataptr RX dataptr size block Receives size bytes to main memory pointed to by dataptr read_rsr Returns the number of bytes the W5100 has stored in its internal receive buffer MODE FUNCTION mode opmode Changes the operating mode of the W5100 closely resembles socket programming A socket is opened on a particular port When opening the socket the user determines if it should be UDP or TCP If TCP there is a listen call if we intend to be a server and a connect call if we intend to be a client UDP is connectionless so this is not needed Data is then transmitted or received by TX or RX method calls Table 8 2 shows a listing of th
23. Step 6 Test the Bug Fix Test Timestamp Bug Fix spin uses the lock approach and tests for memory collisions by leaving in the extra delays to keep that memory collision window wide open The semID variable declaration and locknew lockset and lockclr commands that were added to fix the bug are labeled with Fix in the comments In the Go method the lock is set before the longmove command and is cleared immediately afterwards This is all that s needed in the Go method for memory access and it happens quickly In the TimerMs method which gets executed by another cog the lock gets set before the code starts modifying the ms variable and it continues through the s and then m variables When it s done with the m variable it clears the lock again before the loop repeats Test Timestamp Bug Fix spin Wait till clear set lock Clear lock Wait till clear set lock Clear lock This program tests to verify that semaphores prevent memory memory collisions CON _clkmode _xinfreq xtali pll16x 5 000 000 OBJ debug PST Debug LITE VAR long stack 40 long m s ms t dt long semID PUB Go minutes seconds milliseconds debug Style debug COMMA_DELIMITED debug Start 115200 if semID locknew 1 Crystal and PLL settings 5 MHz crystal x 16 80 MHz Serial communication object Ample stack for prototyping Timekeeping variables Fix Semaphore ID variabl
24. WD j J j juv j ju fro j S Figure 6 5 Schematic showing the motor controller s interface to the Propeller ensure that the robot won t hurt itself even if we make mistakes in our programming We power the chip through a fuse from the batteries and connect the outputs to the motor we wish to drive To control it we connect the direction and pwm input pins to the Propeller pins designated as output pins for this motor see Fig 6 5 for a schematic These inputs determine the state of the switches in the H bridge To continually drive the H bridge we ll use the following assembly code It runs in its own cog and continually outputs configurable patterns to the output pins which are connected to the Propeller Changing the output patterns and timing allows us to change the direction and speed of the two motors org doPWM or dira dirav loop mov ptr par mov i 3 duty rdlong orV ptr Get value to or add ptr 4 mov t outa rdlong timeV ptr Get wait add ptr 4 and t andV or t orV mov outa t add timeV cnt waitcnt timeV 0 djnz i duty jmp loop 242 DANCEBOT A BALANCING ROBOT it long 1 ape long 1 diraV long 1 andV long 1 ptr long 1 orV long 1 timeV long 1 To initialize the code that will drive our motors we ll use the following Spin code It initializes the output patterns configures the DIRA register and starts the previous assembly code in a cog pub setupMo
25. delay clkfreq 1000 follows this form When the waitcnt command is done the variable t stores the cnt register value at the end of the previous time interval which was the instant the waitent command allowed the cog to continue to the next command This value is subtracted from the cur rent value in the cnt register and then compared to the number of clock ticks in delay clkfreq 1000 That s the number of clock ticks in a quarter of a second minus the number of clock ticks in 1 ms which is a value slightly less than the time interval stored in the delay parameter WAITCNT TRICKS WITH RC DECAY The RC Decay measurements in the next chapter rely on this approach to prevent the cog that s taking the measurement from getting stuck when the RC Decay measurement takes longer than the allotted time COGS GET SENT TO DIFFERENT MEMORY ADDRESSES TO EXCHANGE INFORMATION When an application needs two or more cogs to exchange information the applica tion code should be consistent about what memory address or addresses the cogs access Cogs Not Sharing Info Bug spin is an example where the cog executing the Go method assumes the cog executing the Blinker method can see its delay local vari able Meanwhile the cog executing the Blinker method takes its own delay parameter and uses it in a repeat loop Even though each method is relying on a variable named delay they are two separate local variables A local variable can only be accessed
26. n loopLines Loop over lines t2 t1 cmdLoop Track a Pattern We ve gone from tracking an active bright spot to following a passive line on an artificial background Now it s time to track a passive pattern in the real world Our goal for this section is to develop an algorithm and pattern that will steer the robot in practically any environment As an experiment take a look around you and imagine what type of pattern would stand out in our typical cluttered world in computer vision terms we re looking for an appropriate fiduciary pattern In most places a barcode like pattern of repeated black and white lines should do well This pattern TRACK A PATTERN 273 is relatively rare in most settings and we can use a chain of simple vision filters to locate it even in visually cluttered scenes First we need to build a filter that s sensitive to horizontal edges in our video Looking at relative changes in value improves the robustness of our algorithm especially when lighting conditions change The horizontal Sobel filter is quick to implement and does a good job of detecting vertical edges To compute it just replace each pixel with the absolute value of the difference of its horizontal neighbors When we run the horizontal Sobel filter on our pattern we notice that area corresponding to the pattern turns white the filter finds many edges close together in that area Next we need to design a filter that highlights th
27. the Propeller Proto Board with a new one as none of the room board components were soldered to the Propeller Proto Board Using the daughterboard design had enough advantages that we wanted to forge ahead However we didn t want the associated lag time and expense of having a commercial board house etch the boards for us so we went ahead and auto routed the schematic to create a printed circuit board but we then converted to a trace isolation style board Fig 11 15 so it could be cut and drilled using the three axis CNC system available in house A Three Board Solution As this method of creating boards worked rather well we decided to use the same process to create daughterboards for the additional functions that would be required For example each room board would need to be able to send data back to a master board The master board collects room temperatures and cal culates servo positions to control the air registers in each room A new schematic was created for the master board and it was then cut on the CNC system using the same board size and pin footprint as the room board viv Ee n a Ea KRENE ERETEREE RR EARRAN A gt BOo000e Figure 11 14 Preliminary schematic of the room board daughterboard THE HVAC GREEN HOUSE MODELM 415 I l a s a eo See cir ge a i Figure 11 15 Room board daughterboard d
28. 01131 000 E Longitude 11 deg 31 000 E 1 Fix quality 0 invalid 1 GPS fix SPS 2 DGPS fix 3 PPS fix 4 Real time kinematic RTK 5 Float RTK 6 Estimated dead reckoning 2 3 feature 7 Manual input mode 8 Simulation mode 08 Number of satellites being tracked 0 9 Horizontal dilution of position 545 4 M Altitude meters above mean sea level 46 9 M Height of geoid mean sea level above WGS84 ellipsoid 10 Time in seconds since last DGPS update 3 DGPS station ID number A7 The checksum data always begins with For additional information regarding GPS operation and the NMEA standard see the following http en wikipedia org wiki Global_Positioning System http electronics howstuffworks com gadgets travel gps htm http aprs gids nl nmea Reading the GPS Sensor In this experiment we will be using the Parallax GPS receiver module The receiver module has four pins E GND Ground reference supply E VCC 5 V input supply voltage OVERVIEW OF THE SENSORS 329 E SIO Serial data input output in our case we will only use it as an output E RAW Input pin that determines which communications mode to use The RAW input pin allows a user to select whether to use a binary command based communications system when connected to VCC or when connected to GND it con tinuously streams raw NMEA sentences Since we are only interested in the NMEA sentences for this experiment we will connect the RAW pin to GND This
29. 11 9 A servo controlled air register was created for each room and mounted in a central plenum that spanned the house from the cooling tower in front all the way to the back of the building Beneath the send air plenum we created a wire chase to allow us to run wire from each room back to a master control area The Hinged Roof Panels n addition to being able to control the amount of air delivered to each room we needed a way to set a target temperature per room We created hinged roof panels for each room and mounted pushbuttons that would allow an observer to alter the target temperature up or down simply by pressing one of the buttons Above the buttons we added 2 x 16 LCD panels that would display both the current temperature and the target temperature to the observer as shown in Fig 11 10 Once all these mechanical components were mounted it was time to design the electrical systems that would bring this creation to life THE HVAC GREEN HOUSE MODEL 409 aaa Figure 11 10 Hinged top panels with RED BLUE temperature control buttons and LCD displays DESIGNING THE CONTROL ELECTRONICS SCALABILITY AND REAL WORLD CONSIDERATIONS Though we are working with a model system we don t want to preclude the possibil ity that this design may be implemented on a large scale possibly even being used in an actual residential HVAC system Since the Propeller chip has the ability to control multiple servos and to read multiple sen
30. 115200 will prevent any serial messages from being exchanged between the Propeller chip and Parallax Serial Terminal Commenting fp Start will cause all the floating point results to be 0 62 DEBUGGING CODE FOR MULTIPLE CORES AUTHOR S NOTE Forgetting to include Start method calls in application objects is my most common coding error In fact when I demonstrated on the fly floating point examples during Propeller seminars and trainings I forgot the fp start method call on several occasions Each time it took a couple of minutes to figure out and it s amazing how time seems to slow to a standstill while trying to find and fix a bug in front of a large group Even after all that I still almost forgot to include Missing call to a building block object s Start method in my list of most common multiprocessor coding mistakes MISSING I O ASSIGNMENTS IN NEW COG As mentioned in the Architecture that Prevents Bugs section each cog has its own T O direction and output registers Although this solves a number of potential problems there is still one coding error people tend to make configuring the I O from the wrong cog The typical form of this error is code that makes I O pin configurations in one cog and then launches a new cog to control the I O pins If the new cog isn t also configured to work with those I O pins it won t be able to control their output states Furthermore if the cog that launched the new co
31. 1200 1500 4700 Set frication for T Sustain silence briefly Ramp up T Set formants for R fa 0 Ramp down T v go 20 aa 10 Ramp up R ga 30 v go 50 v go 150 Sustain aa 0 Taper down to silence ga 0 v go 100 v go 500 Pause 6649 The timing of the s and t sounds took me a lot of trial and error to get tuned right Even so you can see that the amount of data involved in synthesizing words is quite low compared to making audio recordings of them less than 1 percent To utilize VocalTract it will take some experimentation on your part Once mastered though you will have gained untold insight into the mechanics of speech that you ll be eager to share with others who will be less interested As a side benefit you will be able to add speech to your Propeller applications using minimal resources In parting here is an odd application that uses the StereoSpatializer object to mix and place four separate VocalTracts into a stereo image This demonstrates how the Propeller s multiple processors can be easily put to use in a cooperative fashion to perform complex tasks of trivial value Top object called SpatialBlah see SpatialBlah spin CON _clkmode xtal1 plli6x _xinfreq 5 000 000 voices 4 Voices can be 1 4 buffer_size 1000 Spatializer buffer size OBJ v voices Blah StereoSpatializer 440 SYNTHESIZING SPEECH WITH THE PROPELLER
32. 13 If you were to use an analog accelerometer you could read the accelerometer and a digital pushbutton on the tilt controller and have the XBee send those values automati cally Then the Propeller could accept data at the bot and process it for control action Or you may have an array of sensors in the area and collect data from them as they wake sample send and go back to sleep This page intentionally left blank DANCEBOT A BALANCING ROBOT Hanno Sander Introduction The Propeller s multicog architecture allows you to tackle complex projects one step at a time A project that s keeping me busy is my balancing robot that uses vision to interact with people In the next two chapters I 11 describe how I built my robotic dance partner In this first chapter I ll cover the basics of building a balancing robot The parts Sensors motors and more E The code Which way is up Achieving balance How to avoid falling over E Steering a balanced robot Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_06 The Challenge Balancing robots make a great platform for mobile robots They are highly maneuverable have great traction and move more smoothly and naturally than other designs Balancing robots are mechanically very simple They only have two wheels with which they move through their envi
33. 262f objects and resources 45 48 parallel functionality in 417 pin connections 323 323t PropCV 259 265 semaphores or locks 317 using multiple cogs 6 7f video streaming screenshot 268 269f Propeller as virtual peripheral for media applications 353 397 client host console development 372 386 command console overview 365 command library to slave server 387 388 compiling demo 359 data flow from user to driver 366 driver overview 370 372 371f 371t INDEX 471 Propeller as virtual peripheral for media applications Cont enhancing and adding features to system 389 hardware setup 355 356f intro setup and demo 354 362 354f local command settings 360 361 361f normalization of drivers for common RPC calls in future 371 372 on demand drivers 389 other communication protocols 389 396 putting demo through paces 359 360 359f 360f remote commands sample 361 362 remote procedure call primer 366 370 367f selecting drivers 365 366 software setup and installation 357 358f system architecture and constructing prototype 362 366 363f 364f 365t teaser demo 358 362 Propeller Application 34 launch 5 7f object hierarchy 5 5f objects to build 5 Propeller Assembly Source Code Debugger PASD 83 85 86f assembly debugging session 115 115f development with 110 116 F11 vs F2 114 Propeller Audio Spectrum Analyzer application 168 168f Propeller chips 364f architecture that prevents bugs
34. A number of improvements could be made to this experiment First we could always add sensors We could add a barometric absolute pressure sensor as well as a differential pressure sensor such as the Freescale Semiconductor MPX5050 By using a differential pressure sensor we can connect a tube to one of the ports on the sensor and point it out toward the front of the car The second port is a static reference 352 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER By measuring the difference between the two pressures we can compute the speed of the moving sensor From here we can add three or two depending if you have dual axis rate gyros and a three axis accelerometer Hitachi H48C and by the time we are done we would have a full blown autopilot system with the Propeller at the center Changes to the code could include outputting directly to a KML file so that a user could open up the SD card in a file explorer and directly import the track to Google Earth Another option would be to skip an SD card altogether and connect the Propeller directly to a laptop computer while driving around and streaming the location based data over a serial port A program running on the laptop could then receive the data and save to a KML file while Google Earth is configured to automatically check for updates at a specified rate By doing this you have essentially created a moving map display Exercises 1 Modify the Main_01 spin so that the file
35. Activity log Figure 10 18 A screenshot of the Eltima program in server mode Summary At this point hopefully you see the true power of networking Propeller chips and using them as slaves from a client host computer Not only can simple serial proto cols like RS 232 be used but lower level chip to chip protocols such as SPI TC and CAN control area network can be employed to truly transform the Propeller chip into a virtual peripheral where the user need not know what s inside it since the behavior is exposed via the interface Moreover with the platform developed here and the ideas therein you can easily see how on demand virtual peripher als and real time changes to the cores can be achieved creating a limitless set of possibilities for the client host controller to command the Propeller chip and its multicore architecture Exercises 1 Add mouse support to the CPP and commands so that you can stream the state of the mouse x y buttons until a key is pressed on the local serial terminal EXERCISES 397 Try writing a Visual BASIC C C Perl PHP or other program that opens a serial port up and then controls the CCP by throwing commands at it by building up the command strings programmatically Convert the CPP to work with an SPI interface Then connect another Propeller chip and see if you can slave one Propeller from the other Create a clock counter on the Propeller and add a command in the CCP to re
36. Buttonsank sein Cogunpecttxamene san Opie Pushbutton ain watnotanontxamoie san Enterdresnecnlaadies spin moustnmgt est son PuNDuptessenamus son Hetet uiDuctexSenal som MuIDLOQUDRCrEx ames som StackLenetnDemom oaned son lerminanaionogge son Terminal Lea emret sran Tenes ouieooec san lenmessages son THKTOCK son YT RS Untitled spin Folder and File views provides access to objects on the computer Figure 2 4 Brads Spin Tool BST on a Macintosh Figure 2 5 Propeller Demo Board connected and powered LET S GET CONNECTED 21 PROP PLUG USB INTERFACE TOOL FOR CUSTOM PROPELLER BOARDS Many Propeller boards feature a USB interface If you are not using the Propeller Demo Board see the product s documentation for connection details For discrete Propeller chips Fig 2 6 shows the connection using the Propeller Plug available from www parallax com Refer to the chip s pin names if translat ing from the DIP to the LQFP or QFN packages Propeller Clip or Plug P8X32A D40 24LC256 ANMANRWN A j 29 Ord YZEeX8d bea DIP 40 Propeller DIP to Prop Plug connections If you don t have a Propeller Plug or USB port look for Hardware Connections in Propeller Tool Help for an example connection to an RS 232 serial port Now test the connection Y Perform the Propeller Identification process o Press the F7 key or select the Run Identify Hardware menu item The Pr
37. Every location is accessible as a byte 8 bits word 2 bytes or long 2 words Cog RAM is located inside a cog itself see Fig 1 11 Cog RAM is for exclusive use by the cog that contains it Every register in Cog RAM is accessible only as a long 32 bits 2 words 4 bytes I O Pins One of the beauties of the Propeller lies within its I O pin architecture While the Propeller chip s 32 I O pins are shared among all cogs they are not a mutu ally exclusive resource Any cog can access any I O pins at any time no need to wait for a hub access window The cogs achieve this by gating their individual I O signals through a set of AND and OR gates as seen at the top of each cog in Fig 1 9 The cog collective affects the I O pins as described by these simple rules E A pin is an output only if an active cog sets it to an output E A pin outputs high only if the aforementioned cog sets it high MULTICORE PROPELLER MICROCONTROLLER 13 0000 I I I l Propeller Application Code and Data I I I I RAM 8192 longs 8192 Longs 7FFF 8000 Character Set i 4096 Longs l 256 Characters of BFFF 16 x 32 pixels ROM C000 CFFF 8192 longs D000 DFFF E000 F001 F002 FFFF Figure 1 10 Propeller Main RAM ROM Propeller Assembly Code seas ec and Data c 496 Longs 32 bits each System Special Purpose Variables Registers Ue Benes 32 bits each Figure 1 11 Propeller Cog RAM Whe
38. Frequency Output Frequency output circuits are a common approach for determining the values of resistive and capacitive sensors A common frequency output circuit that utilizes either a resistive or capacitive sensor employs a 555 timer IC to generate frequency signals that are determined by the values of resistors and capacitors connected to the chip The circuit involves two resistors and a capacitor and is called an astable multivibrator in electronics speak This circuit causes one of the 555 timer s pins to send a series of pulses and resistor and capacitor values set both the frequency and the pulse width Changes in either a capacitive or resistive sensor in this circuit result in changes in the multivibrator circuit s output frequency making it a way to determine the sensor s value Since the resistors and capacitors can also control the pulse durations perhaps the temperature sensors inside the Memsic 2125 accelerometer from the previous section uses a similar design to send those pulses at certain durations Figure 4 27 shows examples of Parallax sensors and sensor modules that use fre quency to indicate the values they measure left to right they are the TSL230 Light to Frequency Converter Piezo Film Vibra Tab and Xband Motion Sensor Optical inter rupters such as the circuits that read black white stripes on the inside of robot wheels are also common frequency output devices that indicate motor output speed Parallax Inc Rad
39. Get character from Rx Buffer PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER if Resa gps_buff cptr 0 If replace the character with 0 else gps_buff cptrt Rx Else save the character if gps_buff 2 G if gps_buff 3 G if gps_buff 4 A copy_buffer GPGGAb GPGGAa if gps_buff 2 R if gps_buff 3 M if gps_buff 4 C copy_buffer GPRMCb GPRMCa if gps_buff Q P if gps_buff 1 G if gps_buff 2 R if gps_buff 3 M if gps_buff 4 2 copy_buffer PGRMZb PGRMZa Excerpt from GPS_IO MINI spin Copyright 2007 Perry James Mole The readNMEA method is called when a new cog is started as the main entry point It begins by creating a null string initially and then enters into an infinite repeat loop Inside the repeat loop it clears out the gps_buffer byte string with a call to longfill Next it loops until we have received a ASCII character from the serial port s RX pin using the following code repeat while Rx lt gt Wait for the to ensure we are starting with Rx uart rx a complete NMEA sentence Once the is located we know that we have the beginning of the NMEA sentence and that any character read in afterwards is part of this sentence up until the lt CR gt lt LF gt characters The next section of code reads in and stores the characters from the serial port into the gps_buff and replaces
40. Hanno Sander Introduction The Propeller is powerful enough to capture and analyze video In this chapter I ll look at two vision technologies that can control a robot with computer vision Here s what we are going to cover in this chapter E Computer vision Seeing and understanding the world one pixel at a time E Using computer vision in our robot to interact with people E Developing a vision engine that runs on the Propeller PropCV E Integrating with OpenCV for state of the art computer vision Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_07 VISION GUIDED ROBOTS It s time to build more sophisticated robots With today s technology our robots should no longer require us to program their every move or steer them via remote control Instead of stumbling through the world with touch or proximity sensors our robots should stand up and watch where they re going The future of vision guided robots is bright Let s see how we ll get there The Propeller provides a great entry into vision guided robots It s powerful enough to process video and has enough memory to perform simple vision algorithms But 257 258 CONTROLLING A ROBOT WITH COMPUTER VISION most importantly it s easy to integrate with all sorts of robotic sensors and actuators The Parallax community has written Propeller objects for almost anything you would w
41. However if you want to design your own system and move things around this is no problem you simply have to make slight changes in each of the drivers to accommodate SYSTEM ARCHITECTURE AND CONSTRUCTING THE PROTOTYPE 365 TABLE 10 1 THE I O PIN MAP FOR THE CONNECTIONS TO MEDIA DEVICES 1 0 DEVICE PROPELLER I O PINS USED NTSC video 12 13 14 video LSB to MSB VGA video 16 V 7 H 18 B1 19 BO 20 G1 21 GO 22 R1 23 RO PS 2 keyboard 26 data 27 clock Sound 10 PWM at left channel of stereo headphones Serial coms 30 TX 31 RX the pin changes In most cases you can simply open up the driver and the PUB start method can be investigated to see what the start up pins are and how they are passed into the driver The video drivers take a little more work since you have to decide not only which pins to use but a couple of other settings like upper lower bank broadcast baseband and so on However inspection of the driver comments usually gives hints on how to do this COMMAND CONSOLE OVERVIEW Moving on from the hardware connections of the Propeller Demo Board itself we see that Fig 10 8 shows some more modules including the command console program CCP and the serial terminal The CCP runs on its own core on the Propeller chip and listens to the serial line for user input As the user types on the PC s serial terminal the CCP buffers the text and acts like a single line text editor When the use
42. IF_NZ_AND_C IF_NZ_AND_NC IF_Z ORC IF_Z_OR_NC IF_NZ_ORC IF_NZ_OR_NC If Z clear If C equal to Z If C not equal to Z If C set and Z set If C set and Z clear If C clear and Z set If C clear and Z clear If C set or Z set If C set or Z clear If C clear or Z set If C clear or Z clear If Z equal to C If Z not equal to C If Z set and C set If Z set and C clear If Z clear and C set If Z clear and C clear If Z set or C set If Z set or C clear If Z clear or C set If Z clear or C clear FLOW CONTROL CALL Jump to address with intention to return to next instruction DUNZ Decrement value and jump to address if not zero JMP Jump to address unconditionally JMPRET Jump to address with intention to return to another address TJNZ Test value and jump to address if not zero TJZ Test value and jump to address if zero RET Return to stored address 452 APPENDIX A EFFECTS NR No result don t write result WR Write result WC Write C status WZ Write Z status MAIN MEMORY ACCESS RDBYTE RDWORD RDLONG WRBYTE WRWORD WRLONG Read byte of main memory Read word of main memory Read long of main memory Write a byte to main memory Write a word to main memory Write a long to main memory COMMON OPERATIONS ABS ABSNEG ADDABS ADDS ADDX Get absolute value of a number Get negative of number s absolute value Get negative of a number Get a value or its additive inverse based on C Ge
43. Increment seconds if s 60 If seconds 60 s 0 Set seconds to 0 m Increment minutes if m 60 If minutes 60 m 0 Set minutes to 0 If key pressed display variable list if debug KeyCheck debug Vars m String long m s ms Since the PST Debug LITE object was configured to display comma delimited lists calls to debug Vars result in the variable lists shown in Fig 3 17a After loading the Parallax Serial Terminal COM15 Com Port Baud Rate aud Rate Tx DTR TORTS echo On guaira T Prefs Clear Pause Disable Figure 3 17a Variable display with Parallax Serial Terminal DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 89 Parallax Serial Terminal Disabled Click Enable button t SEE Parallax Serial Terminal Debug LITE 59 ms 996 S9 MS 997 5a Me 998 59 ms 999 0 ms 07 ms O ms 0 ms 5 5 5 5 5 5 5 5 Com Port Baud Rate Tx M DTA M ATS comis x 1520 o ex o i Prefs Figure 3 17b Continued code and placing the cursor in the Parallax Serial Terminal s Transmit windowpane a few quick keypresses to check the timestamp results look encouraging The display in Fig 3 17b was obtained with some modifications to the code to verify that the variable values roll over and increment in the correct order v Before trying the example programs in this section uncheck the Parallax Serial Terminal s Echo On check box T
44. Respond to master board settings Change mode from off heating cooling Change vents from recirculation fresh air Respond to master board information requests Monitor temperature Figure 11 20 System overview flow chart The main job of the master board is to poll each of the room boards retrieve their current temperature retrieve the desired temperature and then perform calculations that are used to direct the operations of the rest of the system A quick recap of all the boards their functions and their interactions is shown in Fig 11 20 The point of building the HVAC green house was to create a test platform that would allow experimentation with different approaches to air system management and to observe how these approaches perform in this small scale environment Though full scale environments may react differently experimentation on a small scale can be quite useful in determining what approaches to use in a full scale environment The flow chart in Fig 11 21 is the first attempt to use an algorithm to balance and maintain the air temperature in the building As you can see in Fig 11 21 we first calculate the average internal air temperature and then compare that with the outdoor air temperature to determine if the system should be in heating or cooling mode The Spin code to accomplish that is listed here Note Lines marked with the symbol are intended to be on
45. SIZING THE STACK _ 41 Tip This source is from PCMProp Chapter_02 Source In_Synch spin Time units of Duration Pin a I I I I I I I I I I Figure 2 22 1 O pin events synchronized with ideal duration Just before the loop Time is set to the current System Counter value Inside the loop we first wait for the moment indicated by Time Duration then perform the I O event The Time Duration expression calculates that next moment and adjusts Time to that moment in preparation for the next loop iteration This technique works for any loop as long as Duration is greater than the longest possible loop overhead Tip You will find an in depth look at tackling timing related bugs in Chapter 3 You can also find out more by looking up Synchronized Delays in Propeller Tool Help or the Propeller Manual Sizing the Stack In All Together Now we mentioned the need for stack space when launching Spin code into another cog Now we ll discuss how to size it The stack used by a cog running Spin code is temporary workspace Within the stack the amount of memory actually used changes with time It grows while evaluating expressions and calling nested methods and shrinks when returning expression results and returning from methods While developing objects it is best to size the stack reserved for new cogs larger than necessary to avoid the strange results that can plague a program whose stack is too small Unt
46. This problem can be corrected by moving the I O pin direction setting to the method that is launched into the new cog IO Declaration Bug Fixed spin VAR long stack 10 PUB Go cognew Blinker stack repeat PUB Blinker dira 5 1 repeat louta 5 waitent clkfreq 4 cnt Array cog executing Blinker Launch a new cog to control P5 Optionally keep cog running P5 gt output in the right cog Infinite loop Invert P5 output register bit Delay for 1 4 s As an aside adding pin and delay parameters to the Blinker method gives the Go method some flexibility for setting I O pin and delay Other Cog Blinks Light spin VAR long stack 10 Array cog executing Blinker 64 DEBUGGING CODE FOR MULTIPLE CORES PUB Go cognew Blinker 5 clkfreq 4 stack Launch new cog repeat Optionally keep this cog running PUB Blinker pin delay Blink light method dira pin 1 Set I O pin to output repeat Repeat loop waitcnt delay cnt Delay 1 4 s outaLpin Invert I O pin output state TIMING INTERVAL ERRORS Although precise timing was not required for the last three blinking light code exam ples there are many other situations where a precise time interval is crucial Examples include the Parallax Serial Terminal s signaling for serial communication with the PC and establishing a sample interval for taking sensor and signal measurements which will be utilized in the next cha
47. conduct much more current than if only a small amount gets reflected back from an infrared absorbing black surface The name charge transfer refers to the fact that the infrared transistor is controlling the current or charge transfer into the capacitor The QTI module is another circuit that has to start with a high signal that discharges the capacitor by pushing the voltage at the capacitor s lower plate up to 3 3 V The QTI sensor needs 3 3 V connected to the White W terminal and 0 V connected to the Black B terminal Then the Red R terminal can be connected to an I O pin for RC measurements For example if you connect the R terminal to P17 Test Simple RC Time can be used to measure this sensor Tip For best results use black vinyl electrical tape on white paper or poster board Not all printers make black marks that absorb infrared Most but not all black white laser printers do a good job but photo printers are definitely hit and miss Pulse and Duty Cycle Outputs Figure 4 21 shows examples of two sensors in the pulse and duty cycle output cat egory the Ping Ultrasonic Distance Sensor and the Memsic 2125 Accelerometer Another example of a sensor that transmits pulses is the infrared receiver introduced in the On Off Sensors That Depend on Signaling section which sends pulses that relay a TV remote s infrared signals The infrared LED inside the remote turns on off rapidly PULSE AND DUTY CYCLE OUTPUTS 145
48. data received by Propeller E DIN Pin 3 Data into the XBee data to be transmitted by Propeller Other pins include a sleep pin Sleep_RQ for low power consumption flow control pins RTS CTS analog to digital ADC inputs digital inputs and outputs DIO among others This chapter will discuss some of these other pin functions but the focus is on simply sending and receiving data between the Propeller and XBees using the DOUT and DIN pins Note Please see the XBee manuals on Digi s web site for in depth discussion and information www digi com and included in the distribution files The XBee has a current draw of around 50 mA and a power output of 1 mW witha range of about 100 m 300 ft outdoors The XBee Pro has a current draw of 55 mA when idle or receiving data and 250 mA when transmitting With a power output of 100 mW it has a range outdoors of 1600 m 1 mi line sight They both have sleep TESTING AND CONFIGURING THE XBee 193 modes with current draws of less than 10 uA but can t send or receive data while sleeping There are different antenna styles as well though the whip antenna is prob ably the most popular Tip Don t get too excited about the distances Line of sight communications rely on height as well as distance Due to ground reflections and deconstructive interference Fresnel losses the heights of the antennas need to be taken into account For good communications at 100 m a height of 1 4 m 4 6
49. diode and transistor 137 144 secure digital card 339 343 synchronous serial 168 174 169f INDEX 473 sensors Cont vision 258 259 258f voltage output of 156 168 wireless sensor network 189 231 Xband Motion Sensor 153 153f Serial Clock signal SCLK 290 296 390 390f serial communication asynchronous 320 client host console development and 377 379 external crystal settings and 65f 66 signals examined 175 179 175f synchronous 172 173f Serial data input output SIO 329 serial LCD unit 409 410 417 418 Serial Peripheral Interface SPI 290 320 320f 353 390 assembly code layer 294 assembly layer 295 297 bus basics 390 392 bus interface of 293 circular buffer 290 291f 391f clocking modes 391 391t electrical interface 290 291f 390f format of EtherX card commands of 293 293f low level chip interfacing 393 394 Mode 0 291 Mode 1 291 Mode 2 291 Mode 3 292 mode descriptions 391 392 timing diagram 291 292f W5100 interface of 293 serial RS 232 protocol 291 serial sensors asynchronous 174 182 174f 180f synchronous 168 174 169f serial terminal output on startup 359 360f serial timing diagram 171 171f serial UART hardware peripheral 321 321f series resistors 136 136f servo motors cable run length and 409 410 controlling multiple 409 PWM controlled 409 set assignment 30 Setup method calls 150 Sigma Delta ADC 160 168 AC signal measurements test 164 167
50. frequency 19 53 Hz 4th resonator frequency 179 3496 Hz nasal amplitude 255 anti resonator level off on linear nasal frequency 19 53 Hz anti resonator frequency 102 1992 Hz frication amplitude 255 white noise volume silent loud linear frication frequency 39 06 Hz white noise frequency 68 gt 2344 Hz Sh Figure 12 4 Documentation from the VocalTract object 432 SYNTHESIZING SPEECH WITH THE PROPELLER The FRICATION output is summed with the NASAL output to make the final product a 32 bit 20 kHz updated audio signal available as both a single ended or differential PCM signal and as a continuously updated LONG in hub RAM Though all parameters are 8 bit within a frame they are interpolated with 24 sub bits so intraframe transitions are very smooth Also frames connect seamlessly with the same precision so there are never any discontinuities in the output signal One thing a user must be aware of is the likelihood of numerical overflow when volume levels get high You ll know if this happens believe me THE QUEST TO GENERATE FORMANTS The resonators in VocalTract that make the formants are very simple but it took a lot of work and luck to figure out how to make them Most resonator algorithms require transcendental math operations which need extreme precision around the nearly asymptotic 1 sine and cosine points This is fine for floating point hard ware systems but a disaster in
51. gt t variable dira pin 1 Set I O pin to output repeat Repeat loop waitcent t t delay Synchronized delay outaLpin Invert I O pin output state In building block objects this is the very same approach that makes it possible for a method call to pass a value to another cog running different code inside the object see Fig 3 4 When the building block object s method gets called that method sets a global variable so that the method executed by the other cog or assembly language code can access it MEMORY COLLISIONS The Propeller chip s architecture eliminates the possibility of memory collisions for any single element in main memory However cogs sharing a group of memory elements can still encounter problems if code is not in place that gives each cog exclusive access to those elements Figure 3 10 shows a typical memory collision scenario for cogs that share more than one main memory element In this scenario one cog has updated two of three variables while another cog jumped in and fetched all three The one cog may have been waiting for a sensor measurement for the third variable so the other cog got two up to date values and one old one As mentioned earlier the Propeller has built in lock bits that cogs can set when they are working on memory and clear when they are done Provided the code in all the cogs that are working with a particular group of shared memory elements follows the same rules and waits for the lock
52. high fidelity tasks But is that the best solution It means the brains of an application must rely on other hardware for high speed tasks and relegate itself to lower priority tasks while waiting for the interrupt of asynchronous events It means systems become more expensive and complex to build often with multiple chips to support the demands It also means designers have the difficult challenge of finding the right special hardware for the job learning that hardware and dealing with any limitations it imposes all in addition to programming the brains of the application in the first place Perhaps the best solution is most apparent in our everyday lives How many times in your life have you wished there were two of you Or three or more Ever needed to finish that report make that call and do those chores while being pressed for quality time with your spouse friends kids or your hobbies See Fig 1 2 Wouldn t it be great even for a short time if you could do multiple things at once com pletely without distraction or loss of speed Maybe we cannot but a multicore device can Multicore Propeller Microcontroller The Propeller microcontroller realizes this dream in its ability to clone its mind into two three or even eight individual processors each working simultaneously with no distractions Moreover it can do this on a temporary or permanent basis with each 4 _ THE PROPELLER CHIP MULTI
53. including I C by Phillips SPI unlike C which has no separate clock is a clocked synchronous serial protocol that supports full duplex communication However TC only takes two wires and a ground whereas SPI needs three wires a ground and potentially chip select lines to enable the slave devices But SPI is much faster so in many cases speed wins and the extra clock line is warranted The advantage of IC is that you can potentially hook hundreds of C devices on the same two bus lines since TC devices have addresses that they respond to The SPI bus protocol on the other hand requires that every SPI slave has its own chip select line Figure 10 13 shows a simple diagram between a master left and a slave right SPI device and the signals between them which are SCLK Serial Clock output from master MOSI SIMO Master Output Slave Input output from master MISO SOMI Master Input Slave Output output from slave SS Slave Select active low output from master SPI is fast since not only is it clocked but it s also a simultaneous full duplex proto col which means that as you clock data out of the master into the slave data is clocked from the slave into the master This is facilitated by a transmit and receive bit buffer that constantly recirculates as shown in Fig 10 14 Figure 10 13 The SPI electrical interface EXPLORING OTHER COMMUNICATIONS PROTOCOLS 391 Master Slave fo faf2y3 4 s 6eq7 fof af2 3 4 s
54. including the time to load your application from EEPROM Don t worry that delay won t increase with the size of your application The Propeller always loads all 32 KB from EEPROM regardless of how many or how few instructions your application contains See Boot Up Procedure in the Propeller Tool s Help to learn more A More Powerful Blink Remember how we said to focus on simple problems first and tasks appropriate for parallel processes will become apparent Our blinking LED serves as one such example process Our application currently performs only one process in one specific way but it could perform this process in many different ways either sequentially or in parallel Let s enhance our method to make it easier to do this In this exercise we ll create a more flexible version of our blinking LED method and we II demonstrate it in sequential operation In the exercise immediately following we ll command multiple processes in parallel We mentioned earlier that a method has a name and contains instructions What might not have been so apparent is that a method is like an action that can be called upon by name causing the processor to perform its list of instructions one at a time As it turns out in the last example we could have called our LED_Blink method by simply typing its name elsewhere in the code like this A MORE POWERFUL BLINK 29 PUB SomeOtherMethod LED Blink Blink the LED This is ho
55. private Merrage Admin Home Calendar Search mambar List Help Parallax Forums gt Public Forums gt Propeller Chip chp Subecribe To Thie Forum Mark Thie Forum Read Last Comment W Topic Threads Showing Forum Page isting Phil Pilgrim PhiPi Yesterday 6 45 PM Nick McClick Yesterday 6 02 PM kuro Yesterday Yesterday 2 51 PM Kit Morton Yesterday 2 15 PM aj Jee O P m 6 Kudos to Gadget Gangster Oldbitcollector WAITPEQ help please Harley OBEX MIT license question W9GFO 3 palin NININA TT TT DUNN ALOOLU LA O LIDIL PM gt Tile size file seek type a file e Newbie question about recieving a number and send it to a DAC northcove E 1 love the Propeller Yesterday 2 06 PM jazzed Yesterday 1 45 PM BPM Yesterday 11 42 AM in Yeste 00 AM irise Yesterday 9 08 AM cessnapilot Yesterday 8 25 AM Leon 260 Yesterday 0 14 AM 654 Ken Peterson Yesterday 6 05 AM 2213 GP inert The Propeller Forum is full of great ideas enthusiastic supporters and endless opportunities to learn gt SPDIF digital audiv output demo Port loader Racing Flight Simulator Motion Control 6 hae accelerometer Broadcast video to be used as a wireless comm link Philldapdl 6 78 MHz crystal Ken Peterson iba 6 Music Synthesizer object wilh General MIDI sound set re B PropxMMS12 D40 Module Up to 1MB 5 3MB s 77 SRAM Figure 2 27 Parallax Propell
56. s QuickSample object uses another cog to monitor the I O pins at up to 20 MHz Here are the minimal steps for adding LSA ViewPort functionality to your code SYNCHRONOUS SERIAL 173 50 20us 100us 200us 500ys lus ims Overview click on name to configure Max Avg val A00500C0 i 508 Ditt Cursors Show A Vert O Edit Variables 0 6 lime msec Connection Connected at 2000 kbps Memory 00 04 00 Triggered on signal Figure 4 41 ViewPort synchronous serial communication Y Add a 400 element frame array Y Declare the QuickSample object along with the Conduit object Z Add the following vp register call before the vp share call Test Gyro with ViewPort spin VAR long frame 400 Stores measurements of INA port 174 _ SENSOR BASICS AND MULTICORE SENSOR EXAMPLES OBJ vp Conduit Transfers data to from PC qs QuickSample Samples INA continuously in 1 Cog up to 20Msps PUB Go yawAde vp register qs sampleINA frame 1 Sample INA into lt frame gt array vp share yawAdc yawADC Share the lt freq gt variable To display the data as shown in Fig 4 41 V Load Test Gyro with ViewPort spin into the Propeller chip Z Click ViewPort s Connect button Z Click the lsa tab Y Click the Plot button next to io in th
57. s code the method SendUpdates is running in a separate cog to allow GetData to monitor for incoming data continuously This allows data to be sent or received independent of the timing The XBee is not in API mode and SendUpdates sends the string values for range theta every two seconds as decimal strings such as the characters 1 O and 5 for the value of 105 three bytes worth of data for one value The unit does this endlessly Pub SendUpdates range theta HM55B start Enable Clock Data XB Delay 1000 repeat range Ping Millimeters PING Pin Read range theta HM55B theta Read Compass XB dec range Send range as decimal value XB tx Send a comma to separate XB dec theta Send bearing XB Delay 2000 Wait 2 seconds and send again Caution The XBee only waits so long in assembling a packet for transmission If the delay between data sent is too long send some data read a sensor and process new data then send the new data it may send it as two different frames To increase the time it waits for more data the RO Packetization Timeout value can be increased In the GetData method the Propeller endlessly awaits data in one cog Once received if the byte is 1 it accepts the next two bytes and uses them for IO number and state to control an output pin This is different from prior examples where we collected a decimal value dataIn XB rx Wait for incoming byte
58. shown in Fig 3 16 is a free yet invaluable tool for anyone who needs to modify existing assembly code or write a Spin assembly language object from scratch Later in this chapter we will see a brief PASD example that demonstrates set ting breakpoints stepping through assembly code checking variable values in the Propeller chip s processor cog and shared Main memory areas and viewing I O pin states 84 DEBUGGING CODE FOR MULTIPLE CORES TABLE 3 1 VIEWPORT TOOLS DEBUGGING INSTRUMENTATION MORE Text Terminal Logic analyzer Indicators and controls IDE style debugger Oscilloscope Fuzzy logic Spectrum analyzer Vision analysis XY plot ViewPort v4 1 64 L mied videu temina amp 88 Debuy S0_My Fest Program 91_My Second Program 00 Debuy S ViewPort Configuration Y E gt De Source Documentation Gar al Uocumentation i3CON aa 14 _clkmode xtall plli6x 15 _xinfreq 5 000_A00 16 YAR i7 long a b str 5 c 18083 19 vp ViewPort Configuration Include this to set up View Spin Files 2 PUB count SP _Tiebug 21 ye sare a c Share global variables with ViewPort Q1_Four Bit Counter 02 Track a Spin Variable b 2 03_RS232 Pattern U4_H gh Frequency Wave U5_Samulated Weather Station resetf 26 elseif a 1 reset 27 at resetD 28 else DOOD0CO30000C070 Memory 00 01 13 Figure 3 15a ViewPort software SURVEY OF PROPELLER DEBUGGING
59. string format into fbuf SDStr ptr Outputs the NULL terminated string ptr to the previously opened file SDdec value Outputs the 32 bit long value to the previously opened file SDhex value digits Outputs the 32 bit long value to the previously opened file with digits count of hexadecimal characters SDbin value digits Outputs the 32 bit long value to the previously opened file with digits count of binary characters 343 344 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER Main Spin Object The main Spin object is the code that ties all the sensor collection and logging together and it runs out of Cog 0 on startup The main Spin object is responsible for creating and initializing the GPS serial parser object the barometer pressure sensor object the TV terminal for display purposes and the SD card file system object On top of managing these additional objects it is continuously reading two input pins that are connected to pushbutton switches that control starting and stopping the SD card file log By using switches and allowing the user to start stop and restart logging multiple data collec tions may be achieved on a single SD card The source code to the main object may be found at the following location Chapter_09 Source Main_01 spin We will not be thoroughly explaining each portion of the source code in this chapter however it is thoroughly commented for easy understanding Instead we will talk about the oper
60. t i cnt Current clock counter dt clkfreq 1000 Ticks in 1 ms repeat Infinite loop waitent t dt Wait for the next ms Before entering the repeat loop timekeeping code uses t cnt to copy the current value of the cnt register to the t variable Remember that the cnt register increments with every clock tick so t cnt copies the time at that moment into the t variable Next the code copies the time increment clkfreq 1000 to a time interval variable named dt Inside the loop waitent t dt adds dt which is the number of ticks in 1 ms to the previously recorded value of t and then waitent waits until cnt register reaches that time The next time the loop repeats it again adds the number of clock ticks in 1 ms to the previous value of t and then waits for the cnt register to get to this next value As long as the other commands in the loop do not take longer than 1 ms to execute this technique ensures that the 1 millisecond time base will be maintained even though the other commands in the loop might take varying amounts of time DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 91 Step 3 Test the Timekeeping Code in Another Cog The Code That Missed the Waitcnt Boat section demonstrated how the waitcnt t dt approach can be unforgiving if the commands inside the loop exceed the time interval 1 ms in this case If debugging commands in the loop take too long to display the values it can cause the next waitcnt
61. the current clock tick count stored by the cnt register into the Blinker method s local variable t Let s assume that when the code gets to t cnt that the cnt register holds the value 600 000 025 After the I O pin assignment the code enters the repeat loop and then waitent tt delay waits for the cnt register which increments with every clock tick to accumulate to 620 000 025 The value that the waitcnt command waits for is tt delay which is equivalent to t t delay Since t stores 600 000 025 and delay stores 20 000 000 the result of t delay stored in t is 620 000 025 Then the waitcnt command waits for the cnt register to accumulate to that value before allowing the cog to continue executing code Next time through the loop tt delay adds another 20 000 000 to t so the waitcnt commands waits for the cnt register to get to 640 000 025 The third time through the loop the waitcnt command waits for 660 000 025 and the fourth time through it waits for 680 000 25 and so on Each time through the loop the waitent command waits for 20 000 000 ticks which is the number of clock ticks in quarter seconds So long as the rest of the commands in the loop take less than one quarter of a second to execute it doesn t matter how long they take because the waitcnt command uses the t variable which accumulates by the number of clock ticks in a quarter of a second each time through the loop Code that Missed the Waitcnt Boat Continuing fr
62. v If it s not currently active click the Start Debugging button in the code tab Z Click dso tab v Inthe Overview table in the lower right area click the Plot buttons next to millisec onds and seconds v Adjust the Horizontal dial to 500 ms div v In the Trigger tab below the Oscilloscope display click Continuous gt Ch1 Fall and Normal DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 105 2 ViewPort v4 1 64 Fie Fl View Configuration Phys Delay Hehe O Test Timestamp Objcc Conduit Documentation TimeStanp Object z stamp Object with ViewPort spin d in code tab s Watch tab s Ose _clkmode xtall plll6x _xinfreq 5 _000_000 Span Files S0_My lirst Progran 91_My Second Program Conduit Fuzzy PER PRT ft eee A A Ert ORN conduit ViewPort conduit obje PropCVFilter 3 Timestamp Object TimeStamp object QuickSanple vill E f 15PUB Go minutes seconds milliseconds 1 16 Cojnfigure ViewPort display amp share minutes throuth milliseco 7 vp config String var minutes seconds milliseconds vp share minutes milliseconds all time Start 1 59 999 Start timestamp cog repeat Main loop timo GotTimo minutes Get a timestamp 2028 0O 0G 00 00 00 0000 00 0A 0A 0A 0A F001 VY vy vy vy vy Teinral 4 minutes ANRA seconds B8DC gt nilliseditiide Sommancds v Connection Connected at 10
63. variable is incremented The Go method s repeat loop checks the timestamp eight times one third of a second apart Find Hidden Bug in Timestamp spin PUB Go minutes seconds milliseconds cognew TimerMs stack Launch timekeeping cog 10 xxAdd 59 xxAdd ms 999 Add repeat 8 Modify to 8 reps Main loop waitent clkfreq 3 cnt xxAdd longmove minutes m 3 Copy timestamp vars debug break Remove debug Vars m String minutes seconds milliseconds 94 DEBUGGING CODE FOR MULTIPLE CORES PRI TimerMs t t cnt dt clkfreq 1000 repeat waitent tt dt mst t waitcnt clkfreq 4 cnt if ms 1000 ms 0 GEF waitcnt clkfreq 4 cnt if s 60 s 0 MEF waitcnt clkfreq 4 cnt if m 60 m i 0 Current clock counter Modify Ticks in 1 ms Infinite loop Wait for the next ms Add 1 to millisecond count xxAdd If milliseconds 1000 Set milliseconds to 0 Increment seconds Add if seconds 60 Set seconds to 0 Increment minutes Add If minutes 60 Set minutes to 0 With this modified program the results of possible memory collisions are now exposed Take a look at the third and fourth lines in Fig 3 19 Parallax Serial Terminal Parallax Serial Terminal COM15 Com Port Baud Rate TX DTR ATS coms 115200 le RX DSR CTS J Echo On Timestamp test memory collisions exposed DEBUGGING TOOLS APPL
64. waitpeq mov waitpne mov sub cmp if_c jmp mov add waitcnt findHSync_ret ret sA ina 8 instr pixel sf video sL sf sL 4 sb sample8Pix sA ina sf video sL sf sL 4 VIDEOSTART sL pixptr pixptr 4 lineCtr sampleLine fieldCtr sampleField syncval sync Wait sf cnt syncval sync Wait sB cnt sB sf sB vSync wc c set findVSync sB cnt sB vblank sB cycPline syncval sync Wait sf cnt syncval sync Wait sB cnt sB sf sB hSync wc c set findHSync sB cnt sB burst sB cycPline for sync for exit if sEnd sStart lt vsyne for sync for exit if sEnd sStart lt hsynec The following Spin code uses the PropC VCapture object in HIVIDEO mode to con tinuously sample video from the camera at 30 fps with a resolution of 240 pixels 200 lines 4 bit pixel This uses even more memory but provides a sharper image 200 lines 240 pixels line 4 bit pixel 1 byte 8 bit 24 000 bytes or 6000 longs 264 CONTROLLING A ROBOT WITH COMPUTER VISION ViewPort v4 1 64 File Edit View Configuration Plugins Debug i Load Connect Stop Mbps E Cz all fuzzy mixed video terminal Oscilloscope Overview click on name to configure Name Plot Edit Min Max _ Avg Val blob 5 18M blobx bloby lo Cursors Show A Diff Vert 2 Horz 4 Edit Variables 0 74 H Scanline at Y 256 T G V
65. www parallax com Fa Figure 4 21 Ultrasonic Distance Sensor and dual axis accelerometer typically in the 38 kHz range Whenever the infrared detector inside the TV senses infrared flashing on and off at 38 kHz it sends a low signal otherwise it sends a high signal The infrared remote controls the amounts of time it transmits the 38 kHz signals to control the pulses that the receiver inside the TV sends to the TV s microcontroller The microcontroller s firmware knows how to interpret these pulses and controls the TV accordingly Radio control also abbreviated RC signals for RC cars boats and planes can also be monitored for the pulses they send with a Propeller microcontroller This makes it possible to give programmed intelligence to remote controlled hobby applications The Memsic 2125 Accelerometer and Ping Ultrasonic Distance Sensor provide two examples of sensors that communicate with pulse durations Both of these devices send pulses to the microcontroller and the pulse durations the amount of time the pulses they send last provide measurements of physical quantities In the case of the Ping it provides an indication of the distance to an object in the case of the accel erometer it provides acceleration information which can in turn be used to indicate velocity and position or just simple tilt by measuring the acceleration due to gravity PING ULTRASONIC DISTANCE SENSOR OBJECT EXCHANGE EXAMPLE Figure
66. 32 768 kHz Low voltage and low power consumption RoHS compatible amp Pb free F f DESCRIPTION The MS5540C is a SMD hybrid device including a precision piezoresistive pressure sensor and an ADC Interface IC It is a miniature version of the MS5534C barometer altimeter module and provides a 16 bit data word from a pressure and temperature dependent voltage MS5540C is a low power low voltage device with automatic power down ON OFF switching A 3 wire interface is used for all communications with a micro controller Compared to MS5534A the pressure range measurement down to 10 mbar has been improved The MS5540C is fully software compatible to the MS5534C and previous versions of MS5540 In addition the MS5540C is from its outer dimensions compatible to the MS54XX series of pressure sensors Compared to the previous version the ESD sensitivity level has been improved to 4kV on all pins The gel protection of the sensor provides a water protection sufficient for 100 m waterproof watches without any additional protection FEATURES APPLICATIONS e Resolution 0 1 mbar e Mobile altimeter barometer systems e Supply voltage 2 2 V to 3 6 V e Weather control systems e Low supply current lt 5 pA e Adventure or multimode watches e Standby current lt 0 1 pA e GPS receivers e 40T to 85T operation temperature e No external components required BLOCK DIAGRAM Input MUX Digital Interface Sensor Memory Interface
67. 4 22 shows how a microcontroller gets a distance measurement from the Ping Ultrasonic Distance sensor The microcontroller has to send the Ping sensor a pulse to make it emit an ultrasonic chirp The duration of the pulse the Ping sensor sends in reply represents the time it takes for the ultrasonic chirp to make a round trip between the sensor and a nearby object Knowing the speed of sound in air the application code can use this time measurement to calculate the distance The Ping sensor requires a pulse that s at least 2 us and returns a pulse that can last anywhere from 115 us to 18 5 ms Immediately after the microcontroller sends the pulse to initiate the chirp it has to change its I O pin direction from output to input and then measure the Ping sensor s reply pulse that indicates the chirp s round trip time 146 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Start Pulse gt p ees 2 lt J Echo Time Pulse I O Pin Vss Figure 4 22 Ping sensor start and echo time signals One of the best things to do when presented with a new sensor is check the Propeller Object Exchange http obex parallax com to find out if an object already exists for measuring the sensor In the case of the Ping sensor there s an object that takes care of all the signaling and time measurement tasks and all you have to do is call its methods V Go to http obex parallax com and enter Ping into the Search field Then
68. 52 54 55 different forms of 17 18f identification dialog showing version and port of 21 22f multicore microcontroller 1 14 packages 7 8f wireless networking of 189 191 190f Propeller Datasheet 136 Propeller debugging tools 78 86 Parallax Serial Terminal 81 83 TV terminal 79 81 80f 81f 117 ViewPort 83 Propeller Demo Board 19 22 20f 30 39f 79 79f 80 287 429 LEDs blinking in parallel 33f LEDs blinking in sequence 31 31f Prop Plug USB interface tool for 21f Propeller Demo Board Rev C 362 Propeller Demo Board Rev D schematic 363f Propeller Education Kit breadboard 80 Propeller Education Kit Labs Fundamentals 134 Propeller hardware 7 14 architecture 8 10f 11 cogs processors 11 12 11t counter modules and video generators 14 Propeller hardware Cont Hub 12 T O pins 11 410 memory 12 pin descriptions and specifications 8 8f 9t System Counter 13 14 Propeller Library 42 55 keyboard object 55 56 Propeller Object Exchange OBEX 45 46f 55 79 120 120f building block object for 56 57 Propeller processors See cogs processors Propeller Professional Development Board 80 Propeller programming blinking LED 25 27 26f building block object 37 38 first Propeller application 22 25 23f 24f hardware 19 22 introduction 15 49 Propeller Demo Board 19 22 20f Propeller objects and resources 45 48 software 18 19 19f solutions to problems 16 17 16f stack sizing 4
69. 6 4 Dig Ch 2 1 Figure 5 26 Displaying data from an XBee sending raw ADC digital data EXERCISE 233 The remote XBee is reading the ADC and digital channels specified and sending a packet containing the data You will not see the LED blink on the sending XBee because no communication enters or exits it through the serial port On the coordinator when a frame with an identifier of 83 ADC Digital data arrives valid data is pulled out and displayed nonenabled channels are 1 PUB Start channel Configure XBee amp PC Comms XB start XB_Rx XB_Tx 0 9600 PC start PC_Rx PC_Tx 9600 XB AT_Init Fast config XB AT_ConfigVal string ATMY MY_Addr XB AT_Config string ATAP 1 Switch to API mode PC str string Coordinator in API mode ready at address PC dec MY_Addr PC Tx 13 Repeat XB API_Rx Wait for API data if XB RxIdent 83 If data identifier is a ADC Dig data PC Str string 13 Data Received from address PC DEC XB srcAddr repeat channel from to 6 Cycle through ADC channels if XB rxADC Channel lt gt 1 Display if not 1 PC str string 13 ADC Ch PC dec channel PC tx PC DEC XB rxADC Channel repeat channel from to 7 Cycle through Digital channels if XB rxBit Channel lt gt 1 Display if not 1 PC str string 13 Dig Ch PC dec channel PC tx PC DEC XB rxBit Channel PC str string
70. 6 7 Figure 10 14 SPI circular buffers The use of the circular buffers means that you can send and receive a byte in only eight clocks rather than clocking out eight bits to send and then clocking in eight bits to receive Of course in some cases the data clocked out or in is dummy data meaning when you write data and are not expecting a result the data you clock in is garbage and you can throw it away Likewise when you do an SPI read typically you would put a 00 or FF in the transmit buffer as dummy data since something has to be sent and it might as well be predictable Sending bytes with SPI is similar to the serial RS 232 protocol You place a bit of information on the transmit line then strobe the clock line of course RS 232 has no clock As you do this you also need to read the receive line since data is being trans mitted in both directions This is simple enough but the SPI protocol has some specific details regarding when signals should be read and written that is on the rising or fall ing edge of the clock as well as the polarity of the clock signal This way there is no confusion about edge level or phase of the signals These various modes of operation are logically called the SPI mode and are listed in Table 10 3 Mode Descriptions E Mode 0 The clock is active when HIGH Data is read on the rising edge of the clock and is written on the falling edge of the clock default mode for most SPI applicat
71. CCP Console Command Program that we are going to run on the Propeller Board to interface with the virtual peripherals via serial ASCII human readable commands There are a number of good terminal programs out there of course the most obvi ous is HyperTerminal but it is very buggy locks up and is a system resource hog I suggest the following terminal programs PuTTY http chiark greenend org uk sgtatham putty download html ZOC http www emtec com zoc Absolute Telnet http www celestialsoftware net You can download all of them from these links and or from Download com In all cases we are going to set them up for serial communications over COMnn where nn is the COM port your USB driver installed the driver at with the fol lowing settings Baud 9600 Parity None Data 8 bits Stop Bits 1 Terminal type VT100 Local echo Off Handshaking Off For example Fig 10 3 shows a screenshot of PuTTY s setup for my PC which has the USB serial port on COM27 Tip Use Control Panel System Hardware Device Manager to locate the new USB serial port Typically it will be a rather high number like COM27 or something ridiculous You will need this to set up your serial terminal program 358 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS iX PuTTY Configuration Category Session Options controlling local serial lines Lagging Terminal Keyboard Serial line to connect
72. Call RS 232 serial link 353 355 RTC See real time clock RX method 308 311 320 Sander Hanno 83 235 Schenk Andy 85 Schwabe Beau 168 SCLK See Serial Clock signal SD card See Secure Digital card SD card adapter 183 184f SD card test 185 185f sdrw_test for PST spin 185 187 Secure Digital SD card 319 322 322f 339 343 commands in SPI mode 339 340 340f 3421 343 logging to 341 Selmaware Solutions 194 semaphore core grabbing 317 SendControl method 228 SendUpdate method 228 sensors analog conversion for 131 133 asynchronous serial 174 182 174f 180f audio spectrum analysis 121 121f barometric pressure 322 324 3231 332 338 337f capacitive 138 139 153 156 188 frequency output 153 155 153f GPS and overview of 322 324 325f GPS module example 179 182 180f GPS receiver reading 328 332 GPS tracking barometric pressure 322 322f LISY300AL yaw rate 170 microcontroller interfacing and 119 122 320 322 MS5540C barometric pressure sensor module 323 336 multicore vs single CPU 320 322 multiple 409 multiprocessing on off example 129 131 on off 122 137 123f 124f 126f 127f 13 If Parallax CO 133 Ping Ultrasonic Distance Sensor 145 148 145f 146f 147f PNA4602 infrared 133 processing and storing data from 182 187 184f pulse and duty cycle outputs 144 152 RC Decay and growth circuit varieties 142 144 resistive 138 140 153 156 187 resistive capacitive
73. Create a system to display production status E Finally build a feature that takes human input to change operating parameters The task is much easier now Solve each of these five smaller problems one at a time with little or no regard for the others Each can be a specialized process that focuses most of its energy on the given task A multicore device like the Propeller can then perform all of these specialized func tions in separate processors each faithfully fulfilling its simple duty despite the com plexities and timing requirements of the other functions running concurrently The final system completely controlled by a single Propeller chip may use a camera for visual product inspection solenoids to kick bad units off the assembly line actuators to adjust the speed one or more Video Graphics Array VGA displays to show system status and one or more keyboards for user input All equipment is standard inexpensive and readily available Ready to Dive In As you follow this chapter s exercises keep in mind that every function we have the Propeller perform for us is just an example process We will use simple example processes like blinking light emitting diodes LEDs to demonstrate an application while focusing on the concepts of Propeller programming In place of each example we could use audio video analog to digital or any number of other possible processes but they would obscure the point The point is
74. DTR M ATSI BreakT Com a Packet Screen Hex Communicating with unit 1 No Response Error for IO change No Response Error for IO change No Response for distance Response for bearing No Response Error for IO change No Response Error for IO change Communicating with unit 2 Reports distance of 80 Reports bearing of 7852 Communi cating with unit 3 Response Error for IO change Response Error for IO change Response for distance Response for bearing Response Error for IO change Response Error for IO change Come 3600 8 N 1 FLOW NONE Rx 597 bytes Figure 5 15 Coordinator responses from automated polling Pub Control_I0 pin state Value XB tx i Send i for IO control XB dec pin Send pin as decimal value XB cr Send CR XB dec state Send state as decimal value XB cr Send CR Value XB rxDecTime 200 Accept value with timeout Next the GetDistance method is called which sends the p instruction accepts return ing data and passes it back for display Then the GetAngle method is called sends the 214 WIRELESSLY NETWORKING PROPELLER CHIPS c instruction and accepts returns and displays data Finally the LEDs are again turned off using Control_I0 sending Os Pub GetDistance mm XB tx p Send p to get range mm XB rxDecTime 50 Accept data with timeout The cycle repeats each end device value pauses longer and s
75. Fig 5 6 Select the COM port that your Propeller is communicating through vV At this point use the Test Query pushbutton to test communications with the XBee Caution As always only one software package can access the same COM port at any time You ll get used to slapping your head when you can t communicate as you go between the Propeller tool software and X CTU Tip If communications fail recheck your hardware and pin numbers reload the Propeller program and verify no other software is using the COM port If you continue to have problems and it is not a brand new XBee the serial baud rate may have been changed or the XBee may be in API mode test various baud rates and check the API box to test If all went well you may have seen the RX and TX lights blink on the board and received a message informing you communications were okay along with the firmware version on the XBee Y Select the Modem Configuration tab on the X CTU software v If your XBee was reconfigured this would be a good time to click the Restore button to return it to the default configuration Z Click the Read button 198 WIRELESSLY NETWORKING PROPELLER CHIPS zizi About PC Settings Range Test Terminal Modem Configuration r Com Port Setup Select Com Port USB Serial Port COMB Baud 600 z Flow Control NONE x Data Bits 8 zl Parity NONE zl Stop Bits 1 z Test Query Host Setup User Com Ports
76. Hardware wiring diagram for bot system 223 224 WIRELESSLY NETWORKING PROPELLER CHIPS To TV NODE 2 Bot Graphic Propeller Demo Board 4h Uiladnladl Figure 5 20 Continued ler Proto Boord LAINI LAME SO ALKAIINE Figure 5 21 Supplying separate power for bot s servo drive v For the bot two 4 AA packs were used with the spare tied under the normal battery pack The second battery pack is used only for servo power Attempts at using a single supply caused voltage and current spikes affecting the Propeller chip s operation The connec tor of the battery pack was cut off and soldered to the servo header power and Vss see Fig 5 21 Other sources may be used but supply voltage should not exceed 7 5 V or the servos can be damaged Use coated wire to strap the batteries under the bot A THREE NODE TILT CONTROLLED ROBOT WITH GRAPHICAL DISPLAY 225 E Ensure the HM55B compass is mounted facing forward and that it is away from large current loads such as batteries and servos The magnetic fields will cause problems with proper compass bearing E The PING sensor is mounted using the PING Mounting Bracket Kit Manually rotate the servo to find the center prior to mounting the bracket Mount the cable header so that servo rotation does not hit it the servo turns further manually than with the code about 45 degrees each way E A battery supply was used on the tilt controller as well for unfettered operati
77. Here s all you need to do see Example1 spin CON _clkmode xtal1 plli6x _xinfreq 5 000 000 OBJ v gt VocalTract EXPLORING THE VOCALTRACT OBJECT 433 VAR vocal tract parameters byte aa ga gp vp vr fl f2 3 f4 na nf fa ff PUB start v start aa 10 11 1 Start tract output to pins 10 11 repeat Keep repeating talk gp rnd 50 100 Set random glottal pitch vp rnd 4 24 Set random vibrato pitch vr rnd 4 10 Set random vibrato rate talk Talk PRI talk setformants 310 2000 3100 3700 Set formants for bEEt v go 1 aa 3 Set breathiness ga 30 Set voiced volume v go 100 Ramp up v go 500 Sustain setformants 730 1700 2500 3400 Set formants for hAt v go 100 Transition v go 500 Sustain setformants 750 1050 2400 3200 Set formants for hOt ga 12 Volume down a little v go 100 Transition v go 500 Sustain setformants 530 950 2400 3200 Set formants for sOfAp v go 100 Transition v go 500 Sustain setformants 580 1200 1500 4700 Set formants for boRRow v go 100 Transition v go 500 Sustain setformants 560 850 2600 3600 Set formants for baLL v go 100 Transition v go 500 Sustain 434 SYNTHESIZING SPEECH WITH THE PROPELLER aa 0 Taper down to silence ga 0 v go 100 v go 500 Pause PRI setformants s1 s2 s3 s4 f1 sl 100 1953 f2 s2 100 1953 f3 s3 100 1
78. I hope you had fun reading this chapter and running the example programs Speech synthesis is a uniquely challenging and rewarding endeavor It s fascinated me for a long time and after writing this chapter I just want to jump back in again and spend a few more months writing more code to speak numbers units and who knows what else I know that if I got into it again I d probably gain all kinds of new knowledge that would further my understanding of how speech works and how it can be done even more efficiently You can do this yourself if you have the interest and patience It would be a fun time 442 SYNTHESIZING SPEECH WITH THE PROPELLER Exercises 1 Synthesize the word he Hint You ll only use one set of formants 2 Synthesize the word she Hint Add to your he program 3 Synthesize la la la to sing Row Row Row Your Boat 4 Synthesize numbers 1 through 10 5 Make a talking clock PROPELLER LANGUAGE REFERENCE Categorical Listing of Propeller Spin Language Elements Elements marked with a superscript a are also available in Propeller Assembly BLOCK DESIGNATORS CON Declare constant block VAR Declare variable block OBJ Declare object reference block PUB Declare public method block PRI Declare private method block DAT Declare data block CONFIGURATION CHIPVER Propeller chip version number CLKMODE Current clock mode setting _CLKMODE Application defined
79. IC PROM 64 bits Fig 1 Block diagram MS5540C The European RoHS directive 2002 95 EC Restriction of the use of certain Hazardous Substances in electrical and electronic equipment bans the use of lead mercury cadmium hexavalent chromium and polybrominated biphenyls PBB or polybrominated diphenyl ethers PBDE DA5540C_003 June 16th 2008 0005540C1193 ECN 1118 Figure 9 7 Intersema barometer module datasheet Courtesy of Intersema for the latest version consult the MEAS Web site at www meas spec com 334 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER barometer and an integrated chip IC that samples the analog output and converts it to digital value called an analog to digital converter ADC It also provides a commu nications interface such that external devices can simply read the values preconverted without having to sample the analog voltage In addition to the piezoresistive sensor the MS5540C contains an internal temperature sensor that we will use in our altitude conversion equations which will be discussed shortly The first page of the Intersema MS5540C datasheet can be seen in Fig 9 7 Calculating Altitude from Pressure In the experiment code we will communi cate to the barometer and access the compensated pressure and temperature values and store those to the SD card along with the GPS received telemetry As part of our post analysis we will look at the differen
80. If c send back the decimal value of the compass bearing 212 WIRELESSLY NETWORKING PROPELLER CHIPS If i accept the next two decimal values and use them for I O and State which sets the I O direction to be an output and the state of the I O RxDecTime is used to accept the decimal values with a timeout This allows the program to continue to run if incorrect data is received following a timeout period Should a timeout occur a 1 is returned to the value In accepting the data note that each decimal value must end in an ASCII 13 or CR or comma see Sec Data Acquisition and Control Using API Mode Finally the actual value of the I O is sent back V Change the coordinator base to a nonexisting end device address DL and try again You should get no data back What we are designing here can be considered a protocol rules of communica tion If you don t follow the rules set forth nothing or even incorrect things may happen When coding protocols we attempt to cover all contingencies regarding what could go wrong and how they will be dealt with such as i3 and no further data What happens if you enter something other than a 1 or 0 for state That contingency is not covered The data between the units is kept simple byte codes and decimal strings This allows short packets between the units and eases using the data in the code Caution Be aware that currently the code can control any of the Propeller chip s I O pins s
81. LED 15 times more quickly and finally pin 23 s LED 26 times very fast see Fig 2 15 Figure 2 15 Demo Board LEDs blinking in sequence 32 INTRODUCTION TO PROPELLER PROGRAMMING Specifically when the application starts the Propeller calls its first method Main The first line of Main is a call to LED_Flash so the Propeller executes each state ment in LED_Flash When the finite loop finishes there s no more code to execute in LED_F lash so the Propeller returns to Main and executes the second line another call to LED_Flash This continues until it has executed all the statements of Main in sequence Then since there are no more statements in Main it returns But to where The Propeller called Main itself so the return from Main causes the processor to terminate All Together Now Now suppose the last application isn t quite what we needed What if we need each blinking process to happen at the same time in parallel instead of one at a time in sequence On a single core device this request would be a nightmare because the timing of each individual process as tested earlier would negatively affect the timing of every process as a group But on a multicore device like the Propeller this is relatively easy With minor changes to our code we ll laun
82. MULTIVARIABLE GPS TRACKING AND DATA LOGGER Joshua Hintze Introduction In this chapter we will use the Propeller to sample and log data from a GPS receiver module and a miniature barometric pressure sensor The received data will be logged to a Secure Digital SD card that is also attached to the Propeller A dataset will be collected from the sensors and post processed using free online software tools and also a spreadsheet program like Microsoft Excel Google Docs or OpenOffice org We will cover the following topics Learn what multicore means and why it s important Overview of the hardware connections between the Propeller and the sensors How to interface to a GPS receiver and barometric pressure sensor How to log sensor data to an SD card Conversion equations between pressure and altitude How to plot waypoint tracks using online tools and Google Earth Let s begin by discussing the advantages of using a multicore processor like the Propeller to capture sensor data versus a sequentially operating single core microcontroller Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_09 319 320 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER SINGLE CPU VERSUS MULTICORE SENSOR READING A vast number of methods are available for interfacing a microcontroller to a sensor This can range from simple asynchronous serial communicat
83. Outputs a single ASCII character to the VGA terminal Sets the X cursor position of the VGA terminal Sets the Y cursor position of the VGA terminal Plays the note on the requested channel with sent frequency and duration Stops the requested channel Stops all channels KEYBOARD COMMANDS These commands are used to read the state of the keyboard kbd kbd reset gotkey kbd keystate Keycode to test state 0 255 Resets the keyboard Tests if a key is buffered in the driver kbd key Until local keypress Prints keys from the keyboard to the local on terminal terminal until a local terminal key is pressed Prints TRUE FALSE if a special keyboard key button is down If you have trouble getting any of the commands to work simply review the code and make sure you are entering the parameters correctly for the parser to process them properly EXPLORING OTHER COMMUNICATIONS PROTOCOLS 389 Enhancing and Adding Features to the System This demo project is just a starting point there are so many ways to add to it and improve it For example you can add more drivers and peripherals like a mouse servos GPS Ethernet and so forth To add a new device you would simply include it as an object in the main program initialize it and then write a handler for it in the CCP Of course you need to have enough cores or cogs to run the new object on since there are only eight However another approach would b
84. Parallax Serial Terminal s Echo On check box This displays text you type in the Parallax Serial Terminal s Transmit windowpane in its Receive windowpane v In the Propeller Tool software load the program into the Propeller chip either with Run Compile Current gt Load RAM F10 or with Run gt Compile Current gt Load EEPROM F11 v As soon as the Propeller Tool software s Communication window reports Loading click the Parallax Serial Terminal s Enable button Don t wait or you might miss the user prompts The Parallax Serial Terminal s transmit windowpane is shown in Fig 3 6 with the number 30 typed into it It s just above the Calculate tangent title in the Receive windowpane s display v Type integer degree angles into the Parallax Serial Terminal s transmit windowpane pressing the Enter key after each one Try 30 first and verify that your results match Fig 3 6 The Propeller will reply by sending the string representation of the floating point result to the Parallax Serial Terminal Creating the forgot to call a building block object s Start method bug is easy Just comment one or both of the Start method calls in Test Float32 spin by placing an apostrophe to the left Then load the modified application into the Propeller chip Since the application depends on the processes the two objects run in other cogs either one will create rather drastic bug symptoms Commenting pst Start
85. Propeller chip s packages Pin Descriptions and Specifications Each package features the same set of pins with the exception that the surface mount packages LQFP and QEN have four extra power pins see Fig 1 8 and Table 1 1 All functional attributes are identical regardless of package see Table 1 2 Architecture Physically the Propeller is organized as shown in Fig 1 1 but func tionally it is like that shown in Fig 1 9 O PAALAXA si ww OANMDAARWNH 40 39 38 37 36 35 34 33 32 31 10207 n 1282 NN 13 gt E P8X32A 25 AYWWXZZ a NotrHMWOnRNDABDOer eee eee ee AN 22 CONDON AWGN N o 22 Figure 1 8 Propeller chip s pin designators MULTICORE PROPELLER MICROCONTROLLER TABLE 1 1 PIN NAME DIRECTION PO P31 1 0 VDD VSS est BOEn l RESn 1 0 XI l XO O PIN DESCRIPTIONS DESCRIPTION General purpose I O Port A Can source sink 40 mA each at 3 3 VDC Logic threshold is VDD 1 65 VDC 3 3 VDC Pins P28 P31 are special purpose upon power up reset but are general purpose I O afterwards P28 P29 are 12C SCL SDA to external EEPROM P30 P31 are serial Tx Rx to host 3 3 volts DC 2 7 3 3 VDC Ground Brown Out Enable active low Must connect to VDD or VSS If low RESn outputs VDD through 5 KQ for monitoring drive low to reset If high RESn is CMOS input with Schmitt Trigger Reset active low Low causes reset all cogs
86. Propeller measures the time from when the I O pin changed to input to the time the voltage at the capacitor s top plate passes the 1 65 V logic threshold Since this sensor circuit measures growth instead of decay the starting state in the rc time method call should be changed from 1 to 0 rc time 18 tDecay This will cause the RC Time object to set the I O pin low to discharge the capacitor and then measure the amount of time it takes the capacitor to charge from 0 to 1 65 V The measurement will be in terms of clock ticks It also would be a good idea in this case to rename the variable from tDecay to tGrowth Tip Converting clock ticks to other time increments is a simple matter of dividing the number of clock ticks in a given unit into the clock ticks in the measurement First define the unit Microseconds can be defined by us clkfreq 1_000_ 000 That s the number of ticks in 1 1_000_000th of a second Next usResult tDecay us converts the number of clock ticks into a number of microseconds A photodiode generates small currents that are proportional to light intensity Figure 4 19 shows a photodiode and a schematic for an RC Decay circuit that incor porates the photodiode The I O pin has to be set high but this time to discharge the capacitor and set the voltage difference across its plates to 0 V When the I O pin changes to input the current from the photodiode charges the capacitor As the voltage across the capacitor
87. RPC function and then calls a handler with the two pointers It s up to the handler to know how to unpack the parameters and generate the results via calling the local function Thus RPC calls necessitate a number of extra steps including 1 Encoding 2 Transporting to server 3 Decoding 4 Executing 5 Encoding 6 Transporting back to client This is obviously not the fastest thing in the world however if the computation workload is two times or more than all the interface steps or if the local process or machine can t perform the computation it s worth it Thus RPC calls and technology allow a process or machine to use subroutines and resources running in another process or another processor or on an entirely different machine In our case we are going to use the concept of RPCs to make calls to another proces sor from the PC s serial interface thus it s a machine to machine call ASCII OR BINARY ENCODED RPCs When designing an RPC system you can make it really complex or really simple The main idea is that you want to be able to call functions in another process processor REMOTE PROCEDURE CALL PRIMER 369 or machine Decisions have to be made about the RPC protocol and how you are going to do things There are no rules for RPC calls unless you are using a Windows Linux Sun or similar machine and want to use one of the operating system s RPC call application programming interfaces APIs When
88. Re center pan servo TRY IT Y Add another device such as speaker to your bot Add a button on the tilt controller and modify code to control the device from the tilt controller Bot Graphics The bot graphics code is responsible for accepting the data and dis playing it graphically on a TV screen Note that this XBee is in API mode so that the RSSI level may be pulled out of the received frame The code looks for one of three incoming byte instructions u m and c Updates u are messages with update data as the data moves with range bearing and drive values limited between 1000 and 2000 and it retrieves RSSI level for display creation Repeat XB API_rx Accept data If XB RxIdent 81 If msg packet if byteLXB RxData u If updates pull out data Get DEC data skipping 1st byte u range XB ParseDEC XB RxDatat1 1 bearing XB ParseDEC XB RxDatat1 2 rDrive XB ParseDEC XB RxDatati 3 1Drive XB ParseDEC XB RxDatat1 4 RSSI XB RxRSSI Update lt 2000 gt 1000 lt 2000 gt 1000 Mapping m strings are used to map what the bot sees without clearing off old data while a mapping pan is in progress Clear c is received once the bot switches back into drive mode after mapping We aren t going to delve too deeply into the graphics creation here as it s not a major subject for this chapter One point of interest is in that many graphic pro gra
89. Scanline at X 657 O O O Source edge face color circle O WebCam jo Propeller O Video lmage File OShow Blob History v videotestipg mer OShow Blob Marker Blob X 0 Y 0 W 0 H 0 Cursor X 657 Y 256 Value 4 Status ok Connection Disconnected Memory 00 00 38 Figure 7 5 Picture imaged by the PropCVCapture object The program uses the Conduit object to stream the video to ViewPort where I can watch the camera s output look at horizontal and vertical scan lines and measure the value of individual pixels See Fig 7 5 for our first picture of the world CON _clkmode xtal1 plli6x _xinfreq 5 000 000 OBJ vp gt Conduit Transfers data to from PC video PropCVCapture Capture video signal pub watchTV videoFrame 6000 a blob vp register video start videoFrame video HIVIDEO vp config string start video vp share blob blob repeat APPLY FILTERS AND TRACK A BRIGHT SPOT IN REAL TIME 265 Apply Filters and Track a Bright Spot in Real Time Now that we can digitize video from a camera into the Propeller s memory we need to do something useful with it We have quite a bit of video data updated at 30 times a second We need to filter this information to provide us with just two variables to control our robot We ll start by implementing a filter that identifies the location of the brightest spot in each frame of video The following ass
90. Serial 1 2 FullDuplexSerial_drv_012 spin PS 2 Keyboard 1 0 keyboard_010 spin Many of the drivers include other subobjects NORMALIZATION OF DRIVERS FOR COMMON RPC CALLS IN THE FUTURE The last thing I want to discuss about the drivers is the interfaces to all of them Since this is a pieced together system of other people s drivers each driver obviously has its own methodology and API For example the NTSC calls look entirely different from the 372 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS keyboard calls and so forth Alas if you were to develop a system from the ground up and design drivers for NTSC VGA keyboard and so on you would be wise to design all the APIs in a similar fashion with conventions for function calls inputs and outputs so that technologies like RPC calls and others could be implemented more easily WHAT IS COM Microsoft s COM technology which stands for component object model is actu ally an example of normalization of data and methods The idea here is that COM defines a binary pattern for data structures and interfacing the methods thus any language that follows the specification can use COM objects Moreover COM objects can be used remotely just like RPC calls in a way using a technology called D COM or distributed COM So the idea of interface and data structure normalization is a good one Client Host Console Development The CCP is the ringlea
91. Source SimpleTCPServer Spin directory Initialize the W510Q eth init gateway subnet ip mac 306 USING MULTICORE FOR NETWORKING APPLICATIONS Open the socket for TCP communication eth open TCP PORT PORT dip Listen for a connection eth listen Display message term pstring string Listening 13 Wait for connection to be established repeat while eth con_est false Display connected message term pstring string Connected to PC 13 13 You can see the order of the methods that need to be called to set up the W5100 for data exchange as a TCP server in the previous snippet Call the init open and listen methods in that order and then call con_est as when needed to determine when and if a connection has been made If the con_est method returns true a connection has been established with a client and you can then call the RX and TX methods to exchange data with the client Do not attempt to receive or transmit data before a connection has been established If the EtherX card will be a TCP client it will call the connect method after it calls the open method This method will tell the W5100 that it will be a client and that it should attempt to establish a TCP connection with a TCP server location at the IP address speci fied in the destination IP address field that we specified in the open method call Once the connect method has been called you need to call the con_est method to det
92. TEMPERATURE SEA LEVEL PRESSURE TEMPERATURE LAPSE RATE SUBSCRIPT b m Pa K K m 0 o 101325 288 15 0 0065 1 11 000 22632 1 216 65 0 0 2 20 000 5474 89 216 65 0 001 3 32 000 868 019 228 65 0 0028 4 47 000 110 906 270 65 0 0 5 51 000 66 9389 270 65 0 0028 6 71 000 3 95642 214 65 0 002 Using some math we can solve the barometric formula for h and substitute in the known variables arriving at the following altimeter calibration formula T 1 P P x 288 15 K 0 00198122 Thus given a pressure we can calculate our height above sea level The equation requires the current sea level corrected pressure Pep for the region in which the sensor is operating An aircraft would normally get this pressure value from the radio tower but we can find it by going to a weather Web site like www weather com Note how ever that the typical units given are in inches of mercury when the equation calls for kilopascals The conversion is 1 in of mercury 3 3860 kPa Reading the Pressure Sensor Unfortunately an object wasn t already created for the MS5540C barometer module on the Parallax object exchange therefore we will make our own Investigating the datasheet we can see that the communications protocol is similar to SPI communications however there are subtle differences Regarding the pin connections we have a data input and data output and a clock that is controlled by an external master device However there
93. TV driver NTSC Cog 4 Graphics driver provides methods like drawing shapes and displaying text on the TV 314 USING MULTICORE FOR NETWORKING APPLICATIONS Cog 5 Monitors the gamepad buttons and transmits the new score via EtherX card to the opponent when a button is pressed Cog 6 Constantly polls the EtherX card to determine if there is a score update from the opponent Here s the Cog 0 game logic code This is the code after we have started all of the drivers initialized the video initialized the EtherX card etc Initialize game variables winloss 0 player_score 0 opp_score Q score_change 0 Create a new lock to manage the EtherX card between cogs eth_lock locknew Start the gamedpad monitor in a new COG cognew MonitorButtons cog_stack Q Start the ethernet monitor in a new COG cognew MonitorEthernet cog_stack 128 J 1 1111111111111111111111111111111111111111111111111111111 Begin the game loop J 1111111111111111111111111111111111111111111111111111111 Draw the playing field gr clear gr colorwidth 3 3 gr textmode 6 6 6 0 gr text 50 60 pscore gr colorwidth 3 3 gr textmode 6 6 6 0 gr text 170 60 oscore repeat if score_change 1 Clear the score_change variable score_change 0 Display the new scores gr clear gr colorwidth 3 3 gr textmode 6 6 6 0 CREATING A SIMPLE NETWORKED GAME 315 pscore Q 30 player_score gr
94. The use of the circular buffers means that you can send and receive a byte in only eight clocks rather than clocking out eight bits to send and then clocking in eight bits to receive Of course in some cases the data clocked out or in is dummy data meaning when you write data and are not expecting a result The data you clock in is garbage and you can throw it away Likewise when you do an SPI read typically you would put a 00 or FF in the transmit buffer as dummy data since something has to be sent so it might as well be predictable Sending bytes with SPI is similar to the serial RS 232 protocol You place a bit of infor mation on the transmit line and then strobe the clock line of course RS 232 has no clock As you do this you also need to read the receive line since data is being transmitted in both directions This is simple enough but the SPI protocol has some specific details attached to it regarding when signals should be read and written that is on the rising or falling edge of the clock as well as the polarity of the clock signal This way there is no confusion about edge level or phase of the signals These various modes of operation are Mode 0 The clock is active when HIGH Data is read on the rising edge of the clock and written on the falling edge of the clock default mode for most SPI applications The clock phase polarity here is zero and Fig 8 14 shows a timing diagram for this Mode 1 The clock is
95. VAR Spatializer parameters word inputl4 angle 4 depth 4 knobs Spatializer delay buffer long buffer buffer_size PUB start i r repeat i from to voices 1 Start voices and connect inputLi v i start Lto spatializer inputs knobs 000 011 100 101 Start spatializer s start input buffer buffer_size 11 1 10 1 repeat Scan for done voices repeat i from to voices 1 if vli done If voice done angleli r Set new random angle depth i r amp SFFF Set new random depth vLil go Start new blah Lower object called Blah see Blah spin OBJ v gt VocalTract VAR Vocal tract parameters byte aa ga gp vp vr fil f2 3 f4 na nf fa ff PUB start v start aa 1 1 1 Start tract no pin outputs return v sample_ptr Return tract sample pointer PUB go Say blah randomly gp rnd 6 120 vp rnd 4 48 rnd 4 30 vr setformants 100 200 2800 3750 v go rnd 100 1000 SUMMARY 441 setformants 400 850 2800 3750 aa 10 ga 20 v go 20 v go 80 setformants 730 1050 2500 3480 aa 20 ga 30 v go 50 v go rnd 20 100Q aa 0 ga 0 v go 100 PUB done return v empty PRI setformants s1 s2 s3 s4 f1 sl 100 1953 f2 s2 100 1953 f3 s3 100 1953 f4 s4 100 1953 PRI rnd low high return low cnt high low 1 Summary
96. Visualizer Web site and then download a KMZ file for viewing in Google Earth stand alone software Summary Throughout this chapter we have covered how to interface a Parallax Propeller toa GPS receiver and a barometric pressure sensor module By using the Propeller s multicore CPU we were able to isolate separate execution paths without the need for difficult threading and semaphore locking that you would find on a conventional CPU This proved especially useful when we communicated with the barometric pressure sensor because of its nonstandard communications protocol If instead we were to interface this sensor to a traditional single CPU microcontroller it would take away precious computation time from the main process in order to service the communications In addition to communicating with the sensors we discussed how to store the log data to a Secure Digital SD card An SD card is ideal for use with embedded processors because of its large capacity in a small footprint Using Parallax s Object Exchange OBEX Web site we were able to find suitable software that facilitated the complex SD card communication and file system handling After completing a test drive the SD card was removed from the experimental hardware and inserted into a PC for post analysis We discussed equations to convert barometric pressure to altitudes and plotted the outputs in both a spreadsheet program and online mapping tools such as www GPS Visualizer com
97. XBee API Enable Switches the XBee from transparent mode AT to a framed data version where the data must be manually framed with other information such as address and checksum This is a powerful mode and will be explored in this chapter Packetization Timeout In building a packet to be transmitted the XBee waits a set length of time for another character If not received in the set time the packet is sent This is why as we typed characters each was sent and echoed back This can be important to change if you have multiple units sending data to one node to ensure that all data sent is received as a single transmission from one unit otherwise you may get data from various nodes intermixed Sets the function of the I O pins on the XBee such as digital output input ADC RTS CTS and others Sample Rate The XBee can be configured to automatically send data from digital I O or ADCs It requires the receiving node to be in API mode and the data parsed for the I O values Received Signal Strength The XBee can be polled to send back the RSSI level of the last packet received CCA Failures The protocol performs clear channel assessment CCA that is it listens to the RF levels before it transmits If it cannot get an opening the packet will fail and the CCA counter will be incremented TESTING AND CONFIGURING THE XBee 203 EA ACK Failures If a packet is transmitted but receives no acknowledgement that data reached the d
98. a single line and wrap here due to space constraints 420 THE HVAC GREEN HOUSE MODEL Master Board Cog Calculate Optimum Values All calculated data is stored in global Calculate variables that can be seen across Average actual temperature cogs Average requested temperature This is accomplished by sending memory pointers for each of the variables from the main object to the cog Calculate The cog updates these values where Vent positions for all rooms they can be used by other cogs Calculate Heat Cold Off The first experimental algorithm for recirculate or fresh air calculating the vent positions is TargetTemp CurrentTemp 10 if value gt 100 then value 100 Compensate for back pressure To compensate for back pressure the experimental method is If sum all rooms vents lt 100 then divide deficit total rooms assign additional value to all rooms Pause for X ms Figure 11 21 Master board cog flow chart Calculate Room averages OverallAverageTemp10X 0 OverallAverageDesiredTemp10X 0 repeat count from to 4 OverallAverageTemp10X OverallAverageTemp10X LONGLRoomCurrentTemp1 X count 4 OverallAverageDesiredl emp10X OverallAverageDesiredTemp10X LONGLRoomTargetTemp10X count 4 OverallAverageTemp10X OverallAverageTemp10X 5 OverallAverageDesiredTemp10X OverallAverageDesiredTemp10X 5 Vent position
99. active when HIGH Data is read on the falling edge of the clock and written on the rising edge of the clock The clock phase polarity here is one and Fig 8 15 shows a timing diagram for this Mode 2 The clock is active when LOW Data is read on the rising edge of the clock and written on the falling edge of the clock The clock phase polarity here is zero and Fig 8 14 shows a timing diagram for this 292 USING MULTICORE FOR NETWORKING APPLICATIONS SPI signals when CPHA 0 Figure 8 14 SPI timing diagram for clock phase polarity 0 Courtesy of Andr LaMothe Mode 3 The clock is active when LOW Data is read on the falling edge of the clock and written on the rising edge of the clock The clock phase polarity here is one and Fig 8 15 shows a timing diagram for this Notice that there is no timing related logic in the method Since the SPI protocol is totally synchronous the master in charge of the clock can run it as fast to maximum SCK CPOL 1 SCK CPOL 0 Present bit Sample bit MOSI SPI signals when CPHA 1 Figure 8 15 SPI timing diagram for clock phase polarity 1 Courtesy of Andr LaMothe ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 293 speed or as slow static if desired as he wants Also notice the data is sent out most significant bit msb to least significant bit lsb For the EtherX card we will operate in SPI Mode 0
100. and because our camera is looking up at the spot will raise the spot in the image Conversely if the spot is too high our robot is too close so it s commanded to drive backwards Translating this algorithm into code is simple We just scale and offset the x y location of the spot to control the robot To illustrate the high speed tracking ability of this filter I can use ViewPort to display the streamed video with a superimposed trail showing the position returned from the filter over the last minute Figure 7 8 shows a screenshot with the grayscale image as seen by the camera and a trail showing the path the bright source took 270 CONTROLLING A ROBOT WITH COMPUTER VISION ViewPort v4 1 64 File Edit View Configuration Plugins Debug Help i Load Connect Stop 1Mbps Welcome code dso isa all__ _ analog fuzzy _ mixed video terminal O oscope Overview click on name to configure i Name PlotEdit Min __ Max blob blobx 0 55 0 72 0 8 bloby 0 6 Cursors Show A Vert z 04 Horz 0 2 Edit Variables LOdMalA 0 3 Time sec H Scanline at Y 378 eae V Scanline at X 665 Source edge face color circle eee O WebCam Propeller O Video lmage File OShow Blob History ce Show Blob Marker Status ok Blob X 146 Y 128 W 9 H 0 Cursor X 665 Y 378 Value 12
101. any occurrences of a comma with a 0 value The reason why we are replacing commas with zeros will become apparent shortly Once a lt CR gt has been encountered the repeat loop ends and the gps_buff should contain a complete NMEA sentence After the sentence has been read in we can check which type of message it was by com paring the first couple of characters This Spin code currently contains support for GPGGA GPRMC and PGRMZ sentences The astute reader might have noticed that PGRMZ does not start with GP even though we mentioned that all NMEA sentences begin with it This is because GPS receiver manufacturers can add their own proprietary NMEA sentences and in this case the PGRMZ is a Garmin GPS receiver s proprietary altitude sentence OVERVIEW OF THE SENSORS 331 Regardless of the message being received the copy_buffer method is called next with arguments dependent on the sentence The copy_buffer method is listed here pub copy_buffer buffer args Copy received data to buffer bytemove buffer gps_buff cptr ptr buffer arg 0 repeat j from to 78 Build array of pointers if byte ptr to each record if byte ptr 1 in the data buffer longLargs arg Null else longLargs arg ptr 1 argtt ptrt The first thing the copy_buffer method does is perform a bytemove copy of the data from the gps_buff to the first argument passed in Next it sets up a pointer to the
102. at any time We need to ensure that nodes don t talk over one another POLLING REMOTE NODES 209 causing collisions on the network and that the receiving units know who the data is from in order to respond appropriately or take some other action XBee using IEEE 802 15 4 works similar to Wi Fi A node listens before it transmits to help ensure that no other node is transmitting at the time this is Clear Channel Assessment or CCA Delivery of data is verified through acknowledgements If the sender does not get a response it tries again This method is known as CSMA CA or Carrier Sense Multiple Access Collision Avoidance Unlike Ethernet which uses collision detection CSMA CD a node cannot listen once it starts transmitting so it cannot detect collisions So the data link layer of communications helps ensure data gets passed properly but it still doesn t assist in higher level functions controlling the who and when of commu nications In the next section we will look at a method of using a Propeller acting as a coordinator to poll end devices for their data USB works in much the same way each device is polled one at a time to see if they need access or have data to send COORDINATOR MANUALLY POLLING REMOTE END DEVICES A hardware configuration similar to the one from the previous section will be used but this time the Propeller needs to be in the communications chain at the base instead of simply using a Prop Plug for XBee co
103. be configured to monitor and stream the I O pin activity to the ViewPort software for display in its logic state analyzer Figure 4 43 shows an A character Logic State Anal At 746mg io E10000C0 6 7 Time msec Figure 4 43 Letter A at 4800 bps 8N1 176 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES transmitted by the P24 I O pin at 4800 bps 8 data bits no parity 1 stop bit These serial port settings are often listed in the abbreviated form 4800 bps 8N1 The ASCII numeric code that represents A is 65 or in binary 01000001 The asynchronous serial message shown in the figure starts high or in resting state Since the baud rate is 4800 bps every binary bit is given a 1 4800 s time window The first leftmost low signal which is called the start bit lasts for 1 4800 s The start bit sig nals that eight more data bits are on their way The first data bit is a high or binary 1 Since asynchronous serial messages transmit the least significant bit first this 1 is the value in bit 0 In the case of the serial A byte the least significant bit or bit 0 is the rightmost 1 in the value 01000001 The next five 1 4800 s time windows are all low transmitting five binary Os for bits 1 through 5 then a high signal for bit 6 and a low signal for bit 7 After the last data bit the I O pin returns to resting state for at least 1 4800 s assuming the protocol requires one
104. bit to clear before setting 74 DEBUGGING CODE FOR MULTIPLE CORES One cog has updated two of the three values Another cog fetches all three values two new and one old Figure 3 10 Memory collision it and working with the memory this bug will never happen The upcoming Debugging Tools Applied to a Multiprocessing Problem section features an example of testing for memory collisions and applying locks to resolve them WRONG ADDRESS PASSED TO A METHOD Let s say that the previous object Cogs Sharing Info Bug fixed spin has been sepa rated into a top level file and a building block object Top File spin and Building Block spin Top File spin gives Building Block spin the nickname blink in its OBJ block The Building Block object has a Blinker method that will run in another cog and is expected to monitor the Top File object s global variable as in Fig 3 5 Following is the working example of such an application Blink Start 5 delay in Top File spin passes 5 to the pin parameter in Building Block s Start method and passes the address of its delay variable to the delayfAddr parameter Building Block s Start method then launches the Blinker method into a new cog and passes along both parameters for the Blinker method to work with The most common bug here is omission of the sign to the left of the delay variable in Top File spin s Start method call If the sign were missing the blink start method call wo
105. bot system was developed for control and monitoring using the graphics ability of the Propeller chip The ability to configure the device and send data between Propeller chips effi ciently and with addressing leads to a wide array of projects that can be implemented Allowing different Propeller chips to perform their own processing and easily com municating with each other brings the excitement of parallel processing to a whole new level In my research with institutions such as Southern Illinois University University of Florida USDA in Texas and the University of Sassari Italy I have been involved in many XBee Propeller and some other controller projects These projects include monitoring corn irrigation needs biological monitoring and monitoring the vibration of citrus fruit as it s shaken from the tree Wireless sensor networks are a powerful and quickly expanding field for remote monitoring and control They are finding use in research and in building plant and home automation The Propeller with its ability to perform parallel processing is an outstanding choice for monitoring and control As mentioned at the outset of this chapter whether you build the projects in this chapter or simply gain an understand ing of the material I hope you can use the base code and principles in projects of your own invention 232 WIRELESSLY NETWORKING PROPELLER CHIPS Exercise A FINAL PROJECT FOR YOU DIRECT XBee ADC DIGITAL DATA F
106. both the Propeller chip s Main RAM and Cog RAM to make sure the values were copied correctly The command cognew entry m launches the assembly code starting at the entry label into a new cog and the address of the Spin variable m is passed to the cog s parameter register The assembly language keyword for this register is par The Main RAM viewer automatically starts displaying Main RAM from the par address Notice that the initial values of 10 59 and 999 are the first three values in the viewer These correspond to the values that were loaded into the Timestamp Dev ASM object s global m s and ms Spin variables Down in the Cog RAM viewer the second line from the top shows that _m stores the value 10 and the third and fourth lines from the top show that _s and _ms store 59 and 999 respectively So the assembly code passed the initialization test The PASD software s Debug menu also has Run Stop Step Step over and Set address for navigating your code while debugging This software is a truly an invalu able tool for debugging Propeller assembly language code For the price of a small download this software can help save significant amounts of development time Summary This chapter focused on debugging code for multiple cogs The best form of debug ging is bug prevention Parallax addressed bug prevention well in the Propeller chip s design by providing features in the chip s architecture and programming languages
107. by specified number of bits Reverse LSBs of value and zero extend Rotate value left by specified number of bits Rotate value right by specified number of bits Shift value left by specified number of bits Shift value right by specified number of bits Shift value arithmetically right by specified number of bits Compare two unsigned values Compare two signed values Compare two unsigned values plus C Compare two signed values plus C 454 APPENDIX A CMPSUB Compare unsigned values subtract second if lesser or equal TEST Bitwise AND two values to affect flags only TESTN Bitwise AND a value with NOT of another to affect flags only MOV Set a register to a value MOVS Set a register s source field to a value MOVD Set a register s destination field to a value MOVI Set a register s instruction field to a value MUXC Set discrete bits of a value to the state of C MUXNC Set discrete bits of a value to the state of C MUXZ Set discrete bits of a value to the state of Z MUXNZ Set discrete bits of a value to the state of Z HUBOP Perform a hub operation NOP No operation just elapse four cycles CONSTANTS NOTE Refer to Constants in the Spin Language Reference section above TRUES Logical true 1 FFFFFFFF FALSE Logical false 0 00000000 POSXS Maximum positive integer 2 147 483 647 7FFFFFFF NEGXS Maximum negative integer 2 147 483 648 80000000 PIs Floating point value for PI 3 141593 40490FDB REGISTER
108. call the associated driver by sending messages to it with the parameters and execute the commands that the user initially requested CLIENT HOST CONSOLE DEVELOPMENT 381 This whole process is rather interesting so let s take a look at a couple of examples to see what s going on one example of a locally processed command and one that sends messages to the drivers Local Command Processing Example Local commands are between the user and the console program and do not send messages to the drivers In the CCP there are only three local commands so far one clears the screen one prints out the help menu and the third redefines the prompt I know how useless but it s cool Let s take a look at the CLS clear screen command since it s not only a local command but also uses VT100 codes and is the first command tested by the CCP handler loop Here s the code for the CLS handler Clear the terminal screen command if strcomp tokens string CLS Send the standard VT100 command for clearscreen serial tx ASCII_ESC serial txstring string 2J Clear screen serial txstring system_start_string serial tx ASCII_CR serial tx ASCII_LF Let s take a moment to ponder its simplicity We know that all the user input has been split into the tokens array so the first entry should be the command itself therefore the parser tries to match CLS in this case Assuming it has a hit the han
109. code itself and is part of the other case default for you C C programmers Here s the code other Insert character into command buffer for processing input_buff input_buff_index ch Echo character to terminal terminal must be in non ECHO mode otherwise you will see input 2x serial tx ch Case 2 Is the character an editing character such as lt BACK_SPACE gt If so erase the character in the buffer and echo it out as well This gives the user a crude edit feature he can at least back up a bit and retype something Here s the code for that ASCII BS Backspace edit command Insert null if input_buff_index gt 0 input_buff input_buff_index ASCII_NULL Echo character serial tx ch 378 _ USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Case 3 The user is done entering data into the command line buffer and wants the console to process it and hopefully send an RPC to the appropriate driver This is where all the action takes place and the tokenization of the input string into whole substrings so that the command handlers can query the string and test for properly formatted command strings Here s the code that is executed when the user hits lt RETURN gt at the serial terminal ASCII_LF ASCII_CR Return Newline serial tx ASCII_CR serial tx ASCII_LF Print the buffer if input_buff_index gt 1 At this point we have the command buf
110. currently being supervised by the United States Air Force in Colorado Initially developed in the early 1960s for the military it became available for civilians in 1995 A GPS receiver operates by receiving signals from a constellation of satellites that are orbiting the Earth see Fig 9 5 Thirty two satellites orbit the Earth allowing for OVERVIEW OF THE SENSORS 325 Propeller Demo Board Ve is SAW H Ni Br T L lan La aN A Y P fy j x oct oe a 3 i a a ain S mi om me a Figure 9 4 Propeller Demo Board connected to experi ment sensors Figure 9 5 GPS satellite constellation 326 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER complete coverage with a little bit of overlap Each satellite continuously transmits three messages at 50 bps for 30 s yielding a message length of 1500 bits Encoded in the first message is the time of week the current week of the year and the satellite health information In the second message the satellite broadcasts its current posi tion also known as its ephemeris Finally in the third message is a table of all the other satellites and the course positional information The table of satellites is known as an almanac Each data transmission is modulated into a higher frequency signal before being sent to earth The two most common signals L1 and L2 operate at 1575 42 MHz and 1227 60 MHz respectively The L1
111. debugging testing and veri fication For assembly language debugging the PASD is a must All of these software packages make use of objects that reside in one of the Propeller microcontroller s cogs and communicate with PC software to provide variable information and status Remember that if you run into a bug that s a real brain teaser check back with the list at the start of the Common Multiprocessor Coding Mistakes section Also keep in mind that different segments of code in a multicore application are executed simul taneously This will help prevent bugs as well as make the ones that do appear in your code easier to spot Exercises 1 Incorporate the ASM timestamp code into a building block object 2 Design a full timekeeping object 3 Expand the Keyboard_Demo object so that it allows you to enter numeric values that can be placed into variables Hint Save time by borrowing and modifying DecIn code from the Parallax Serial Terminal object This page intentionally left blank SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Andy Lindsay Introducing Sensors by Their Microcontroller Interfaces The Propeller microcontroller s multicore architecture greatly simplifies getting infor mation from many sensors and sensor arrays The techniques for monitoring run of the mill sensors like switches and resistive elements with the Propeller are similar to those used with most microcontrollers However thornier pr
112. delay mechanism What do you do when you want to wait for five minutes Well of course you check the current time add five minutes then watch the clock until that time is reached The waitcnt command makes the Propeller watch the clock until the desired moment is reached The expression within waitcnt s parentheses is the desired moment to wait for Both clkfreq and cnt are built in variables that relate to time Think of clkfreq as one second and cnt as the current time So the expression clkfreq cnt means one second plus the current time or one second in the future Information Clkfreq contains the current system clock frequency the number of clock cycles that occur per second Cnt contains the current System Counter value a value that increments with every clock cycle The value in cnt doesn t relate directly to the time of day however the difference between the value in cnt now and its value later is the exact number of clock cycles that passed during that time which is a useful number for timing For accurate timing see Timing Is Everything Challenge Try changing the code so the LED is on for roughly one eighth of a second and off for one second Hint f is the divide operator RAM versus EEPROM If you followed the last example you now have a happily blinking LED on your devel opment board Will it continue to blink after a reset or power cycle v Try pressing the
113. even when using low pin count intelligent devices For example if each room had a 2 x 16 serial LCD display a servo motor two pushbutton switches a temperature sensor and two indicator lights the minimum pin count per room would be as follows 5 V power GND Serial LCD signal Servo motor control Button 1 to gnd Button 2 to gnd l wire temperature sensor LED1 LED2 OGOONODOGAAAN As the Propeller chip typically has 28 available pins this design would only allow three rooms to be monitored before all the pins on the chip had been allocated The one Propeller design also called for more expensive components such as serially con trolled LCD displays and 1 wire temperature sensors as well as additional expenses in cabling because readily available four pair CAT 5 cable doesn t contain enough wires So for implementation either two CAT 5 cable runs would need to be run from each room back to the wiring closet or special order wire containing at least nine leads would need to be purchased If One Propeller Is Good As the single Propeller design was clearly not feasible we started to look for other design ideas The next logical step was to see if we could place the sensors and controls closer to the processor We started looking at placing one Propeller in each room as this idea solved multiple problems and provided additional benefits First the wiring issue would become much less complex as we need only sup
114. executed on multiple cores and the client host can then communicate to these modules over a simple serial link and issue remote commands Moreover more advanced software could be developed that allows the host client to request peripherals be loaded on demand creating a truly robust system Based on the model developed in this chapter you will be able to not only control the Propeller chip over a simple RS 232 serial link but also create a platform that can be used for SPI serial peripheral interface or other high speed chip to chip low level wired links with little modification With that in mind here s what s in store E Introduction setup and demo E System architecture E Remote procedure call primer E Virtual peripheral driver overview E Client host console development 353 354 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS E Exploring the command library for the slave server E Enhancing and adding features to the system E Exploring other communications protocols Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_10 Overview Setup and Demo Before we start into the technical material of this chapter let s first discuss the goal of the design the hardware setup the software install anything needed and in general get ready for the project To enable as many people as possible to use t
115. fixed point math architectures Also you could easily spend more time computing ever changing resonator coefficients than you would actually computing the resonator state for each output sample I needed a simpler way to build a resonator Fortunately the CORDIC algorithm came to my rescue CORDIC is an ingenious technique developed in the 1950s by Jack E Volder that uses binary shifts and adds to perform the transcendental functions In a nutshell it can rotate X Y coordinates efficiently without the edgy numerical sensitivities of commonly used resonator algorithms In each of VocalTract s resonators the incoming signal is summed into Y of an X Y point which defines the state of the resonator Then that point is CORDIC rotated by an angle directly proportional to the formant s center frequency The resulting Y of the X Y point is passed on to the next resonator When in band excitation is received the X Y point grows further from 0 0 as it rotates around Out of band excitation causes the amplitude to decay to the point where the resonator pretty much just passes its input through to its output If this wasn t simple enough since the step angle fed to each formant s CORDIC rotator is directly proportional to the formant s center frequency simple linear interpolation is used to slide each formant from one frame s setting to the next Goodbye math headaches Let s now re create those six vowel sounds that I recorded
116. functioning it s definitely a coding error that needs to be fixed Delay Beyond Interval spin This code has a bug that causes the cog to stop executing code for almost 54 seconds when the button connected to P21 is still pressed when the LED changes state CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz VAR long stack 10 Stack for cog executing Blinker PS 100 9 LED 3 3 lt GND h Pushbutton P6 100 9 P21 lA LED 10 kQ GND GND Figure 3 9 Test circuit 70 DEBUGGING CODE FOR MULTIPLE CORES PUB Go cognew Blinker 5 clkfreq 4 stack Blinker method gt new cog PUB Blinker pin delay t Blink light method t t ent Get current cnt register value dira 6 1 Set P6 to output dira pin 1 Set I O pin to output repeat Repeat loop waitcnt tt delay Synchronized delay repeat while ina 21 1 xxx BUG outa 6 1 Turn on P6 outa 6 0 Turn P6 back off outaLpin Invert I O pin output state The application intended to have the light connected to P6 turn on when the pushbutton connected to P21 was pressed This is easy to do without disrupting the cog s timing because the ina 21 register will store 1 when the pushbutton is pressed or 0 when it s not pressed To make the P6 light turn on outa 6 needs to store 1 to turn the light off outa 6 should store 0 So the assignment outa 6 ina 21 wil
117. go 2500 v go 500 Pause between breaths This should clear up any confusion about the Propeller being able to sleep What about consonant sounds I ve made a lot of little discoveries about synthesizing consonants by observing spectrographs and then experimenting with VocalTract You can easily do the same Sometimes it s necessary to speak very slowly and distinctly into the spectrograph in order to see otherwise subtle phenomena Looking at the actual waveform can give important hints too particularly around plosives i e t p and k where there is silence It turns out there is just a handful of basic recipes you need to know in order to make VocalTract pronounce any consonant The biggest divider among consonants is whether they are voiced or unvoiced That is is the glottal pulse going or is there just breathiness This distinction halves the number of basic consonant recipes 436 SYNTHESIZING SPEECH WITH THE PROPELLER TABLE 12 2 RELATED CONSONANTS VOICED UNVOICED burl pear do to van fan girl curl Zoo sue jock chalk this thin measure pressure Take a look at Table 12 2 Say each of these word pairs aloud and note the voiced unvoiced difference in the underlined consonant The only difference within these sets of consonants is when your glottal pulses are going You lI note that the rest of your vocal tract is in the same exact state when making either sound
118. go webinar Summary Together we built our own object that evolved into a building block other developers could use Along the way we learned about methods I O loops decisions timing and single core versus multicore processing The next chapter will build up your object debugging skills and then you ll have the foundation you need to dive into the many fascinating projects that fill the remainder of this book EXERCISES 49 Exercises To further your learning experience we recommend trying the following exercises on your own 1 Explore the Propeller Library and Demos included with the Propeller Tool Compile and run as many as possible and take the time to study the code 2 Modify the examples we built to perform tasks of your choice Can you make an application that performs three or four different tasks at once 3 Log on to the Propeller Forum and read through and even post to some of the recent threads This page intentionally left blank DEBUGGING CODE FOR MULTIPLE CORES Andy Lindsay The chapter title Debugging Code for Multiple Cores might sound a little like a computer science or engineering course topic that students struggle through and then wax poetic about how hard it was later in life If that s the kind of challenge you were looking for sorry you won t find it here As with application development debugging multicore applications with the Propeller microcontroller is typic
119. in the three dimensional location radius space Once the transform has been applied finding the circle is a quick matter of finding the maximum in the location radius space Enough math Now let s get back to the Propeller and find some objects with OpenCV OpenCV and Propeller Integration I designed ViewPort s architecture to allow myself and others to add functionality to the program through the use of plug ins I developed the OpenCV plug in to make it easy for Propeller users to add state of the art computer vision to their robotic creations OPENCV AND PROPELLER INTEGRATION 277 Figure 7 11 Propeller integrated with ViewPort running OpenCV filters without having to learn C or set up a development environment for OpenCV People have been doing computer vision research with OpenCV for quite some time but integrating it with real world devices like sensors and actuators wasn t easy With the plug in and the Propeller people have the best of all worlds easy integration with all sorts of real world sensors and actuators with the Propeller and state of the art vision algorithms from OpenCV all presented with a simple interface inside of ViewPort Figure 7 11 shows a diagram of an OpenCV enabled Propeller application To perform sophisticated computer vision the OpenCV code is run on the host PC to take advantage of the faster processor and larger amount of memory available there There s a big difference between the 32
120. indicate success This brings us to Table 9 4 which is a short listing of SD SPI commands that must be supported and their respective response bytes Logging to the SD Card Through the use of the SD SPI commands a processor can read from and write to an SD card a sector at a time The next step would be to implement software for reading a file system from those sectors We will not cover file systems in this book however for further reading see the following Chapter_09 Docs MS_fat_white_paper doc http en wikipedia org wiki File_Allocation_Table Instead of creating our own object for SD card support we will be using the FSRW Spin object by Radical Eye Software Again this can be found on the Parallax Object Exchange Web site or it can be found here Chapter_09 Source CODE fsrw spin Chapter_09 Source CODE sdspi spin The FSRW SD card object has a number of public methods for mounting opening reading and writing to a file which are documented in Table 9 5 TABLE 9 3 COMMAND LIST FOR SD SPI MODE CMD ID ABBREVIATION SDMEM MODE SDIOMODE COMMENTS CMDO GO_IDLE_STATE Mandatory Mandatory Used to change from SD to SPI mode CMD1 SEND_OP_COND Mandatory CMD5 IO_SEND_OP_COND Mandatory CMD9 SEND_CSD Mandatory CSD not supported by SDIO CMD10 SEND_CID Mandatory CID not supported by SDIO CMD12 STOP_TRANSMISSION Mandatory CMD13 SEND_STATUS Mandatory Includes only SDMEM information CMD16 SET _BLOCKLEN Mandatory CMD17 READ_SIN
121. is no chip select which is common on SPI devices Another difference between this device s communication and SPI is that there are no established data lengths instead the barometer uses the notion of start flags three bits high and stop flags three bits low with commands embedded in between This means that we cannot use an SPI object from the Object Exchange Web site either Instead we will need to control manually the signals to the chip this is known as bit banging We will not cover any more details of the communication in this book since the 336 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER datasheet dedicates a few pages to it instead we will discuss how to read and convert the barometer s registers into a temperature compensated pressure The MS5540C data sheet and Spin source code object to read the pressure and temperature values from the MS5540C can be found on the FTP site at this location Chapter_09 Docs ms5540c pressure_sensor pdf Chapter_09 Source abs_pressure_01 spin Referring to Fig 9 8 we can see a flow chart of operations provided from the manu facturer to execute in order enabling us to read the pressure and temperature output We will refer often to this figure while describing the steps to conversion shown in Fig 9 8 The first step is to read the factory 16 bit calibration words out of the barometer s memory and convert the words into calibration coefficients which will be used later i
122. know before we call the RX method if data is available The EtherX driver has a Spin method to read the receive size register called read_rsr If this method returns a non zero number there is data in the W5100 for us to read The other thing we need to address here is the difference between a call to RX when we have a socket type of TCP versus a socket type of UDP Assuming there is already data in the W5100 internal buffer waiting for us to read when our socket type is TCP and we read data from it we will read only the data that was received by the W5100 When we have a socket type of UDP every received packet of data will have an eight byte header appended to it by the W5100 This header consists of the IP address of the received packet four bytes the source port two bytes and the data size two bytes So if you specified the socket type as UDP and were expecting your PC to send you 32 bytes you would in fact read 40 bytes from the W5100 when you read the data from its internal buffer Just as with the transmit buffer of the W5100 the receive buffer of the W5100 can only store 2048 bytes by default Don t let the W5100 get too much data into it before you read or your data will be corrupt Just as with the transmit buffer you can config ure the W5100 to have a larger receive buffer using the write method provided by the EtherX driver Receive Size Register The last application method is the read_rsr method which will read the r
123. lockelr semID Set lock on time variables Copy times to caller s vars Clear lock on time variables Current clock counter Ticks in ims Infinite loop Wait for the next ms Set lock Add 1 to millisecond count If milliseconds 1000 Set milliseconds to 0 Increment seconds if seconds 60 Set seconds to 0 Increment minutes If minutes 60 Set minutes to 0 DEVELOPMENT WITH VIEWPORT ViewPort has a code view that provides an IDE style debugger for the top level object You can use ViewPort to monitor variable values set breakpoints run pause and step You can also use it to modify variable values before continuing from a breakpoint In addition ViewPort makes it possible to look at variable behavior graphically with oscilloscope logic analyzer spectrum analyzer and other tools For analysis of the timekeeping application the oscilloscope can provide graphical verifications that the timekeeping object functions as intended Note New ViewPort functions and features are on the horizon at the time of this writing To check for updated versions of code examples from this section that are compatible with the latest version of ViewPort go to ftp propeller chip DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 103 com PCMProp Chapter_03 Source As mentioned earlier the latest version of ViewPort is available for a 30 day free trial from www parallax com The ViewPort software communi
124. locks in Spin programs essentially boils down to the following code excerpt This code first checks out a lock bit using lockneuw and it stores the result 0 7 or 1 if no locks are available in a variable named semID Next code in any cog that accesses the memory has to wait for that lock bit to be clear before setting it and modifying the Main RAM The repeat until not lockset semID loop does this by repeatedly setting lockset Since lockset returns the previous state of the lock it will return true if it was already set by another cog In that case the repeat loop will keep trying until lockset returns 0 When it returns 0 the fact that lockset was called means it was set to 1 this time by the cog waiting for access Since the condition of the repeat loop is not lockset semID when it returns 0 the NOT of 0 is TRUE so the repeat loop will allow the code to move on and access the shared memory As soon as the code is done with the shared memory it should immediately use lockclr semID to clear the lock and minimize the amount of time other cogs have to wait for memory access Code in one cog if semID locknew 1 If lock check one out pst Str String Error no locks Else display error 96 DEBUGGING CODE FOR MULTIPLE CORES repeat until not lockset semID Shared memory operations lockelr semID code in anther cog repeat until not lockset semID Shared memory operations lockelr semID
125. map data 228 WIRELESSLY NETWORKING PROPELLER CHIPS BOT NETWORK CODE Bot Tilt Controller For the tilt controller in the SendControl method if the button is pressed a series of p s is transmitted With the amount of data flying some missed bytes on reception are normal and this helps ensure the bot gets a p instruction for a panning map operation If not pressed the accelerometer is read for the X and Y axis 90 to 90 degrees O level and the drive for each servo is calculated by mixing the two axes of tilt for a final servo value of 1000 to 2000 the range of servo control for each The data is sent as a d packet for drive Forward accel x 90 offset scale 1 Read and calculate 90 to 90 degree for turn Turn accel y 90 offset scale Scale and mix channels for drive 1500 stopped Left_Dr 1500 Forward 3 Turn 3 Right_Dr 1500 Forward 3 Turn 3 In the AcceptData method which is running in a separate cog incoming packets are analyzed if update data u or map data m and the local LEDs are updated Based on the range eight 1s are shifted to the left eight positions then shifted right again based on the range 100 This allows one LED to light for every 100 mm or 0 1 m out to 800 mm or 0 8 m outa 16 23 11111111 lt lt 8 gt gt 8 range 10Q Bot Code For the bot controller in Start received bytes are analyzed with a timeout If any data is not received for 1500
126. mentioned in Chap 1 all cogs are physically identical rather than being specialized for certain functions This allows any cog to be as useful as any other cog for any task so itis not necessary to assign code to a specific chunk of hardware unless desired as the Spin language certainly provides for this This allows the next available cog to handle whatever task is presented and there is no need to determine if unexpected behavior is a result of code waiting for or running in a certain type of core LANGUAGE AND PROGRAMMING CONVENTIONS THAT HELP PREVENT BUGS The Spin and Assembly languages incorporated into the free Propeller Tool software have a number of features that help prevent multiprocessing bugs For example the lock bits have a set of commands that help manage main memory Likewise there is a set of cog commands to give the developer more control over the hardware if desired For example a cog can be selected and launched by number with coginit so the developer can know exactly which process is happening where Code can also be launched into the next available cog with cognew report where it landed with cogid and a cog s ID used with cogstop will shut down that cog An arrangement similar to this is incorporated into objects available from the Propeller Object Exchange because it allows building block objects to launch code into the next available cog without interfering with any cogs that the application might already be us
127. not just use a GPS for calculating the altitude and the answer would be You can However up until the mid 1990s GPS receivers were not available for civilian aircraft so the altimeter based upon atmospheric pressure was the method for calculating altitude Also under certain environmental conditions the GPS receiver may not be capable of receiving the satellite radio waves for example in a deep canopy of trees inside most buildings or underground In our experiment we will add a small microelectromechanical systems MEMS piezoresistive barometric pressure sensor MEMS devices are a new fascinating method for creating mechanical devices on silicon substrates that were originally meant for electronics Through the fabrication of a silicon chip a micromachining process can produce both mechanical and electrical components making for orders of magnitude smaller mechanical sensors and actuators The barometric pressure sensor we will be using is an Intersema MS5540C miniature barometer module shown in Fig 9 7 This unique device includes both a piezoresistive OVERVIEW OF THE SENSORS ikntersema MS5540C RoHS MINIATURE BAROMETER MODULE e 10 1100 mbar absolute pressure range a e 6 coefficients for software compensation stored on chip D Piezoresistive silicon micromachined sensor e Gf Integrated miniature pressure sensor 6 2 x 6 4 mm 16 bit ADC 3 wire serial interface 1 system clock line
128. object PUB Go tDecay pst Start 115200 repeat waitent clkfreq 10 cnt rc time 18 1 tDecay Display measurement pst Str String pst CE pst HM pst Dec tDecay Start Parallax Serial Terminal Repeat loop Refresh display at 10 Hz Measure P17 decay circuit tDecay RESISTIVE CAPACITIVE DIODE TRANSISTOR AND OTHER 141 Tip The reason the Time method requires the address of a result variable instead of just returning its value is to make simultaneous measurements in other cogs possible with the same method call that works for sequential decay measurements The potentiometer example in the on off sensors section only returned a 1 or a 0 In this example the potentiometer s analog range of motion is digitized into approximately 6000 different values from 0 to just over 6000 A 0 measurement indicates that the dial is turned all the way counterclockwise and 6000 indicates all the way clockwise The Parallax Serial Terminal in Fig 4 17 indicates that the knob has been turned about 4000 6000 or two thirds of the way clockwise This digitized measurement represents the decay time in terms of 12 5 ns clock ticks The RC Time object utilizes one of the cog s counter modules to take the measurement Code in the object configures the counter module to count the number of clock ticks during which it detects a high signal above 1 65 V applied to the I O pin by the RC circuit While the counter modu
129. object based Spin language lends itself to objects that solve tricky or complex sensor problems and the Propeller Tool Software s Propeller Library and the Propeller Object Exchange are two fantastic resources for getting objects that can save many hours that might otherwise be spent on writing code from scratch This chapter also included some examples of writing code from scratch for on off sensors as well as for an A D converter using the data sheet and timing diagrams Although this chapter featured brief explanations of each sensor keep in mind that any given sensor typically has a wealth of published information to support it Many companies that manufacture and sell sensors have a vested interest in making sure that people who want to incorporate their sensors into projects and products succeed Any sensor Parallax manufactures and or distributes has a product page and on that product page there will almost always be a Downloads section with PDF documentation that explains how the sensor works and includes a test circuit and example code that shows how to get measurements from it Exercises 1 Use Timestamp spin to record when an object is detected with infrared 2 Write a program that displays the gyro s rate of rotation in degrees per second Consider making use of the Propeller Library s FloatMath object 3 Design a program that allows you to control the cursor s placement in the Parallax Serial Terminal with an acceleromete
130. on the m s and ms variables Those are the object s three global variables shared by the cog executing the TimerMs method and the cog executing other methods such as GetTime and SetTimer This design allows the application object s code to concern itself with just one thing getting the timestamp whenever it needs it As you examine the Timestamp Object DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 101 keep in mind that all the methods except TimerMs are executed by the same cog that s executing the Test Timestamp Object s methods In other words the same cog that s executing the repeat loop in the Test Timestamp object makes a call to time GetTime executes the code in the Timestamp Object s GetTime method and returns Meanwhile the Timestamp Object s TimerMs method is executed by a different cog The Timestamp Object s GetTime and SetTimer methods both use the memory access approach shown in Fig 3 4 and they rely on the TimerMs method executed by another cog to keep the m s and ms variables updated with the current time Timestamp Object spin Supplies minutes seconds milliseconds timestamp upon request VAR long stack 40 Ample stack for prototyping long t dt m s ms Timekeeping variables long semID cog Semaphore ID and cog variables PUB Start minutes seconds milliseconds success Start timekeeping in a new cog Parameters minutes starting minutes count seconds starting sec
131. or presence of the desired object has been calculated the robot can react appropriately for example drive to the beer bottle and pick it up with its gripper Central to this whole process is the design of the vision filters Users familiar with photo editing software like Adobe Photoshop have plenty of experience with filters In Photoshop I can apply the brighten filter to make my image brighter So how does the program accomplish this behind the scenes The picture is Camera NTSC Frame grabber Captures video signal Decodes video signal images on into digital representation sensor which it writes to memory Nugget to control Marella robot Filters image data to extract meaning Figure 7 1 In a vision sensor video is filtered to yield a nugget which controls the robot PROPCV A COMPUTER VISION SYSTEM FOR THE PROPELLER 259 made up of many individual pixels thousands in each row with thousands of rows Each pixel has a color that s specified by some number of bytes For example a 24 bit color image might use one byte to specify how red the pixel is one byte to specify how blue and one byte to specify how green for a total of three bytes When the brighten filter is applied the individual bits in each byte of every pixel are manipulated to make the image brighter for example by adding a value to each byte In computer vision filters have to be applied continually ideally as fast as new images co
132. outline Tip PUB is only one of many block designators that provide structure to the Spin language There are also CON and VAR constant and global variable declarations OBJ external object references PRI private methods and DAT data and assembly code Look for Block Designators in Propeller Tool Help or the Propeller Manual The dira 16 1 and outa 16 1 statements set I O pin 16 to an output direc tion and a logic high state respectively Both dira directions and outa output states are 32 bit variables whose individual bits control the direction input output and output state low high of each of the Propeller s corresponding 32 I O pins The colon equals is an assignment operator that sets the variable on its left equal to the value of the expression on its right We could assign full 32 bit values to each of these two variables however when working with I O pins it s often more convenient to target a specific bit The number in brackets 16 forces the assignment operator to affect only bit 16 of dira and outa corresponding to I O pin 16 A BLINKING LED 25 Tip The Propellers 32 I O pins are general purpose each can be an input or output and each can drive the same voltage current levels All of the Propeller s eight processors can read any pin as an input but a processor must set a pin s direction to output if it wants to use it as an output To learn more search for I O Pin
133. packets received and signal strength Z Block the area between the XBees or move the remote XBee to another room and test the effect on RSSI level Note In theory you should never see a bad packet malformed data in the received data from the XBee such as in the Terminal window All data is error checked and retried if there is no response or if the error check fails You should receive either good data or no data at all The serial link issue with the XBee is a more probable cause than an RF issue with bad data Now that we have an RF link going it s time to discuss and test some XBee configurations XBee CONFIGURATION SETTINGS As seen the XBee has numerous settings that can be configured This configuration can be performed through the Configuration window through the Terminal window or through strings sent out from the Propeller Let s first take a look at some of the more important settings shown in Table 5 1 for this chapter we will use only a few and others of interest should you delve deeper with your experiments Click the Modem Configuration tab of the X CTU software to view the settings Clicking any setting will give a brief description and range of values at the bottom of the window OK let s test out a few things v Test and verify your loop back setup by sending a string Y Under Modem Configuration change DL to 1 v Click Write V The XBee should be updated Click Read and verify Z Go to the Termina
134. pin 16 to high waitent clkfreq cnt Delay for some time outa 16 0 Set I 0 pin 16 to low waitent clkfreq cnt Delay again Tip This source is from PCMProp Chapter_02 Source LED_Blink spin Caution Indention is important here make sure to indent the lines under repeat by at least one space Also the mark that appears in some places is an apostrophe character 26 INTRODUCTION TO PROPELLER PROGRAMMING Figure 2 11 Demo Board LED blinking V Compile and download this application by pressing F10 or by using the Run gt Compile Current gt Load RAM menu item Now the LED on I O pin 16 should blink on and off at roughly 1 second intervals see Fig 2 11 No more is this a simple wire alternative EXPLANATION Are you wondering what s to the right of the dira 16 1 statement yet That s a comment Comments describe the purpose of code they mean absolutely nothing to the Propeller but everything to the programmer and his or her friends This one begins with an apostrophe meaning it s a single line code comment There are other types of comments that we ll learn about soon but for now just remember that comments play a vital role in making your code understandable Impress your friends Use comments generously Take a look at the rest of the comments in the program and you should clearly see what each Spin statement do
135. pst DecIn Get degrees Convert to floating point radians radians fp Radians fp FFloat degrees Calculate tangent 60 DEBUGGING CODE FOR MULTIPLE CORES cosine fp Tan radians Display result pst Str String Tangent pst Str fs FloatToString cosine Test Float32 spin works correctly since both of the Parallax Serial Terminal and Float32 objects Start methods were called and the interactive testing for floating point tangent calculations is shown in Fig 3 6 To enter numbers into the Parallax Serial Terminal click the Transmit windowpane before typing The Transmit windowpane is just above the Receive windowpane and in Fig 3 6 it has the number 30 entered into it just above the first line in the Receive windowpane that reads Calculate tangent If this is your first time running the Parallax Serial Terminal follow these instructions V Make sure your Propeller chip s power supply and programming cable are connected v In the Propeller Tool software make sure Test Float32 is the active tab In other words the Test Float32 spin code should be displayed in the Propeller Tool soft ware s Editor pane v In the Propeller Tool software click Run Identify Hardware F7 and make a note of which COM port the Propeller is connected to Then in the Parallax Serial _ Parallax Serial Terminal Disabled Cli O X Calculate tangent Enter degrees 60 Tangent 1 73
136. register access CONSTANTS TRUE Logical true 1 FFFFFFFF FALSE Logical false 0 00000000 POSX Maximum positive integer 2 147 483 647 7 FFFFFFF NEGX Maximum negative integer 2 147 483 648 80000000 PI Floating point value for PI 3 141593 40490FDB VARIABLE RESULT Default result variable for PUB PRI methods UNARY OPERATORS Positive X unary form of Add Negate X unary form of Subtract a5 Predecrement X or postdecrement X and assign A Preincrement X or postincrement X and assign AA Square root Absolute value x Sign extend from bit 7 X or postclear to 0 X ay Sign extend from bit 15 X or postset to 1 X Random number forward X or reverse X lt Decode value modulus of 32 0 31 into single high bit long gt Encode long into magnitude 0 32 as high bit priority Bitwise NOT NOT Boolean NOT promotes non 0 to 1 Symbol address ee Object address plus symbol value 448 APPENDIX A BINARY OPERATORS Note All operators in the right column are assignment operators lt gt lt lt gt gt and and Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or Or gt s lt gt lt lt gt gt lt Constant assignment CON bl
137. robot has two wheels we can drive the wheels at different speeds to steer it This is similar to how tanks are steered and controlled If we speed up the left wheel while slowing the right wheel our robot will turn to the right without affecting the bot s balance This differ ential steering can be carried so far that we re driving one wheel forward and the other backwards resulting in the bot spinning about its own axis Accelerating a balanced robot to a new speed is more complex than it first appears Let s start with a simple experiment Balance on your toes and try to run Most people will slowly lean forward and only start running when their body is tilted to a certain angle If we started running right away we would fall backwards because our feet would be too far in front of our center of gravity Decelerating to a stop requires you to run a bit faster until you re tilted backwards at which point you can gradually slow down If your legs were stopped suddenly because they were tripped you would fall For a balancing robot things get even more complicated because the robot has no heel with which to start a lean and can t move its upper body to change its center of gravity The only thing the bot can do is drive its wheels So to lean forward in order to move for wards the robot first has to drive backwards Similarly when the robot wants to slow down it first has to speed up to lean itself backwards Controlling these comp
138. s FAT 16 routines with secure digital card layer The beauty of this system is that both the Propeller and a PC can read from and write to an SD card that has been formatted with the FAT16 file system and the object supports SD cards up to 4 GB John Twomey also expanded on this object with methods that can store strings and numerical values An SD card adapter from www ucontroller com shown in Fig 4 48 makes prototyp ing Propeller applications with an SD card simple and convenient Note in Fig 4 49 that it only takes six wires to connect Tip Aside from being used to store large volumes of sensor data SD cards have been used for numerous synchronized MP3 displays such as fireworks stage lighting and even fountains The Propeller chip s multicore architecture lends itself to these projects because separate cogs can be assigned to playback SENSOR BASICS AND MULTICORE SENSOR EXAMPLES 184 OE GZ BZ LZ 9Z GZ pZ EZ ZZ IZOZ GI St s e re eee eeneeeeeee eeoese eae eaeeaeee oeoeev ee eeeeee a eee ee ee eae eee eevee ee OE 62 8Z Z 92 SZ vz EZ Pewee eee eae J TS eeeeresee z eee eeeoee wioo xejjeied A CEREECLT TI Das Figure 4 48 SD card adapter UController com SD Card Adapter PO VSS VDD P1 x z i Q Z oO Q a x l 8 P2 cS DI P3 Figure 4 49 SD card adapter schematic and wiring QUESTIONS ABOUT PROCE
139. serial communications system since it s well under stood every computer has a serial port well they used to and the signaling is easy and relatively high speed up to 115 200 bps However even with pure binary encoded RPC calls and 115 200 bps that results in a throughput of RPC calls of about 360 s based on a 32 byte RPC call serial record This is hardly enough to do much more 390 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS than print terminal text play some sound read keyboards and so on No real work can be accomplished with standard serial Hence we need to take it to the next level and explore some of the more advanced serial communications protocols that are faster than RS 232 Two schemes come to mind immediately SPI serial peripheral interface and TC inter integrated circuit Both of these protocols are electrical and packet based and support speeds in the MHz range 25 MHz roughly is common for SPI Therefore with either of these protocols we can increase our command bandwidth for RPC calls by a factor of nearly 10 to 100 fold Before we talk about how we might use these protocols and rewrite the current serial code let s take a few moments and review a crash course on both protocols for those readers who aren t familiar with the technical specifications of each protocol SPI BUS BASICS SPI was originally developed by Motorola It s one of two popular modern serial stan dards
140. serial port over TCP IP Remember turn off your firewall or make sure to poke a hole in the port s you use for the con nection Figure 10 18 is a screenshot of the program s graphical user interface GUD it s rather slick 396 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Ss g Serial to Ethernet Connector 5 0 by Eltima Software mK z a Z Delete an i P Heip za 2 Edit ey Delete ex Delete al a Create mirror Help za Advanced mode Serial to Ethernet Connector 3 Create connection Edit connection i Mirror connection mB COM2 Server E amp Local COM27 Real 9600 N 8 1 comer Server Update a Port status Not opened not cr Local TCP port 5000 i thy Net status Listening Select connection type you want to create A A Protocol RAW 3 a Maximum client connections 4 SB Active connections 0 4P Encryption Disabled 3 Authorization Disabled pi Sent 0 Bytes Select port type you want to create Q Received 0 Bytes g Select Serial Port COM27 v C Create as virtual serial port a 5000 2 Server connection will be waiting for incoming client connections and actually will share Ee local serial port into network Please select TCP port which clients will connect to then click Create connection Please enable Advanced mode if you need more settings like port opening settings underlayer data transmission protocol and encryption 2 lt gt
141. site in the Chapter_10 Docs spi directory I C BUS BASICS The I C bus is a little more complex than the SPI bus interface and protocol The reason is that the I C bus uses only two signal lines SDA data SCL clock thus more proto cols and conventions must be followed to avoid bus contention and other issues Second P C supports up to 128 devices simultaneously connected to the bus This feature makes TC superior for daisy chaining devices together as well as cheaper Of course you never get something for nothing and the C bus is not without its shortcomings First it is nowhere near as fast as SPI SPI can operate at 25 MHz and even up to 50 MHz P C on the other hand averages around 100 kHz with 400 kHz being fast and with many new devices supporting 1 to 2 MHz Thus SPI is at least 25 times faster But that s not the whole story The added overhead that the T C protocol attaches to communica tion addressing commands and so on slow down the protocol even more Thus IC devices tend to find their way into slower peripherals where speed isn t an issue but addressing many devices is For example with serial memories and sensors where the device itself is slow the 100 to 400 kHz average speed of I C is more than enough for our application However you will see SPI devices in very high speed applications such as video and audio Figure 10 15 shows an architectural diagram of how the I C bus is laid ou
142. that keeps loop timing precise The command t cnt just before the Blinker method s repeat loop copies the current number of clock ticks stored in the cnt register to the variable t Then every time through the loop the command waitent t delay adds the number of clock ticks in delay to t and then waits until the cnt register catches up These synchronized delays were first introduced in Chap 2 Correct Loop Interval spin CON _clkmode _xinfreq xtali pll16x Crystal and PLL settings 5 000 000 5 MHz crystal x 16 80 MHz VAR long stack 10 Stack for cog executing Blinker 68 DEBUGGING CODE FOR MULTIPLE CORES PUB Go cognew Blinker 5 clkfreq 4 stack Blinker method gt new cog PUB Blinker pin delay t Blink light method t t ent Get current cnt register value dira pin 1 Set I O pin to output repeat Repeat loop waitent tt delay Synchronized delay outaLpin Invert I O pin output state The clkfreq register stores the number of clock ticks in 1 s and in the case of Correct Loop Interval spin that s 80 000 000 since the system clock is configured to run at 80 MHz When the cogneuw command launches the Blinker method into a new cog the Blinker method call passes 5 to the Blinker method s pin parameter and clk freq 4 to its delay parameter In this case the delay parameter receives the result of clkfreq 4 which is 80 000 000 4 20 000 000 Next the command t cnt copies
143. the building and keep from feeding fresh air to the fire Another real world requirement has to do with backpressure When the blower fan turns on it generates a specific number of cubic feet per minute of air In order to operate properly a certain amount of air must be allowed to exit the ducting system If the room air registers are closed backpressure may develop possibly causing the condenser coil to freeze up the blower fan to overheat and the compressor to be damaged With such serious consequences avoiding backpressure in the system is a major concern Though a Peltier solid state heat pump does not suffer from backpressure issues the way a typical HVAC compressor based system would we decided to implement the backpressure detection correction system in anticipation of dealing with real world issues To make the concept both easy to implement and to understand we decided to use the equivalent value of 100 percent open of one air register as the minimum outlet amount that must be available whenever the blower fan and heat pump were running This makes it simple as it can be expressed as four of the room s registers set to O percent and one of the room s registers set to 100 percent or as each of the five rooms air registers set to a position of 20 percent open A simple backpressure routine was added to the master board software to manage distributing the error so backpressure would automatically be regulated b
144. the fact that its Hub gives each cog main memory access in a round robin fashion two different processors accessing a group of longs during the EXERCISES 117 same time can still result in corrupted data This typically happens when one cog is partially done updating a group of values that another cog is reading The cog doing the reading might read two new values and one old value for example The Propeller has built in memory semaphore bits called locks that can be incorporated into code to prevent these memory collisions Other common memory bugs include forgetting to use the operator to pass an address of a variable to a method instead of its value For Spin methods that get launched into new cogs make sure to allocate enough stack space for them because another common bug happens when a method running in another cog doesn t have enough stack for all the calculations it needs to do Liberal use of debugging tools with each step of application development will help keep bugs out and reduce overall development time The TV_Terminal object can be used to display messages from the Propeller chip as well as to test certain demonstration objects posted to the Parallax Object Exchange The Parallax Serial Terminal software and its accompanying object are also excellent for simple tests and the PST Debug LITE object can further automate some of the debugging tasks ViewPort provides an IDE style debugger along with graphical analysis tools for
145. the same directory with the PASD software and PASDebug object E Verify that the object s system clock settings are at least 5 MHz with an external crystal The next example and the one included with PASD uses the same 80 MHz system clock settings from the Parallax Serial Terminal and ViewPort examples E Comment any other code that might try to access the programming port ViewPort Parallax Serial Terminal etc E Add a declaration for the PASDebug object OBJ dbg PASDebug lt Add for Debugger E After the cognew command that launches the assembly routine into a cog add a call to the PASDebug object s Start method that passes the address where the assembly code starts 31 and 30 are the Propeller I O pins used for COM port communication through the Propeller programming tool cognew entry m at dbg start 31 30 entry debugger SE E At address 0 in the code just after org and the entry point label add the PASD Debugger Kernel DAT org Entry entry Sere S E Debugger Kernel add this at Entry Addr long 34FC1202 6CE81201 83C120B S8BCOEQA SE87COEO3 S8BCOEGA long SEC7COE 5 SAGBC1207 5C7CQ003 5C7C0003 S7FFC S7FF8 Note that each of these PASD additions starts with and ends with Since at the time of this writing the Propeller Tool software does not perform conditional compilations 112 _ DEBUGGING CODE FOR MULTIPLE CORES this saves time adding and remov
146. to COM2 Bell Features J Window Speed baud Appearance Behaviour Translation Stop bits Selection Colours Connection Flow control Data Proxy Telnet Rlogin SSH Serial Select a serial line Configure the serial line Data bits Parity Figure 10 3 A screenshot of PuTTY setup for my PC with the USB serial port on COM27 TEASER DEMO Let s go ahead and try the system out and see if we can get it working before delving into how the system works and design issues To get the program to work you need to set up the hardware including the Propeller Demo Board and all the peripheral con nections to TV VGA keyboard and so on Then the software must be compiled and loaded into the board itself via the Propeller Tool Finally you need to launch a serial terminal and connect it to the USB serial port that the FTDI chip in the Propeller Demo Board is currently using Then with the terminal program you will make a connection to the Propeller Board and start throwing commands at the CCP which processes the commands parses them and then passes calls to each of the cores running the various media drivers Basically you need to make sure that the serial terminal is on the right COM port and then press Reset on the Propeller Demo Board so everything starts up OVERVIEW SETUP AND DEMO 359 Then you will see the CCP display some initialization as well as see output on the NTSC and VG
147. to apply We ll use two additional longs to point to the first pixel in the source and destination video buffers To make the system flexible we ll allow filters to access any number of additional parameters to configure their behav ior The following assembly code implements the scripting engine which continually applies our vision filters to the vision buffers Video Input Video Buffers Video Filter Chain Buffer 0 Raw input ie Buffer 1 Invert brightness n Buffer 2 i Edge detection Buffer 3 RE Barcode detection Figure 7 6 Video filter chain scripting language and video buffers APPLY FILTERS AND TRACK A BRIGHT SPOT IN REAL TIME 267 org 0 doEdit mov cemdPtr par cmdLoop rdlong action cmdPtr add cmdPtr 4 rdlong dest cmdPtr add cmdPtr 4 rdlong src cmdPtr add cmdPtr 4 mov n len add action jmpTable jmp action jmpTable jmp doEdit jmp dolimit jmp doinvert jmp dodiff jmp dochaos jmp domax jmp dopattern jmp docopy Last we ll need some methods to let other programs specify which filters to run in their engine The following Spin code lets users programmatically add two types of filters those taking a value argument and those that don t The start method is used to start a cog which will then continually cycle through the filters con 0 None Threshold Invert Difference Chaos Max2 Pattern Copy Fuzzy maps var long cmd 20 pub start tVptr tmode start a cog to co
148. value that the Start method returns By con vention the Start method returns nonzero if it succeeded in launching a cog or zero if it failed because all the cogs are already in use After the Start method call the example code uses accel x to get the x axis pulse measurement and accel y to get the y axis pulse measurement Note that both the accel x and accel y method calls also are embedded in text Dec method calls so the TV_Terminal object displays the result returned by each method call After 20 measurements the application calls accel stop to stop the cog Next it demonstrates measurements in the same cog by first calling the Init method then accel get_XY Notice that the accel get_XY XVal YVal call passes variable addresses to the method which indicates that the get_XY method stores the measurement results in those variables After the method returns both the XVal and YVal variables should store the results of the accelerometer x and y axis pulse measurements MXD2125 Simple Demo spin CON _CLKMODE XTAL1 PLL16X _XINFREQ 5 000 000 Constants used by the Accelerometer Object Xout_pin 0 Propeller PO to MX2125 Xout Yout_pin 1 Propeller P1 to MX2125 Yout VAR long XVal YVal PULSE AND DUTY CYCLE OUTPUTS 151 OBJ text tv_text Located in default Library accel MXD2125 Simple PUB Setup text start 12 Separate cog example load a cog with accelerometer driver text dec accel star
149. we need a means to display the graphics of the game on the screen We will also need to monitor the gamepad and when a button is pressed increment our score and send the new score to the opponent Last we need to monitor the EtherX card to see if the opponent has sent us his updated score CREATING A SIMPLE NETWORKED GAME 313 TRADITIONAL MICROCONTROLLER APPROACH For some perspective let s look at how your traditional low power cheap micro controller would implement this funtastic game The majority of the time is spent drawing the image on the TV screen The vertical sync is typical when anything other than video in a game sampling the gamepad sound game logic network ing etc is dealt with If you are unfamiliar with game programming the vertical sync is the time on the TV when the electron gun swings from the bottom of the screen to the top There is some time during the horizontal sync as well although small if the pro grammer is clever Again if you are unfamiliar with game programming horizontal syncs are when the TV s electron gun swings from the far right of the tube to the far left of the tube to draw the next line The horizontal sync time is often spent determin ing what data to write during the next line so it is usually not practical to do any game logic sound gamepad sampling etc during this time It is important to note that the timing for writing an image to a TV is precise Even one clock cycle differe
150. with developing objects and using them The objects aren t the fastest the coolest or the best necessarily they just work and get the job done and in most cases are the reference objects developed by Parallax initially with small changes by myself and other authors The idea was to have the NTSC VGA audio and keyboard all running at the same time and be able to access these devices In the future you might want to use other objects or improve these for more specific needs In any event referring to Fig 10 10 the objects used are shown in Table 10 2 All of the drivers and their subobjects are included in the Source directory for this chapter located in the PCMProp Chapter_10 Source directory If you look on the Parallax Object Exchange site you should be able to find all these drivers however we will use the ones from my chapter and my sources since I made slight modifications to each of them to make things easier VIRTUAL PERIPHERAL DRIVER OVERVIEW 371 Console Control Program prop_serial_slave_010 spin top level object i OSLN YON oipny SETE gt keyboard_010 spin pseogkey JEUSS Figure 10 10 The virtual drivers used for the project TABLE 10 2 OBJECTS USED IN PROJECT FUNCTION VERSION TOP OBJECT FILE NAME CCP 1 0 prop_serial_slave_010 spin NTSC 11 TV_Text_Half_Height_011 spin VGA 1 0 VGA_Text_010 spin Audio 5 2 NS_sound_drv_052_11khz_16bit spin
151. without being prompted The receiver will accept the string in API mode and pull out the source address RSSI level and data It will then send back strings to blink the LED on the end device Z Open and modify the DL value in API_Mode_End spin for each of your end devices The value doesn t matter as long as it is not more than 255 FF We are sending only one byte to hold the address in our example Note that the X CTU software uses hexadecimal values when configuring as opposed to decimal Y Download API_Mode_End spin to your end device s Y Download API_Mode_Coor spin to your coordinator Y Open and monitor the coordinator s Terminal window The resulting data should be similar to that shown in Fig 5 18 X CTU COM6 About 5 x PC Settings Range Test Terminal Modem Configuration Line Status Assert ae eee pe Close Assemble a Show mam ora M RTS Break Com a Packet eB Screen z Coordinator in API Data Received from Message String Ping Distance Compass bearing RF Signal strength Data Received from Message String Ping Distance Compass bearing RF Signal strength Data Received from Message String Ping Distance Compass bearing RF Signal strength mode ready at address 0 address 1 107 4276 107 4276 55 address 1 107 4358 107 4358 54 Figure 5 18 Example of terminal data from API data at coordinator USING THE XBee API MODE 219 In the end device
152. you design your own RPC protocol it s up to you In our case I decided that since we are going to have a human on one end making the calls via a serial terminal the RPC protocol should be ASCII This of course requires more bandwidth and is slower than binary Next since it is human readable the RPC calls take a format that look more like commands rather than strings of bytes representing data Thus our models used in this project should be easy to use and remember for a human The next step up would be to still use ASCI formatted data that is human readable but to make it more abstract For example instead of having a command like this NTSC Print Hello we might encode NTSC as a single number and Print as another number and then the Hello would stay as is 25 Hello As you can see this version of the ASCII protocol is much smaller we have saved bytes already It s still human readable but not as warm and fuzzy The entire RPC string is 11 bytes including NULL terminator But can we do better Sure if we encode in binary we don t send the longer ASCII text we send the actual byte data Therefore the binary encoding would look like this Byte 0 Byte 1 H e 1 1l o0 where byte 0 and 1 would represent the NTSC and Print subfunctions In this case the entire RPC call costs seven bytes but isn t human readable anymore since byte 0 1 are in binary and could be anyth
153. 0 03 byteLguay t2 write 00 04 byteLguay 3 ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 301 Subnet write 00 05 byte write 00 06 byte write 00 07 byte write 00 08 byte subnet subnet 1 subnet 2 subnet 3 MAC write 00 09 byte write 00 0a byte 00 0b byte mac mact1 mact2 mact3 write write 00 0c byte write 00 0d byte write 00 0e byte mact4 mact5 IP write 00 0f byteLip write 00 10 byteLipt1 write 00 11 byteLipt2 write Q0 12 byteLipt3 You can see that the method takes the four arguments to the init method which are pointers to arrays and writes their values to the corresponding register addresses of the W5100 Keep in mind that the arguments are array pointers and you would fill in the values on the arrays in your application before calling this method Also you need to make sure that the arrays are byte arrays not the default 32 bit arrays An example of calling this method from your application might look like the following from the SimpleTCPClient program that is included in the Chapter_08 Source SimpleTCPClient Spin directory VAR byte dip 4 byte subnet 4 byte ipLl4 byte gateway 4 byte mac 8 byte buffer 256 OBJ term gt tv_terminal_010 spin Instantiate the terminal object eth gt W5100_drv_011 spin Instantiate the W5100 driver PUB be
154. 00 transmit 307 308 application programming interface API 369 ARP See Address Resolution Protocol ASCII See American Standard Code for Information Exchange ASM Cog Example spin 76 77 78 ASPIRATION 431 Assembly code 5 7f assembly language code 76 78 assembly layer of SPI 295 297 assignment operator 30 463 INDEX astable multivibrator 153 asynchronous events 3 asynchronous serial communication 320 asynchronous serial sensors 174 182 174f GPS module example 179 182 180f serial communication signals examined 175 179 audio spectrum analysis 121 121f automatic polling with Propeller 212 214 213f Avery Shane 281 Avery Digital 288 294 backpressure 422 Baker Paul 150 balancing indoor climates 400 402 barometric formula 334 constants 334 335t barometric pressure sensors 322 324 3231 332 338 calculating altitude from pressure 334 335 reading 335 336 337f 338 big endian format 340 bit banging 335 bitwise operator 30 bitwise ORing 336 Blinker method 68 blinking in parallel Propeller 32 34 33f blinking LED 25 27 26f 31 31f more flexible version 28 32 test circuit 62 62f block argument 310 Block Designators 24 block group indicators 26f blocking 310 311 Bluetooth 191 Boe Bot Robot 222 224 222f 224f boot process 359 359f bot code 228 230 bot graphics 226 227f 230 231 bot network code 228 231 bot code 228 230 bot graphics 230 231 bot tilt cont
155. 00 kbps Figure 3 21 ViewPort timestamp variable monitoring v Adjust the trigger threshold along the left of the display so that it is in the middle of the milliseconds triangle wave v Click the stop button v Click the Cursor tab and then click the Horizontal and Vertical cursor buttons Horizontal and vertical cursors will appear as dotted lines on the Oscilloscope dis play The cursors can be clicked and dragged and the Cursors section in the lower right ViewPort Cursors table displays the time difference between the vertical cursors and the amplitude difference between the horizontal cursors v Drag the vertical and horizontal cursors so that they frame one of the triangles in the milliseconds trace in Fig 3 22 v Examine the Cursors table 106 DEBUGGING CODE FOR MULTIPLE CORES A ViewPort 4 1 64 Oscilloscope toscale DC AC Off Q Oc AC Off Name Plot Cdit Min Max Avg Val minutes C 11 second C 23 27 25 29 milliseh dx 31 986 497 49 Cursors Show A B Diff ven 3 2935 3945 NS Hora millisctor e 11 9 986 998 cs i ersi Measure Figure 3 22 ViewPort dso view The Cursors table should indicate that the difference between the vertical cursors is about 1 s and the difference between the horizontal cursors is about 1000 ms The cursor mode slider also has Pan and Zoom features for getting a closer look at a
156. 1 45 timing 38 41 39f Propeller Proto Board 80 Propeller Proto Board USB 412 413 416 Propeller Tool software 18 19 19f 45 Documentation view 37 37f Parallax Serial Terminal 43 45 44f 45f Spin and Assembly languages in 55 Stack Length object 41 42 Propeller Webinar 47 48f proportional integral derivative controllers PID 250 PST Debug LITE 81 83 82f display 130 131 130f Parallax Serial Terminal development and 86 102 Test Time Counting spin 87 90 PUB LED Blink 25 36 PUB LED On statement 24 PUB mode opmode 299 PUB out c command 386 PUB write 298 PUB public methods 24 pulse and duty cycle outputs 144 152 Memasic 2125 Accelerometer module 148 152 Ping Ultrasonic Distance Sensor 145 148 145f 146f 147f pulse width modulation PWM 240 410 432 pushbutton array 127 129 127f Pushbutton Decisions spin 126 127 pushbuttons of on off sensors 122 129 126f pull down and pull up resistors 123 124f PuTTY terminal program 357 358f PWM See pulse width modulation 472 INDEX QTI module 143 144f R 232 291 RAM 5 6f EEPROM vs 27 28 RAW See Input pin determining communication mode RC Decay 188 circuits 138 139 growth circuit varieties and 142 144 waitent tricks with 71 RC Decay measurement 137 139 138f in Parallax Serial Terminal 141 141f potentiometer position example 139 142 139f RC time measurement 137 RCFAST setting 64 66 read and write layers of Eth
157. 100 100 Mbps and full duplex call the mode method with opmode equal to 0 Start and Stop The only other two methods that don t use the read and write methods are the start and stop methods You should recognize these as they are used in practically all drivers for the HYDRA We ll discuss the stop method first as it is the most simple It simply stops the SPI layer and frees the cog it runs on There done The start method starts the SPI layer written in assembly which handles the actual bit banging of the SPI data to the W5100 in a new cog and returns the new cog number that the SPI layer lives in If you choose to call the mode method it should be called before the start method All other Spin method calls including read and write should be called after the start method has been called The code for start and stop is shown here PUB start okay This is the public start method It starts a new cog at the assembly entry point Start the SPI code in a new COG stop okay cogon cog cognew entry SPIRW gt O PUB stop Stops driver frees a cog if cogon cogstop cog Init The init method should be called right after the start method It initializes the W5100 by telling it what our gateway subnet IP address and MAC address are The init method is shown here PUB init gway subnet ip mac Init the registers Gateway write 00 01 byteLguay write 00 02 byteLguay 1 write 0
158. 16 this application demonstrates how one of the PST Debug LITE s display modes can be customized for different debugging tasks As an aside removing the debug Style method call could be more beneficial here since it would then display the I O pin direction and states along with the variable values CONVERTING ANALOG SENSORS TO ON OFF SENSORS Many analog sensors can be incorporated into circuits that behave as on off sensors by virtue of the fact that Propeller microcontroller I O pins have a 1 65 V input threshold voltage Provided the voltage applied to an I O pin set to input is in the 0 to 3 3 V range a cog interprets voltages above 1 65 V as binary 1 and voltages below 1 65 V as binary 0 For example the voltage output at the potentiometer s W terminal in Fig 4 9 varies from 0 to 3 3 V as the knob is turned Half of its range of motion will result in voltages above 1 65 V and the other in voltages below 1 65 V So as the potentiometer s knob is turned from one end of its range to the other the voltage at its W terminal will pass the 1 65 V threshold at about the halfway point and the Propeller can detect this as a change from 0 to 1 or in the other direction from 1 to 0 V Test the circuit shown in Fig 4 9 with P18 to P16 Input States spin Keep an eye on the middle of the three binary digits it s the one that displays the state of P17 3 3 V W Pot 10 kQ P17 Ff fe FF T Figure 4 9 Potentiometer in an on o
159. 164f 165f circuit and signals 160f component values 163 164f DC signal measurements test 161 164 162f multicore signal acquisition analysis and display 167 168 object 56 signaling dependence of on off sensors 133 135 sine waves 429 single CPU multicore sensor vs 320 322 single core devices 321 interrupts on 4 SIO See Serial data input output size argument 310 Slave Select signal SS 290 390 390f slave server command library to 387 388 multicore processor as 353 Sobel filter 273 socket buffer 308 socket programming 303 304 Software tools for debugging 78 86 Solid State Gyro 168 169f solid state relays SSRs 137 SOUND command 382 384 sound commands 388 source MAC 282 Southern Illinois University 231 spectrographs analyzing speech with 427 430 VocalTract synthesis in 434f 437f speech spectrographic analysis of 427 430 speed 389 of object 269 270f UDP and 284 SPI See Serial Peripheral Interface SPI_DONE 298 Spin code 5 7f for green house model 420 423 Spin compiler 33 Spin language 27 Spin Operators 30 SPI_RD 298 SPIRW global variable 298 SPIRW variable 296 SquareWave object 134 135 SS See Slave Select signal SSRs See solid state relays Stack Length object 41 42 stack sizing 41 45 stack space 33 method in new cog outgrows 78 Stack test 43 45 44f 45f Stanford University 274 286 star wiring design 409 410 start method 36 55 56 150 300 multiprocesso
160. 19 352 dataptr argument 310 D COM See distributed COM Debugger Kernel label 114 debugging 322 architecture that prevents bugs 52 54 55 62 building block objects design guidelines 56 57 code for multiple cores 51 117 cogs exchanging information at different memory addresses 71 73 common multiprocessor coding mistakes 58 78 development with Parallax Serial Terminal 86 102 development with Propeller assembly debugger 110 116 establish precise time base in another cog 90 fix bug exposed by testing 95 96 forgotten literal indicator for assembly language code 76 78 incorporate into building block object 99 102 language and programming conventions to prevent bugs 55 56 memory collisions 73 74 74f 93 94f method in new cog outgrows stack space 78 missing call 58 68 466 INDEX 466 debugging Cont missing I O assignments in new cog 62 64 Parallax Serial Terminal 81 83 PASD 83 85 86f Propeller features that simplify 52 56 remove test code 98 99 survey of Propeller tools 78 86 survey of software tools 78 86 test bug fix 96 98 test in same cog 87 90 test timekeeping code in another cog 91 92 92f testing multiprocessors involved 93 95 timing interval errors 64 71 tools applied to multiprocessing problem 86 116 TV terminal 79 81 80f 81f 117 variable display with 86 87 86f 87f ViewPort 83 102 110 252 252f wrong address passed to method 74 76 Dec Equipment Corp 379 380f Def
161. 2071 Enter degrees 45 Tangent 1 Enter degrees 30 Com Port Baud Rate 6 TX F DIA F ATS OTS COM15 115200 F o AY DSA Prefs Clear Paice Figure 3 6 Calculate tangents with a floating point object COMMON MULTIPROCESSOR CODING MISTAKES 61 Terminal software set the Com Port drop down menu to the COM port number you got from the Propeller Tool software V Set the Baud Rate drop down to 115200 so that it matches the baud rate passed to the Parallax Serial Terminal object s Start method with the Test Float32 spin object s pst Start 115200 method call When you load a program that exchanges messages with the Parallax Serial Terminal into the Propeller chip with the Propeller Tool make sure to click the Parallax Serial Terminal s Enable button as soon as the Propeller Tool software s Communication window reports Loading If you wait too long to click the Parallax Serial Terminal s Enable button it might have already missed the Propeller chip s user prompt messages If that s the case and you used the Propeller Tool s Run Compile Current gt Load RAM F10 to load the program you will have to reload it If you instead used Run gt Compile Current Load EEPROM F11 you can restart the program by either pressing and releasing the Propeller board s Reset button or double clicking the Parallax Serial Terminal s DTR check box VY Make sure there is a check mark in the
162. 292 293 Mole Perry James 329 MonitorButtons method 315 316 MonitorEthernet method 315 317 MOSI SIMO See Master Output Slave Input signal most significant bit MSB 297 324 Motor cog 252 Motorola 290 Mouse objects 57 MP3 downloads 284 MS5540C barometric pressure sensor module 323 336 MSB See most significant bit MSL See mean sea level multicore Propeller chip silicon 1f multicore Propeller microcontroller 3 14 concept 5 7 hardware 7 14 lack of interrupts on 4 using 5 7 multicores 1 advantages of processor 320 322 creating simple networked game 312 317 defined 2 3 Ethernet and Internet protocols 281 286 287f EtherX add in card for Propeller powered HYDRA 287 312 importance of 3 microcontroller designs 52 for networking applications 281 318 networking approach to game programming 313 317 sensor vs single CPU 320 322 slave 353 multiline comment 30 multiple keyboards 362 multiprocessing of clones 4f debugging tools applied to problems 86 116 multitasking vs 2 on off sensors example 129 131 multiprocessor related coding mistakes 58 78 cogs exchanging information at different memory addresses 71 73 forgotten literal indicator for assembly language code 76 78 multiprocessor related coding mistakes Cont memory collisions 73 74 74f 93 94f method in new cog outgrows stack space 78 missing call to building block object s start method 58 62 missing I O assignments in new co
163. 2J so to send this to the terminal you would send ESC 2J to the terminal This string will not print but is interpreted by the VT 100 emulator and clears the screen If you are interested in learning more about VT100 commands try the Wikipedia entry here http en wikipedia org wiki VT 100 380 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Figure 10 12 A DEC VT100 terminal Our console application is simple thus it doesn t need or use many of the VT100 fea tures but they are there if needed The main features we need are for the user to be able to type and edit via BACKSPACE and for the console application to perhaps clear the screen scroll or change a color not supported yet Thus the interface from the user s perspective is a simple prompt similar to DOS that the user can type commands into ISSUING COMMANDS TO DRIVERS The previous two sections described how the user input is entered parsed into tokens and stored into the tokens array so we have everything we need to discuss the command handlers and their communication with the drivers To review the idea is that once the tokens array has the tokens in it the handlers need to query the strings and test for valid commands Once found the associated handler is entered and the strings are extracted from the array and converted into the appropriate format integers values and so on The next step for the handler is to
164. 3 3V Headphone Amp Yellow G j G a0 G So i oOo i Ss wo N vt N eip These three resistors These three sets of two 1 HF form a 1 volt 75 ohm 3 bit DAC that is used to generate baseband and broadcast video PGND SGND C4N This resistor is only required for aural subcarrier in broadcast mode Figure 10 7 resistors form 1 volt 75 ohm 2 bit DACs that are used to generate red green and blue Propeller Demo Board Rev D schematic Courtesy of Parallax Inc 364 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS VGA NTSC TV Audio Amp PS 2 Keyboard A 4 4 4 VGA Core NTSC Core Audio Core Keybaord Core COGi COG i 1 COG i 2 COG i 3 RS 232 Serial Core COG i 5 COG i 6 Propeller Chip To PC System level modular schematic For this project it was decided to use NTSC VGA audio serial and PS 2 keyboard devices This uses up a minimum of five processing cores leaving us three cores for other things and for future expansion Of course one core is used for the CCP thus we are left with two ultimately for expansion As shown in the figure the NTSC signal is on pins 12 13 and 14 VGA is on pins 16 23 audio is on pin 10 or 11 the PS 2 keyboard is connected to pins 26 and 27 and finally the serial is on pins 30 and 31 This is basically a standard Propeller Board Rev C D pin map Table 10 1 shows the pin map in more detail
165. 308 Transmit windowpane 60 61 60f Tri Axis Accelerometer 168 169f trilateration GPS 326 327f TSL230 Demo spin 155 TSL230 Light to Frequency Converter 153 155 153f TTL See transistor transistor logic TV terminal 79 81 80f 81f 117 TX method 307 308 320 IART See Universal Asynchronous Receiver Transmitter CLA 286 CSB 286 DP See User Diagram Protocol DP header 285 286f DP socket 303 305 308 nited States Department of Defense DOD 324 niversal Asynchronous Receiver Transmitter UART 320f 321 321f niversity of Florida 231 niversity of Sassari Italy 231 SHS GEN CO By SB oR A Cage Ga ar Gi E INDEX 475 University of Utah 286 U S Geological Survey USGS 348 USDA Texas 231 User Diagram Protocol UDP 282 283f 284 TCP differences from 284 user input loop 366 USGS See U S Geological Survey VAR global variable declaration 24 36 VCC See 5 V input supply voltage verifying RAM communication dialog 24 24f vertical sync 313 VGA See Video Graphics Array VGA commands 388 VGA monitor 359f VIBRATO 431 video filter chain scripting language and video buffers 266 266f Video Graphics Array VGA 17 30 VIDEO4 option 266 268 View Serial Character with ViewPort spin 176 177 ViewPort 83 84f 85f 102 110 176 177 adding terminal functionality 106 110 109f DanceBot balancing robot and 251 255 254f debugger 252 252f dso view 104 106f input output sig
166. 32 333f inverted pendulum problem 236 T O pins 11 bugs and 52 map for connection to media devices 364 365t missing assignments in new cog 62 64 out of synch with ideal duration 40 40f protecting 136 136f shared access 52 53f IP See Internet Protocol IP addresses 282 284 ip array 303 IP header 282 283f 285 285f 286f IR LED See infrared light emitting diode jmp loop command 78 Kalman filter 246 252 253 keyboard commands 388 Keyboard objects 57 Keyboard_Demo spin 80 81 keyboards multiple 362 Keyhole Software 351 Keyhole Markup Language KML file 351 362 KML file See Keyhole Markup Language file KMZ file 351 Kuhlman Jim 157 labor inertia 423 LaMothe Andr 287 288 353 LAN See local area lan network LED_Blink method 28 29 LED_Flash method 30 34 36 38 LEDs See light emitting diodes level shifter with two FET transistors 136 137 137f light and push button circuits 62 light emitting diodes LEDs 17 blinking in parallel 33f blinking in sequence 31 31f flashing 34 schematic for exercises 23f Lindsay Andy 51 119 222 Linux file system 339 LIS3LV02DQ 247 248 listen connect and connection established method 305 307 LISY300AL yaw rate sensor 170 local area lan network LAN 282 local commands 359 processing example 381 382 to terminal 387 local variables 30 lock management commands 95 lockclr 317 locknew keyword 317 locks 54 lockset 317 low
167. 396f Excel 319 348 executable image 34 face detector 278 279f FAT file system 339 FDDI See fiber distributed data interface fiber distributed data interface FDDI 282 FIFO See First In First Out file transfers 284 file upload box 349 349f Find Hidden Bug in Timestamp spin 93 94 findmax filter 273 First In First Out FIFO 321 5 V input supply voltage VCC 328 329 Flash object 37 38 Flash spin 34 flat memory architecture 5 Float32 58 59 FloatString 59 forgotten literal indicator for assembly language code 76 78 assembly language example 76 77 inside ASM Cog Example spin 78 formants generating 432 synthesizing 429 430 frame grabber of PropCV 259 264 Freescale Semiconductor MPX5050 351 frequency output of sensors 153 155 153f FRICATION 431 432 FSRW SD card object 341 343r full duplex UART 320f 321 FullDuplexSerial_Mini spin 329 330 fuzzy logic control 248 251 249f fuzzy speed classes 249 fuzzy spin 250 game programming 312 317 multicore approach using Propeller 313 317 traditional microcontroller approach to 313 INDEX 467 games Button Masher 281 312 317 creating simple networked 312 317 creation 313 Halo 284 HYDRA hobby video 281 Garmin GPS 330 gateway array 303 GetData method 219 220 Global Positioning System GPS 324 satellite constellation 325f global variables 33 GLOTTAL 431 GND See Ground reference supply pin Google Docs 319 Google Earth 351 3
168. 4 WIRELESSLY NETWORKING PROPELLER CHIPS PPPS EEE lt y TPP RF Comms Sent and Returned USB Comms to Base XBee Remote XBee with Loop Back PC and Software Figure 5 3 Configuration and testing diagram Figure 5 3 shows the diagram for this test A PC will communicate directly to an XBee and a remote XBee is set up with a loop back jumper In the loop back the DOUT line of the XBee is tied to its DIN so that any RF data it receives is looped back into the device to send it out again via RF The following is a list of the hardware and software used for this test but there are many ways to achieve the same results Essentially a means is needed to communicate to an XBee serially from the PC and means to supply power to the base and remote XBees Equipment and other software E 2 Propeller Demo Boards Parallax E 2 XBees www digikey com E 1 Prop Plug Parallax E 1 AppBee SIP LV from Selmaware Solutions www selmaware com E X CTU software from Digi International www digi com The AppBee SIP LV is simply a carrier board for the XBee providing 3 3 V power from the Demo Board and access to I O in a breadboard compatible header Figure 5 4 shows the AppBee SIP LV and a drawing of the physical connections to the XBee TESTING AND CONFIGURING THE XBee 195 x 9 9 O a _ oF a gt 2 3 eo AD3 DI030 oRESET RTS AD6 DIO60 PWMOIRSSI ASSOC ADS DIOS oPWM1 o ODT
169. 4602 infrared sensor which can be found in many TV sets and other entertainment system components If this sensor detects infrared flashing on off in the 38 kHz range it sends a low signal otherwise it sends a high signal In the circuit in Fig 4 11 it sends a low signal if the infrared light is reflected by a nearby object otherwise it sends a high signal It might seem like another cog would be required for sending the 38 kHz signal but that s not the case Each of the Propeller microcontroller s eight cogs has two counter 38 kHz Detect J No Detect wate g S y sedi P2 2 kQ P5 A D Meee 3112125 i zeer J eee meeeeee sees eszn le Figure 4 11 Infrared object detector 134 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES modules A counter module is a configurable state machine that s capable of performing a variety of tasks independently for its cog One of those tasks is square wave generation and counters are capable of generating frequencies that range from 0 Hz to 128 MHz Information Other examples of independent tasks that counter modules can perform include pulse generation pulse and decay measurement and duty modulation for digital to analog D A conversion and that s still just scratching the surface For more information about counter modules get the Propeller Education Kit Labs Fundamentals PDF textbook from www parallax com and consult the Counter Modules a
170. 463 This page intentionally left blank ABOUT THE AUTHORS Shane Avery graduated from Cal Poly San Luis Obispo with a bachelor s degree in computer engineering and from Cal State Northridge with masters in electrical engineering His graduate work focused on system on chip design in FPGAs and ASICs At Ziatech Intel he debugged single board CompactPCI computers for the telephony industry He then worked with a toy company Logic Plus developing the Verilog code for the FPGA inside a toy video camera that would insert static images onto the background Currently he works for the United States Navy designing and devel oping embedded hardware for new military weapons This year he began his first company focusing on embedded electronics called Avery Digital Chip Gracey President of Parallax Inc has a lifelong history of invention and creativity His early programming projects included the famous ISEPIC software duplication device for the Commodore 64 and various microprocessor development tools yet he is most well known for creating the BASIC Stamp Chip Gracey is the Propeller chip s chief architect and designer His formal educational back ground is nearly empty with all of his experience being the result of self motivation and personal interest Chip contin ues to develop custom silicon at Parallax Vern Graner has been in the computer industry since being recruited by Commodore Business Machines in 1987 He ha
171. 5 in turn indicate the acceleration sensed by each axis Pulses that PULSE AND DUTY CYCLE OUTPUTS 149 Figure 4 24 Inside the Memsic Accelerometer Excerpt from Smart Sensors and Applications Parallax Inc last 5 ms indicate zero acceleration along an axis and pulse durations can deviate from 5 ms by 1 25 ms g where g is the acceleration due to gravity If 1 g is applied to an axis the pulse durations transmitted will be 3 75 ms Likewise accelerations from 0 to 1 would range from 5 to 6 25 ms Tip According to the device s datasheet the MXD2125 reports acceleration in terms of duty cycle which is the ratio of high time to signal cycle time In practice just the high pulses are equally accurate for this particular sensor Aside from examining object documentation example programs that accompany objects from the Propeller Library and Propeller Object Exchange can provide clues on Y axis tilt Y Axis X Axis X axis tilt Figure 4 25 Memsic communication 150 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES how to use them There are several objects for the Memsic 2125 Accelerometer Module in the Propeller Library and on the Propeller Object Exchange including MXD2125 MXC2125_Simple and Memsic2125 They all also have demonstration objects in the Propeller Tool Software s Examples Library folder All of them are designed for a TV display which is well and good if you are in the habit of using a TV f
172. 5 100 Q Za P3 Green Vss P5 Vss PING Figure 5 11 Remote unit with PING and compass delay 3000 Guard time for AT mode XB str string Send AT command request delay 3000 Guard time XB str string ATDL 0 CN Send code to set DL 0 XB tx 13 Send carriage return The command codes from the Propeller are passed to the XBee using the FullDuplexSerial object duplicating your serial terminal Through this method any number of commands may be sent to the XBee for configuration changes on initialization or during operation Those 3 second guard times can cause lag during operation but we ll deal with that soon In the SendData method you can see that the range and direction theta are read from the devices Using a combination of text strings and XB dec decimal methods the data is sent to the base XBee where it is passed through to the PC for monitoring in the Terminal window Figure 5 12 is a sample output of received data repeat range Ping Millimeters PING Pin Get range in mm theta HM55B theta Get bearing 0 8191 XB str string 13 13 Ping Range mm Send string to base XB dec range Send range as decimal XB str string 13 Direction 0 8192 Send string to base XB dec theta Send bearing as decimal delay 500 Short delay before repeat 208 WIRELESSLY NETWORKING PROPELLER CHIPS x cTu COM6 lol x About PC Settings Range Test
173. 52 Google Maps 350 350f GPS See Global Positioning System GPS altitude vs pressure altitude 348 348f GPS Float packages 180 182 181f GPS Google Map track with speed 350 350f GPS module sensor example 179 182 180f GPS receiver 322 322f 324 332 civilian 316 reading sensor 328 332 GPS tracking barometric pressure sensors 322 322f main Spin object 344 346 portable and multivariable 319 352 GPS tracking experiment 346 351 data analysis 347 351 plotting GPS tracks 348 351 GPS trilateration 326 327f GPS Visualizer Web site 348 351 gps_buff 331 GPS_IO_Mini spin 329 331 332 Gracey Chip 52 157 427 Graner Vern 399 graphical user interface GUI 395 396f green house model control electronics design for 409 417 goals of 402 layout of 408 408f sketch of 403f software design for 417 423 Spin code for 422 423 structural mechanical elements in 402 408 ground method 320 Ground reference supply pin GND 328 329 growth circuit varieties 142 144 GUL See graphical user interface GWS PG 03 247 Gyro module See Parallax 1 Axis Gyro Module gyro out gyrOT 253 Gyroscope Demo spin 170 gyroscopes 246 gyrOT See gyro out Halo game 284 H bridge schematic 240 240f heating ventilation air conditioning HVAC 399 balancing 400 402 control electronics for 409 417 in green house model 402 403 software design for 417 423 Hebel Martin 189 HELP command 360 361f hierarchy arrows 26
174. 5f e0 f3 9e 57 51 7f 50 18 96 3a METEEN 29 b vU OU d9 00 UU UU VU VU Frame 60 bytes Raassamhiadi TCP 4470 hytas Transmission Control Protocol cp 20 bytes Figure 8 8 Screen capture of WireShark P 224 D 224 M 0 Drops 0 EtherX Add in Card for the Propeller Powered HYDRA The platform that we will use to demonstrate the networking application for the Propeller is the HYDRA Game Development Kit with the EtherX card The HYDRA Game Development Kit was built around the Propeller and was designed by Andr LaMothe at Nurve Networks LLC The HYDRA has many of the same features as the Propeller Demo Board including PS 2 mouse PS 2 keyboard VGA and NTSC PAL video just to name a few Unique to the HYDRA are the NES connectors for the gamepad the HYDRA Net for networking two HYDRAs directly and an expansion connector If you d like to learn more about the HYDRA a fantastic book about it was written by 288 USING MULTICORE FOR NETWORKING APPLICATIONS 3 3 5 0 V Supplies VGA Port RCA Video Connector Z Composite NTSC PAL Compatible 128K EEPROM Pi RCA Audio Connector Z RJ 11 Networking Port Full Duplex 1 5 Mbit USB2SER Network Noise Compatible Filter Programming Port Game Cartridge Port Mini USB Programming Port PS 2 Keyboard Port PS 2 Mouse Port Nintendo NES Compatible Game Port Figure 8 9 HYDRA Courtesy of Andr LaMothe Andr LaMothe and is incl
175. 600 bps V Load the program into the Propeller chip and remember to click the Parallax Serial Terminal s Enable button as soon as the Propeller Tool s Communication window displays the Loading message 66 DEBUGGING CODE FOR MULTIPLE CORES vV Verify that the Parallax Serial Terminal displays the Convert decimal to hexadeci mal message y Comment the _clkmode and _xinfreq system clock directives by placing an apos trophe to the left of each one This will make the Propeller Tool software s Spin compiler ignore these directives and instead use the default internal RCFAST clock settings VY Use the Propeller Tool software to load the modified program with a clock con figuration bug that throws off the serial communication signal timing into the Propeller While running the modified program the Parallax Serial Terminal will probably display garbled messages similar to those on the right side of Fig 3 8 To fix the bug uncomment the _clkmode and _xinfreg system clock directives and load the corrected program back into the Propeller chip Test Missing Clock Settings spin CON Comment these two declarations to create the timing bug _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object PUB go value pst Start 9600 Start Parallax Serial Terminal cog pst Str String Convert
176. 8 1 1 and your subnet to 255 255 255 0 and your MAC address would be 00 70 6e 69 73 0a Technically you should apply to IEEE for your own MAC address especially if you intend to produce a commercial product based on the W5100 But in reality for educational purposes all you need to do is be sure that the MAC address isn t the same as any other Ethernet device in your local network Again as you see here you should call the init method after the start method and before you call the open method which we will discuss next Open and Close Socket programming has been around for a long time as an attempt to standardize network interfaces The W5100 loosely models the socket programming scheme It supports up to four independent sockets at a time The EtherX driver only supports one socket at a time but there is nothing stopping you from modifying the driver to support all four sockets Sockets need to be opened in the W5100 and that is why we have the open method call To open a socket on the W5100 we need to tell it whether the socket is a UDP socket or a TCP socket what the source and destination ports are and the destination IP address Actually if you set up the W5100 to be a TCP server the destination IP address is not known at the time when you open the socket that value can be anything as it will be ignored The open method is shown here PUB open type source_port dest_port dest_ip temp temp2 This method will op
177. 9128 456789 Bit 0 lt Nibble gt Byte gt wora gt Checksum RFC 768 NEE Checksum of entire UDP segment and pseudo Please refer to RFC 768 for the complete User header parts of IP header Datagram Protocol UDP Specification Copyright 2008 Matt Baxter mjb talpipe org www talpipe org mjb Drawings Figure 8 7 UDP header field inspection Figure 8 8 is a screen grab of WireShark capturing data on a request to a web server The upper pane shows the packets that have been grabbed it shows these in real time as they come into the computer The middle pane shows a header breakdown of the packet The lower pane shows a complete hex dump of the entire data Clicking on a header in the middle pane will highlight the corresponding data in the hex dump In the screen capture the TCP header is highlighted A copy of the WireShark program can be found on the ftp propeller chip com FTP site in the PCMProp Chapter_08 Tools directory ORIGINS OF THE INTERNET The origins of Internet are military in nature The first Internet was developed by the Advanced Research Projects Agency ARPA which now is called DARPA they added the word defense and was a simple packet switching network that initially only linked up UCLA Stanford UCSB and the University of Utah It s hard to imagine that at one time the entire Internet consisted of four computers ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 287
178. 953 f4 sh 100 1953 PRI rnd low high return low cnt high low 1 Recording the audio output of this program into our spectrograph we get the data shown in Fig 12 5 4 Spectrum Display Manana Aa mamian yin eal Pipars ath th bli ht i fe nnn nm ln A Mile a hes ch tn Figure 12 5 A spectrograph of the vowels synthesized by Example1 spin EXPLORING THE VOCALTRACT OBJECT 435 You can see the formants transition as they did in the original voice recording Compare the waveforms in the top panes as well They look a little different but they sound similar Speech is a rather inexact phenomenon thankfully By making ga 0 in the previous program you will hear the vowels whispered since there is some breath noise via aa You can tell from listening to the synthesis that the transi tion from one vowel to another makes nice diphthongs For example going from bEEt to hAt makes yeah Vowel speech is pretty straightforward in this way How about some breathing sounds Try modifying the PRI talk method in the previ ous program as follows see Example2 spin PRI talk setformants 880 1075 2350 3050 Set inhale formants v go 1 aa 30 Slowly ramp up v go 1000 v go 500 Sustain aa 0 Slowly ramp down v go 1500 setformants 500 800 1100 2325 Set exhale formants v go 1 aa 10 Ramp up v go 500 aa 0 Slowly ramp down v
179. A and hear some sounds these are all the systems booting Compiling the Demo To load the demo into your Propeller Demo Board locate the top level source file in the following directory on the ftp propeller chip com site PCMProp Chapter_10 Source prop_serial_slave_010 spin This file of course relies on a number of other objects but they are all within the same Source directory so the program should compile and download with no problems Also there is an archived zip of the entire project within the Source directory Once you have compiled and downloaded the program into the flash memory of the Propeller Demo Board F11 is the shortcut on the Propeller Tool the program will immediately start booting and displaying on the VGA and NTSC making sounds and outputting to the serial terminal If you don t have all these devices hooked up no worries just hook them up and press the Reset button on the Propeller Board Putting the Demo through Its Paces Figure 10 4 shows photos of what you should see on your NTSC and VGA monitors as the system boots Your terminal should also show some initialization and startup strings along with a final prompt as shown in Fig 10 5 At this point we are ready to go and start typing commands to the CCP Let s try a couple of commands and see if things are working There are two kinds of commands local commands and remote commands Local commands simply control the terminal program and are process
180. A ViewPort v4 1 64 Test Timestamp Object with ViewPout E vents Source Documentation x 20PUB Go Go method 21 Configure ViewPort for Terminal communication variable display and share vptx through count 23 vp config String start terminal terminal 1 24 vp config String var vptx vprx minutes seconds milliseconds coun 5 vp share yptx count NyCode 26 waitent ent clkfreq vp clear Spin Files p time Start 10 59 999 Start timestamp cog vp RxF lush Clear bufter 31 apia Ma n i 3 time GetTime minutes Get a timestamp vp Dec Count Count to Terminal if count 10 Call alarm when count Alar count 4 39PUB Alarm Alarm method 40 hl vp Str String Alarm Display alarm string in lermi 421 counts Clear count variable gt Sanaa aM Ro CG Ae AF OF 1 0080 FC OC SC BE 24 00 G CO 01 03 02 14 00 Q A Ai AN ANA CA A minutes 8026 seconds 0D2C mililisediiinis count 8034 Connection Connected at 1000 kbps Figure 3 23 Terminal stepping and variable modification v With ViewPort in code view open Test Timestamp Object with ViewPort Events spin v Click the Start Debugging button v Place your cursor in the Terminal field and press the ENTER key a few times Each time the Watch window should update the variable values v Hover your mouse cursor over the buttons to the right of the Start Debugging button to make their flyover la
181. ASCII 13 CRs or by commas In sending decimal values an API_DEC does not exist Numbers unless sent as raw byte values must be converted to a string and sent that way The Numbers spin object can aid in the conversion such as sending the range in API mode XB API_str num ToStr range num DEC But that s the only thing that could be sent since once called the string is transmit ted in a frame To keep our data together another method is used to assemble a string packet manually before sending it This will be demonstrated in the example coming up In API mode all data to be sent in one transmission must be assembled first Note Both transmitter and receiver do not need to be in API mode One side can be using transparent transmission and the receiver using API reception and vice versa This makes our job a little easier 218 WIRELESSLY NETWORKING PROPELLER CHIPS DATA ACQUISITION AND CONTROL USING API MODE In this example we will continue using the coordinator and end device s hardware but use API mode instead for data reception and transmission on the coordinator The end devices have the ability to transmit at any time while we have it on a delay another option may be to use sleep mode for low power consumption and have it wake to transmit or have it transmit only when some event takes place such as a range being too close someone is near The end device will send a string for the values range and theta
182. Application command Note 1 The last two commands are not mandatory but help differentiate if the card is SD or MMC Only SD can reply to these commands Note 2 Refer to Fig 9 10 for encoding of response byte Note 3 When reading a block a data token of FE will be received after the initial response code of 00 Then the next bytes will be the sector data Note 4 After the write command is sent the SD card expects the data token FE to follow signifying the host is ready to send bytes TABLE 9 5 AVAILABLE METHODS FROM FSRW SD CARD OBJECT PUBLIC METHOD NAME DESCRIPTION mount basepin Resets the SD card connected to the base pin into SPI mode and attempts to read the FAT16 file system popen s mode Opens a file named s for read write or append operation pclose Closes and flushes the header and write buffer to the previously opened file pread ubuf count Reads from the previously opened file and stores into ubuf with count bytes pwrite ubuf count Writes from ubuf into the previously opened file with count bytes pputc c Outputs a single byte c to the previously opened file pgetc Reads and returns a single byte from the previously opened file pflush Flushes any unwritten header metadata and write buffers to the previously opened file opendir Closes the previously opened file and prepares the read buffer for calls to nextfile nextfile fouf Finds the next file in the root directory folder and copies its name in 8 3
183. CLIENT HOST CONSOLE DEVELOPMENT 383 Case STOP if strcomp tokens 1 string STOP channel 3 Enter handler Channel 0 3 argl atoi2 tokens 2 4 Issue command to sound core if argl gt 0 snd StopSound arg1 Case STOPALL if strcomp tokens 1 string STOPALL repeat argl from to 3 snd StopSound arg1 End if sound There is a lot going on here so let s focus on one subfunction the PLAY code Locate the highlighted fragment in the previous sample that looks like this Case PLAY if strcomp tokens 1 string PLAY Once the match for PLAY has been found we are good to go and simply need to convert the next three values into numbers representing channel frequency and dura tion This is where more error handling is needed Currently I assume the user has typed numbers into these spots such as SOUND PLAY 100 10 which would indicate to play a 100 Hz tone on channel 0 with a duration of 10 seconds But he could have typed SOUND PLAY Alpha beta zulu This would get passed to the parser and the custom atoi2 conversion func tions I wrote would blow up Thus to make this more robust the atoi2 func tions that convert strings to integers need to test if a string is numeric In any event assuming the parameters are valid tokens 2 tokens 3 and tokens 4 are con verted to integers and then we have all we need t
184. CORE MICROCONTROLLER Figure 1 2 Clones can multiprocess processor sleeping until needed consuming almost no power yet waking in less than 10 millionths of a second to handle events CLEAR YOUR MIND OF INTERRUPTIONS If you know all about interrupts on single core devices forget it now Interrupts can be troublesome for real time applications and are nonexistent in the multicore Propeller Why With a device like the Propeller you don t need them Just focus a processor on a task that needs such handling it can sleep until the needed moment arrives and won t negatively affect the rest of the application s efforts The multicore Propeller is a system of homogenous processors and general purpose T O pins Learn to use one processor and you know how to use them all There s no specialized hardware to learn for demanding tasks just assign another processor to the job This incredibly useful hardware has inspired many who may otherwise have not considered multicore technology for an embedded system application Tip Since its inception multicore technology has continued to evolve to give us many kinds of devices tools and schemes A quick review of multicore on Wikipedia www wikipedia org reveals the many ways the term is applied to a variety of unique hardware designs We will focus on a solid foundation built with simple rules and proven results These concepts can help you regardless of the multicore platform yo
185. Change the DL of the coordinator base XBee to 1 In the Terminal window type some p s and c s If your end point at address 1 is awake you should get values back for compass bearing and range finder distance V For this next test use the Assemble Packet window Type and send the following o Type 13 and then hit Enter o Type 1 and then hit Enter o Click Send V Change the 1 to a 0 and send again vV Test again by using 4 instead of 3 V What you should see is LEDs on P3 and P4 turning on with 1 and off with 0 NQN NNN Figure 5 14 is an image of our communications test CTU COM6 5 x About PC Settings Range Test Terminal Modem Configuration i DRF ry F Assemble Clear Show DTR RTS IV Break Com a Packet a a Remote unit ready at address 1 Send Packet Byte count 7 Display FIR Close Send Data Clear ASCII Figure 5 14 End device responses to requests POLLING REMOTE NODES 211 Looking at the end device s code data communications with the XBee is now through the XBee_Object This is an object I wrote for easing some data communication and configuration issues It uses FullDuplexSerial but greatly extends it Tip The XBee_Object can be downloaded from Parallax s Object Exchange http obex parallax com If you have previously downloaded it be sure it is version 2 or higher It is also included in the book s distributed files XB AT_Init initialized the XB
186. Cog 1 and then post clears the Cog variable to zero We clear it so an additional call to Stop does nothing Tip You can find out more about the commands cognew cogstop and if and the post clear operator in the Propeller Tool Help or Propeller Manual You may have noticed the first comment in Start and Stop begins with two brackets This is not a mistake it s yet another type of comment a document comment Use it for embedding documentation right inside the object that can be seen using the Propeller Tool s Documentation view see Fig 2 19 USING OUR BUILDING BLOCK OBJECT Now that our Flash object is ready others can use it by including its name in an OBJ block like this one OBJ LED gt Flash Include Flash object Propeller Toul Flash File Edit Run Help Select Documentation 3 LEDs Flash view to see an object s Mash I C FullSowce Condensed Summary Documentation x compiled documentation Object Flash Interface a PIIR Start Pin Duratian Fount Ee Propelter Library Demos piip Stap H Parallax Inc A A Propeller Tool v1 26 Program 19 Longs gt Examples Variable 10 Longs 4 Heb O Library The Start method s doc gt PE Kit PUB Start Pin Duratiun Court O Hel v comments show up here lt gt Start flashing led on Pin for Duration a total of Co 4x4 keypad ReaderDEMO spn A 4D8803_DEMO spin PUB Stop COIL_demo spin Debug_Led_
187. DP_Header1 4 false eth RX data 4 false lockelr eth_lock Set the opponents score to the data received opp_score data CREATING A SIMPLE NETWORKED GAME 317 Determine if we lost if winloss and opp_score 5 winloss 2 Set the score_change variable score_change 1 else lockelr eth_lock There s one last topic to cover concerning multicore networking You ll notice that we ve created a lock in Cog 0 using the locknew keyword Resource manage ment is a huge concern in multicore processing As an example let s assume that two cores want to write to a serial port or SPI in our case First the two cores cannot write at the same time This is especially true in an architecture like the Propeller with no dedicated serial logic such as a UART where the cores need to bit bang the I O What is needed is a mechanism for one core to know if a particu lar resource is being used by someone else One way to solve this problem is with something called a semaphore Using our serial port example if a core wanted to send data out to a serial port it would first look to see if the semaphore corresponding to the serial port were available If so the core would grab it Once the core has grabbed the semaphore the core keeps it until giving it up and then the core can send data out the serial port knowing that another core will not stomp on the output After the data has been output on the serial
188. Debugging Tools Applied to a Multiprocessing Problem 86 Summary 116 Exercises 117 15 51 vii viii _ CONTENTS Chapter 4 Sensor Basics and Multicore Sensor Examples 119 Introducing Sensors by Their Microcontroller Interfaces 119 On Off Sensors 122 Resistive Capacitive Diode Transistor and Other 137 Pulse and Duty Cycle Outputs 144 Frequency Output 153 Voltage Output 156 Synchronous Serial 168 Asynchronous Serial 174 Questions about Processing and Storing Sensor Data 182 Summary 187 Exercises 188 Chapter 5 Wirelessly Networking Propeller Chips 189 Introduction 189 Overview of Networking and XBee Transceivers 191 Hardware Used in This Chapter 193 Testing and Configuring the XBee 193 Sending Data from the Propeller to the PC 204 Polling Remote Nodes 208 Using the XBee API Mode 214 A Three Node Tilt Controlled Robot with Graphical Display 221 Summary 231 Exercise 232 Chapter 6 DanceBot a Balancing Robot 235 Introduction 235 The Challenge 235 Building the DanceBot 238 Controlling the DanceBot 255 Summary 255 Exercises 255 Chapter 7 Controlling a Robot with Computer Vision 257 Introduction 257 Understanding Computer Vision 258 PropCV A Computer Vision System for the Propeller 259 Apply Filters and Track a Bright Spot in Real Time 265 Following a Line with a Camera 270 Track a Pattern 272 State of the Art Computer Vision with OpenCV 274 OpenCV and Propeller Integration 276 Summary 279 Exercises 280 Chapter 8 Us
189. Decimal to Hexadecimal Heading repeat Main loop pst Chars pst NL 2 Carriage returns Prompt user to enter value pst Str String Enter decimal value value pst DecIn Get value Announce output pst Str String pst NL Your value in hexadecimal is Display hexadecimal value pst Hex value 8 COMMON MULTIPROCESSOR CODING MISTAKES 67 Incorrect Loop Interval Code Incorrect Loop Interval spin has the correct clock settings but its timing is not yet precise because there is still a bug in the way the repeat loop is written The repeat loop currently delays for one quarter of a second inverts the state of the I O pin and repeats the loop again The loop is going slower than 4 Hz because the repeat and outa 5 commands both take time to execute and there s nothing in the loop that compensates for it Furthermore adding more commands to the loop would cause it to take even longer to repeat Incorrect Loop Interval spin CON _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz VAR long stack 10 Stack for cog executing Blinker PUB Go cognew Blinker 5 clkfreq 4 stack Blinker method to new cog PUB Blinker pin delay Blink light method dira pin 1 Set I O pin to output repeat Repeat loop waitcnt delay cnt Delay 1 4 s outaLpin Invert I O pin output state Correct Loop Interval spin shows a simple modification
190. ED 0 Q0CGQ40C dec 12377260 C 010 66BFE822 or outa LEO_16 SAAAAAAAA dec 3 jS C 011 04BFE023 andn vuta LE0_17 F trom Addr PAN JIE SCFC3C1B call wait C 013 64BFE821 led_state_2 andn outa LED 8 Value Label C MG RaRFFR22 andn outa LENAR 5C7C0017 1551630359 wait ret O 815 brt z3 or outa LEU_1 spn000004 4 BlinkCounter o s00FF 9 1 16711651 LEDS O 016 5cCFC3C18 vait sooee0001 1 LEO_ 22 sBBN1BNBR bb5ib LEU_16 cODA2AAAA 131972 LED_17 S0rc3ced DlinkCounter 1 sAPRPSAAR GAAAAAAA RlinkFreq 867C3E05 BlinkCounter 5 wz 8005701A2 1750592514 WaitCourter 5c 68000C 7 tinit s41 C3628 1105999400 S5C7CANAF jmp led_state_t 10987654321098765432109976543210 HBBL4BE 1 mov Wa tLCounter cnt L 6OBC4A24 add WaitCounter BlinkFreq FOBC4A24 waitcnt WaitCounter BlinkFreq SC7CO017 wait_ret ree VARIABLES PC 019 Z U C U Figure 3 16 PASD environment Debugging Tools Applied to a Multiprocessing Problem This section chronicles the development of an object that manages a timekeeping pro cess in a separate cog and makes use of the software packages introduced in the previ ous section to test and debug at various stages For the sake of keeping the example programs short the timekeeping object will only track minutes seconds and millisec onds An expanded version of the object that provides full calendar information can be obtained from http obex parallax com DEVELOPMENT WITH THE
191. Flash object s Start method 4 The waitcnt statement waits long enough for our LED_Flash method to be fully exercised at least one iteration of its repeat loop RUNNING THE STACK TEST Now it s time to run the test The Stack Length object outputs its result serially on the Propeller s programming port To receive the information you need a simple terminal application As it so happens the Propeller Tool installer includes one called Parallax Serial Terminal vV Start the Parallax Serial Terminal software o An icon for it may have been placed on your desktop during installation or you may find it in your computer s Start gt All Programs Parallax Inc Propeller Tool path o A window should appear similar to Fig 2 23 V Select your Propeller s programming port from the Parallax Serial Terminal s Com Port field V Select 115200 from the Baud Rate field vV Arrange the Parallax Serial Terminal and Propeller Tool windows so you can get to each one quickly with the mouse V Select the Propeller Tool software When you selected the Propeller Tool software did you notice something happened with the Parallax Serial Terminal The title bar top of window and the lower right 44 _ INTRODUCTION TO PROPELLER PROGRAMMING Transmit pane type i text here to transmit to Parallax Serial Terminal oO the Propeller Receive pane text from the Propeller appears here Control panel set port baud r
192. GING CODE FOR MULTIPLE CORES CON _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz x 16 80 MHz OBJ vp terminal ViewPort conduit object time Timestamp Object TimeStamp object VAR long vptx vprx long minutes seconds milliseconds count PUB Go Go method Configure ViewPort for Terminal communication variable display and share vptx through count vp config String start terminal terminal 1 vp config String var vptx vprx minutes seconds milliseconds count vp share vptx count waitent cnttclkfreq vp clear time Start 10 59 999 repeat if vp rxcheck lt gt 1 vp RxFlush time GetTime minutes Start timestamp cog Main loop If key in buffer Clear buffer Get a timestamp vp Dec Count Count to Terminal if count 10 Call alarm when count 10 Alarm PUB Alarm Alarm method vp Str String Alarm count Clear count variable Display alarm string in Terminal The Test Timestamp object makes it possible to effectively utilize ViewPort s debugging features including terminal stepping and variable modification shown in Fig 3 23 To debug the Test Timestamp Object with ViewPort Events spin object follow these steps V Copy Test Timestamp Object with ViewPort Events spin to C Program Files View Port mycode DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 109
193. GLE_BLOCK Mandatory CMD18 READ _MULTIPLE_BLOCK Mandatory CMD24 WRITE_BLOCK Mandatory CMD25 WRITE_MULTIPLE_BLOCK Mandatory CMD27 PROGRAM_CSD Mandatory CSD not supported by SDIO CMD28 SET_WRITE_PROT Optional CMD29 CLR_WRITE_PROT Optional CMD30 SEND_WRITE_PROT Optional CMD32 ERASE_WR_BLK_START Mandatory CMD33 ERASE_WR_BLK_END Mandatory CMD38 ERASE Mandatory CMD42 LOCK_UNLOCK Optional CMD52 IO_RW_DIRECT Mandatory CMD53 IO_RW_EXTENDED Mandatory Block mode is optional CMD55 APP_CMD Mandatory CMD56 GEN_CMD Mandatory CMD58 READ_OCR Mandatory CMD59 CRC_ON_OFF Mandatory Mandatory ACMD13 SD_STATUS Mandatory ACMD22 SEND_NUM_WR_BLOCKS Mandatory ACMD23 SET_WR_BLK_ERASE_ COUNT Mandatory ACMD41 SD_APP_OP_COND Mandatory ACMD42 SET_CLR_CARD_DETECT Mandatory ACMD51 SEND_SCR Mandatory SCR includes only SDMEM information Note The command code IDs start at 40 64 For example CMDO 40 0 40 CMD17 40 17 51 342 TABLE 9 4 SUBSET OF SD SPI COMMANDS NEEDED TO IMPLEMENT SD CARD DRIVERS COMMAND MNEMONIC ARGUMENT RESPONSE 2 DESCRIPTION 0 40 GO_IDLE_STATE None 01 Resets SD card and places in SPI mode 1 41 EXIT_IDLE_STATE None 01 Exits reset mode 17 51 EAD_SINGLE_BLOCK 3 Address 00 Reads a block at byte address 24 58 WRITE_BLOCK 4 Address 00 Writes a block at byte address 55 77 APP_CMD 1 None 00 Prefix for application command 41 69 SEND_APP_OP_COND 1 None 00
194. IED TO A MULTIPROCESSING PROBLEM 95 display The timestamp should never contain 1000 milliseconds or 60 seconds The previous keypress example program might have exposed this same bug over time but it would have taken a lot of keypresses Step 5 Fix the Bug Exposed by the Testing Locks provide an effective remedy for the memory collisions that can occur when two cogs exchange memory using a group of variables The Propeller microcontroller s main memory has eight semaphore bits called locks or lock bits and the Spin language has a set of commands for using them The locknew command checks out a lock bit from the pool Once a lock bit has been checked out lockset and lockclr can set and clear it and lockret can return it to the pool Cogs that access common memory then use code that checks a given lock bit before accessing memory If the lock bit is set the code makes the cog wait for the other cog accessing the memory to clear it first If the lock bit is not set the cog has to set it before accessing the memory and then clear the bit when it s finished accessing the memory LOOKING UP LOCKS The lock management commands are available in both Spin and Propeller Assembly The Propeller Manual discusses the use of locks in detail and has code examples for both languages in their respective reference sections The Propeller Manual is avail able in print and is included as a tagged PDF in the Propeller Tool software s Help Using
195. IN SAMPLE_TICKS adeVal the SigmaDeltaADC Spin object updates the adcVal vari able with the latest measurement every 2000 clock ticks This results in a 40 kHz sampling rate because 2000 clock ticks at 80 MHz is 1 40 000th of a second The test program only checks the adeVal variable at a rate of about 10 Hz but applications that need to check at a faster sampling rate can do so If a sampling rate needs to be faster than 40 kHz the assembly version SigmaDeltaADC ASM should be used because it can accept sample intervals less than 2000 clock ticks Gain can be applied to A D measurements by adjusting the resistor values in the Sigma Delta ADC circuit shown in Fig 4 32 By choosing a larger feedback resistor Rf and a smaller input resistor Ri it takes more cycles of low signals from the feed back pin to cause the voltage to swing down below 1 65 V if it s above and vice versa With the slower response the input pin causes the counter module to accumulate high signals for more clock cycles than when the resistors were matched The result is a larger ADC measurement for the same voltage input which is essentially the same result that could be obtained by passing the signal through an amplifier The advantage to setting gain with the resistors is it eliminates the need for an amplifier in some situations which SENSOR BASICS AND MULTICORE SENSOR EXAMPLES 3 3 V C1 Voltage apt A Input Pin Feedback Pin Rf i GND Figure 4 32
196. INTERFACE From the user s perspective the command line interface is a prompt on the serial terminal running VT100 emulation software This interface gives the user a powerful terminal edit ing and rendering capability if we wish to support the entire VT100 command list VT100 TERMINALS VT100 is a specification that was developed by Dec Equipment Corp in the 1970s as a method of how a mainframe or mini computer would interact with dumb terminals Figure 10 12 shows a vintage VT 100 terminal Back then people couldn t afford to put complete computers on everyone s desk so terminals were in wide use The VT 100 like many other specifications is a command language that allows the terminal to draw text on the screen scroll change colors make sounds and so forth These capabilities are more than enough to support user input crude editing and even games Thus most serial terminals support the VT100 standard as we use it Of course we aren t using much of the standard In fact the only VT100 commands we are using are to clear the screen and home the cursor The interesting thing about the VT100 commands is how they are sent to the terminal There are a couple ways to do it but the most commonly used method is to send the ESCape character 27 followed by and then the command string Thus most commands look like ESC xx x where xx are ASCII characters For example the clear screen com mand is
197. IRW This indicates that it is done repeat until SPIRW SPI_DONE The driver wrote the result to datain Thus that is the value that we will return ret_val datain You can see that the read method has two input parameters a0 and a1 These rep resent the address you want to read from The read method will then set these address parameters to the global variables add and add1 It will then set the SPIRW global vari able to 1 which is equal to the constant SPI_RD set in the CON section of the driver The read method then waits until the SPIRW global variable is set to 0 which is equal to the constant variable SPI_DONE set in the CON section of the driver Remember that the SPI layer will clear the SPIRW global variable to 0 when it is done with the SPI trans action Thus this method will block which means it will wait doing nothing until the SPI layer completes the transaction It then returns the value that is stored in the datain global variable which is where the SPI layer writes the result of the transaction The write method is just as simple as the read method as shown here PUB write a al dout Call this method to write a byte from the W5100 via SPI The arguments are three bytes that contains address byte 0 address byte 1 and the data we wish to write See W5100 data sheet for what registers these actually address Note that the datain global variable will be overwritten during this process
198. KB of RAM available on the Propeller and the multiple gigabytes available on most PCs Running on the host PC also allows us to tap OpenCV s various input options to process video from a variety of sources We can still process the grayscale video captured by the Propeller based PropCV frame grabber but we can also process video from USB webcams Ethernet cameras and video files Configuring OpenCV s input source and filter options can be done through ViewPort s graphical interface or programmatically in Spin code The results of OpenCV filtered video is shown inside of ViewPort and the location of found objects is continually sent to the Propeller where it can be used to steer robots Let s take a look at a Propeller program that incorporates OpenCV The following Spin code allocates four variables pos x y and sum It shares these variables with the PC running ViewPort using the vp share method from the Conduit object One line of code configures the video widget to take webcam0 as a source use face as the mode and pass the result to the variable called pos This line is powerful It s telling ViewPort to look for a human face with its webcam And most impor tantly it s configuring ViewPort to continually update Spin variable pos with the location of that human face We can use the location of the face to control our robot make our system interactive or like the Spin code shows calculate using the
199. Mesh series Series 2 uses the ZigBee communications standard on top of 802 15 4 for WSNs to provide self healing mesh networks with routing This chapter will focus exclusively on the XBee 802 15 4 and its higher power sibling the XBee Pro 802 15 4 These will be referred to as simply the XBee Key benefits of using the XBee include the ability to perform addressing of individual nodes on the network data is fully error checked and delivery acknowledged and data can be sent and received transparently simply send and receive data as if the link between devices were directly wired XBees operate in the 2 4 GHz frequency spectrum An image and a drawing of an XBee are shown in Fig 5 2 The XBee is a 20 pin module with 2 0 mm pin spacing This can cause some aggravation when working with breadboards and protoboards which have 2 54 mm 0 1 in pin spacing but solutions to this will be addressed 192 WIRELESSLY NETWORKING PROPELLER CHIPS XBee 1 oVCC DO oDOUT D1 ODIN D2 a N N Pe x FH NWEHELADMIWOOO oD08 D3 ORESET RTS AD6 OPWMO RSSI ASSOC ADS5 oPWM1 o Reserved ON SLE ODTR SLEEP_RQ DI8 CTS D OGND AD4 D Doon oanh WDM Figure 5 2 XBee module and pins Don t get scared The XBee has a large number of pins but for most of this chapter we will use only four E Vcc Pin 1 2 8 V to 3 4 V Propeller Vdd voltage E GND Pin 10 Propeller Vss E DOUT Pin 2 Data out of the XBee
200. N video to steer the robot while the remaining six cogs are used to balance the robot with its multiple sensors see Chap 6 for more details To make our pattern robust at different distances we can repeat it at various scales When we now place this pattern on our belt we can start dancing with our DanceBot Stepping closer to the robot makes the image of our pattern move up in the robot s field of vision this causes the robot to move backwards and maintain a set distance from us Stepping to one side of the robot causes the pattern to move horizontally which com mands the robot to turn and face us While dancing with my robot I discovered some interesting behavior that I hadn t planned on When I jumped up or crouched down the robot would change its set distance to me When I turned around thereby covering the pattern the robot also turned around It no longer detected the pattern and went into search mode where it turned on its axis This level of vision guided interaction is still quite novel but it s all possible with a simple camera an ADC and a couple of the Propeller s eight cogs State of the Art Computer Vision with OpenCV The PropCV objects give us a good foundation to perform computer vision with the Propeller We ve explored all the components that make up a vision sensor the frame grabber the chain of vision filters and the multiple vision buffers to store our images The Propeller is fast enough to do
201. NS D2 OFF D2 Display pressure and temperature value NOTES Readings of D2 can be done less frequently but the display will be less stable in this case For a stable display of 0 1 mbar resolution it is recommended to display the average of 8 subsequent 1 2 pressure values version consult the MEAS Web site at www meas spec com Example Word1 46940 Word2 40217 Word 25172 Word4 47212 C1 23470 C2 1324 C3 737 C4 393 C5 628 C6 25 D1 16460 D2 27856 UT1 25248 dT 2608 TEMP 391 39 1T OFF 5220 SENS 49923 xX 23093 P 9716 971 6 mbar Figure 9 8 Steps to reading the pressure sensor Courtesy of Intersema for the latest 338 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER Read in the data words for temperature and pressure d1 read_data_word 111 1010 000 00 Value for data 1 d2 read_data_word 111 1001 000 0 Value for data 2 After we have received the current data words for pressure and temperature we need to calculate the temperature at which the sensor was factory calibrated One thing you may have noticed from Fig 9 8 is that this calibration temperature value is constant and will not change so to save calculation time we have moved this outside the conversion loop The relevant Spin code is shown here calib_temp 8 c5 20224 Notice that the equation uses integer and not floating point numbers even though the calibration temperature can be
202. ONTROLLED ROBOT WITH GRAPHICAL DISPLAY 221 The difference between the XBee Object s API_str and API_txPacket is that strings cannot have byte values of 0 a string ends with a byte value of 0 Our packet has a byte value of 0 for possibly either pin or state so we needed to specify that it would be sent as a packet and then provide the number of bytes in it Here are some examples of transmitting API data to address 5 Sending a simple string XB API_str address string XB API_str 5 string Hello To send a string with a value such as Range range value in objects declare num numbers XB API_NewPacket XB API_addStr string Range XB API_addStr num ToStr range num dec XB API_str 5 XB API_Packet To send just a byte in the packet XB API_tx 5 13 Working in API mode can be intimidating but its benefits are many The XBee Object has multiple methods for interfacing with the XBee in both modes with example code It would be of benefit to read through the object documentation as well as the XBee manual TRY THESE V Modify the end device code so that it sends data only if range lt 100 mm v Adda pushbutton to the coordinator Have it control an LED on the end device it s not a good idea to have two different cogs trying to send data comment out the code to blink the LED on reception of data A Three Node Tilt Controlled Robot with Graphical Display OVERVIEW AND CONST
203. PARALLAX SERIAL TERMINAL The previous chapter and earlier examples in this chapter utilized the Parallax Serial Terminal object to make the Propeller chip communicate with the Parallax Serial Terminal software running on the PC So the Parallax Serial Terminal object s and software s usefulness for quick tests at various stages of object development has already been demonstrated This section will extend those examples and use the PST Debug LITE object which has method calls that add convenience to setting breakpoints and displaying lists of variable values DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 87 Step 1 Test in the Same Cog Let s say your Propeller application needs an object to make periodic timestamps of the minute second and millisecond when a series of events occurs and a quick scan of http obex parallax com didn t yield any candidates Why not take a stab at writing a timestamp object from scratch One way to get started would be to test and make sure the code that s counting time gets the correct sequence for minutes seconds and milliseconds Test Time Counting spin uses the PST Debug LITE object s features to verify that the code counts time increments in the correct sequence The object does not yet have millisecond pacing it s just going as fast as it can in Spin The object declares PST Debug LITE in the OBJ block and gives it the nickname debug At the beginning of the TimerMs method debug Styl
204. PLICATIONS Shane Avery Introduction In this chapter we will show how to make use of the multiple cores in a Propeller to create networked applications We will explore the reasons why having multiple cores provides the programmer with a new paradigm for creating applications The platform for this will be the HYDRA hobby video game development system with the EtherX Ethernet add in card running a simple game called Button Masher Since the focus of this chapter is networking before we get to the Button Masher example we will take a look at Ethernet and Internet protocols such as TCP IP and UDP IP Here s what we will cover in this chapter E Ethernet and Internet protocols E EtherX add in card for the Propeller powered HYDRA E Creating a simple networked game Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_08 Ethernet and Internet Protocols Before we begin talking about the EtherX card and how to use it we need a basic understanding of computer networks Computer networking is a complicated field of study in computer science which encompasses different protocols and topologies that 281 282 USING MULTICORE FOR NETWORKING APPLICATIONS take years of studying to grasp However we will narrow our focus to the Ethernet link layer and the common Internet protocols such as TCP IP ETHERNET Ethernet was developed by
205. PROM object that allows the application to make backup copies of segments from the Propeller chip s Main RAM to the external EEPROM and other methods for retrieving the stored data This article and its objects are available from http forums parallax com Be careful with how you apply the Propeller EEPROM object the Propeller Tool software overwrites the lowest 32 KB in EEPROM when the Load EEPROM feature is used for programming There are three ways to prevent overwriting your data E If data is stored in the lower 32 KB and a separate program is intended to be loaded for retrieving the data the Load RAM feature can be used to program the Propeller and the data on the EEPROM will remain intact E A feature for reporting collected data can be incorporated into the application so that a separate program does not need to be loaded into the Propeller chip E Replace the 32 KB 24L C256 EEPROM which is just enough for storing Propeller applications with a larger one such as the 64 KB Microchip 24LC512 Values stored at any address above 32 K in these larger EEPROMs will be safe from being overwritten by EEPROM programming This approach is probably the best for prototyping These techniques are discussed in greater detail in the PE Kit Tools EEPROM Datalogging article For larger volumes of data the Propeller Object Exchange has an entire section devoted to data storage One object that stands out in terms of usefulness is Tomas Rokicki
206. PROPELLER PROGRAMMING Calls to LED_Flash in previous exercise are now cognew LED_Flash 16 30 5 StackA the first parameter of cognew which starts a new cognew LED Flash 19 15 15 StackB cog to run them in parallel cognew LED Flash 23 7 26 StackC Figure 2 17 Method call with parameters Our Main method changed the way we call the LED_Flash method Now each of our calls is the first parameter of cognew commands as shown in Fig 2 17 Cogneu as the name implies starts a new cog to run the method indicated by its first parameter When the statement cognew LED Flash 16 30 5 StackA is executed a new cog starts up to run the LED_Flash method with the parameters 16 30 and 5 The second parameter of cogneu Stackf directs the new cog to its assigned workspace The operator returns the address of the variable it s attached to so the new cog locates its workspace in the memory starting at the address of StackA As Main executes it starts three other cogs each running LED_Flash with different parameters and using different workspaces then Main runs out of code causing the first cog the application cog to terminate As each of the remaining cogs finish executing their instance of LED_Flash they individually terminate leaving absolutely no cogs running and no LEDs flashing Wrapping It Up So far we ve created a nice method to perform our desired task flashing an LED It s been en
207. RISLEEP_RQIDI8 CTS DIO70 oGND AD4 DIO40 www selmaware com Figure 5 4 AppBee SIP LV carrier board and drawing with physical connections Tip Another good source of carrier boards and other XBee accessories is www sparkfun com Search their web site for XBee ESTABLISHING PC TO XBee COMMUNICATIONS The first task is to communicate with the XBee directly from the PC for configuration changes and monitoring Figure 5 5 shows two ways of establishing communications using the Propeller as a serial pass through device or communicating directly with the XBee using the Prop Plug as a serial interface Either method allows the serial connec tion between the PC and the transceiver If you are using the Propeller to pass serial communications the program Serial_ Pass_Through spin should be downloaded using F11 If the serial communications port is closed in the software the Propeller may be cycled when the DTR is toggled reloading the Propeller from EEPROM Using F11 ensures a cycling of the Propeller will reload the correct program The program itself is simple but highlights the power of Propeller Microcontrollers that provide multiserial communications are difficult to find Two instances of the 196 WIRELESSLY NETWORKING PROPELLER CHIPS s5 DA 15 P 32 b Using Propeller Plug Figure 5 5 Two methods of PC communications with XBee FullDuplexSerial object establish the transparent link Data from the PC is sent to
208. ROM and RAM memory shared by all processors Figure 1 1 Close up of multicore Propeller chip silicon MULTICORE PROPELLER MICROCONTROLLER 3 Lucky for us technique and technology have evolved to give us devices like the Propeller microcontroller It is now quite natural to create multicore applications After reading this book you may find yourself wondering how you ever got along without it Why Multicore Why is multicore so important After all thousands of applications have been built using single core devices While that s true despite the successes there have always been two obstacles imped ing progress asynchronous events and task fidelity E Asynchronous events are things that occur when you least expect them They are inherently hard to handle in a timely manner with a single core device E Task fidelity is the level of attention given to an activity The lower the fidelity the lower the precision with which the task is carried out These are two opposing entities each vying for the precious time of a single pro cessor As asynchronous events increase the fidelity of existing tasks suffers As the demand for task fidelity increases fewer asynchronous events are handled With a single core device balancing these two competing demands often means requiring processor interrupts and specialized hardware Processor interrupts allow asynchronous events to be addressed while specialized hardware remains focused on
209. RRRRRRRRRRRRRRRRRRRRRRRRR RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR That s all tolks 3 Returned from start 0 Com Port Baud Rate Gi COME v 115200 x OR a Prefs G Pau Figure 4 50 SD card test SENSOR BASICS AND MULTICORE SENSOR EXAMPLES pst Start 115200 and all term out calls were replaced with term Char The method calls that you should examine in the top level object start with sdfat sdfat mount sdfat opendir sdfat popen sdfat pputc sdfat pcclose and sdfat pgetc Although many of their functions can be guessed make sure to read the documenta tion comments in the fsrw object to find out more sdrw_test for PST spin CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object sdfat fsrw VAR byte tbuf 20 PUB go x pst Start 115200 Start Parallax Serial Terminal x start pst Str string Returned from start pst NL pst Dec x pst NewLine PUB Start r sta bytes pst Str string Mounting pst NL sdfat mount 0 pst Str string Mounted pst NL pst Str string Dir one pst NL sdfat opendir repeat while sdfat nextfile tbuf pst Str tbuf pst NewLine pst Str string That s the dir pst NL pst NewLine r sdfat popen string newfilex txt W pst Str s
210. RUCTION A three node network for controlling and monitoring a robot will be explored for the last project in this chapter The system shown in Fig 5 19 has E A Propeller Demo Board network node address 0 with an accelerometer to measure angle of inclination on two axes for the tilt controller 222 WIRELESSLY NETWORKING PROPELLER CHIPS NODE 0 Bot Tilt Controller NODE 2 Bot Graphics Propeller Demo Board Networked Bot Propeller Proto Board on Boe Bot Chassis Figure 5 19 3 Node bot network diagram E A robot on the network address 1 using a Propeller Proto Board on a Boe Bot robot chassis with HM55B compass PING range finder on a servo bracket and LEDs E A Propeller Demo Board on the network address 2 driving a TV for video display of the graphical display Figure 5 20 shows the wiring connection diagram for each of the nodes Note that in switching to the Proto Board we will change the I O pins used for the XBee Hardware construction tips for bot v Ifyou are not familiar with the Boe Bot robot you may want to look through Robotics with the Boe Bot by Andy Lindsay available for download at www parallax com education to familiarize yourself with the basic hardware and servo operation NODE 0 Bot Tilt Controller Propeller Demo Board Uv O Unladnlnlad oooogoo000 P23 NODE 1 Bot Propeller Proto Board on Boe Bot Chassis Extra Battery 4 PPA gSSWH Figure 5 20
211. S DIRAS Direction register for 32 bit port A DIRBS Direction register for 32 bit port B future use INAS Input register for 32 bit port A read only INB Input register for 32 bit port B read only future use OUTAS Output register for 32 bit port A OUTBs Output register for 32 bit port B future use CNTS 32 bit system counter register read only CTRAS Counter A control register PROPELLER LANGUAGE REFERENCE 455 CTRBS Counter B control register FRQAS Counter A frequency register FRQBS Counter B frequency register PHSAS Counter A phase locked loop PLL register PHSB Counter B phase locked loop PLL register VCFGS Video configuration register VSCLS Video scale register PAR Cog boot parameter register read only UNARY OPERATORS Note All operators shown are constant expression operators AA lt gt I Positive X unary form of Add Negate X unary form of Subtract Square root Absolute value Decode value 0 31 into single high bit long Encode long into value 0 32 as high bit priority Bitwise NOT Address of symbol BINARY OPERATORS Note All operators shown are constant expression operators xk lt gt Add Subtract Multiply and return lower 32 bits signed Multiply and return upper 32 bits signed Divide and return quotient signed Divide and return remainder signed Limit minimum signed Limit maximum signed Shift arithm
212. S RCFASTS TESTN ADD ELSEIFS IF_NZ_AND_NC MUXC RCL TJNZ ADDABS ELSEIFNOTS IF_NZ_OR_C MUXNC RCR TJzZ ADDS ENC IF_NZ_OR_NC MUXNZ RCSLOWS TOS ADDSX FALSE E A MUXZ RDBYTE TRUE ADDX FILES IF_Z_AND_C NEG RDLONG TRUNCS AND FIT IF_Z_AND_NC NEGC RDWORD UNTILS ANDN FLOATS me Z ENC NEGNC REBOOTS VARS BYTES FROMS Tipe ZaNERG NEGNZ REPEATS VCFG BYTEFILLS FRQA IF_Z_OR C NEGX RES VSCL9 BYTEMOVES FRQB IF_Z_OR_NC NEGZ RESULTS WATTCNT CALES HUBOP INAS NEXTS RETS WAITPEQ CASES ips INB NOP RETURNS WAITPNES CHIPVER IFNOTS JMP NOTS REV WATTVID CLKFREQS IF RE JMPRET NR ROL Wc CLKMODES IP GES LOCKCLR4 OBUS ROR WHILES CLKSET IF_ALWAYS LOCKNEW ONES ROUNDS WORDS CMP JF BF LOCKRET oR SAR WORDF ILLS CMPS iB LOCKSET9 ORG SHL WORDMOVES CMPSUB TESCA LONGS OTHERS SHR WR CMPSX IF_C_AND_NZ LONGFILLS ouTAS SPRE WRBYTE CMPX IF_C_AND_Z LONGMOVES OUTB STERS WRLONG 458 APPENDIX A CNT WFC E _ 7 LOOKDOWNS PARY STRCOMPS WRWORD COGID WF _C NE LOOKDOWNZS PHSAG STRINGS WZ COGINIT IF_C_OR_NZ LOOKUPS PHSB STRSIZES XINPUT COGNEWS WFC OR LOOKUPZS RIS SUB XOR COGSTOP TOES MAX PLL1XS SUBABS XTAL1 CONS MESNOG MAXS FLL SUBS XTAL2 XTAL3 a Assembly element s Spin element d dual available in both languages reserved for future use UNIT ABBREVIATIONS Computer Memory byte 8 bits word 2 bytes 16 bits long 2 words 4 bytes 32 b
213. SSING AND STORING SENSOR DATA 185 and synchronized events Likewise with sensor applications One or more cogs can be acquiring sensor data and another cog can be storing the most recent measurements and timestamps to the SD card Figure 4 50 shows a test from the fsrw and friends 1 6 package that was adapted for the Parallax Serial Terminal It was originally designed for a television display The test opens the SD card reads the root directory creates a file with some R characters and then closes the SD card The program can be modified to examine the contents of the SD card as well or you can examine it with your PC provided you have an SD card reader or SD card to USB adapter If you don t SD card to USB adapters are inexpensive and available at many office supply computer retail and electronics outlets Although sdrw_test spin was written for a TV display porting it to sdrw_test for PST spin for use with the Parallax Serial Terminal was simple because the TV Terminal and Parallax Serial Terminal objects text and number display method calls are simi lar It was mainly a matter of replacing the TV_Terminal object declaration with one for the Parallax Serial Terminal Then the term Start method was updated to Parallax Serial Terminal Disabled Click Enable button to co DEK Mounting Mounted Dir NEWFILEX TXT TESTDOC TXT That s the dir Opening returned 0 Wrote file Opening returned 0 RRRRRRRRRRRRRR
214. Sigma Delta component values in turn reduces the number of components and system complexity If the ratio of input to feedback resistors is reversed it results in attenuated A D measurements which allows the ADC to work with larger voltage input ranges if needed Test Sigma Delta AC Signal Measurements Figure 4 33 shows a Sigma Delta microphone monitoring circuit built into the Propeller Demo Board The 0 1 uF capaci tor in the figure is called a coupling capacitor and it allows the mic s AC signals to pass through stripped of any DC component Regardless of the DC offset the microphone signals were riding to the left of the coupling capacitor the voltage fluctuations AC signals transfer to the 1 65 V offset that the counter module maintains on the right side of the coupling capacitor Tip This circuit can also be built with the Propeller Education Kit and a condenser mic available at hobby electronics stores For the PE Kit make sure to use the 100 pF capacitors marked 101 that come with the kit instead of the 1 nF capacitors the Propeller Demo Board uses Electret Vdd Vdd Mic T G 10 KQ 1 nF U U P8 0 1 UF P9 100 KQ T 1 nF Vss Figure 4 33 AC Sigma Delta circuit connected to a microphone VOLTAGE OUTPUT 165 As mentioned earlier condenser microphones including the electret mic convert fluctuations in air pressure to fluctuations in voltage The Sigma Delta ADC does a great job of measuring these voltages and t
215. Since that interval was our ideal delay time it didn t account for the overhead of the rest of the instructions in the loop The real delay between any two occurrences of our looped event is the time it took to start the loop iteration plus the time to perform the event plus our idealized loop delay For our application timing accuracy isn t vital but for many applications accurate timing is a must For example code like the following causes a cumulative error in the moment the I O pin toggles compared with the ideal moment in time as seen in Fig 2 21 Note that the Count Duration and Pin symbols are long variables dira Pin Set Pin to output repeat Count 2 Loop Count 2 times outa lPin Toggle I O pin waitent Duration cnt Delay for some time Tip This source is from PCMProp Chapter_02 Source Out_Of_Synch spin In contrast with just a slight rewrite of the code it uses a single moment in time Time 0 in Fig 2 22 as an absolute reference for all future moments and perfectly synchronizes the I O pin events to those moments Note that the Count Duration Pin and Time symbols are long variables dira Pin Set Pin to output Time cnt Determine reference moment repeat Count 2 Loop Count 2 times waitcnt Time Duration Delay for some time outaLlPin Toggle I O pin Time units of Duration m f d LE LL Figure 2 21 1 O pin events out of synch with ideal duration
216. SomeMethod calls LED_Flash with parameters 2 The parameter values are copied into LED_Flash s parameter variables 3 LED_Flash references those PUB LED_Flash Pin Duration Count values via their parameter Flash led on PIN for Duration a total of Count times names Duration is in 1 100th second units Figure 2 14 Method call with parameters 30 INTRODUCTION TO PROPELLER PROGRAMMING To the method the parameters are local variables for its own use It can read them and manipulate them without affecting anything outside of itself In our new method the two lines following the declaration are a different type of comment a multiline comment Multiline comments begin with an open brace and end with a close brace and can span more than one line of code The Duration clkfreq 100 Duration statement means Make dura tion equal to clkfreq divided by 100 and multiplied by Duration s original value Remember clkfregq is like one second so dividing it by 100 is 1 100th of a second and multiplying that by Duration gives us a multiple of 100ths of a second Note the comment above the line The dira 16 23 statement is a twist on an old theme Recall that dira controls T O pin directions and the number in brackets is the bit or I O pin to affect This state ment is a clever way to affect all the bits from 16 to 23 at once So what do they get set to The trailing operator when u
217. TCP and UDP Both have port information but TCP guarantees that the data will get there whereas UDP does not That means if a packet of data is lost TCP will continue to resend until the packet reaches its destination Also TCP provides flow control meaning it will try to find the optimum speed to send the data as fast as possible without losing too much data UDP simply sends the data and hopes for the best Which should you choose Typically UDP is chosen when speed matters It takes more time to verify that packets have arrived and to resend when needed as is the case with TCP Typically in UDP data is constantly sent so if you lose a data packet it s not that big a deal because another packet will come along soon A game like Microsoft s Halo would be an example of a UDP game as the game needs to constantly update player position orientation and action If UDP packets begin to get lost there is a momentary hiccup but the game will happily continue on once it gets the next packet TCP based games are used when data loss matters more than time A networked chess game is a good TCP example because you would only send the data when a player makes a move and that data must arrive or else the opponent would never know it s his or her turn A good rule of thumb for games is that real time games use UDP and turn based games use TCP UDP AND TCP WHICH DOES THE INTERNET CHOOSE Any real time streaming data will be UDP and this incl
218. TOOLS 85 A ViewPort v4 1 64 Weke code dsu h mied video temina Timescale 10ms a5 Oscilloscope A ey a ee Overview click on name to confiqure Name Plot CditiMin Max lAwg lVal a Ou4u I2 vg 59 pm m pm pm str i Ka OIG 253k Cursors Show JA R Diff Ven taa Horz re Edit Variables gt o 200 Figure 3 15b ViewPort tools PASD WHERE TO GET IT The latest version of PASD is available as a freeware download from the PASD debugger Project page on Andy Schenk s Insonix company site www insonix ch propeller prop_pasd html This is a German language site with a link you can click for automatic Google translation to English The accolades and thank you messages on the Parallax Forum thread where Andy first unveiled this software contribution to the Propeller community are indeed well deserved http forums parallax com forums default aspx f 25 amp m 214410 86 DEBUGGING CODE FOR MULTIPLE CORES wr PASD PASD_AsmDebugDemo cOOBAOAAA dec A j L SOVBVUYYJ dec J RP Addr Code Source A SOB1EQO1F dec 1966111 LJ 00C AOBFEC20 tinit dira LEOS seepheaoe d o aan RGRFER2M outa LENS 200000000 dec A o WHE HAF CSEMM mov KlinkLounter SFFFSFFFF dec 393217 Oo 200000000 dec 0 i 804400011 dec 72089617 OOF 66BFE621 led state 1 or outa L
219. Terminal Modem Configuration Line Status Assert ene wees sme Close Assemble Clear Show esloos DTR M RTS Break Com 2 Packet E iej Remote unit Ready Ping Range mm 264 Direction 0 8192 1634 Ping Range mm 260 Direction 0 8192 1552 Ping Range mm 277 Direction 0 8192 1471 Figure 5 12 Sample output in Terminal window of range and bearing TRY IT v Try adding a simple device such as a pushbutton and reporting its state back to the PC If you are out of I O you may remove the LEDs Polling Remote Nodes In an LR PAN nodes typically come in one of three flavors E Coordinators help manage the network from controlling communications to assign ing information to devices E End devices are used to read and control devices on the network E Routers are used to pass data between nodes at distances too far to reach directly There is nothing prohibiting end devices from talking to one another and once a network is established the coordinator s job may come to an end In this chapter we will refer to the base unit the one at the PC as a coordinator because it will help con trol communications and be a common collection point Our remote nodes will be end devices that we will monitor and control Multinode communications can be tricky Aspects to be dealt with include Which node can send data when When data arrives who is it from Do nodes need permission to talk or can they do so
220. Test spin Stop flashing led lt gt Propeller Snare spin yj lt 1 1 HeadUnly Insert Lompiled Figure 2 19 Documentation view 38 _ INTRODUCTION TO PROPELLER PROGRAMMING This includes our Flash object that we saved in the previous steps and gives it the nickname LED Now we can refer to methods within the Flash object using nickname methodname syntax like this LED Start 16 30 5 Blink LED 16 five times slowly This statement calls LED s Start method That method in our Flash object launches another cog to run the private LED_F lash method using the parameters given 16 30 and 5 Remember the recent exercise where we launched our LED_Flash method on three separate LEDs at the same time Now that we ve neatly wrapped the critical code in our Flash object other objects can achieve the same glory quite easily Check out the following code v Ina new edit pane enter and save this code Store it in the same folder as Flash spin and name it LEDs spin OBJ LED 3 Flash Include Flash object PUB Main LED Start 16 30 5 Blink LED 16 five times slowly LED 1 Start 19 15 15 Blink LED 19 fifteen times faster LED 2 Start 23 7 26 Blink LED 23 twenty six times fastest Tip This source is from PCMProp Chapter_02 Source LEDs spin Z Download this application to the Propeller As this example shows since our Flash object does the major work our new applica
221. The Official Guide PROGRAMMING AND CUSTOMIZING THE MULTICORE PROPELLER aaee ae AJ NZ PA Me f Shane Avery Chip Gracey Vern Graner Martin Hebel Joshua Hintze Andr LaMothe Andy Lindsay Jeff Martin and Hanno Sander PROGRAMMING AND CUSTOMIZING THE MULTICORE PROPELLER MICROCONTROLLER This page intentionally left blank PROGRAMMING AND CUSTOMIZING THE MULTICORE PROPELLER MICROCONTROLLER THE OFFICIAL GUIDE PARALLAX INC Shane Avery Chip Gracey Vern Graner Martin Hebel Joshua Hintze Andr LaMothe Andy Lindsay Jeff Martin Hanno Sander oo New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto The McGraw Hill Companies Copyright 2010 by The McGraw Hill Companies Inc All rights reserved Except as permitted under the United States Copyright Act of 1976 no part of this publication may be reproduced or distributed in any form or by any means or stored in a database or retrieval system without the prior written permission of the publisher ISBN 978 0 07 16645 1 6 MHID 0 07 16645 1 3 The material in this eBook also appears in the print version of this title ISBN 978 0 07 166450 9 MHID 0 07 166450 5 All trademarks are trademarks of their respective owners Rather than put a trademark symbol after every occurrence of a trademarked name we use names in an editorial fashion only and to the benefit of the
222. The first dataptr is the memory address of the byte array that the EtherX driver will write the data to that it reads from the W5100 The next argument size stipulates the maximum number of bytes that the RX method should write to the memory pointed to by dataptr For example the receive buffer that you have allocated in the HYDRA may only be 32 bytes in size and the W5100 may have received 40 bytes from the Internet In this case you want to be sure that the EtherX driver doesn t write 40 bytes worth of data into a buffer that you have only allocated 32 bytes for The next argument block we will skip for a second The method will return the actual number of bytes written to the buffer pointed to by the dataptr argument As an example let s again say you had a 32 byte receive buffer set up in the HYDRA that was pointed to by the dataptr argument and the W5100 had only 16 bytes worth of data that it had received The EtherX driver will write 16 bytes to the buffer pointed to by the dataptr argument and return a value of 16 In our first example where the W5100 contained 40 bytes but only wrote 32 bytes to the buffer the return value would be 32 The third argument in the method block is a Boolean variable that will instruct the RX method what to do if there is currently no data waiting for us in the W5100 If there is no data we can do one of two things The first is to wait until data is available this is called blocking The pro
223. The processing and tokenization phase results in an array of token strings these might be text numbers or symbols that are ready to be passed to the command processor for inspection Command processing and execution The command processor is a handler that inter rogates the previously tokenized input data and looks for commands in the stream If a command is found it continues to process the command pattern and looks for the parameters that should follow it The parameters if any are extracted and then the proper handler is entered The handler is where the action happens Each handler is connected to its respective driver and can send and receive messages from it So when an NTSC command is parsed for example the handler simply calls the NTSC driver and passes the request for execution Remote Procedure Call Primer Even if you don t have a degree in computer science you have probably used remote procedure calls or RPCs in one form or another or even invented them unknowingly REMOTE PROCEDURE CALL PRIMER 367 The idea of a remote procedure call came about in the 1970s actually so it s a rather old concept The basic idea is simple for one process program to be able to call use a subroutine or function in another process program It s more or less a form of inter process communication RPCs are a little different from DLLs or libraries since they are passive entities that are loaded on demand RPCs are more l
224. This is the only mode that the W5100 operates in The HYDRA has no built in support for SPI so we must bit bang the protocol ourselves The bit banging of the SPI protocol lives as assembly code that fits completely in a cog Communication with the W5100 is exclusively on a register addressed basis This means that any read or write to the W5100 will be to a register that has an address All registers will have a 16 bit address and 8 bit data Every read or write to the W5100 will be four bytes long The first byte is the command read or write the next two bytes are the address and the last byte is the data Writing a byte from the HYDRA to the W5100 on the MOSI line will only be valid for a write During a read the final byte that you need to read will be on the MISO line The SPI format is shown in Fig 8 16 W5100 BUS INTERFACE The W5100 actually has two interfaces an SPI and a bus interface The bus inter face is actually far more efficient in transferring data to or from the W5100 This bus interface requires 15 address pins 8 data pins and 4 control pins The HYDRA was unable to accommodate this because there weren t enough I O pins mapped to the expansion connector Keep this in mind if you are designing the W5100 into a new project Also the next generation chip called the W5300 which promises data rates of more than 70 Mbps contains only a bus interface no SPI a
225. This means that controlling the ga parameter differently will be the key to making one sound versus the other Let s do girl and curl To make these g c sounds you can initially set f1 to zero and set f2 and f3 to the average of the following vowels f2 and f3 In other words F1 will sweep upwards rapidly and F2 and F3 will begin in the center and then head down 6699 and up respectively to their final vowel positions This is the base recipe for g and c sounds The difference between g and c is when the glottal pulses start early for g and late for c Substitute the following method for PRI talk in our program see Example3 spin PRI talk setformants 1350 1350 4700 Set formants for G C before R v go 1 aa 20 Set breathiness v go 25 make brief G C turbulence setformants 580 1200 1500 4700 Set formants for R ga 30 Voice up for G skip for C v go 150 Transition to R ga 30 Sustain voice up for C v go 100 Sustain voice up for C v go 200 Sustain EXPLORING THE VOCALTRACT OBJECT 437 setformants 560 850 2600 3600 Set formants for L v go 250 Transition v go 100 Sustain aa 0 Taper down to silence ga 0 v go 100 v go 500 Pause You should hear girl If you comment out the first ga 30 you will hear curl as the glottal pulses will start later Commenting out both ga 30 l
226. Trail com Now that you have the basics of plotting a GPS track you can play around with some of the advanced options on the GPS Visualizer Web site For example we can add another field to the CSV file that contains the GPS speed In this case we would add another header called speed then when we go to plot the data the GPS track will be color coded as shown in Fig 9 14 We have created a couple different CSV files with 100 JG hybrid SUMMARY 351 speed and altitude so that you can try out the advanced options on the GPS Visualizer Web site The extra CSV files are located here Chapter_09 Source Logs GPS Visualizer_Lat_Long_Alt csv Chapter_09 Source Logs GPS Visualizer_Lat_Long_Speed csv One more feature of the GPS Visualizer Web site that I would like to point out is that they allow you to export your data as a KMZ or a KML file KML stands for Keyhole Markup Language and it is essentially an XML file with tags recognized by their program Keyhole Software created a mapping program called Earth Viewer that they sold mostly to the government until they were acquired by Google in 2004 After Google purchased the company they renamed the software Google Earth and released a free version in 2005 The KML file allows users to input map markers tracks pictures and even moving objects into Google Earth A KMZ file is Zip compressed container around the KML file This means that we can upload our simple ASCII CSV files to the GSP
227. University of Florida and funding through a USDA grant He has also collaborated with researchers at the University of Sassari Italy in biological wireless monitoring using parallel processing which was presented at a NATO conference in Vichy France Joshua Hintze graduated from Brigham Young University with bachelor s and master s degrees in electrical engineer ing His main research focus was unmanned aerial vehicles where he helped create the world s smallest fully func tional autopilot patent received Before graduating Josh took a research position at NASA Ames Research Center in Moffett Field California At NASA Josh designed algorithms for landing autonomous helicopters by scan ning potential landing locations with stereo cameras and machine vision algorithms Josh is cofounder of Procerus Technologies that builds and ships autopilots all over the world many of which end up in military applications He has written numerous published articles and was the author of Inside The XGS PIC 16 Bit published by Nurve Networks Andr LaMothe holds degrees in mathematics computer science and electrical engineering He is a computer scientist 3D game developer and international best selling author He is the creator of Waite Group s Black Art Series as well as the series editor of Course PTR s Game Development Series Best known for his works in computer graphics and game development he is currently th
228. Using the term most significant bit here is a bit of a misnomer Technically the global variables are 32 bits This means that the most significant bit is the 32nd bit of the variable When we say most significant bit here we mean the most significant bit that we care about which is the eighth bit because we send data to the W5100 one byte at a time After the address is sent to the W5100 the SPI layer will shift out just like the address variables the value in the next global variable called dataout at the same time it shifts in the data from the MISO line to the global variable called datain It does this whether the operation is a read or a write In the case of a write datain will contain 0x03 as per the W5100 documentation In the case of a read the MOSI line will output whatever data is located in the dataout which is fine since the W5100 will ignore whatever this value is during a read operation In other words even when we want to read data from the W5100 we will output a byte on the MOSI line as though we are writing The W5100 knows that we are performing a read operation so it will ignore it Keep in mind that whenever you perform a write operation to the W5100 the previous value of the global variable datain will be wiped out and now contains 0x03 The last thing the SPI layer will do is set the SPIRW variable back to zero The SPI layer was never intended to be directly accessible to the application layer To change
229. V Battery Rechargeable battery to power motors and circuit ViewPort Debugging environment BUILDING THE DANCEBOT 239 Propeller e Motors Figure 6 3 DanceBot mechanics show ing frame motors and circuit board TABLE 6 2 PROPELLER PINOUTS PROPELLER I O PIN PURPOSE 3 4 26 27 12 13 6 7 5 8 30 31 28 29 19 23 24 Motor control Drive 2 H bridge chips with two pins to control the motor s direction and speed Position Read pulses from quadrature encoder to calculate position and speed of one motor Accelerometer Communicate with Accelerometer chip using 12C to measure acceleration Gyroscope Send and receive timed pulses to the gyroscope to measure the robot s change in tilt Serial communication Allow ViewPort running on the PC to monitor and configure the robot EEPROM Read the robot s program from the EEPROM Vision see next chapter Clock the ADC with a 10 MHz signal and read the digital representation of the camera s signal 240 DANCEBOT A BALANCING ROBOT Figure 6 4 H bridge schematic showing four switches controlling motor s direction To control the direction of each motor we ll use an electronic circuit called an H bridge The H bridge applies voltage across the motor in either direction to drive forwards backwards and even turn Looking at Fig 6 4 you ll see why the circuit is called an H bridge The four switches surrounding t
230. Xerox PARC in the 1970s as an implementation for a local area network LAN and was standardized by the Institute of Electrical and Electronics Engineers IEEE In theory Ethernet can pass any kind of data the user would want The Ethernet standard not only defines what needs to be passed from device to device to be valid data but also defines the wiring and physical standards It has become the de facto standard for local area networks replacing older standards like Token Ring and fiber distributed data interface FDDI A valid Ethernet frame contains between 64 and 1518 bytes The first 14 bytes of the frame comprise the header which contains a destination MAC source MAC and Ethertype Then there is the payload data followed by a 4 byte checksum A MAC address is a 6 byte unique address for every Ethernet device made You may also hear this referred to as the physical address The Ethertype indicates to the Ethernet device a little about what kind of data the payload is because in theory the payload could be anything Internet protocols such as TCP IP will have an Ethertype of 0 x 800 The last four bytes are used to compute the CRC32 checksum This is just fancy talk for an algorithm that verifies that the data that was sent was sent correctly Figure 8 1 shows an Ethernet frame INTERNET PROTOCOLS For Internet protocols the first piece of data in the payload is the Internet Protocol IP header This IP header contains a lot of informati
231. YNCHRONOUS SERIAL 169 DS1620 981501 O23AA Figure 4 37 Sensors with synchronous serial communication has to use to communicate with the IC Since sensors with synchronous serial interfaces tend to be popular objects that support them also tend to be published on the Parallax Object Exchange PARALLAX 1 AXIS GYRO MODULE A gyro sensor is a useful ingredient for self balancing robots as well as inertial guid ance and autopilot systems The Parallax Gyro Module measures the rate of angular rotation velocity about the axis perpendicular to the module s PCB shown in Fig 4 38 In other words you can think about the axis sticking up from the top of the module as the handle of a top that you can twist to spin and the gyro provides information about how fast and in which direction it s spinning clockwise or counterclockwise This angular velocity is called the yaw rate 170 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES poration Figure 4 38 Rotational velocity Gyroscope Demo spin is demonstration code for this gyro that integrates rotational velocity measurements over time to calculate rotational position It displays the rota tional position with the Parallax Serial Terminal as you rotate the board as shown in Fig 4 39 The first time you run the code the angle will probably drift Adjust the TRIM constant at the beginning of the program until the angle stays still when the board is not rotating Then rotate the board
232. ZING SPEECH WITH THE PROPELLER TABLE 12 1 FORMANT FREQUENCIES OF SOME SPOKEN VOWELS BEET HAT HOT SOAP BORROW BALL F4 3700 3400 3200 3200 4700 3600 F3 3100 2500 2400 2400 1500 2600 F2 2000 1700 1050 950 1200 850 F1 310 730 750 530 580 560 99 66 the formants In sequence I will pronounce the vowels beet hat hot soap borrow ball Yep r and 1 are vowels in synthesis Looking at the spectrograph we can glean the formant frequencies for each vowel Table 12 1 lists the first four formant frequencies F1 F4 observed for each vowel If we can synthesize these formants we can re create those vowel sounds Now Pll introduce the VocalTract object This is the neatest piece of software P ve ever written and it s the kind of program that the Propeller chip was designed for All the demos for this chapter were developed on the Propeller Demo Board but they will work with a minimal Propeller chip setup as long as you have audio output connec tions to pins 10 and a simple R C filter The featured spectrograph program and all code examples can be downloaded from this FTP address ftp ftp propeller chip com PCMProp Chapter_12 The VocalTract object synthesizes a human vocal tract in real time using a simple frame of 13 byte size parameters All you have to do is change any parameters of interest within the frame then tell it how fast to transition to the new frame It will in
233. _COOL_INSIDE LONG AirSupply FRESH_AIR if OverallAverageDesiredlemp10X lt outsideTemp Recirc LONG BlowerFanPower POWER_ON LONG PeltierPower POWER ON LONG PeltierDirection PELTIER_COOL_INSIDE LONG AirSupply RECIRCULATE Once the mode of operation is determined a comparison between the average desired temperature and the current outdoor temperature could be made If bringing the outside air into the rooms would allow them to reach their target temperature without activating 422 THE HVAC GREEN HOUSE MODEL the heat pump the control board may be instructed to open the cooling tower bypass doors allowing outside air to be sent into the rooms This fresh air mode of operation could also be used in conjunction with various gas sensors to react to an unhealthy air situation For example a buildup of carbon monoxide due to leaving a fire burning a propane leak from a stove heater or even a broken sewer line allowing methane into the building all could be dangerous even life threatening situations It would be possible using sensors currently available from Parallax to detect these situations and not only alert the building occupants by sounding an alarm but also activate the fresh air mode This would bring fresh air indoors and vent the dangerous gases out of the building In the event that a fire is detected every room vent could be instructed to close in order to reduce the spread of smoke through
234. _LF serial txstring system_start_string serial tx ASCII_CR serial tx ASCII_LF serial txstring prompt If you want to change where signals are on your particular development board the initialization section is the place to start For example the serial driver is started on pins 31 30 which are the standard TX RX pins for the programming of the Propeller chip However you might want to add another serial port and connect it to pins 1 2 thus you would simply change the 31 30 to 1 2 and you re in business CLIENT HOST CONSOLE DEVELOPMENT 377 SERIAL COMMUNICATIONS PARSING AND TOKENIZATION After initialization the code immediately falls into the main repeat loop which begins with the following code repeat Attempt to retrieve character from serial terminal ch serial rxcheck Character ready in receive buffer if ch lt gt 1 Process character test for carriage return or basic EDITing characters like back space case ch This code is more or less the input port to the program The call to serial rxcheck checks if a character is ready in the receive buffer if so returns it oth erwise it returns 1 If a character is received the case ch statement is entered which has three primary cases Case 1 Is the character a non edit character and non return If so simply insert it into the edit buffer and echo it out on the serial terminal This is actually the last case in the
235. a Integrated Debugger Not used Motors Not used Figure 6 11 System diagram with ViewPort DanceBot and six active cogs ViewPort to make sure all parts of our robot are working correctly before we put it all together to start balancing First refer to Fig 6 11 to see how all the pieces fit together The diagram shows ViewPort graphically showing the state of the system on a PC It s connected to the Propeller with a serial connection where data can be sent to or from the bot The Propeller is running code that we ve discussed in this chapter on six of the eight available cogs The Motor cog continually outputs direction and pulse width modulation data to the H bridges to drive the motor while the Position cog continu ally runs code from the motor spin object to track where the robot is by monitoring the quadrature encoder The Kalman cog continually reads the accelerometer and fuses this measurement with the gyroscope reading with a Kalman filter to produce a clean and steady tilt measurement Finally the Conduit cog sends data to and from ViewPort while the Spin cog executes the main fuzzy logic code to keep the robot balanced Now that we understand the system let s take some measurements Let s start by looking at the states of the Propeller s I O pins using ViewPort s LSA view Since the Propeller s I O pins are connected to sensors and actuators looking at their state will tel
236. a fraction of a degree Celsius At first it may not be apparent but the microcontroller multiplies any fractional number by 10 This means we can use integer math for all of our calculations which is handy since the Propeller does not have dedicated hardware for floating point processing Now it is time to calculate the actual temperature that the barometer is currently at while also determining the difference between the calibration temperature and current temperature and storing it as the variable dt The code for this step is as follows remember that the output variable temperature is 10 times degrees Celsius Compute temperature difference from calibration dt d2 calib temp Actual temperature in 1 degrees C temperature 200 dt c6 5 gt gt 10 Finally we can calculate the temperature compensated pressure by first calculating some intermediate variables offset sensitivity and x Then we use the intermedi ate values to compute the final temperature compensated pressure in units of 10 times millibars The code is shown here Calculate temperature compensated pressure in 1 mbars offset c2 lt lt 2 c4 512 dt gt gt 12 sensitivity cl c3 dt gt gt 1 24576 x t sensitivity d1 7168 gt gt 14 offset pressure x 10 gt gt 5 2500 The abs_pressure_01 spin object requires one new cog for its operation and provides public methods for accessing the last read pressure and te
237. a resolution of 1280x1024 or higher and a fast Internet Store Search Results connection or each should be downloaded in its entirety before viewing Subtotal 0 Cart Content wv w gt WHV Files Yz resolution video MP4 tull resolution video View at double size 200 press alt 3 in Windows Media View at normal size 100 press Ctri 3 in VLC Media layer or Player or Ctrit4 in VLC Media Player We recommend viewing Alt 2 in Winduve Media Player We recommend using VLC Media wth Windows Media Player or VLC Media Player Player or Quicktime although Windows Media Player can be made to play MP4 flee az wall Clock Speed Timing Question or Topic Details wav Configuring typical clock settings Answered by Jeff Martin 03 13 09 Nie Duration 0 44 Ilow do you pause a cog Answered hy Jeff Martin 03 13 09 i Duration 0 42 Multiple Propeller chips driven by the came clock Answered by Chip Gracey 05 17 09 damn Nie What is the projected speed of the Propeller 2 sens Answered hy Chip Grarey oat 3 ed Ne uration 0 22 Poi Propeller One instruction per clock cycle Answered by Chip Gracey dad te revel F uration 1 27MB What is the average speed of the Propeller 2 s hardware multiply B Ve Answered by Chip Gracey OARS bom Propeller PiL stability clack switching and granularity Answered by Chip Gracey 03 17 09 Jam S Nuration 1 70 JAMR Cg irer Figure 2 28 Propeller Webinars www parallax com
238. about an axis By monitoring the position of the disk the sensor can determine changes in orientation This technique is accurate but the implementation is typically large and complex Recently piezoelectric technology has dramatically simplified these sensors Modern devices rely on the same gyroscopic physics but instead of depending on a spinning disk they vibrate a piezoelectric material Similarly to rotating gyroscopes the vibrating object tends to keep vibrating in the same plane as it is rotated This is measured electronically and yields an inexpensive but accurate sensor for measuring change in tilt We can try to calculate tilt by integrating the change in tilt measured by the gyroscope sensor This will work for a while but our calculation will drift as the sensor s value isn t perfect When we integrate the sensor s value we also integrate any error and this will add up quickly and make our result meaningless So at this point we have two sensors that are great for measuring tilt and change in tilt under special conditions The MEMS accelerometer is great for measuring tilt over long periods and the piezoelectric gyroscope is great for measuring rate of tilt over short periods What to do Luckily a mathematical function exists that s appropriate especially for this case The Kalman filter can be used to fuse the raw sensor readings from the gyroscope and the accelerometer to produce clean tilt measurements The compl
239. ace to exit To deal with this Circulation fan Cooling device Return air Fresh air door closed Exhaust vent closed Figure 11 6 CAD cutaway drawing of cooling tower bypass doors in recirculate mode THE HVAC GREEN HOUSE MODEL 407 Circulation fan Cooling device Exhaust vent open Send air Fresh air Return air Figure 11 7 CAD cutaway drawing of cooling tower bypass doors in fresh air mode a servo controlled exhaust vent flap Fig 11 8 was added to the end of the return air duct When this flap is opened the air exiting each room is vented out the opposite side of the house from the fresh air intakes on the cooling tower Besides being used for emergency house ventilation or for cooling heating the house with external air the cooling tower bypass could also be activated manually creating a healthier atmosphere by bringing more fresh air into the house or even as a way to reduce odors from cooking or smoking Figure 11 8 Servo controlled exhaust vent flap at the end of the return air duct in closed position 408 THE HVAC GREEN HOUSE MODEL Circulation fan Air return Cooling device Heat load simulator Servo controlled vent Figure 11 9 CAD drawing of final design configuration The Final Layout In the final design we settled on five rooms each one a different size to simulate different sized rooms in a typical house as shown in Fig
240. ad it out Try increasing the serial baud rate and see how fast you can get and maintain reliable communications Add another USB2SER port to the project and run the serial terminal through this serial port while using the built in serial port on the Propeller Demo Board only for programming and downloading code Add error handling to all the commands in the CCP so the correct number of param eters types and values are checked Using the NTSC commands see if you can write a Pong style game by drawing and removing characters from the screen Control it from Visual BASIC C C Perl PHP or some other language running on the PC with an open serial port to the CPP This page intentionally left blank i THE HVAC GREEN HOUSE MODEL Vern Graner Introduction In this chapter we will explore a Propeller powered HVAC heating ventilation air conditioning energy saving green house model This experimental platform takes advantage of the Propeller chip s low cost and high versatility allowing us to experi ment with intelligently managing a scale model of a typical residential central heating and cooling system Through a combination of low cost components and some powerful software objects we can easily explore different methods to boost HVAC system efficiency reduce oper ating costs and ultimately make the environment more comfortable for the building s inhabitants During our exploration we will be covering t
241. adsheet contains a column for the converted pressure sensor from kilo pascals to altitude in meters above sea level Now that we have this pressure converted we can compare it to the GPS reported altitude Figure 9 12 shows an overlaid plot of the GPS altitude and the pressure sensor altitude Notice in Fig 9 12 how the GPS reported altitude and the pressure sensor s measured altitude are closely matched especially near the end of the dataset A possible explana tion for the beginning of the dataset being mismatched is that when data collection had begun the GPS was still acquiring and locking onto more satellites As the receiver found these other satellites its positional accuracy increased One interesting experi ment you might try is to adjust the spreadsheet cell containing the local region s air pressure Notice how the overall altitude drops or rises when modifying this cell this shows how important it is that airplanes receive the correct pressure information from the airport Plotting GPS Tracks In addition to altitude we have a number of other fields we can plot We could plot the temperature reported from the pressure sensor over time or the number of satellites the GPS was locked onto Probably the most interesting plot comes from plotting the GPS location tracks A great Web site that assists with plotting GPS tracks is located at www gpsvisualizer com The GPS Visualizer Web site is a free do it yourself mapping Web site tha
242. al pixels in a frame we need a faster solution The ADC08100 is a 20 100 Msps eight bit analog to digital converter Given the correct clock signal it will output the digital equivalent of the input analog voltage on its eight digital data outputs We ll use one of the Propeller s 16 hardware counters to clock the ADC at 10 MHz and read the result on pins 0 7 see Fig 7 3 for the schematic ADC08100 28 VOD f GND VOD CCAM3 A VOD as GND Sa vse V5 Video La GND H gt cro CND A cno lt GND Gamma CNO GND F 3 CND 6 a GND GNO Figure 7 3 PropCV schematic showing camera ADC and Propeller interface PROPCV A COMPUTER VISION SYSTEM FOR THE PROPELLER 261 Now that we ve finished our vision hardware we can use ViewPort to verify that the camera and ADC are working We ll use a short Spin program to generate a 10 MHz clock signal for the ADC and use the QuickSample object to quickly sample the INA register Our ViewPort configuration tells ViewPort to decode the ADC s digital data stream and show an analog presentation within ViewPort on a 50 us timescale CON _clkmode xtall pll16x _xinfreq 5 000 000 OBJ vp Conduit Transfers data to from PC qs QuickSample Samples INA up to 8QMHz Freq Synth pub demoADC a frame 1600 Frame stores 1600 samplest configuration vp register qs sampleINA frame 1 vp config string var io adc decode io 7 vp con
243. all amount of technology could make a large difference in energy efficiency as well as the comfort level of the building inhabitants CHOOSING THE STRUCTURAL MECHANICAL ELEMENTS A number of smaller decisions needed to be made before the construction of the model house began For example we wanted all the electronic and mechanical devices to be vis ible so using quarter inch thick clear plastic panels for the walls ducts and structural com ponents was a must In Fig 11 1 you can see the preliminary sketch with clear panels The trade off was that this type of material doesn t do a very good job of insulating the rooms from ambient temperatures external to the model or from adjacent rooms To compensate for this we did away with windows and doors in the rooms to make each one a sealed environment Each room would only receive air from a single air register and would exhaust air through a single return air vent We also oversized some components in effect using brute force to overcome heat loss gain from the construction materials For example at our scale size of approximately 1 in 1 ft the air registers in each room are nearly 1 1 2 ft wide by 1 ft tall and the air circulation fan would be a whopping 5 ft tall The HVAC Itself The next consideration for this test system was exactly how we were going to cool or heat the air We searched in vain for an actual Freon based HVAC system with an associated external
244. ally easier than debugging equivalent single core time sliced implementations The Propeller microcontroller s architecture programming language and object design conventions all work together to minimize the likelihood of coding errors aka bugs They also help keep any coding errors that do sneak in on the surface where they are easier to spot In addition there are a number of healthy coding habits that help prevent multiprocessor coding mistakes as well as software packages useful objects and techniques you can use to reduce the time it takes to find and correct coding errors These preventative measures software packages and bug finding and correcting techniques are the focus of this chapter as it introduces the following E Propeller features that simplify debugging E Object design guidelines for preventing multiprocessing bugs E Common multiprocessor coding mistakes E Survey of Propeller debugging tools E Debugging tools applied to a multiprocessing problem The most common root cause of coding errors that do make their way into Propeller multicore applications is our natural tendency to forget that segments of the application code get executed in parallel Thinking in multiprocessing terms seems like it should 51 DEBUGGING CODE FOR MULTIPLE CORES be a simple thing to remember but especially at first it s all too easy to forget Once forgotten obvious bugs can start to seem subtle and difficult to find at least u
245. alue Wait for pin s to be not equal to value Wait for video sync and deliver next color pixel group PROPELLER LANGUAGE REFERENCE 445 FLOW CONTROL IF Conditionally execute one or more blocks of code ELSEIF ELSEIFNOT ELSE IFNOT Conditionally execute one or more blocks of code se ELSEIF ELSEIFNOT ces ELSE CASE Evaluate expression and execute block of code that satisfies a condition OTHER REPEAT Execute block of code repetitively an infinite or finite number of times with optional loop counter intervals exit and continue conditions FROM 10 one STEP UNTIL WHILE NEXT Skip rest of REPEAT block and jump to next loop iteration QUIT Exit from REPEAT loop RETURN Exit PUB PRI with normal status and optional return value ABORT Exit PUB PRI with abort status and optional return value MEMORY BYTE Declare byte sized symbol or access byte of main memory WORD Declare word sized symbol or access word of main memory LONG Declare long sized symbol or access long of main memory BYTEFILL Fill bytes of main memory with a value WORDF ILL Fill words of main memory with a value LONGF ILL Fill longs of main memory with a value BYTEMOVE Copy bytes from one region to another in main memory WORDMOVE Copy words from one region to another in main memory LONGMOVE Copy longs from one region to another in main memory 446 APPENDIX A LOOKUP LOOKUPZ LOOKDOWN Get value at index 1 N from a list Get value at zero
246. alue 12 cae Connection Disconnected Memory 00 00 47 Figure 7 12 Author s head detected by OpenCV s face detector Summary I ve had a lot of fun building the vision guided DanceBot with the Parallax Propeller and ViewPort The Propeller s unique architecture of eight identical cogs made it easy to split the problem of guiding a balancing robot with vision into manageable pieces Depending on the performance required I could either write the code in the high level object based Spin language or dive down to assembly to write completely determin istic code The PropCV objects introduced in this chapter are a great start for adding simple computer vision capabilities to any Propeller robot The OpenCV plug in for ViewPort allows state of the art computer vision applications to be developed with the Propeller 280 CONTROLLING A ROBOT WITH COMPUTER VISION Exercises 1 Build another filter for the PropCV engine and verify that it does what you intended 2 Build a robot that others can program by sketching the intended path with a laser While it s being programmed your robot should track the location of the bright est spot Your robot should then drive a path that resembles the one taken by the laser light 3 Experiment with the OpenCV filters Mount the webcam on a servo controlled by the Propeller Have the camera follow your face a red ball or even a circle USING MULTICORE FOR NETWORKING AP
247. am excerpt shared I O pin access PEPENE Ey Wet yey er a Wat nt Vs Wel Cy ener en We PARE Haar Wt se E Hn Wee er OY Trigger Cursors Vertical r Horizontal CH1 2Vv DI 1ms DIV m VOLTS CH2 2V DIV_ _50KS7s E 1S56V ea E gt BMP Z 833Hz Figure 3 2 Signal modulation with two cogs sharing I O pin access 53 54 DEBUGGING CODE FOR MULTIPLE CORES sharing an I O pin and the lower trace is a copy of the modulator cog s signal which stops the upper trace s carrier signal whenever it s high Low level main memory access collisions are another example of a potential debugging problem that could have been left to the programmer to prevent Memory access collisions can occur if two processors attempt to access the same 32 bit long in memory at the same instant Low level memory access collisions are prevented in the Propeller microcontroller by giving each cog Main RAM access in the round robin fashion shown in Fig 3 3 This completely eliminates the possibility of low level memory collisions because each cog takes its turn accessing memory elements This also frees the application from any concerns about taking turns at accessing individual memory elements and immensely simplifies the code In addition to 32 K bytes 8 K longs of Main RAM each cog has its own 2 K bytes 512 longs of Cog RAM Each cog has exclusive access to its own Cog RAM without taking turns which can be usef
248. and the angle and needle gauge in the display will faithfully follow the board s rotational position Information At the time of this writing the Parallax Gyro has not yet been released and the photo and example code here are all in the prototype phase For the latest test demonstration and object code check the LISY300 Gyroscope Module product page at www parallax com The LISY300AL yaw rate sensor on the Gyro Module transmits the module s rate of rotation as an analog voltage which gets measured by an ADC101 10 bit ADC Parallax Serial Terminal Disabled Click nable button to continue Ces 3 3 V Com Pot tether o r Compot athe o a Figure 4 39 Rotational position display SYNCHRONOUS SERIAL 171 that s also on the module This ADC digitizes the voltage value for the microcontroller Remember from the Peripheral ADCs section that the digitized voltage value from an ADC is digitized voltage 2 input voltage input voltage range The analog voltage indicating no rotation should be 1 65 V With a 3 3 V supply and reference voltage the 10 bit ADC measurement should be digitized voltage 1024 1 65 3 3 512 4 3 The output range of 1 65 V 1 65 V corresponds to 300 degrees per second rotational velocity Another way to look at it is that ADC measurements of 512 512 correspond to 300 degrees per second So the microcontroller can calculate the yaw rate with thi
249. ant to interface with Integration is typically as simple as downloading an object and running the code in one of the Propeller s eight cogs Once you ve configured your robot adding vision capabilities is a matter of choosing how much sophistication you require ViewPort s PropCV vision engine provides simple vision capabilities and runs on as little as one of the Propeller s cogs Yet the OpenCV vision engine integrated into ViewPort gives you access to state of the art computer vision recently used to win the Defense Advanced Research Projects Agency DARPA competition by guiding a car autonomously through an urban setting Understanding Computer Vision A touch sensor is easy to understand When something touches the sensor the switch closes and the robot can react to that event A vision sensor is a bit more complex First the robot s camera or set of cameras needs to image the environment by focusing and registering the incoming light and turning it into a video signal The video signal is digitized and stored in the processor s memory Vision filters are applied in a vision chain to analyze the scene At the end of the vision chain the large amount of incom ing video data has been processed into the nugget that tells the robot what it needs to know See Fig 7 1 for a diagram For example the robot can sense the location of a guide pattern the presence of an obstacle or even the location of a beer bottle Once the location
250. apability so that it may directly transfer received data into the larger main memory without any CPU intervention Regardless of the process a single CPU micro controller almost always becomes interrupted when new sensor data is required to be CPU Interrupt Flags Peripheral Hardware Serial Data Register a NE Rx d EER A O E a C F a __ShiftRegister Po Figure 9 2 Serial UART hardware peripheral 322 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER read and saved This can become a time consuming operation as any CPU registers that are currently being operated on including any status registers must be stored this is called a context switch If a processor is continuously being interrupted to service sensor data requests a large amount of time is spent switching between processes in the extreme condition where a CPU may spend all of its time jumping back and forth between interrupts that it can become deadlocked and no real work is performed Putting aside CPU time wasted from context switching debugging software pro grams that have multiple processes and threads of execution to capture data using a single CPU resource can become a logistical nightmare Trying to trace execution paths with debugging equipment while the CPU is being interrupted can become problematic However difficult as these challenges sound this has been the method of operation for decade
251. ar Sensor 7 Distance Contra Figure 4 27 Frequency output sensor examples 154 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES An example object that is prewritten for the TSL230 Light to Frequency Converter is the ts1230 spin object in the Propeller Library Following is an excerpt from the ts1230 object in documentation view including a connection diagram for the TSL230 chip This object assumes that the user has studied the other documents on the TSL230 product page at www parallax com that explain how it works The short version of these documents is as fol lows The TSL230 transmits frequency signals that indicate light levels When the TSL230 transmits higher frequencies it indicates brighter light levels and lower frequencies indi cate dimmer light levels The TSL230 has two different types of scaling input sensitivity and output frequency Input sensitivity can be scaled for different lighting conditions and output frequency can be scaled for the microcontroller application Referencing the sche matic with pin map in the ts1230 object documentation excerpt Pins 1 and 2 are named SO and S1 and signals applied to those pins scale the device s input sensitivity for a variety of lighting conditions For example if S1 S0 01 meaning 0 V is applied to S1 and 3 3 V is applied to SO the scaling is 1x suitable for bright lighting conditions including full sun S1 SO 10 is 10x sensitivity which is useful for in
252. ard chip select low asserted P3 SD DI SD card data in P4 SD SCK SD card clock in P5 SD DO SD card data out P6 Barometer SCK Barometer serial clock in P7 Barometer DO Barometer data out P8 Barometer DI Barometer data in P9 Barometer Master Clock Barometer master clock input 32 768 kHz P12 NTSC Out 0 NTSC Output 0 P13 NTSC Out 1 NTSC Output 1 P14 NTSC Out 2 NTSC Output 2 P15 NTSC Out 3 NTSC Output 3 P16 Start Switch Start push button switch input P17 Stop Switch Stop push button switch input P18 LED Mounted LED indicator for SD card mounted P19 LED GPS Sats LED indicator enabled when satellite lock is 3 or greater P20 LED Heartbeat LED indicator toggles when recording a data segment P21 LED Pressure Good LED indicator for barometer temperature is in valid range P22 LED Recording LED indicator enabled when logging is on To make this experiment easier to produce we will use the Parallax Propeller Demo Board since it already has a number of hardware connections for TV video out prototyp ing areas and light emitting diodes LEDs on board Plus it already has all the neces sary components for operation such as power supplies EEPROM for program storage clock inputs and hardware interfacing mechanical connections For a GPS receiver we will be using a Parallax GPS receiver module Item Code 28146 There is also a barometric pressure sensor module MS5540C by Intersema that we will cover in depth later on Finally a standard Secure D
253. ards The same IR sensor and SIRC object when added to the room board would allow the room occupant to control the temperature using a simple IR remote control for example use channel up and channel down signals to adjust the temperature set point Add speech synthesis to provide voice alerts During an alarm condition 1 e detected unhealthy air or fire using verbal alerts would allow the room occupant to know to what the alarm issue relates without having to be close enough to the board to read the LCD screen In addition if an IR remote was being used to adjust the target temperature for the room voice feedback could be used to tell the user what tem perature they have selected Select some rooms for fresh air and others for recirculated air If some occupants preferred fresh air in their rooms while others preferred recirculated air it would be possible to meet both preferences by alternating the air handling method between the rooms To accomplish this the air register in a selected room or rooms would be set to 100 percent open while the air registers in the remaining rooms would be placed in the 100 percent closed position Next position the bypass doors to the fresh air positions and start the blower fan After a few moments reverse the process for the rooms that have selected recirculated air 426 THE HVAC GREEN HOUSE MODEL 5 Mix recirculated and fresh air As the bypass door
254. as a coprocessor that allows a microcon troller to request predigested information The raw GPS receiver without the copro cessor is shown on the right Since the Propeller chip has multiple processors an application can incorporate an object that launches a cog as a coprocessor to serially communicate with the GPS receiver digest the NMEA sentences and return requested information Figure 4 46 shows a circuit with the raw GPS receiver connected to the Propeller chip The wire harness that accompanies the receiver has six lines If you only plan on using the device with microcontrollers consider removing the RS232 TX and RX lines if the RS232 TX line is inadvertently connected to a microcontroller I O pin the 3 to 15 V output could damage the I O pin or even the microcontroller 180 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Figure 4 45 GPS receivers with and without coprocessors While numerous objects on the Propeller Object Exchange support GPS two that really stand out for simplifying application development and reducing prototyping times are I K6vesdi s GPS Float packages GPS Float Demo and GPS Float Lite Demo The demonstration programs use the Parallax Serial Terminal to display GPS info and take care of the floating point calculations required for a variety of navigation tasks In addi tion to the well documented GPS_Float and GPS_Float_Lite objects the demonstration programs in each package feature method cal
255. asure which way is down The approach that most resembles that of the human ear are various inclinometers These range from mercury filled glass tubes to pendulums which all use the earth s gravity to determine which way is down All these devices work by measuring the acceleration of gravity Recently small micro electromechanical systems MEMS accelerometers have become available to the hobbyist MEMS accelerometers use a small cantilever beam with a known mass to measure the direction of a force by sensing how the cantilever bends see Fig 6 7 They re a single chip solution which means they re small and inexpensive The one problem with all these inclinometers is that on a moving robot gravity is not the only acceleration When the robot speeds up is bumped or drives over a rough surface the acceleration due to gravity might be small Capacitative C Figure 6 7 Mechanics of a MEMS accelerometer showing cantilever sensor Force 246 DANCEBOT A BALANCING ROBOT relative to the other forces Averaged out over a long time these devices may be accu rate but for short periods in a moving vehicle their output isn t accurate enough for a balancing robot Gyroscopes don t directly measure tilt but are great for accurately measuring the change in tilt of an object Traditionally gyros had a spinning disk gimbaled inside an enclosure The disk remains in the same orientation even when the sensor is rotated
256. at a glance 127 A 0D 1B 24 25 5B 3A 3D 2E 2C 23 00 20 Backspace Line feed Carriage return Escape for hex for binary Null character Space Null pointer null character NULL 0 The VAR section has very few globals The majority of them are to support the parser and keep state globally for the parser and tokenizer Here is a listing of the VAR section 374 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS VAR long byte long byte byte long long long long long long long cogon cog input_buff 80 input_buff_index tok_buff 80 prompt 32 tok_buff_index token_ptr tokens 16 num_tokens cmd_token cmd_data_ptr cmd_parse_index Ids for cogs Storage for input buffer Index into current position of command buffer Storage for token buffer during processing Storage for user prompt Index into current position of tokenbuffer Used to point to output token from tokenizer Array of pointers to parsed tokens ready for processing Number of tokens in token array A single command token ptr to command token Index of command token in array General parameters used during parameter extraction long argl arg2 arg3 arg4 State vars for strtok_r function basically static Locals that we must define long strtok_string_ptr long strtok_s
257. at is worse is when both sensors send their payload at exactly the same time requiring the microcontroller to capture and act upon the data arriving at its input pins simultaneously Since microprocessors and microcontrollers have historically been single core meaning a single CPU contained inside that acts upon a sequential set of instructions this problem has been solved by adding peripheral hardware for many of the standard interfaces These hardware peripherals capture and buffer data into separate memory buffers without CPU intervention For example a typical Universal Asynchronous Receiver Transmitter UART that is capable of receiving serial data will contain a shift register that clocks in each bit of data into an 8 or 16 bit register Once enough data bits have been clocked in the serial data is then copied to another register and a flag is set in the CPU to indicate that serial data has been received The CPU must react to this flag by interrupting its current flow of program execution and then copy the received serial data from the saved buffer into main memory If it does not act in a timely fashion the received serial data could be lost See Fig 9 2 for an overview of this process Now the previous example is grossly simplified hardware peripherals may con tain multiple levels of First In First Out FIFO buffers so that the CPU does not get interrupted as often The peripheral may also contain Direct Memory Access DMA hardware c
258. ate and other communication attributes here Com Port Baud Rate Prefs Clea Pause Sr Figure 2 23 Parallax Serial Terminal default display button control panel change to let you know the Parallax Serial Terminal has closed the serial port see Fig 2 24 This is important because it lets the Propeller Tool software open the port to download our application V Start the download of our modified Flash object and during the download click the Enable button of the Parallax Serial Terminal Com Port Baud Rate x T DIRT ATS comia x 115200 x a O DSA O l 7g M Echon Prefs A Enable Click this button to enable the terminal this opens the serial port Figure 2 24 Control panel of Parallax Serial Terminal waiting for enable PROPELLER OBJECTS AND RESOURCES 45 Parallax Serial Terminal COM14 Stack Usage 3 The stack test shows the resulting utilization 9 longs Figure 2 25 Stack utilization message from Propeller After our modified Flash object is downloaded the Parallax Serial Terminal will open the serial port and wait for input The pin 16 LED will flash as expected and a message will soon appear in the receive pane see Fig 2 25 Now we know we only need to reserve 9 longs of space for the LED_Flash meth od s stack We can adjust the stack size remove the temporary code and publish our object VAR long Cog Holds ID of started cog long Stack 9 Stack works
259. ation Paul Atkinson Schematic design PCB fabrication and assembly Figure 11 23 The room board LCD display when unsafe air conditions are detected EXERCISES 425 James Delaney Software design 3 D CAD design and system assembly testing Jake Ivey Carpentry Gray Mack Hardware prototyping software design and implementation Parallax Inc Component supplier I would also like to thank Andr LaMothe and Ken Gracey for inviting me to par ticipate in this book and Chip Gracey for making the Basic Stamp and the Propeller chip a reality Exercises During the creation of the house and the various discussions that ensued some ideas were tossed around but not implemented that I thought might be a good jumping off point for anyone wanting to explore a system similar to this one Some of the idea would require little or no modification to the basic system as built 1 Adding an IR infrared sensor to the master board By adding an inexpensive IR receiver module and using the SIRC object to decode Sony IR signals you could essentially use a handheld IR transmitter to control the system In addition the NTSC video output could be routed to a conveniently located TV monitor This would allow the operator to review and change the system settings from their home entertainment system or to monitor the HVAC conditions using picture in picture technology available on many TV sets Adding an IR sensor to the room bo
260. ation as a whole Take a look at the flow chart describing the inner workings of the main object in Fig 9 11 Referring to Fig 9 11 the first thing the main Spin object does after startup is to initialize the GPS barometer and TV terminal objects Each of these objects starts a separate cog for execution as they begin their data collecting and TV output operations The next step is to test whether the Propeller can successfully communicate and read in the FAT16 file system of the attached SD card This is a reasonable test because the SD card may not be inserted and the user wishes to only watch the TV terminal display Now if the SD card was not found the TV terminal is updated with the message Failed to mount SD After a brief period enough for users to see the TV terminal message the screen is cleared and we enter into an infinite loop that reads the current states from the GPS and barometer objects and prints them to the TV terminal If a user wishes to insert a card after startup he would need to reset it for the SD mounting test This would be a good starting place for improving the main object but I leave that up to you If an SD card was found the directory contents of the SD card in the root folder are read and displayed to the screen Once again the execution pauses so that users may read the directory listing and then the main object enters into the infinite repeat loop Likewise when the SD card is not mounted the GPS an
261. ay variable values and I O pin states that bring simple mistakes to light with minimal hair pulling There is also an object named PST Debug LITE available through the Propeller Chip forum s Propeller Education Kit Labs Tools and The eyboord uorls Se dees the 7 Termine Figure 3 13 TV terminal output 82 DEBUGGING CODE FOR MULTIPLE CORES Applications thread at http forums parallax com This object extends the functionality of the Parallax Serial Terminal object to provide some additional debugging options Figure 3 14 shows an example of a display you might see if you incorporate the PST Debug LITE object into your application Parallax Serial Terminal COM15 Com Port Baud Rate g TX M DTR ATS coms x 115200 z e ax psr crs Om Prefs Clear Pause Disable Figure 3 14 PST Debug LITE Display in the Parallax Serial Terminal SURVEY OF PROPELLER DEBUGGING TOOLS 83 PST Debug LITE allows you to add breakpoints and commands that display I O pin states and their directions as well as lists of variables and their values with a few simple commands sprinkled into your code This is one example in a set of free resources available for debugging others are available through the Propeller Chip forum s Getting Started and Key Thread Index at http forums parallax com VIEWPORT For more elusive bugs as well as for folks who are accustomed to IDE style PC pro gramming environments Hann
262. based index 0 N 1 from a list Get index 1 N of a matching value from a list LOOKDOWNZ Get zero based index 0 N 1 of a matching value from a list STRSIZE Get size of string in bytes STRCOMP Compare a string of bytes against another string of bytes DIRECTIVES STRING Declare in line string expression resolved at compile time CONSTANT Declare in line constant expression resolved at compile time FLOAT Declare floating point expression resolved at compile time ROUND Round compile time floating point expression to integer TRUNC Truncate compile time floating point expression at decimal FILE Import data from an external file REGISTERS DIRA Direction register for 32 bit port A DIRB INA INB OUTA OUTB CNT CTRA CTRB FRQA FRQB PHSA PHSB VCFG Direction register for 32 bit port B future use Input register for 32 bit port A read only Input register for 32 bit port B read only future use Output register for 32 bit port A Output register for 32 bit port B future use 32 bit system counter register read only Counter A control register Counter B control register Counter A frequency register Counter B frequency register Counter A phase locked loop PLL register Counter B phase locked loop PLL register Video configuration register PROPELLER LANGUAGE REFERENCE 447 VSCL Video scale register PAR Cog boot parameter register read only SPR Special purpose register array indirect cog
263. beginning of the buffer and zeros out an argument counter Finally a repeat loop is entered that loops over the entire buffer looking for those zeros that we replaced commas with When a 0 is encountered it saves a copy of the memory location to the args array that was passed in as the second argument to the copy_buffer method When execution returns from the method we have a copy of the original received NMEA sentence with commas replaced with zeros and an array of long pointers to each of the original comma separated sections NULL TERMINATE A question that you might be asking yourself is Why did we replace the commas with zeros when we could have just as easily searched for commas in the copy_buffer method The reason why is because the standard convention for storing strings that have variable length is to NULL terminate or end them with a O value Having strings NULL terminated helps other methods determine when to stop reading characters from memory without needing to know the length of the string beforehand Now that we have pointers to the individual fields of the NMEA sentence string we can return them to the parent Spin object that created the GPS_IO_Mini spin object with methods like the following pub GPSaltitude return GPGGAaL8 332 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER pub time return GPGGAaLO pub latitude return GPGGAal1 pub date return GPRMCa 8 Ihave sl
264. bels appear Use them to locate the Pause Step Over and Step Into buttons J Next click the Pause button and repeatedly click the Step Over button 110 DEBUGGING CODE FOR MULTIPLE CORES The yellow highlighter indicating the line that gets executed will not step into the if vp RxCheck lt gt 1 statement s code block because there is no character waiting in the terminal object s receive buffer v Click ViewPort s Terminal field and press your keyboard s ENTER key Then click the Step Over button three more times This time the yellow highlighter that indicates the active line of code should advance into the code under the if block The third step will place the active line at the vp Dec count line The next line will only call the Alarm method if count is equal to 10 v Hover the cursor over the count variable in the if count 10 line and wait for the flyover with the variable value to appear v Click the value in the flyover and change it to 10 Z Click the Step Into button The active line highlighter should jump into the Alarm method In the Calls window it will indicate that the code being executed is in the Alarm method After the vp str call the Alarm text should appear in the Terminal Also try this Y Set a breakpoint on vp Dec count by clicking the line number next to that line of code Then click the Start Debugging button v A red breakpoint marker should appear on that line Sinc
265. beyond what the HYDRA EtherX driver provides in the application methods you would need to use the read and write methods In actuality all the other methods that are provided for the application layer in the EtherX driver use these two methods We will now explore these other application methods Application Methods Layer While you could simply use read and write to use the EtherX there are still a lot of sticky details about what data you need to send and to what addresses to actually make the EtherX card useful Application methods exist to provide a means for you to use the EtherX card without actually needing to know the gritty details of how the W5100 works This is great for getting an application running and learning about Ethernet and in the Internet in general but I encourage you to look at the methods and the W5100 documentation itself to understand what is going on Mode Method One of the only application methods that does not use the read and write methods is the mode method This allows you to change the mode of the W5100 to change the speed and half full duplex of the W5100 By default the Ethernet interface of the EtherX operates at 10 Mbps and at full duplex Pull up and pull down resistors on the EtherX card set the mode by default so if you never call the mode method the card will power up and come out of reset as 10 Mbps full duplex However you can change this if you are so willing Be careful though as the EtherX card can b
266. by the method that declares it so the Go and Blinker methods are accessing different instances of a variable with the same name and each instance resides at a different memory address So regardless of the value entered into the Parallax Serial Terminal s Transmit windowpane the Blinker method will continue to toggle the LED at the rate it received when the Go method launched it into a new cog Y Remember to set the Parallax Serial Terminal software s Baud Rate back to 115200 before running this example program Cogs Not Sharing Info Bug spin This program demonstrates a bug where different cogs fail to exchange information because they are both using local variables named delay 72 DEBUGGING CODE FOR MULTIPLE CORES CON _clkmode _xinfreq xtali pll16x 5 000 000 VAR long stack 10 OBJ pst Parallax Serial Terminal PUB Go delay pst Start 115200 Crystal and PLL settings 5 MHz crystal x 16 80 MHz Stack for cog executing Blinker Go method Start Parallax Serial Terminal cog cognew Blinker 5 clkfreq 4 stack Blinker method gt new cog repeat Main loop pst Str String Enter delay ms Prompt user input delay pst DecIn clkfreq 100Q User input gt delay var PUB Blinker pin delay t t ent dira pin 1 repeat waitent tt delay outaLpin Since all methods in an object can access global variables the solution to this problem
267. cates with the Propeller through an object named conduit that launches a variable monitoring and communication process into another cog For debugging the conduit object has to be configured by the top level object s Spin code to work with the ViewPort debugger The spin files that will be debugged also have to be placed in the same directory with certain objects that are packaged with the ViewPort installation Below is a list of general steps for preparing a spin application for debugging with ViewPort E Copy objects into C Program Files ViewPort mycode E Open the top object with ViewPort by clicking the code tab and then using File gt Open to find the file E Remove any object that might try to communicate with the PC through the Propeller chip s programming connection for example Parallax Serial Terminal or PST Debug LITE For debugging make sure the Propeller s system clock is set to 80 MHz Declare the conduit object typically by adding vp conduit to the OBJ block Call the conduit object s config method and pass it a list of the variable names Pass the start and end addresses of the contiguous list of variables that you want to be able to monitor and update to the ViewPort object s share method The variable names passed to the config method must correspond with these variables Test Timestamp Object with ViewPort spin started out as the program in the previ ous example Test Timestamp Object spin W
268. ce shall be included in all copies or substantial portions of the Software xvii xviii INTRODUCTION THE SOFTWARE IS PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM DAMAGES OR OTHER LIABILITY WHETHER IN AN ACTION OF CONTRACT TORT OR OTHERWISE ARISING FROM OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE SPECIAL CONTRIBUTORS Parallax Inc would like to thank their team members Chip Gracey for inventing the amazing Propeller chip Ken Gracey for envisioning this book Joel Bump Jacobs for creating the original cartoons in Chapters 1 and 2 Rich Allred for the majority of the illustrations in Chapters 1 through 5 Jeff Martin Andy Lindsay and Chip Gracey for authoring their chapters and Stephanie Lindsay for coordinating production with McGraw Hill Parallax also thanks Andr LaMothe for authoring his chapter and for heading up the team of authors from the Propeller community Martin Hebel Hanno Sander Shane Avery Joshua Hintze and Vern Graner Special thanks go to Jon Titus for so generously providing the Foreword and to Judy Bass at McGraw Hill for find ing this project worthwhile and making it happen THE PROPELLER CHIP MULTICORE MICROCONTROLLER
269. ced at a fairly high pitch The component frequencies of the sound might be diffi cult to discern from the Oscilloscope pane but the Spectrum Analyzer pane s cursor tool can be placed at the top of each spike to measure its frequency and amplitude The sound is primarily composed of three sine waves with the lowest frequency at 468 Hz Like the potentiometer version of the code the SigmaDeltaADC Spin object takes care of all the interactions with the circuit in another cog and constantly updates the top file s adcVal variable The Conduit object is running in a third cog and streaming the values of the adcVal variable to ViewPort for display in the analog view s Oscilloscope and Spectrum Analyzer panes The program has some vp config calls that were set first with ViewPort s dials and knobs After that they were copied from ViewPort using Configuration gt Copy to Clipboard When pasted into the top file they appear as vp config calls These vp config calls cause ViewPort to automatically set the dials and knobs accordingly after the ViewPort software s Connect button is clicked ViewPort v4 1 504 Welcome code dso sa al limescale i Set to Camera Overview click on name to configure Name Plot Edit Ihn Max Avg val Oss a2 fhas 558 Show A B Ditt Edit Variables on Disconnecte
270. ces between the altitude given by the GPS and the barometer For now let s look at the math on how to compute your altitude given a pressure reading The following is the barometric formula It is the formula used to calculate pressure at differing altitudes less than 86 kilometers km above sea level g0 M P P i oe I T L th h where P Static pressure Pa T Standard temperature K L Standard temperature lapse rate K m h Height above sea level m h Height at bottom of layer b meters e g h1 11 000 m R Universal gas constant for air 8 31432 N m mol K g0 Gravitational acceleration 9 80665 m s M Molar mass of Earth s air 0 0289644 kg mol The constants P T Lp and h are different depending on which region of the atmosphere you are in and are listed in Table 9 2 In our experiment we will be gathering the data while driving a car around a resi dential neighborhood so we can safely use the values from altitudes extending from 0 to 11 000 m above sea level P 101325 Pa Standard Temperature 288 15 K Temperature Lapse Rate 0 0065 K m For additional information regarding the derivation of the barometric formula see the following Web site however the formula is derived from the ideal gas law pV nRT http en wikipedia org wiki Barometric_formula OVERVIEW OF THE SENSORS 335 TABLE 9 2 BAROMETRIC FORMULA CONSTANTS HEIGHT ABOVE STATIC STANDARD
271. ch each instance of LED_F lash into a separate cog processor to execute in parallel Information Whats a cog It s the Propellers name for each of its processors They are called cogs since they are simple and uniform like the cogs on gears that mesh with others of their kind to induce change Their simplicity assures reliability and as a collective they deliver powerful results Here s the updated code Try it out now We ll explain it in a moment VAR long StackA 32 Stack workspace for cogs long StackB 32 long StackC 32 PUB Main cognew LED Flash 16 30 5 StackA Launch cog to flash led cognew LED Flash 19 15 15 StackB And another for different led cognew LED Flash 23 7 26 StackC And a third all at same time PUB LED Flash Pin Duration Count Flash led on PIN for Duration a total of Count times Duration is in 1 1 th second units ALL TOGETHER NOW 33 Duration clkfreq 100 Duration Calculate cycle duration dira 16 23 Set pins to output repeat Count 2 Loop Count 2 times outaLlPin Toggle I O pin waitcnt Duration cnt Delay for some time Tip This source is from PCMProp Chapter_02 Source LED_MultiFlash spin Y Download this application to the Propeller and note how it behaves differently from the last exercise Now all three LEDs blink simultaneously at different rates and different counts but each exactly the way they did before see Fi
272. cing robot In the past the necessary sensors motors and processing power were more difficult to locate and expensive to buy In particular nanotechnology and parallel processing have opened the doors to today s balancing robots Low cost accelerometers using nano scale cantilevers and small solid state ceramic gyroscopes are readily available and easy to use Being able to run multiple programs in their own processor while sharing a global memory makes it easier to build and test the software required for the robot The fun really starts when a balancing robot is combined with computer vision see the next chapter Computer vision allows the robot to see the world and interact with it By tracking a target object like a human the balancing robot can literally dance with THE CHALLENGE 237 its partner it becomes a DanceBot By being tall and maneuverable the DanceBot more closely resembles a dance partner than a four wheeled car or stationary mecha nism It can face its partner by turning on its axis and moving forwards and backwards to maintain a desired distance Interacting with a robot by dancing is more intuitive and pleasing than using remote controls or even worse programming it Even young children can get in the action see Fig 6 2 in which my kids are interacting with my DanceBot Like people balancing robots continually move to stay balanced they don t stand still They continually move slightly forward and sli
273. click Go V Locate and download Ping Demo by Chris Savage from Parallax V Unzip the package V Open the Ping object and click the Documentation button to view this object in Documentation view Figure 4 23 shows the Ping object in Documentation view Note that it has Inches Centimeters and Millimeters methods so no additional math is required to convert echo time to distance Each of those methods takes care of the math and returns a distance value Also note the 1 kQ resistor in series between the Ping sensor s SIG terminal and the I O Pin In addition to series resistance built into the Ping the 1 kQ resistor is sufficient to protect the Propeller I O pin s 3 3 V input from the Ping sensor s 5 V output If you decide to try out the Ping sensor with a Propeller chip make sure to include this resistor Judging from the Ping object s documentation no Init or Start method call is required so a simple call to the Centimeters method should return the distance mea surement in centimeters This makes test code easy to write but keep in mind that no Start method also means that the code is executed in the same cog The code will be measuring pulse signals from the Ping sensor that last up to 18 5 ms which can cause unwanted delays in a cog s code execution In the event that 18 5 ms is too long for code in a given cog the application can launch another cog for Ping measurements with the cognew command Code execu
274. clock mode read only CLKFREQ Current clock frequency _CLKFREQ Application defined clock frequency read only CLKSET Set clock mode and clock frequency 443 444 APPENDIX A _XINFREQ _STACK _FREE RCFAST RCSLOW XINPUT XTALL XTAL2 XTAL3 PLL1X PLL2X PLL4X PLL8X PLL16X Application defined external clock frequency read only Application defined stack space to reserve read only Application defined free space to reserve read only Constant for _CLKMODE internal fast oscillator Constant for _CLKMODE internal slow oscillator Constant for _CLKMODE external clock osc XI pin Constant for _CLKMODE external low speed crystal Constant for _CLKMODE external med speed crystal Constant for _CLKMODE external high speed crystal Constant for _CLKMODE external frequency times 1 Constant for _CLKMODE external frequency times 2 Constant for _CLKMODE external frequency times 4 Constant for _CLKMODE external frequency times 8 Constant for _CLKMODE external frequency times 16 COG CONTROL COGID COGNEW COGINIT COGSTOP REBOOT Current cog s ID 0 7 Start the next available cog Start or restart a cog by ID Stop a cog by ID Reset the Propeller chip PROCESS CONTROL LOCKNEW LOCKRET LOCKCLR LOCKSET WAITCNT WAITPEQ WAITPNE WAITVID Check out a new lock Release a lock Clear a lock by ID Set a lock by ID Wait for system counter to reach a value Wait for pin s to be equal to v
275. code ran until it stopped at the breakpoint v Arrange the windows as shown in Fig 3 24 lt b PASD Timestamp Dev ASM BEE T MainRAM viewer Fie Debug COM Help O47C L SAAAAAAAA D480 L SAAANANIB P Addr Code Source A A484 L SAAAAAZE A48 L 500013060 Debugger Kernel add this at Enti Sera anae 34FC1202 long 34FC1202 S6 CE61201 58301208 s6BCOEO EC COEOS long SEC7COEO5 SAABC1207 s5C 700003 s5C7CO l dec from Addr A o ur COG RAM viewer AABCEFFA addr par BBBC5A33 rdlong _m addr Addr Value BOFCEBD4 add addr 4 820 __ 008903E8 BaBC5C33 rdlong _s addr C20 sone psseh st 02E SAAAAAAIB BAFCE6A4 add addr 4 A2F SAAAAA3E BSBC5E33 rdlong _ms addr 030 00013880 SOFC66A4 add addr 4 031 SOOAAAOAA 013 0A8BC6A33 rdlong _dt addr W 014 BAFC66A4 add addr 4 10987654321098765432109876543210 015 B6BC6233 rdlong sID addr 816 AABCE5SF1 mov t ent ro 017 80BC64IA add E 018 F BC643A timekeeper waitent t _dt 819 8AFC5E01 add O1A 863C5E2C Q1B ABESSEOO C 21C 80E8SCAL La Ain ARFCRKCAFN ONOOSBOOOOROR00000000000 PC 018 Z 0 C 0 PinputL H Output L H Figure 3 24 PASD assembly debugging session 116 DEBUGGING CODE FOR MULTIPLE CORES The assembly code between the Debugger Kernel and timekeeper label copies the contents of the m s and ms Spin variables in Main RAM to Cog RAM registers named _m _s and _ms PASD lets you examine
276. command to miss the value of the cnt register that it s waiting for In that case the cnt register will eventually get back to that target after it rolls over One way of preventing the debugging code from interfering with the time base is to launch the time counting code with the precise delay into another cog A separate cog can then monitor the time counting values Test Timestamp from Other Cog spin launches a version of the TimerMs method that has been modified for precise timing into another cog Meanwhile the cog executing the Go method allows you to periodi cally sample timestamps through the Parallax Serial Terminal by placing the cursor in its Transmit windowpane and then periodically pressing a key on your computer keyboard Test Timestamp from Another Cog spin This example program demonstrates an initial test of some timestamp prototype code that fails to expose a memory bug IMPORTANT This code has a hidden bug CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ debug PST Debug LITE Serial communication object VAR long stack 40 Ample stack for prototyping long m s ms t dt Timekeeping variables PUB Go minutes seconds milliseconds debug Style debug COMMA_DELIMITED Configure debug display debug Start 115200 Start debug cog cognew TimerMs stack Launch timekeeping cog repeat longmove minutes m 3 Copy T
277. cond parameter gets copied to the cog s par register which is acces sible to the assembly code In this case the second parameter is asmCt The Spin code expects the assembly code to update its asmCt variable with each repetition of its counting loop and the cog executing the Go method displays the value once per second COMMON MULTIPROCESSOR CODING MISTAKES 77 Asm Cog Example spin CON _clkmode _xinfreq xtali pll16x 5 000 000 VAR long asmCt OBJ pst PUB Go t dt cognew AsmCounter AsmCt pst Start 115200 t c cnt dt clkfreq repeat waitcnt t dt pst Home pst Str String pst NL AsmCt pst Dec asmCt Parallax Serial Terminal Constant declarations Crystal and PLL settings 5 MHz crystal x 16 80 MHz Variable declarations Spin variable Object declarations Parallax Serial Terminal spin Go method Launch ASM code into new cog Start Parallax Serial Terminal cog Current cnt register gt t variable Set up 1 second delay interval Repeat loop Synchronized delay To top left of terminal Display text Display deciaml asmCt val DAT DAT block org ASM address reference Entry AsmCounter mov addr par Parameter reg gt addr mov count 0 count 0 loop add count 1 count 1 wrlong count addr asmCt count see note jmp loop Jump up 2 lines Uninitialized data addr res 1 Cog RAM registers
278. count res 1 NOTE wrlong count addr copies the cog s count register to asmCt which is a variable at the address asmCt in Main RAM 78 DEBUGGING CODE FOR MULTIPLE CORES Inside ASM Cog Example spin The DAT block in Spin programs can contain data and or assembly code The org directive gives the assembly code a reference inside the cog for the addresses of labels such as AsmCounter address 0 loop address 2 and so on As men tioned previously the cognew command passed the address of the Spin asmCt variable as the second argument in the cognew command and that address gets copied to the cog s par register The command mov addr par copies the contents of the par register to a register named addr which was declared in the uninitialized data section at the bottom of the DAT block The instruc tion mov count 0 copies the value 0 to a register named count which was also declared in the uninitialized data section Without the literal indicator the command would instead copy the contents of address 0 to the register named count Since the contents of address 0 in this example would be the machine language code for the mov addr par assembly language command the jmp command would send the program to the wrong address The command add count 1 adds 1 to the register named count Next wrlong count addr copies the value of count a cog RAM register to an address in Main RAM Since addr stores a copy of par which in turn sto
279. criptions and specifications 8 8f 9t cogs processors 11 12 11t PING 284 Ping Ultrasonic Distance Sensor 145 148 145f 146f 147f object exchange example 145 148 PING Ultrasonic Range Finder 205 207f plosives 435 PNA4602 infrared sensor 133 polling remote nodes 208 214 automatic polling with Propeller 212 214 213f end devices 209 212 209f 210f Position cog 252 post clear operator 37 potentiometer 131 131f 141 position example 139 142 139f power on reset delay 28 precise time base establishment 90 pressure altitude vs GPS altitude 348 348f prevention of bugs 52 54 55 62 116 PRI private methods 24 36 printable ASCII characters 177 178f Printable Ascii Table spin 178 179 printing CMYK in 275 processing and storing sensor data 182 187 data transmission from Propeller to PC 187 saving and retrieving 183 187 184f synchronizing 182 183 processing and tokenization 366 processors See cogs processors PROMPT command 360 381 PropCV 259 265 260f 274 frame grabber 259 264 PropCVCapture object 263 264 264f 268 Propeller automatic polling with 212 214 213f blinking process in parallel 32 34 33f block diagram 8 10f computer vision software for 259 265 debugging simplified by 52 56 downloading to 5 6f integration and OpenCV 276 279 277f microcontroller 51 117 multicore approach to games using 313 317 multiple servos sensors and 409 NTSC waveform captured by
280. ct spin l 1 a PING 8 GND 5V SIG T tl 21 kQ 4 O Sea I Pin P15 CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ ping Ping Ping Ultrasonic Sensor object pst Parallax Serial Terminal Serial communication object PUB go cmDist pst Start 115200 Start Parallax Serial Terminal repeat cmDist ping Centimeters 15 Get cm distance Display measurement pst Str String pst CE pst HM cmDist pst Dec cmDist waitent clkfreq 10 cnt Update display at 10 Hz MEMSIC 2125 ACCELEROMETER MODULE CODE FROM OBJECT EXCHANGE Figure 4 24 shows what happens inside the Memsic 2125 Accelerometer Module s MXD2125 chip when it gets tilted This chip is actually a small chamber with a heating element in the middle and temperature sensors at each side of the chamber on both the X and Y axes Just as soda sloshes around in a bottle in response to either acceleration or tilt the distribution of hotter and cooler nitrogen gas trapped in the chamber behaves similarly which is how the temperature sensors provide acceleration measurements This is an example of microelectromechanical systems MEMS technology Circuits built into the MXD2125 chip convert the temperature values to pulse trains that indicate the distribution of hot and cold gasses in the chamber These pulse trains shown in Fig 4 2
281. cy top button is pressed pst CE PUB MiddleButton pst Str String pst NL Warning middle button is pressed pst CE PUB BottomButton pst Str String pst NL Note bottom button is pressed pst CE MULTIPROCESSING EXAMPLE With objects that take care of the multiprocessing grunt work multicore application code becomes exceedingly simple Consider P16 Multiprocessing Example spin If it weren t for the convention that a call to an object s Start methods results in one or more launched cogs it would be difficult to tell that this program is making use of three cogs The top object executes in one cog and both the PST Debug LITE and Timestamp objects have code that other cogs execute Since the two building block objects have methods that take care of information exchanges with the code running in the other cogs P16 Multiprocessing Example spin just looks like it s a single loop that makes a few method calls P16 Multiprocessing Example spin CON _clkmode _xinfreq xtali pll16x Crystal and PLL settings 5 000 000 5 MHz crystal x 16 80 MHz SENSOR BASICS AND MULTICORE SENSOR EXAMPLES OBJ debug PST Debug LITE Serial communication object time TimeStamp Object TimeStamp object PUB Go minutes seconds milliseconds debug Style debug COMMA DELIMITED Configure debug display debug Start 115200 Start Parallax Serial Terminal time Start Q 2 Q Start times
282. cycle 313 close method 303 304 close socket 303 304 CLS See clear screen command CMYK cyan magenta yellow and black 275 cnt 27 Code in one cog 95 96 code in parallel 5 7f coding errors common root cause of 51 52 multiprocessor related 58 78 Cog 0 game logic 314 315 Cog commands 37 Cog RAM 11 114 12 13f cogid 55 Cognew 34 INDEX 465 cognew 55 command 37 keyword 315 cogs processors 5 11 12 111 32 for Button Masher 313 315 communication between 54 exchanging information at different memory addresses 71 73 T O pin access shared by 52 53f 54 launched on Spin code 7f multiple and debugging 52 54 Propeller using multiple 6 7f start and stop to manage 36 Cogs Not Sharing Info Bug spin 71 72 Cogs Sharing Info Bug fixed spin 72 73 74 cogstop command 37 color blob finder 276 colored objects 275 COM See Component Object Model command console program CCP 365 373 373f command library to slave server 387 388 command processing and execution 366 commands 359 comments 26 Component Object Model COM 372 computer vision 236 software for Propeller 259 265 computer vision of robots 258 259 258f filters and bright spot in real time 265 269 270f following line with camera 270 272 271f OpenCV and Propeller integration 276 279 277f state of the art with OpenCV 274 276 track pattern 272 274 computers Ethernet and Internet protocols 281 286 283f 287f route
283. d Memory 00 00 43 Figure 4 35 Say aaaaaahhhhhh VOLTAGE OUTPUT 167 Display Mic with ViewPort spin CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz SAMPLES 2000 Clock ticks per measurement FB_PIN 9 Sigma delta ADC feedback pin IN PIN 8 Sigma delta ADC input pin OBJ Object declarations adc Si gmaDeltafdc Spin vp Conduit Declare Sigma Delta ADC object PUB go adcVal Go method with local variables Configure ViewPort vp config string var v1 acdc ac vp config string start analog vp config string dso view vl of fset 0 4037 scale 40 trigger vl gt auto timescale 50Qus ynode manual vp config string lsa timescale 10ms timeoffset 0 vp share adcVal adcVal Start adc object pass feedback and input pins number of ticks per sample amp address of adcVal adc Start FB_PIN IN PIN SAMPLES adcVal repeat Repeat loop keeps this cog going Note New ViewPort functions and features are on the horizon at the time of this writing To check for updated versions of code examples from this section that are compatible with the latest version of ViewPort go to ftp propeller chip com PCMProp Chapter_04 As mentioned earlier the latest version of ViewPort is available for a 30 day free trial from www parallax com Multicore Signal Acquisition Analysis and Displa
284. d analyze what the video of a properly programmed robot would do It becomes apparent that a good strategy is to average the location of the darkest pixel in each line This is quite robust easy to program and gives a good control signal to the robot The following assembly code filter is used for this task Integrating this filter with the rest of the DanceBot is straightforward We just use the average position of the line to control the direction of the robot while it s moving along at a set speed The following assembly code filter averages the location of the darkest pixel in each line Watch a video of my DanceBot using this filter to follow a black line here http mydancebot com viewport videos 272 CONTROLLING A ROBOT WITH COMPUTER VISION doLowest rdlong add mov mov loopLines mov sub mov loop rdlong add mov mov limit mov and cmp if_c add if_c sub if_c mov ror ror djnz add djnz add add add djnz wrlong jmp t1 cmdPtr t1 points to seexy will be written with sum of pos of lowest item cmdPtr 4 t2 0 t2 is sum of pos n linesNpanel Loop over panel x longsNline Loop over line x 2 val 15 Reset val old sre Loop over longpixels src 4 m 8 new 2 tmp old tmp 15 tmp val wc c set if vi lt v2 new 15 val 1 35x t3 is pos of lowest item new 4 old 4 m limit dest 4 x loop Loop over longpixels t2 3 src 8 dest 8
285. d automatic With manual scaling the parent object can expect a value from 0 to 1 6 MHz for a given level of input sensitivity If the measurements approach either of those values the application object has to detect it and adjust the TSL230 s input sensitivity scale With automatic input sensitivity scaling mode the Start method s autoscale parameter is set to true and the object takes care of all this So instead of results from 0 to 1 6 MHz with three different scale options 1x 10x and 100x the object simply reports results from 0 to 160 M which is a measurement range inclusive of all three scale settings When connecting the TSL230 to the Propeller chip make sure to observe the ctrlpinbase and ctrlpinbase 1 convention in the object s documentation It s shorthand for saying that the Propeller I O pin number connected to TSL230 Pin 2 has to be one larger than the I O pin number connected to TSL230 pin 1 For example if you connect TSL230 pin 2 to Propeller I O pin P25 TLS230 Pin 1 MUST be connected to Propeller I O pin 24 Test code that utilizes the ts1230 object also utilizes a TV display but the code is simple enough that porting it for use with the Parallax Serial Terminal is not a problem The ts1230 DEMO spin object is in the Propeller Tool Software s Propeller Library Examples folder The tv_text object s Term out D method has the same effect on a TV monitor that the Parallax Serial Terminal object s pst NewLine m
286. d barometer outputs are displayed to the TV terminal Next the Propeller tests to see if we are currently recording Remember the user must initiate the recording with a pushbutton switch If the Propeller is recording the SD card is written to using a combination of the FSRW methods SDStr SDdec and pflush It is important that we call pflush after every write to the SD card in our applica tion This is for the sake of the user in case he or she forgets to stop the recording before ejecting or powering down the system Without pflush being called the file header metadata would not be written to the SD card and a PC s operating system would not be able to recognize the file length and location without it Finally regardless of whether the data is being recorded we arrive at the input pushbutton switch test If the SD card is currently being recorded we test to see if the MAIN SPIN OBJECT 345 Initialize GPS Barometer TV Terminal Objects Draw TV Draw TV terminal with terminal with GPS and Barometer GPS and Barometer Outputs Outputs Test Stop Start recording buttons ki Figure 9 11 Flow chart of main Spin object STOP pushbutton switch is pressed If so we stop recording and close the file Now if we were not recording to the SD card and the START pushbutton switch is pressed we first look for a unique file name to open To locate a unique file name we search the root folder for a file named se
287. d more accurately So what s involved We ll start by building a frame grabber to digitize video from a camera for storage in the Propeller s main memory Then we will continue by building different filters to process the video and recognize different objects FRAME GRABBER I designed PropCV to work for any video source that can output a National Television System s Committee NTSC composite signal which makes the solution highly flexible I used a 20 grayscale camera that fits on my fingertip while others use professional quality camcorders with autofocus and a servo driven zoom lens I have chosen the C Cam 2A camera for the DanceBot It measures just 16 x 16 x 16 mm uses less than 100 mW at 5 V and only has one option the gamma setting See Fig 7 2 for the complete vision hardware for my robot The output signal consists of a 1 V peak to peak composite video signal when terminated into 75 ohms Like other NTSC composite 260 CONTROLLING A ROBOT WITH COMPUTER VISION Figure 7 2 C Cam 2A grayscale camera and ADC sources you can watch the camera s output on your TV by simply connecting it to the composite Teaching the robot to understand what the camera sees is a bit harder so we ll take it one step at a time To start we have to digitize the analog signal To sample slower waveforms with the Propeller you would use delta sigma modulation with a capacitor and resistor but since we need to resolve the individu
288. data The TX method is called to transmit data its code is shown here PUB TX dataptr size tptr offset startadd aQ al counter temp Call this method to send data via the W5100 Read the offset so we know what the starting address is of the TX buffer tptr read 04 24 Read the transmit pointer tptr tptr lt lt 8 tptr read 04 25 offset tptr amp S7FF 2K of buffer determines mask of 7FF startadd 4000 offset Add offset to the starting address Write the data to the W5100 internal memory buffer repeat counter from to size 1 al startadd amp SFF a startadd amp SFFQQ gt gt 8 write a0 al byte dataptr offsettt offset offset amp S7FF 2K of buffer determines mask of 7FF startadd 4000 offset Add the offset to the starting address dataptrt t Update the offset counter and write it back to the W5100 tptr counter temp tptr amp SFFQQ gt gt 8 write 04 24 temp temp tptr amp SFF write 04 25 temp Tell the W5100 to write the data write 04 01 20 308 USING MULTICORE FOR NETWORKING APPLICATIONS You can see that the method takes two arguments The first is a pointer to a byte array that contains the data you want to send The second argument specifies how many bytes you actually want to send The driver writes the number of bytes you specify in the size argument from the address in main memory starti
289. data and the variable indicating where the brightest spot is CON _clkmode xtal1 pll16x _xinfreq 5 000 000 OBJ vp gt Conduit Transfers data to from PC video PropCVCapture Capture video signal and view in Viewport ve PropCVFilter Applies vision algorithms to video pub vision videoFrame 6000 blob b1 x y w h vp register video start videoFrame video VIDE04 1 video buffer var blob b1 x y u h vp config string dso view blob vp config string vp config string video view blob vp config string start video vp share blob b1 ve start videoFrame video VIDE04 Apply vision ve filter 1 0 ve invert Invert pixels from to 1 ve filter 2 0 ve tdifference Calculate difference from to 2 ve filtervalue 3 0 ve threshold 1 Only show brightest spots ve filtervalue 0 0 vetmax b1 Find maximum Figure 7 7 shows a screenshot of the video streamed from the Propeller Notice the original image in the upper left quadrant the negative of the image in the upper right quadrant then the horizontal edge filtered image in the bottom left quadrant and the thresholded image in the bottom right quadrant Also the marker represents the location of the brightest spot as found by the findMax filter We now have two channels of information updated at 30 times a second with which we can drive the two control channels of a robot speed and direc
290. der of the whole project it ties together the user input RCP commands drivers and initialization and monitoring into a single process running on a single core In this section we are going to discuss the program in brief and take a look at some of the code Referring to Fig 10 11 the CCP is a Spin program that begins with the usual Propeller declarations to initialize the Propeller chip for the target hardware In this case that s a Propeller Demo Board The init code is shown here CON _clkmode xtal1 plli6x Enable ext clock and pll times 16 _xinfreq 5 000 000 Set frequency to 5 MHz _stack 128 Accommodate stack Next there are some constants to make parsing easier that define a number of ASCII symbols here s an excerpt CLOCKS _PER_MICROSECOND 10 Used for delay function ASCII codes for ease of parser development ASCIT_A 65 ASCII _B 66 ASCII_C 67 ASCII_D 68 ASCII_E 69 ASCII_F 70 ASCII_G 71 ASCIT_H 72 ASCII_O 79 CLIENT HOST CONSOLE DEVELOPMENT 373 Cog 0 Core 0 Handlers Figure 10 11 ASCII_BS ASCII_LF ASCII_CR ASCII_ESC ASCII_HEX ASCII_BIN ASCII_LB ASCII_SEMI ASCIT_EQUALS ASCII_PERIOD ASCII_COMMA ASCII_SHARP ASCII_NULL ASCII_SPACE Input RX Lives cena E EE P ES PC settings VT100 9600 N 8 1 To I O devices we eeeeeee gt Messages passed to drivers Each object running on via sub function calls another core The command console program
291. direction registers for all I O pins and to make I O pin states follow a simple set of rules all the cogs I O pin direction and output settings pass through the top set of OR gates shown in Fig 3 1 With this arrangement if one cog sets an I O pin register bit to output a different cog can still leave its I O pin direction register bit set to input and even monitor the state of the I O pin to find out what signals the other cog is transmitting The rule for multiple cogs controlling outputs is also simple If one or more cogs control the same I O pin output a cog sending a high binary 1 in the output register bit will win and the I O pin will be set high even if other cogs have binary Os in the same output register bits This scheme makes it possible for one cog to modulate higher speed on off carrier signals that another cog is transmitting Whenever the modulating cog sends a high signal the carrier signal s low signals don t make it through When the modulating cog sends a low signal the carrier s high and low signals can make it through Figure 3 2 shows an example where the upper trace is the signal from two cogs Counter B PLL Video Generator 1 O Output Reg O Direction Reg Counter A PLL Video Generator O Direction Reg Counter A PLL Counter B PLL Video Generator 1 0 Direction Reg Counter A PLL Video Generator 1 O Direction Reg a a 7 lt po 2 c 2 Q Oo Pin Inputs Figure 3 1 Block diagr
292. disabled and I O floating Propeller restarts 50 ms after RESn transitions high Crystal Input Connect to crystal oscillator pack output XO left disconnected or to one leg of crystal resonator with XO con nected to the other depending on CLK register settings No external resistors or capacitors are required Crystal Output Feedback for an external crystal May leave disconnected depending on CLK register settings No external resistors or capacitors are required TABLE 1 2 SPECIFICATIONS ATTRIBUTE DESCRIPTION Model Power Requirements External Clock Speed System Clock Speed Internal RC Oscillator Main RAM ROM Cog RAM RAM ROM Organization I O pins Current Source Sink per I O Current Draw 3 3 VDC 70 F P8X32A 3 3 volts DC max current draw must be lt 300 mA DC to 80 MHz 4 MHz to 8 MHz with Clock PLL running DC to 80 MHz 12 MHz or 20 kHz may range from 8 MHz 20 MHz or 13 kHz 33 kHz respectively 64 KB 32 KB RAM 32 KB ROM 512 x 32 bits each Long 82 bit Word 16 bit or Byte 8 bit addressable 32 CMOS signals with VDD 2 input threshold 40 mA 500 pA per MIPS MIPS Freq MHz 4 Active Cogs OF Cog 0 Cog 1 Cog 2 I oa om om et om BL 1O Output Register 5 i a 2 5 0 g 8 z Video Generator Video Generator 1O Output Register 1 O Output Register I O Direction Register V O Direction Register I O Direction Register I O As
293. dler is entered ignores any other strings and simply starts sending the VT 100 clear screen command to the terminal ESC 2J That s it Of course there is no error handling so the user could type CLS as well as CLS your momma and both would work since the your and momma strings would be ignored If you like you can add more error handling yourself Let s take a look at one more local command the PROMPT string com mand This command allows you to redefine the prompt to something different than Ready gt This is really for fun and serves no earth shattering purpose Here s the code Prompt redefinition function elseif strcomp tokens Q string PROMPT bytemove prompt tokens 1 strsize tokens 1 1 The parser tries to match PROMPT in this case statement and then enters the handler if a match is found Now something interesting happens next The handler needs more data from the tokens array in fact the next element in the array after the command will be the string the user wants to change the 382 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS prompt to so the code uses tokens 1 as the string pointer and updates the global prompt string Remote Command Processing Example This is where things get really inter esting Each remote command is tested just as the local commands but the dif ference is that instead of doing someth
294. dn 4 ror old 4 djnz m dodiffb djnz n loop wrlong dest val jmp cmdLoop We can build additional filters to invert an image look for edges and apply a thresh old Unlike Photoshop we want to apply our filter continually to new frames coming from our frame grabber We also want to chain multiple filters together linking the output of one filter to the input of another To do this we ll implement the concept of a video buffer and a simple scripting language see Fig 7 6 for a diagram In the last section we allocated one contiguous array in memory and used the PropCVCapture object to write new frames of video into that array at high resolution From now on we ll continue allocating one array in memory but treat it as four separate video buffers We ll name the first 1500 longs of the buffer Quadrant 0 and display this in the upper left inside area of ViewPort Our frame grabber will fill this buffer with raw video from the camera if we use the VIDEO4 option We ll name the remaining 4500 longs Quadrants 1 2 and 3 and display them in the upper right bottom left and bottom right areas respectively Using our scripting language we ll filter frames to and from these video buffers You can think of each of these buffers as a temporary video variable that we use for our video calculations We ll keep our scripting language simple For each script action we ll store one long that indicates which filter
295. door lighting and 11 is 100x sensitivity for low lighting conditions Pins 8 and 7 are S3 S2 and signals applied to them can optionally slow down the output frequency for slower microcontrollers 2 2 k k k k k k k k k k k k k K k k k K K K OK OR K K K K K K TSL230 Light to Frequency Driver v1 0 Author Paul Baker Copyright c 2007 Parallax Inc See end of file for terms of use FORO IIIB AIG FORO RIO BO AAIIICGIORIRIORIG IIIA IIIA IGK Taos TSL23 light to frequency sensor v1 0 driver with manual and auto scaling capabilities ctrlpinbase 1 S o 3 8 _ ctrlpinbaset1 2 S1 s2 7 r 3 0E Out 6 inpin ak 4 GND Vdd 5 3 3V l aK K ak 2 k k k k k k k k k k k k k k k k k K K K K k k k k k K k k k k k k k k K K K k k K K K K K K K K K K K K Object tsl1230 Interface PUB Stop PUB Start inpin ctrlpinbase samplefreq autoscale okay PUB GetSample val PUB SetScale range Program 50 Longs Variable 6 Longs FREQUENCY OUTPUT 155 With a maximum output frequency in the neighborhood of 1 6 MHz there s no need for the TSL230 to slow its output frequencies down for the Propeller That s why the object documentation shows both pins 8 and 7 grounded to disable any output frequency down scaling The object documentation also explains that there are two input sensitivity scaling modes manual an
296. duty cycle or signal decay or performing delta sigma A D and duty modulated D A conversion Information We put these powerful state machines to good use in later chapters Summary We learned what multicore is about and why it s important We also explored our multicore hardware in preparation for the journey ahead The next chapter will apply this hardware a step at a time while teaching simple problem solving and multicore programming techniques Exercises To further your learning experience we recommend trying the following exercises on your own 1 Carefully consider opportunities for multicore devices How could a self propelled robot be enhanced using multicore What if it had multiple legs and arms 2 Think about ways humans exhibit multicore traits Yes we have only one mind but what keeps our heart beating and our lungs pumping while we are busy think ing about this What about learned reflexes Keep this in mind when applying multicore hardware to future applications INTRODUCTION TO PROPELLER PROGRAMMING Jeff Martin Introduction The most reliable systems are built using simple proven concepts and elemental rules as building blocks In truth those basic principles are valuable for solving many everyday problems leading to solid and dependable results Together we ll apply those principles in step by step fashion as we learn to program the multicore Propeller in the following
297. e Configure debug display Start debug cog xxxFix If no locks in pool DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 97 debug Str String Error no locks cognew TimerMs stack 10 59 ms 999 repeat 8 waitent clkfreq 3 cnt repeat until not lockset semID longmove minutes m 3 lockelr semID debug break Fix Display error message Launch timekeeping cog x Add x Add x Add Modify to 8 reps Main loop xxAdd xxxFix Wait for lock set Copy timestamp vars xxxFix Clear lock Remove debug Vars m String minutes seconds milliseconds PRI TimerMs t t cnt dt clkfreq 1000 repeat waitent tt dt repeat until not lockset semID mstt waitent clkfreq 4 cnt if ms 1000 ms Q stt waitent clkfreq 4 cnt if s 60 s mt waitcnt clkfreq 4 cnt if m 60 m 0 lockclr semID Current clock counter Modify Ticks in 1 ms Infinite loop Wait for the next ms xxxFix Wait for lock set Add 1 to millisecond count xxfAdd If milliseconds 1000 Set milliseconds to 0 Increment seconds x Add if seconds 60 Set seconds to 0 Increment minutes xxfAdd If minutes 60 Set minutes to 0 Fix Clear lock Judging by the Parallax Serial Terminal display in Fig 3 20 the bug has been fixed As this program runs you ll be able to see a visible pause be
298. e pan has 1500 subtracted recall that 1500 is a centered servo The result is multiplied by 2047 90 degrees with 8191 being a full 360 degrees and divided by the full range of pan Finally an m is sent followed by range and angle of the servo plus the pan offset This repeats for each value of pan from 1000 to 2000 in increments of 15 steps or 1 35 degrees 15 90 degrees 1000 steps 1 35 degrees Once mapping is complete the system will wait until another p is received to exit pan mapping mode while sending a c to clear the video display The variable mapping is used as a flag to prevent the SendUpdates code running in a separate cog from sending updates while mapping Pub Map panValue Method turns servo from 45 to 45 degrees from center in increments and gets ping range and returns m value at each increment SERVO Set Right 1500 Stop servos SERVO Set Left 1500 SERVO Set Pan 1000 Pan full right XB Delay 1000 Pan right to left repeat pan from 1000 to 2000 step 15 SERVO Set Pan panValue Range Ping Millimeters PING Pin Get range calculated based on compass and pan PanOffset panValue 1500 2047 1000 230 WIRELESSLY NETWORKING PROPELLER CHIPS XB TX m Send map data command XB DEC Range Send range as decimal XB CR XB DEC 8191 Theta PanOffset Send theta of bearing XB CR XB delay 58 XB delay 1000 SERVO SET Pan 1500
299. e debug COMMA_DELIMITED configures PST Debug LITE to display comma delimited lists Since PST Debug LITE is really just the Parallax Serial Terminal object with some additional features its Start method needs to be called in the same way the Parallax Serial Terminals object s Start method is called Test Time Counting spin uses debug Start 115200 Near the end of the TimerMs meth od s repeat loop debug KeyCheck checks the PST Debug LITE object s serial receive buffer to find out if the Parallax Serial Terminal sent a character that was typed into its Transmit windowpane If the Propeller chip receives a character from the Parallax Serial Terminal the debug Vars m String long m s ms method call passes the address of the m variable along with a string copy of the variable declaration that starts with the m variable Test Time Counting spin First test of timestamp code verifies proper counting sequence CON _clkmode xtal1 plli6x _xinfreq 5 000 000 Crystal and PLL settings 5 MHz crystal x 16 80 MHz OBJ debug PST Debug LITE Debug object VAR long m s ms PUB TimerMs debug Style debug COMMA_DELIMITED debug Start 115200 repeat Timekeeping variables Configure debug display Start debug cog Infinite loop 88 DEBUGGING CODE FOR MULTIPLE CORES ms Add 1 to millisecond count if ms 1000 If milliseconds 1000 ms Q Set milliseconds to 0 s
300. e elsewhere in the program can use that label to make the program jump to that label and continue executing code from there The most rudimentary example of this is to label one line of code with loop then later in the code another line uses the jump to address jmp instruction to send the program back to the loop label The command should read jmp loop and the literal indicator causes program execution to jump to the instruction at the Cog RAM address of label A common mistake is to simply type jmp loop instead If the literal indicator gets left out the contents of the actual machine language instruction a binary value that corresponds to add count 1 in the following example instead becomes the Cog RAM jump target address and the program wanders off somewhere unexpected loop add count 1 wrlong count addr jmp loop Assembly Language Example As an aside Asm Cog Example spin has an assembly language routine that counts and rapidly updates a Spin variable named asmCt When cognew launches an assembly routine into a cog the first argument is the address of a label where the cog should start executing assembly language code The address of the first line of assembly code that should be executed in Asm Cog Example spin is AsmCounter The second parameter is typically the address of a Spin variable in Main RAM that will be used for information exchange between the assembly code and the Spin code The value in the se
301. e API methods SPI Assembly Layer The lowest level of the driver is the SPI layer We ll discuss in detail here how it works but all details aside all it really does is send and receive bytes using SPI The SPI layer is written completely in assembly code and is designed to live wholly in a cog with its 396 bytes The first thing that the SPI layer does is set the correct pins to input or output as needed to enable communication between the HYDRA and the W5100 via SPI Once that is done we take the W5100 out of reset Since there is no power up reset on the W5100 the HYDRA needs to reset the W5100 sometime after power up We take care of this by pulling down the reset pin of the W5100 on the EtherX card which will 296 USING MULTICORE FOR NETWORKING APPLICATIONS hold the W5100 in reset mode when the device is turned on It is up to the HYDRA to take the W5100 out of reset by setting the reset line to the W5100 to logic high Thus the W5100 is held in reset until the SPI assembly code portion of the driver is started in a new cog After that the SPI layer looks at global variables to determine what to do next Five global variables are used to interface the Spin methods of the driver to the SPI layer Since the variables are global they reside in main memory and are accessible by all cogs including the one where our SPI layer is located The first global variable is the SPIRW variable The main loop of the SPI layer will constantly lo
302. e CEO of Nurve Networks LLC which develops and manufactures embedded systems for educational and entertainment channels Additionally he holds a teaching position currently at Game Institute ABOUT THE AUTHORS xiii Andy Lindsay is an applications engineer and a key member of Parallax s Education Department To date Andy has written eight Parallax educational textbooks including What s a Microcontroller Robotics with the Boe Bot and Propeller Education Kit Labs Fundamentals These books and their accompanying kits have gained widespread accep tance by schools in the United States and abroad and some have been translated into many languages Andy earned a Bachelor of Science in electrical and electronic engineer ing from California State University Sacramento He has worked for Parallax Inc for over ten years where he continues to write teach and develop educational products Jeff Martin is Parallax s senior software engineer and has been with the company for 13 years and counting He attended California State University Sacramento studied many areas of computer science and earned a Bachelor of Science in system s software In 1995 Jeff visited Parallax to purchase a BASIC Stamp 1 He rapidly learned and mastered the original BASIC Stamp and was shortly after offered a position to support it and other Parallax products He is currently in the R amp D department and is responsible for Parallax software IDEs k
303. e Parallax Serial Terminal The Propeller Library s Keyboard_Demo spin makes use of both the Keyboard and TV_Terminal objects to demonstrate a PS 2 keyboard this requires both circuits shown in Fig 3 12 v N a PALA A J v a S titteiiises D www porollox com a a Ono Figure 3 11 Propeller Demo Board 80 DEBUGGING CODE FOR MULTIPLE CORES VddVdd Keyboard PS 2 10 KQ 10 KQ P12 1 1kQ P13 C gt P26 560 Q C P27 P14 100 Q 2702 Figure 3 12 TV terminal and keyboard circuits The left side of Fig 3 12 shows the Propeller Demo Board s 3 bit D A converter DAC circuit that the application uses to generate baseband video with the TV_Terminal object This circuit is also built into the Propeller Professional Development Board and it can be constructed on the Propeller Education Kit breadboard and the Propeller Proto Board using the Parallax RCA to Breadboard adapter The right side of Fig 3 12 shows the PS 2 Keyboard circuit from the Propeller Demo Board This circuit is also built into the Propeller Professional Development Board and can be constructed on the Propeller Education Kit breadboard with the Parallax PS 2 to Breadboard Adapter or on the Propeller Proto Board with either the PS 2 to Breadboard Adapter or the Propeller Proto Board Accessory Kit The Keyboard_Demo spin object s OBJ block declares the TV_Terminal and key board objects giving them the nicknames term and kb Both o
304. e ViewPort overview table Asynchronous Serial Sensors that communicate with asynchronous serial protocols are typically equipped with microcontroller coprocessors Examples of such asynchronous serial sensors include the Parallax GPS module and RFID reader shown in Fig 4 42 The Propeller chip uses asynchronous serial signaling to communicate with the Parallax Serial Terminal The serial communication activity is visible on I O pin P30 in Fig 4 41 That s the Propeller chip transmitting serial messages that contain ViewPort data to the USB adapter on its way to the PC For most Propeller boards there is a USB to serial converter in the Propeller s programming tool that converts incoming USB Figure 4 42 GPS and RFID modules ASYNCHRONOUS SERIAL 175 signals to serial messages and it also converts outgoing messages from serial to USB signals On the PC side a driver that supports the USB serial chip on the Propeller s programming tool converts incoming USB messages back to serial messages and it also converts outgoing messages from serial to USB signals Tip The Propeller chip can also be programmed directly through a COM port using RS232 serial communication instead of USB see the Propeller Tool Help EXAMINING SERIAL COMMUNICATION SIGNALS For a closer look at serial communication the Parallax Serial Terminal object can be configured to transmit 4800 bps serial messages to an I O pin and the QuickSample object can
305. e best way to make sure you don t miss any is with a Search Replace All lines with Add comments can be removed Likewise all the lines of code with Remove can be uncommented and all the lines with Modify can be unmodified It s important that you don t forget to restore dt clkfreq back to dt clkfreq 1000 After one last test to make sure the code still cor rectly timestamps events it s ready to get incorporated into a building block object Test Timestamp Bug Fix Full Speed spin This program tests to verify that semaphores prevent memory memory collisions at full speed no slow motion delays CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 99 OBJ debug PST Debug LITE VAR long stack 40 long m s ms t dt long semID PUB Go minutes seconds milliseconds debug Style debug COMMA_DELIMITED debug Start 115200 if semID locknew 1 debug Str String Error no locks cognew TimerMs stack repeat repeat until not lockset semID longmove minutes m 3 lockelr semID debug break Serial communication object Ample stack for prototyping Timekeeping variables Fix Semaphore ID variable Configure debug display Start debug cog xxxFix If no locks in pool Fix Display error message Launch timekeeping cog Main lo
306. e functions are so common I decided to bring them out as separate commands and add to the command list Therefore you can actu ally make the user experience from a command point of view easier since now the user or RPC client doesn t have to remember some cryptic clear screen code but simply needs to remember CLS This is converted by the handler into the appropriate driver clear screen home backspace tab 8 spaces per set X position X follows set Y position Y follows set color color follows return printable characters wordfill screen 220 screensize col row 0 col row 0 if col col repeat print while col amp 7 0C flag c return newline other print c cols rows c amp 7 ao messages and the results are the same EXPLORING THE COMMAND LIBRARY TO THE SLAVE SERVER 387 Exploring the Command Library to the Slave Server In this section we are going to briefly look at all the commands supported by the CCP in a reference fashion Some simple conventions for the format of commands E Parameters are shown in braces E All numbers are in ASCII format in human readable format E Commands and subcommands are case insensitive LOCAL COMMANDS TO TERMINAL These commands control the terminal itself and do not send messages to any of the drivers Cls Clears the terminal screen help Prints the help menu prompt s
307. e no character is in the buffer the code still can t get to it v Click the Terminal and press the ENTER key The active line highlighter will appear over the breakpoint V Change the value of count to 10 again but this time try the Step Over button V Stepping over the Alarm method call should cause the Alarm message to appear in the Terminal pane but the active line of code should jump back to the if vp rxcheck line DEVELOPMENT WITH THE PROPELLER ASSEMBLY DEBUGGER PASD is a must if you plan on writing assembly code for your objects Assembly language is great for making high performance versions of Spin objects and it can also be used to tackle certain tasks that the interpreted Spin language might not be fast enough for An example of the speed improvements that can be attained with assembly language is the SimpleSerial Spin object s top baud rate of 19 2 kbps compared to ViewPort s conduit object which uses assembly language to support rates up to 2 Mbps Like ViewPort and the Parallax Serial Terminal the PASD software relies on an object PASDebug spin running in another cog to send it information The code being debugged needs to declare the object and receive some slight modifications before it can be examined with PASD Here are the general steps for setting up an object for debugging with PASD DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 111 E Copy the test code and any objects it relies on into
308. e same can be said for the parallel LCD There are Propeller objects that make interacting and updating a parallel LCD as simple as interacting with the more expensive serial controlled LCD 418 THE HVAC GREEN HOUSE MODEL units A serial communication object can handle the complexity of sending and receiv ing data over a network with other devices So based on these capabilities the room board would handle the servo motor the LCD the temperature sensors the humidity sensor user interface status lights and network communications Since we knew there would be more than one room board and we were hoping to reduce the wiring costs by using a daisy chain wiring configuration we decided to use an open collector communication approach and allow all the boards to share the transmit and receive pins To make sure that only one board at a time would be trans mitting a polling method of communication was chosen where the master board would call each room board and only then would the room board send an answer to the master board To differentiate the room boards we placed a bank of four jumpers connected to Propeller pins PO P3 to allow us to set an ID number allowing a maximum of 16 room boards on our network at one time The room boards would simply ignore any poll request that did not begin with their unique address Since the master board needs only two pins to perform its duties as the network master i e just transmit and r
309. e to have an on demand system where you could start and stop cogs with other objects as needed to manage the number of cogs running at once For example say you don t have room for both a keyboard and mouse at the same time but you want to support them Thus you would make a func tion that when you tried to talk to the mouse if it wasn t running it would terminate the keyboard processor then start the mouse and vice versa ON DEMAND DRIVERS Another more advanced idea is on demand drivers In this design you would have a multitude of drivers on EEPROM or secondary storage then you would pull them into memory on the fly start them up on processors and then the console or RPC client would be able to send commands to them SPEEDING THINGS UP We briefly discussed the merits of human readable ASCII text and why the decision to go that route was used However we also touched upon using ASCII to encode commands not in human readable form and finally going to 100 percent binary In the exercises section at the end of the chapter there will be a couple challenges to take what we have now and speed it up but start thinking about it now Next we ll talk about more advanced chip to chip protocols and take the serial terminal out of the loop and create a truly high speed system that runs in the MHz range and is appropriate for chip to chip communications Exploring Other Communications Protocols This project uses a simple RS 232
310. each clock tick at which the input pin detects a high signal In this way the counter module works to maintain 1 65 V at the input pin The capacitors slow down the voltage response at the input pin to the highs and lows the feedback pin sends so the voltage at the input pin only deviates slightly from 1 65 V as the feedback pin rapidly transitions between 3 3 and 0 V every time it detects a slight deviation below or above the 1 65 V input threshold The interplay between a cog s counter module and the Sigma Delta circuit makes it possible to digitize the analog voltage input The cog configures the counter module to count the number of clock ticks when the voltage at the input pin is above 1 65 V which turns out to be proportional to the voltage input If it so happens that the voltage input is already at 1 65 V the input pin detects high signals about half the time adding 1 to the counter module s phase accumulation register commonly referred to as the phase register for every clock tick at which a high signal is detected If the voltage input is instead 2 2 V the input pin will detect and count high signals two thirds of the time and the feedback pin will send low signals two thirds of the time to keep the voltage at the input pin at 1 65 V Likewise if the voltage input is 1 1 V the input pin will detect a high signal only one third of the time and the feedback pin will only send low signals one third of the time and of course high si
311. easure the length of the gyro s output signal Con gyroQutP 5 gyroInP 8 pub doGyro gyroTime diraLgyroQutP ctra 10101 lt lt 26 001 lt lt 23 GyroInP set up counter for gyroin measured lag till pulseout frqa 2 repeat outa GyroOutP phsa GyroDone cnttgyrol ime waitcnt GyroDone outa GyroOutP gyro phsa gyroO0ffset For our accelerometer let s look at the LIS3LVO2DQ a three axis 2 g digital MEMS Linear Accelerometer It s a low cost sensor that uses multiple miniature cantile vers to measure acceleration in three axes It runs on 2 16 to 3 6 V and uses the common TC or SPI serial protocols for communication Since it is digital we just need to provide it with power and ground and two lines to the Propeller for communication To use it we need to first initialize several control registers that set various filters and ranges and then we query it periodically to read the accelerometer s values Here s the Spin code which uses James Burrows i2cObject from the Propeller Object Exchange 248 DANCEBOT A BALANCING ROBOT init accelerometer a i2c Init accelSDAP accelSCLP true i2c writeLocation ACC3D_Addr 20 1101 0111 8 8 ctrl_regl power on 16 hz no self test all axis on i2c writeLocation ACC3D_Addr 21 0010 0000 8 8 etrl_reg2 2g update continuously big endian no boot 12bit i2c writeLocation ACC3D_Addr 22 0000 0000 8 8 etrl_reg3 no f
312. eceive lines it has plenty of pins and processing power to allow for an advanced intuitive graphical user interface By using the NTSC video output object it is a straightforward process to display statistical information about system performance and present an advanced graphical user control interface through an embedded NTSC video monitor For our experimental platform we are currently imple menting the NTSC video output to display current temperature target temperature and vent position for each room on a Parallax Mini LCD A V color display Fig 11 19 Haster Board vi 0 Room Cur Temp Target Temp Vent 50 110 N Outside 70 F COOL RECIRC Pressure OK Figure 11 19 The NTSC monitor with the preliminary system test data displayed THE HVAC GREEN HOUSE MODEL 419 System Overview All needed data is displayed on NTSC Master Board Periodically calculate optimum values for room boards and control board Periodically poll room boards for actual temperature and desired temperature Periodically update room qr Room Board LCD display Monitor temperature Monitor button presses Respond to master board information requests Respond to master board board vent positions vent position settings Periodically update control board with heating or cooling and recirculating or fresh air Periodically poll Control board for outside air temperature Control Board
313. eceive size register It will return the number of bytes that the W5100 has stored in its receive buffer for you to read If this method returns a non zero number there is data in the W5100 for us to read This read_rsr method is also handy in determining if we have read all the data out of the W5100 For example if we make a call to the RX method and specify that we should read and store 32 bytes from the W5100 to the main memory of the HYDRA pointed to by the dataptr argument and the return value is 32 we have a problem We don t know if there are more bytes in the W5100 for us to read Remember we specify 312 USING MULTICORE FOR NETWORKING APPLICATIONS a maximum amount of bytes to be written to the main memory in the HYDRA If we store that maximum amount of data there could still be more in the W5100 waiting for us to read it But how could we know The answer is to call the read_rsr method If after we call RX with a size argument of 32 and we get a return value of 32 and we call the read_rsr and it returns 0 then we know we got all the data If it returns a non zero value we know there is still data left over in the internal W5100 buffer for us to read out The code for this method is shown here PUB read rsr ret_val Read the receive size register This will return the value in the receive size register in the W510 A non zero value indicates that there is data to be read ret_val read 04 26 ret_val r
314. eces all fit together To begin with the Propeller is running a number of drivers on multiple cores NTSC graphics terminal VGA graph ics terminal keyboard driver and sound driver Each of these drivers takes a single core Now by themselves they don t do much So the glue of the system is the CCP which is pure Spin code that not only issues commands to the drivers but also is the interface from the serial terminal running off chip the PC and the Propeller chip itself Thus the CCP runs on its own core controlling the media cores as well as handing user input from the serial line which at its other end has a serial terminal running in VT100 mode like PuTTY was used here With the system in this known state let s review exactly what happens in each phase when the system boots Initialization After reset the software simply loads each of the drivers for NTSC VGA keyboard and serial Finally the main PUB start method of the CCP is entered and the system begins listening to the serial line User input loop As the user types over the serial terminal the CCP listens to the input Thus there is a little toy editor that understands character input backspace editing and the lt RETURN gt key which means process this line Processing and tokenization When the user enters a line of text the CCP has no idea what it means thus the text needs to be processed and tokenized into meaningful strings of data
315. ecome unstable at 100 Mbps It is no big deal that the default of the EtherX operates at 10 Mbps as the SPI interface to the W5100 is so much slower than 10 Mbps that you would never notice the difference in addition all Ethernet devices are backward compatible to 10 Mbps But if you wanted to operate the device at 100 Mbps this is the method you would call to do so If you choose to call the mode method it must be called before you start the EtherX driver This is because one of the first things the EtherX driver does is take the W5100 out of reset once the W5100 is out of reset you shouldn t change the mode of the device Thus the mode method first checks to see if the EtherX driver has already been started and if so it will do nothing The method is shown here PUB mode opmode temp Call this method with the value wanted for opmode before the start method is called If the start method has already been called then this method will do nothing if cogon Q Be sure driver not already running DIRA 70000 Set pins 16 18 to output temp opmode lt lt 16 Shift our arg 16 bits left OUTA amp SFFF8FFFF Clear all outputs on pins 16 18 OUTA opmode Set only required pins on pins 16 18 300 USING MULTICORE FOR NETWORKING APPLICATIONS Functionally all the mode method does is set the pins that map to the W5100 mode pins to output and set them according to the opmode input parameter To make the W5
316. ed locally by the terminal core processor that is running the command line interpreter Local commands are used to talk to the terminal set things change fonts query the time and so forth I have only implemented a couple of local terminal commands for illustrative purposes but you can add more In a moment we will see these in action NTSC Driver Initielized Serial Paid rp Sound Driver VGA Driver Initialized Keyboard Driver Initielized Serial Driver Initialized Ready gt Sound Driver Initialized Keyboard Driver Initialized Ready gt Figure 10 4 Boot process as the system starts out as output on the NTSC left and VGA right monitors 360 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS COM27 PuTTY er Master Figure 10 5 The serial terminal output on startup after a reset The remote commands are more useful and do the actual heavy lifting These com mands actually send messages to the various cores cogs running the media peripherals and hence allow us to control the cores via the serial terminal We can do things like print to the NTSC terminal play a sound read the keyboard and so on All of these things are being processed by the cores of the Propeller in parallel but we can access them remotely over the serial terminal via commands Local Commands Sample HELP This command simply prints out the system HELP Go ahead and type HELP into the CCP and watch the HELP scroll b
317. ee to AT mode allowing for short guard times using ATGT so instead of six seconds to modify a configuration it can be done quickly in code XB AT_ConfigVal allows passing an AT command and a value to set configura tions such as the DL and MY addresses The underlying code switches the XBee to com mand mode sends data and exits using the short guard times Enable XBee for fast configuration changes XB AT_Init Set MY and DL destination address XB AT_ConfigVal string ATMY MY Addr XB AT_ConfigVal string ATDL DL_Addr In the ProcessData method XB rx is used to tell the Propeller to wait for one charac ter or byte of data It then tests this character to determine what set of actions to take dataIn XB rx Case datalIn p p PING distance range Ping Millimeters PING Pin Read PING in mm XB dec range Send range as ASCII decimal value XB cr End decimal string with CR c Compass theta HM55B theta Read Compass XB dec theta Send theta of bearing as decimal XB cr End with carriage return MA i 1 0 control IO XB rxDecTime timeout Accept IO number w timeout state XB rxDecTime timeout Accept state 1 0 w timeout if state lt gt 1 dira I0 Set direction of pin outal10 state Set state of pin XB dec outa 1I0 Send state back for verification XB cr End decimal string with CR If p send back the decimal value of the range finder
318. elay in Top File spin s Start method call Blinker would have received and attempted to use the value 20 000 000 for the address of the Top File object s delay variable and any update the Top File object makes to the value of its delay variable would go unnoticed as Blinker executed its repeat loop in another cog Building Block spin VAR Variable declarations long stack 20 cog Stack array amp cog variable PUB Start pin delayAddr success Start blinking process in a new cog Parameters pin I O pin number to send the high low signal delayfddr Address of the long variable that stores the delay Returns zero if failed to start or nonzero if it succeeded Launch process into new cog and return nonzero if successful success cog cognew blinker pin delayAddr stack 1 76 DEBUGGING CODE FOR MULTIPLE CORES PUB Stop Stop blinking if cog If cog is not zero cogstop cog 1 Stop cog amp set cog to zero PUB Blinker pin delayAddr t Method blinks light Updates rate based on value in parent objects variable at delayfAddr t i ent Current cnt register gt t variable dira pin 1 Set I O pin to output repeat Repeat loop waitent tt long delayAddr Delay from parent object s var outaLpin Invert I O pin output state FORGOTTEN LITERAL INDICATOR FOR ASSEMBLY LANGUAGE CODE In Propeller assembly language a line of code can have a label and then a line of cod
319. embly code is passed some configuration about the location and size of the video to filter and then searches for the maximum value in our array of pixel brightness values Since our frame grabber has packed 8 four bit pixels into each 32 bit long we need to make sure to look at each individual pixel by first decoding it This filter processes one pixel every five instructions The filter pro cesses only data not sync marks or color bursts so let s calculate if it s fast enough to process the incoming data 1 pixel S instructions line 120 pixels frame 100 lines 20 M instructions sec 333 frames sec New frames are only coming in at 30 fps so the Propeller is fast enough to apply multiple filters to incoming video in real time doMax setup ptrs to positions mov dnp src src points to first pixel add dnp bytesNline dnp is one row below src sub n 15 Number of pixels to inspect mov dest Location of pixel mov sum 0 Brightest value so far loop rdlong old src add src 4 rdlong dn dnp add dnp 4 mov m 8 mov new 0 dodiffb mov tmp old and tmp 15 Decompress 4 bits out of a long mov t1 dn and t1 15 tl pixel down add tmp t1 tmp pixel value of two vertical pixels cmp tmp sum wc c if tmp lt sum 266 CONTROLLING A ROBOT WITH COMPUTER VISION if_c jmp notMax Found a new maximum mov dest sum So save the position and value shl dest 16 add dest n mov sum tmp Reset max notMax ror
320. emisphere we would need to multiply the longitude decimal degrees by negative one We are not going to explain the details of entering formulas into a spreadsheet program here instead we have already imported and data manipulated the CSV log file and stored it as a Microsoft Excel XLS file This file is located here Chapter_09 Source Logs SENSOR_5_20_2009 xls In addition to the latitude longitude conversion the Excel file converts the pressure from 1 millibars to kilopascals for use in the altimeter calibration formula we discussed previously Now in order to convert the measured pressure into altitude above sea level we first need to find out the local region s air pressure at mean sea level MSL This is known as the altimeter setting Since this value is constantly changing depending on the weather like a high or low pressure system moving in from a storm we need to obtain this information beforehand In fact this is how aircraft operates because they will radio the tower before takeoff and adjust their altimeter accordingly This informa tion can be obtained from a local airport or more easily obtained from a weather Web site For example we recorded the local air pressure previous to the drive test at 32 02 in of mercury or 101 65 kPa from www weather com 348 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER GPS Alt m Altitude m Figure 9 12 GPS altitude versus pressure altitude The Excel spre
321. en either a TCP or UDP socket based on the type argument The source_port and dest_port are the source and destination port numbers The last argument is meant to be a four byte array that stores the destination IP We could have just made this a long arg but this format is more human friendly Set the socket type so that other method know if we are TCP or UDP socket_type type Configure socket for UDP for TCP TCP is the default if socket_type UDP write 04 00 2 else write 04 00 1 304 USING MULTICORE FOR NETWORKING APPLICATIONS Configure source port temp source_port gt gt 8 amp SFF temp2 source_port amp SFF write 04 04 temp write 04 05 temp2 Configure dest port temp dest_port gt gt 8 amp SFF temp2 dest_port amp SFF write 04 10 temp write 04 11 temp2 Dest IP write 04 Qc byteLdest_ip write 04 Qd bytel dest_ipt1 write 04 Qe bytel dest_ipt2 write 04 f byteL dest_ipt 3 Open socket write 04 Q1 1 You can see that the method has four parameters passed into it The first is the type which is either 0 or 1 A 0 means UDP and a 1 means TCP The CON sec tion defines UDP to be 0 and TCP to be 1 for easier readability The next two arguments are the source and destination ports The final argument is a pointer to a byte array of the destination IP This value doesn t make sense if we int
322. end to be a TCP server as we cannot possibly know the IP address of the client that may attempt to connect to us Thus if we intend to be a TCP server this value can be anything because it will be ignored Notice that the open method will set the socket type source and destination ports and then the destination IP address before actually opening the socket If you choose to not use the open method and instead open a port yourself using the write method be sure not to open the socket until these are set Do not attempt to change the socket type ports or des tination IP after the socket has been opened If you need to change one of these parameters close the port first The close method will close a socket After the close method has been called the socket will no longer send and receive data on that socket Once closed however you can change the socket type source and destination ports and destination IP address Then if you wanted you could reopen the socket and those new parameters will take effect The following is the code for the close method PUB close Close the socket write 04 01 10 ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 305 Listen Connect and Connection Established If you choose open the socket as a TCP socket you need to determine if you will be a TCP server or a TCP client TCP will establish a connection before data is exchanged Two methods will work to establish a connection which o
323. ense Advanced Research Projects Agency DARPA 259 Delay Beyond Interval spin 69 71 69f destination MAC 282 Digi International 194 dira 24 26 Direct Memory Access DMA 321 Display Mic with ViewPort spin 167 Display P16 Input States spin 125 distributed COM D COM 372 DMA See Direct Memory Access DNS See Domain Name System document comment 37 Documentation view 37 37f DOD See United States Department of Defense Domain Name System DNS 284 drivers data flow from user to 366 issuing commands to 380 386 normalization of for common RPC calls in future 371 372 on demand 389 overview 370 372 371f 371t selecting 365 366 DS1620 Digital Thermostat 168 169f dso view in ViewPort 104 106f dual axis accelerometer 144 145f Duration 29 30 41 duty cycle outputs See pulse and duty cycle outputs Earth Viewer program 351 Echo On check box 61 EEPROM 5 6 6f 28f 39f EtherX card and signals of 290 RAM vs 27 28 end device nodes 208 ephemeris 326 Ethernet frame 282 282f 285 285f 286f Ethernet protocols 281 286 287f Ethertype 282 EtherX add in card for Propeller powered HYDRA 287 312 application methods layer 299 312 application programming interface 294 312 read and write layers 297 299 EtherX card 282 288 289f electrical interface of 290 293 290t SPI mode 0 293 EtherX Ethernet add in card 281 EtherX software model 294 294f Eltima Software Serial to Ethernet Connector 395
324. entral Hub controls access to the mutually exclusive resources such that each cog can access them exclusively one at a time Think of the Hub as a spinner or propeller that rotates and gives each cog access to key resources for a set time Hub operations use the Propeller Assembly language instructions rather than the aptly named higher level Spin language The Propeller s main memory is one of the mutu ally exclusive resources You would not want two programs to try to access memory simultaneously or to modify a value in use by another cog The Propeller chip and Parallax offer users another less tangible asset a devoted cadre of users and developers Parallax has an active Propeller Chip forum with more than 430 pages of posts that go back to early 2006 Parallax forum membership has reached more than 17 000 registered members Run a Google search for Parallax Propeller and you ll find individual projects discussions products and code If you run into a problem getting your hardware or software to work someone XV xvi FOREWORD on the Internet usually has a suggestion or comment often within a few minutes Parallax also offers many add on devices such as accelerometers ultrasonic range sensors GPS receivers and an image sensor that help bring projects and designs to fruition rapidly Over the years I have worked with many types of processors from early eight bit devices to new ARM based chips But none
325. er Forum at forums parallax com The top threads contain links to many valuable Propeller resources More tips and examples can be found by joining a Propeller Webinar a live web based meeting or viewing archived webinars at www parallax com go webinar see Fig 2 28 This is a way to connect to Parallax staff and get an inside look at how to use the multicore Propeller 48 INTRODUCTION TO PROPELLER PROGRAMMING gt Propeller Webinar Archives Windows Internet Explorer Ge lt ee ee mgn geed a ek Ue dr p propeter webinar Archives l R D wh Eeew Qs gt Home gt Store gt Product Into N d Education N X SS Lawan Propeller Webinar Archives uppart Hame Product Information Downloads Discussion Forums This iz a collection of audio video recordings from past Propeller Webinars These webinars were onginally hosted live wth a participating audience that attended via their computer Tor the benefit of all we have provided the important parts of each webinar Webinars as a series nf short topical clips in hath WMV and MPs formats Object Pxrhange Tech Support Would you like to attend a live webinar View our webinar schedule for more details Consultants Resources Company Viewing Tips Many ot these clips consist of computer screen captures at a resolution of 1280x1024 to demonstrate software source r code elc For the besl expejente they should be viewed on monitors with
326. erX card 297 299 read method 297 298 300 read_calib_word 336 read_data_word 336 338 readNMEA method 330 read_rsr method 311 312 READY command 361 real time clock RTC 324 real time streaming 284 receive method 308 311 receive size register 311 312 remote commands 359 processing example 382 386 remote keyboard 362 remote nodes polling 208 214 Remote Procedure Call RPC 353 ASCII or binary encoded 368 369 compressing for more bandwidth 369 370 primer 366 370 367f simplified strategy 370 remove test code 98 99 repeat instruction 25 26 repeat keyword 315 repeat loop 67 reset button LED after pressing 27 resistive sensors 138 140 153 156 187 in RC decay circuits 138 139 resistors pull down and pull up 123 124f resonators 432 response code binary bit encoding format 340 341f RFID reader 174 174f RGB color space 275 RJ 45 connectors 412 413 Robotics with the Boe Bot Lindsay 222 robots 221 225 222f 223f controlling with computer vision 257 280 speed of 269 vision guided 257 258 robots computer vision 258 259 258f filters and bright spot in real time 265 269 270f following line with camera 270 272 271f robots computer vision Cont OpenCV and Propeller integration 276 279 277f state of the art with OpenCV 274 276 track pattern 272 274 rotation velocity 169 170f round robin memory access 54 54f routers 208 283 RPC See Remote Procedure
327. ermine if a connection has been made Do not attempt to receive or transmit data before a con nection has been established The con_est method will return true when the connec tion has been established and will return false if a connection has not been established Following is a snippet of code from SimpleTCPClient that shows how to use connect and con_est It can be found in the Chapter_08 Source SimpleTCPClient S pin directory Initialize the W510Q eth init gateway subnet ip mac Open the socket for TCP communication eth open TCP PORT PORT dip Display message term pstring string Connecting 13 Connect to the PC eth connect ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 307 Wait for connection to be established repeat while eth con_est false Display connected message term pstring string Connected to PC 13 13 You can see that the processes for setting up the W5100 as a TCP server and as a TCP client differ by only one line You use listen for a TCP server and connect for a TCP client Other than that the process is the same Whether you choose to implement your socket as a UDP TCP client or TCP server the next thing you need to do is send and receive data This is accomplished using the RX and TX methods which we will discuss next Transmit Once the socket has been opened and a connection established if you are a TCP socket type you can send and receive
328. ers EXPLORING OTHER COMMUNICATIONS PROTOCOLS 395 VT100 Emulator Ethemet TCP IP 192 168 x x Remote Machine Local Machine Serial packets embedded within TCP IP packets by server and extracted from TCP IP Serial 5 Server client The remote PC thinks its Physical talking to a local COM port butis COM port actually communicating with a remote port on the server machine COMnn Virtual COM port EZTTTTTTTTTTTT Figure 10 17 Serial over TCP IP connection and then we can create a virtual serial connection over the Internet to connect our serial port to Figure 10 17 shows this setup The idea is that we run a program on the PC that is connected directly to the Propeller s serial port Then we run another program on a remote PC these programs link up and then tunnel the serial port through TCP IP transparently so the COM port on the remote PC seems as if it were local on the remote machine Presto we can send com mands to our little project over the Internet A number of programs can do this Go to www download com and search for serial over internet serial over TCP IP serial port redirector and see what comes up One of my favorites is called the Eltima Software Serial to Ethernet Connector located at www eltima com products serial over ethernet It allows you to set up a server on one machine that serves out the serial port and then a client on another machine that accesses the
329. es We ll explain what is new to us We ve seen repeat before as an endless loop that did nothing but now it s more useful This repeat is a loop that endlessly executes a series of four statements within it Did you notice that the statements under it are indented That s important It means they are part of the repeat loop In fact by default the editor indicates that these are part of the loop by displaying little hierarchy arrows next to them as in Fig 2 12 PUB LED Blink Hierarchy arrows called block group es indicators automatically appear to point out code that belongs to a group in this case the last four statements are part of an endless repeat loop dirali6 1 repea outali6 1 waitcnt clkfreq cnt outa 16 A waitcnt clkfreq cnt Figure 2 12 A close up of the LED_Blink method as it appears in the editor RAM VERSUS EEPROM _ 27 INDENTATION IS IMPORTANT The Spin language conserves precious screen space by omitting begin and end markers on groups of code Just as we rely on indention in outlines to show which subtopics belong to a topic Spin relies on indention to know what statements belong to special control commands like repeat You can toggle the block group indicators on and off by pressing Ctrl I Spin will understand the indention either way The waitcnt command is something we haven t seen before It means Wait for System Counter and serves as a powerful
330. es ala leila P22 1121 Jo lt 1 lt 171 S lo lt jlcl ello g je ejje C CD D CD T 32 _ _ _ _ Pin Inputs le System Counter Data Bus Address Bus CLOCK Configuration Register Hub and cog interaction z We Ped cd E P BIRISI MULTICORE PROPELLER MICROCONTROLLER 11 The cogs processors are all alike and work together as a team sharing access to all system hardware main memory System Counter configuration registers I O pins etc Let s look closely at some notable components shown in Fig 1 9 Cogs processors The Propeller contains eight processors called cogs numbered 0 to 7 Each cog contains the same components and can run tasks independent of the others All use the same clock source so they each maintain the same time reference and all active cogs execute instructions simultaneously Tip Propeller processors are called cogs because they are simple and uniform like the cogs on gears that mesh with others of their kind to induce change Their simplicity assures reliability and their collective delivers powerful results Cogs start and stop at runtime to perform independent or cooperative tasks simul taneously As the developer you have full control over how and when each cog is employed there is no compiler driven or operating system based splitting of tasks between multiple cogs This explicit parallelism empowers you to deliver deterministic timing power consum
331. ese areas where multiple edges occur close together The algorithm I chose keeps a running total of the last eight pixels When we chain this filter with the horizontal Sobel filter it has the effect of finding large areas that contain strong horizontal edges caused by multiple black and white stripes For our last filter we ll reuse the findmax filter we designed two sections ago By chaining these three filters together we find the location of the maximum running total of vertical transitions in other words we find a black white striped pattern We can now use the location of the found object to steer our robot without any active input When used with the DanceBot we end up using all eight cogs see Fig 7 10 for a dia gram of the complete system Two cogs are used by PropCV to capture and process ViewPort Debugger Propeller with 8 Cogs DanceBot Software Frame Grabber NTSC gt ADC gt 4 Pins Memory Image Processing Frame gt Variables Position my Encode pulse i length phase QuickSample Sample IO pins at up to 80 Msps alman Gyro Monitor Change Variables 50 Hz update to Analyze Data eliminate drift ee OpenCV Vision Engine Fuzzy Control as ae PhysX World Simulation Measure tilt balance Integrated Debugger 5 i keep position Motore Proportional fwd rev Conduit Share data Figure 7 10 Complete DanceBot system diagram 274 CONTROLLING A ROBOT WITH COMPUTER VISIO
332. esign At first this master board had both an NTSC output to be used for a GUI and the components to control the blower fans and heat pump After thinking about real world requirements we decided that it would be more realistic to have the control compo nents located outside the house or in the attic near the HVAC equipment Subsequently we decided that a third board would need to be created that would host all the high amperage control components that would operate the heat pump and the blower fans This board would also host a sensor that would read the outdoor ambient temperature and humidity to be used for determining if the outside air were suitable to use for indoor heating or cooling As this board would be nearer the blower fans in the cooling tower we placed headers for servo motors to control the cooling tower bypass doors as well as the return air bypass vent flap With its feature set complete we dubbed this new board the control board Another round of autorouting and CNC cutting drilling now left us with three board styles room master and control all with the same physical size and pin configu ration but with different component loads and roles Figure 11 16 shows the results 416 _ THE HVAC GREEN HOUSE MODEL W a 2 Mi i Figure 11 16 The room master and control daughterboards before being stuffed and soldered After stuffing soldering and carefu
333. estination EA is incremented The XBee performs two retries before failure Additional retries can be added by using the RR setting AT Command Options CT AT Command Timeout Once in command mode this sets how long of a delay before returning to normal operation GT Guard Time When switching into AT command mode this defines how long the guard times should be absence of data before the command line so that accidental mode change is not performed By changing DL to 1 data is intended for an XBee at address 1 The default settings on XBees are a DL of 0 and an MY of 0 Previously we were sending data to a node at address 0 from a node at address 0 and vice versa Be aware the XBee actually does receive data sees it is not the intended node and then dumps it instead of passing it to the DOUT pin to which the RX LED is connected Let s now try configuring using the Terminal window Due to timeouts you may have to type a little fast so you may need a few attempts Enter the following lines do not type what is in parentheses Press enter after each line except for V Wait three seconds since you typed anything last this is guard time V Do not press ENTER Z Wait a few more seconds and you should see that it is now in command mode v ATDL Requests the current DL value it should return 1 Z ATDL 0 Sets the DL address to 0 Z ATDL Again requests the DL address which should be 0 Z ATCN Exits AT comma
334. et of NMEA sentences SGPGGA 123519 4807 038 N 01131 000 E 1 08 0 9 545 4 M 46 9 M 10 3 47 lt CR gt lt LF gt SGPGSA A 3 04 05 09 12 24 2 5 1 3 2 1 39 lt CR gt lt LF gt SGPRMC 123519 A 4807 038 N 01131 000 E 022 4 084 4 230394 003 1 W 6A lt CR gt lt LF gt The first thing to notice is that each sentence begins with a and ends with a carriage return lt CR gt and a line feed lt LF gt ASCII character Also each field in the message is separated by a comma Near the end of each NMEA sentence is an asterisk x that signals that the following two bytes after the asterisk is an error checking code To compute the error checking code on your own you would eXclusive OR XOR all the bytes between the and the and then test it against the transmitted error checking code before accepting the message Each sentence type can be identified by its first field GPGGA GPGSA GPRMC etc There are many sentence types but they all begin with GP Once you have identified 328 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER the sentence type you can then parse out the individual elements that are separated by commas For example if we look at a GPGGA sentence it could be separated as follows SGPGGA 123519 4807 038 N 01131 000 E 1 08 0 9 545 4 M 46 9 M 10 3 47 lt CR gt lt LF gt GGA GLOBAL POSITIONING SYSTEM FIX DATA 123519 Fix taken at 12 35 19 UTC 4807 038 N Latitude 48 deg 07 038 N
335. et_val lt lt 8 ret_val read Q4 27 Creating a Simple Networked Game To show how to use the Propeller to implement networked applications in a mul ticore environment we will create a simple networked game since the HYDRA is a game development platform after all Our new game will be called Button Masher The game is on a split screen where the player s score appears on the left and the opponent s score appears on the right Whenever the player hits any button on the gamepad his score is increased Conversely whenever the opponent hits a button his score is increased The first person to hit a button five times is the winner The entire source code for Button Masher is found in the Chapter_08 Source ButtonMasher Spin directory Also most readers will not purchase two HYDRAs to network together although it is a blasty blast so a C program was created that will send an updated score to the HYDRA whenever you press ENTER That way you can simulate another HYDRA using your PC You can find this program executable and source in the Chapter_08 Source ButtonMasher C directory A key thing here is that when the player presses a button he increments his score and sends his new score to the opponent in an Ethernet packet using the UDP protocol Of course when the opponent presses a button his score is incremented and he sends an Ethernet packet to the player So what will we need to implement this game Of course
336. ete theory behind the Kalman filter is beyond the scope of this book but let s look at the basics According to Wikipedia The Kalman filter is an efficient recursive filter that estimates the state of a linear dynamic system from a series of noisy measurements http en wikipedia org wiki Kalman_filter What does this mean Being an efficient recursive filter means that the algo rithm processes signals to accentuate the good while reducing the bad Recursive filters have an internal state that is updated every timestep Estimating the state of a linear dynamic system from a series of noisy measurements means that the Kalman filter s internal state is an estimate of a system that is linear and dynamic In our case the two inputs are from a linear and dynamic system one the change in tilt as measured by the gyroscope being the derivative of the other tilt as measured by the accelerometer A good analogy is that the Kalman filter automatically selects the filter values so that the low pass filtered accelerometer measurement corresponds with the high pass filtered gyroscope measurement So we can use the Kalman filter to filter and fuse our noisy signals to estimate the state of our system we can accurately calculate tilt from our signals For our code we have to understand that we need to run the Kalman filter continually and that it runs in two phases predict and update During the predict phase the state estimate fr
337. ethod has on the Parallax Serial Terminal According to the example code the TSL230 chip s Out pin is connected to PO and the TSL230 s SO pin 1 and S1 pin 2 are connected to Propeller T O pins P1 and P2 Note that connecting TSL230 pin 1 to Propeller I O pin P1 and TSL230 pin 2 to Propeller I O pin P2 follows the ts1230 object s the ctrlpinbase and ctrlpinbase 1 convention Also note that since autoscale is set to true the ts1230 object will automatically adjust its input sensitivity to the ambient lighting conditions s123 DEMO spin CON _clkmode xtall pll16x _XinFREQ 5 000 000 OBJ term tv_text Ifs lt ts1230 PUB Go term Start 12 lfs Start 0 1 10 true repeat waitcnt 80_000_000 10 cnt term dec 1fs GetSample term out QD 156 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Voltage Output Voltage output sensors are common and many circuits transform resistive or capacitive sensors into voltage output sensors Two examples of voltage output sensor circuits are in the Converting Analog Sensors to On Off Sensors section The potentiometer circuit in Fig 4 9 and the photoresistor circuit in Fig 4 10 both transform resistive sensors into voltage output sensors These sensors transmit continuous ranges of output voltages analog voltages that indicate the quantities the sensors measure Their out puts are commonly referred to as DC because they fluctuate gradually over ti
338. etic right 456 APPENDIX A lt lt gt gt Bitwise Shift left Bitwise Shift right Bitwise Rotate left Bitwise Rotate right Bitwise Reverse Bitwise AND Bitwise OR Bitwise XOR Boolean AND promotes non 0 to 1 Boolean Boolean Boolean Boolean Boolean Boolean Boolean OR promotes non 0 to 1 Is equal Is not equal Is less than signed Is greater than signed Is equal or less signed Is equal or greater signed SYNTAX SYMBOLS hh u Binary number indicator as in 41010 Quaternary number indicator as in 2130 Assembly here indicator String designator as in Hello Group delimiter in constant values or underscore in symbols Assembly literal indicator Assembly local label indicator List delimiter in declared data Code comment designator Document comment designator In line multi line code comment designators In line multi line document comment designators PROPELLER LANGUAGE REFERENCE 457 Reserved Word List These words are always reserved whether programming in Spin or Propeller Assembly _CLKF REQ CONSTANTS IF_NC_AND_NZ MIN PLL4XS SUBSX _CLKMODES CTRAS IF_NC_AND_Z MINS PLL8XS SUBX _FREES CTRB IF_NC_OR_NZ Mova PLL16XS SUMC _STACKS DATS IF_NC_OR_Z MOVD2 POsxd SUMNC _XINFREQS DIRAS F NES MOVI PRIS SUMNZ ABORTS DIRB IF_NEVER MOVS PUBS SUMZ ABS DJNZ IF_NZ MUL3 QUITS EST ABSNEG BESS IF_NZ_AND_C MUL
339. evaporator condenser small enough to fit in our dollhouse scale building but were unable to discover any inexpensive units this small Luckily we were able to find a small scale solid state heat pump that used a Peltier THE HVAC GREEN HOUSE MODEL 403 Figure 11 1 Preliminary Google sketch of HVAC green house device Typically used in portable electric iceless coolers for RVs and cars Peltier devices can act as both a cooling and heating device The Peltier device we used Fig 11 2 consisted of a 40 mm square thermoelectric heat pump The device conveniently operates on 12 volts DC and draws 5 A of current On our test power supply running at approximately 12 3 V we measured the hot side at 183 6 F and the cold side at 56 2 F In order to reverse the hot and cold sides all you need to do is reverse polarity of the applied 12 volts DC The Cooling Tower We mounted the Peltier device in a clear polycarbonate cooling tower with 12 V high speed fans on both the external waste heat sink and the internal supply heat sink that would serve to heat or cool the inside of our model house This cooling tower Fig 11 3 was made as a separate enclosure allowing us to remove it from the model for maintenance or cleaning and also for access to the send and return air ducts and the center wiring channel aka wire chase The Air Registers As we now had the capability to cool and warm air we needed a way to
340. examples in this chapter provide some basics on how a variety of sensors work how the Propeller microcontroller interacts with different sensors to get measurements and how to write programs that orchestrate the microcontroller s interactions with the sensors Wherever possible pointers to more information are included In general www parallax com has a page for any given sensor that Parallax manufactures or dis tributes and the first place to look for more information about a given sensor would be in the Downloads section on the sensor s product page Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_04 On Off Sensors On off sensors send high or low signals depending on whether a certain physical prop erty was detected The most common on off sensors are pushbuttons and switches other examples include infrared and beam break detectors Many more sophisticated sensor modules include an onboard microcontroller and or onboard electronics to provide an on off output for reduced prototyping effort at a higher price Examples of this kind of sensor include the Parallax passive infrared PIR sensor for motion detection sound level sensors and gas sensors such as carbon monoxide methane and Propane gas Figure 4 3 shows examples of some of these sensors including the pushbutton switches PIR and carbon monoxide sensors Tip With some extra work or
341. exercises You ll be running a Propeller application in no time and writing your own in mere minutes You ll learn that you can achieve quick results perform time sensitive tasks and use objects and multiple processors to build amazing projects in little time In addi tion you ll know where to find an ever growing collection of documentation examples and free open source objects that an entire community of developers is eager to share with you In this chapter we ll do the following Cover the available forms of the Propeller Install the development software and connect our Propeller Explore the Spin language with simple single core examples Run our examples on a Propeller in RAM and EEPROM Create a simple multicore example Make a building block object Adjust timing and stack size Find out where to learn more Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_02 16 INTRODUCTION TO PROPELLER PROGRAMMING What s the Secret How can you build incredible multicore systems without getting lost in the details Surprisingly there s no real secret In fact teachers have been drilling the solution into our heads for years Solution Break big problems into smaller simpler ones and solve them individually Then put the individual solutions together to tackle the original problem see Fig 2 1 That s it For applications deal
342. extension on the output file is csv instead of log 2 Modify the Main_01 spin such that instead of outputting a comma separated values file it outputs a KML file for use with Google Earth 3 Add to the NTSC terminal display so that it shows the current logging status such as Logging On Off 4 Adda digital compass for example the Hitachi HM55B compass module available from Parallax and record the logged heading Then compare the compass s heading to the GPS s heading and explain any discrepancies 5 Shine a flashlight onto the barometric pressure sensor and witness the change in pres sure recorded Try varying the intensity of the light by applying a piece of fabric over the flashlight before shining it onto the sensor USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Andr LaMothe Introduction In this chapter we are going to explore one of the most exciting uses of multicore pro cessing using the multicore processor as a slave server to a host client processor or computer The multicore slave is issued commands via an RPC remote procedure call architecture enabling the multicore processor the Propeller chip in our case to execute commands on multiple processors with nearly zero load to the host client issuing the commands With this kind of architecture and a proper communications protocol s various virtual peripherals can be loaded into the multicore processor and
343. ey printed manuals and hard ware maintenance for core product lines Jeff collaborates closely with Chip Gracey and the rest of the R amp D group on the Propeller product line from hardware to soft ware and documentation Hanno Sander has been working with computers since he programmed a lunar lander game for the z80 when he was six Since then he graduated from Stanford University with a degree in computer science and then started his corporate career as an Internet entrepreneur He moved to New Zealand in 2005 to spend time with his growing family and developed sophisticated yet affordable robots starting with the DanceBot His technical interests include computer vision embedded systems industrial control control theory parallel computing and fuzzy logic About Parallax Inc Parallax Inc a privately held company designs and manufactures microcontrollers embedded system development tools small single board computers and robots that are used by electronic engineers educational institutions and hobbyists This page intentionally left blank FOREWORD In the early and mid 1970s semiconductor companies offered only a few rudimentary microprocessors that most people have never heard of or have long forgotten Now though engineers scientists entrepreneurs students and hobbyists can choose from a wide spectrum of processors some of which include two four or more processor cores that let a chip pe
344. f Hintze Joshua 319 HMS55B Compass Module 205 homogenous processor design 5 Honeywell 400 horizontal Sobel filter 273 horizontal sync 313 HSV hue saturation and brightness 275 Hub 12 116 hub and cog interaction 54 54f HVAC See heating ventilation air conditioning hybrid fuzzy logic cascading PID controller 250 251 250f HYDRA Game Development Kit with EtherX card 287 312 289f 290t SPI assembly layer and 295 296 HYDRA hobby video game 281 HYDRA Net 287 HyperTerminal 357 PC See Inter Integrated Circuit IC See integrated chip IDE style debugger 102 IEEE See Institute of Electrical and Electronics Engineers if command 37 Incorrect Loop Interval Code 67 68 90 Incorrect Loop Interval spin 67 indentation 25 27 infrared light emitting diode IR LED 133 infrared object detector 133 133f init method 300 303 initialization 366 375 376 Input pin determining communication mode RAW 329 Insonix 85 Institute of Electrical and Electronics Engineers IEEE 282 303 integrated chip IC 334 intelligent devices 410 interface technologies 320 322 320f INDEX Inter Integrated Circuit I C 290 320 320f 390 bus basics 392 393 392f low level chip interfacing 393 394 internal clock 38 41 Internet origins of 286 UDP or TCP choice 284 Internet Protocol IP 281 286 287f headers 282 283f interruptions 4 Intersema MS5540C miniature barometer module 323 3
345. f these objects have Start methods so both the TV terminal and keyboard processes get launched into other cogs The application s repeat loop then takes the result of the keyboard object s getkey method and passes it to the TV_Terminal object s hex method which displays the hexadecimal value of the keyboard key that was pressed on the TV Keyboard _ Demo spin CON _clkmode xtall plli6x _xinfreq 5 000 000 OBJ term gt tv_terminal kb gt keyboard PUB start i start the tv terminal term start 12 term str string Keyboard Demo 13 SURVEY OF PROPELLER DEBUGGING TOOLS 81 start the keyboard kb start 26 27 echo keystrokes in hex repeat term hex kb getkey 3 term out After a quick look at the TV_Terminal object s methods we see it has an out method that will cause TV_Terminal to echo the actual keystroke on the display Here is a modified repeat loop for displaying the keyboard characters instead of their hexadecimal values Figure 3 13 shows the TV_Terminal output after some typing on the PS 2 keyboard echo keystrokes repeat term out kb getkey PARALLAX SERIAL TERMINAL The Parallax Serial Terminal introduced in Chap 2 and featured in earlier examples in this chapter also provides a convenient first line of defense for catching program bugs and circuit errors By adding a few lines of code at key points in a program the Parallax Serial Terminal can displ
346. fer so we can parse it copy it bytemove tok_buff input_buff input_buff_index Null terminate it tok_buff input_buff_index 0 tok_buff_index input_buff_index Reset buffer input_buff_index 1 Tokenize input string num_tokens 0 Start the tokenization of the string this function mimics the C strtok_r function more or less strtok_r tok_buff string token_ptr Continue tokenization process now that First token has been found repeat while token_ptr lt gt NULL Upcase the token before insertion StrUpper token_ptr Insert token into token array tokensl num_tokens token_ptr Get next token strtok_r NULL string token_ptr End repeat tokenization CLIENT HOST CONSOLE DEVELOPMENT 379 The code fragment does not perform any kind of syntactic analysis whatsoever or validation All we are interested in is striping delimiters from the string and then break ing out the tokens in the string For example here s a sample command line sound play 100 10 lt RETURN gt The parser breaks this into an array of string pointers that looks like this tokens 0 gt SOUND 2 tokens 0 gt PLAY tokens 0 gt 0 tokens 0 gt 100 0 tokens 0 gt 10 0 along with computing num_tokens and setting it to 5 Notice that the strings are converted to uppercase and the comma and white space are removed THE COMMAND LINE
347. ff circuit 132 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES A photoresistor s resistance varies with light intensity on its cadmium sulfide ele ment This analog sensor can be converted to a digital sensor for the Propeller chip by placing it in series with a fixed value resistor and then connecting the node between the two resistors to an I O pin as shown in Fig 4 10 As the light levels change the photoresistor s resistance changes and the voltage between the photoresistor and the fixed resistor in Fig 4 10 also changes For that particular circuit brighter light levels reduce the photoresistor s resistance which in turn makes the voltage between the two resistors increase Dimmer light levels cause an increase in the photoresistor s resistance so the voltage between two resistors decreases To set the threshold simply measure the resistance of the photoresistor at the light level that should cause the circuit s output to be 1 65 V and then pick a fixed resistor of the same value For example if the photoresistor s resistance is measured at 10 kQ with the light level applied that should cause the transition the fixed resistor should also be 10 kQ Reason being the voltage between two equal resistors in series is half the voltage applied across both of them Since 3 3 V is applied across both resistors the voltage between them when they are equal will be 1 65 V which is the Propeller chip s I O pin threshold voltage
348. fig string dso view adc trigger adc lt 15 timescale 50us vp share 0 Freq Synth A 8 10 00 000 Drive ADC with 1 MHz clock repeat Refer to Fig 7 4 for the waveform we ve captured from the camera The waveform represents one of the 425 scan lines The signal starts with a horizontal sync pulse fol lowed by the NTSC color burst and then 50 us of data In an NTSC signal the begin ning of a frame is indicated by a vertical sync where the signal is at its minimum for a specified time Each scan line is marked by a horizontal sync where the signal is also at its minimum but for a shorter time than the vertical sync We won t worry about the color burst signal as PropCV will only decode the grayscale information not the color The 50 us of data represent the pixel s brightness by the reconstructed analog signal value The peak in the analog signal indicates a bright object in the middle of the camera s view The following assembly code implements a simple low resolution frame grabber It detects the horizontal and vertical sync marks and then packs the pixel data into memory It captures 100 lines of video each with 120 pixels with 16 gray levels This consumes quite a bit of the Propeller s 32 KB of RAM 100 lines 120 pixels line 4 bit pixel 1 byte 8 bit 6000 bytes or 1500 longs We can distinguish between vertical and horizontal sync marks by the different amounts of time that the signal stays at i
349. from the application object The process that the building block object launches into another cog then uses those memory addresses to update and or moni tor one or more variables in the application object Instead of object Start value1 value2 the application object would use object Start varaiblel variable2 to pass addresses of variables that the application object expects the building block object to work with Once the building block object knows these addresses it passes them to a Spin or assembly language coded process that it launches into another cog That process can use the memory addresses to read directly from and or write directly to the application object s variables as shown in Fig 3 5 Code in the application object can then exchange information with the other cog by simply writing to or reading from those variables There are also other less common variations and combinations of the two cog infor mation exchange arrangements just discussed In some cases they are used to support a particular set of tasks the building block object is expected to perform Regardless of the design the building block object s documentation should be clear about how it exchanges information with the application object and the documentation should also be clear about what its public methods do the parameters they expect and the values that return The object should also be thoroughly tested to verify that it functions as advertised
350. ft is recommended Information For more insight on distance height issues and calculations search the web for Fresnel clearance calculation Though the XBee is ready to go right out of the box it is feature rich and can be configured for specific applications Hardware Used in This Chapter The following is a list of hardware used in this chapter and their sources but as you read through you II find it s not written in stone We recommend you read through the chapter to understand how the hardware is used before making an expensive investment 2 Propeller Demo Boards Parallax 1 Propeller Proto Board Parallax 1 Prop Plug Parallax 3 XBee 802 15 4 Series 1 modem transceivers www digikey com 3 AppBee SIP LV XBee carrier boards www selmaware com or other styles avail able on www sparkfun com 1 PING ultrasonic sensor Parallax 1 HM55B compass module Parallax 1 Memsic 2125 accelerometer inclinometer Parallax 1 Boe Bot chassis Parallax 1 Ping Servo Mounting Bracket Kit Parallax 2 Additional Boe Bot battery holders or other portable battery source Miscellaneous resistors Testing and Configuring the XBee An important step in constructing a complex project is to make sure the individual devices work properly and their use is understood In this section the XBees will be tested con figuration settings explored and means of configuring these devices discussed 19
351. g 2 16 There is no difference in each individual LED s behavior This is the beauty of a multicore device like the Propeller You can focus your time on a simple implementation of a process with no regard to other parts of a final application and then simply connect the individual parts together in the end And this can be done with many different types of processes not just multiple instances of the same process EXPLANATION Our application code didn t change much In fact the LED_F lash method didn t change at all First we added a new block at the top of the code a VAR block which declares a block of global variables The statement long StackA 32 reserves 32 longs 128 bytes of memory and calls it StackA The declarations for StackB and StackC are similar As the comment indicates this memory is for cog workspace Information When a cog executes Spin code it needs stack space that is temporary workspace to process method calls and expressions The Spin compiler automatically assigns the first cog s workspace for the main application code but additional cogs launched on Spin code need manually assigned workspace Thirty two longs is more than enough for this example We show how to determine how much is enough later in Sizing the Stack Z Fastest Blink P23 om Z Faster 5 Blink Figure 2 16 Demo Board LEDs blinking in parallel 34 INTRODUCTION TO
352. g 62 64 PASD 83 85 86f timing interval errors 64 71 ViewPort 102 110 wrong address passed to method 74 76 MXD2125 chip 148 152 MXD2125 Simple Demo spin 150 151 NASAL 431 432 National Marine Electronics Association NMEA 179 327 National Television Systems Committee NTSC 259 260 262f 324 359f 415 418 418f NES connectors 287 networked bot 225 226f networking and XBee transceivers overview 191 193 networking applications in green house model 410 411 multicore use for 281 318 nickname method calls 150 nickname methodname syntax 38 NMEA See National Marine Electronics Association nodes base and remote 205 206f nonblocking 311 NTFS file system 339 NTSC See National Television Systems Committee NTSC commands 387 NULL terminate 331 Nurve Networks LLC 287 OBEX See Propeller Object Exchange OBJ external object references 24 block 38 Object design guidelines 56 57 Object Exchange Web site 329 object not detected 135 135f object method calls 56 56f objects 5 5f on demand drivers 389 on off sensors 122 137 123f converting analog sensors to 131 133 multiprocessing example 129 131 with outputs greater than 3 3 V 136 137 potentiometer in 131 131f pushbutton array 127 129 127f pushbuttons 122 129 126f signaling dependence of 133 135 single pushbutton 124 125 124f open and close sockets 303 304 INDEX open method 303 304 OpenCV 274 276 colored
353. g never needed to control the I O pins there isn t any reason for its code to make any I O pin configurations at all In that case the code that the new cog executes is the only code that needs to configure its I O registers For example IO Declaration Bug spin launches a process that is supposed to make a light blink but the light emitting diode LED in Fig 3 7 won t blink because the I O pin was set to output by the cog executing the Go method The cog executing the Blinker method never sets its I O pin to output so it has no control over the I O pin s output state LIGHT AND PUSHBUTTON CIRCUITS The light and pushbutton circuits in this section are explained in more detail in Propeller Education Kit Labs Fundamentals 4 I O and Timing Basics Lab A more basic introduction to these circuits and examples of building them from schematics is also included in early What s a Microcontroller chapters Both are free downloads from www parallax com P5 100 Q Figure 3 7 Blinking light GND test circuit COMMON MULTIPROCESSOR CODING MISTAKES 63 IO Declaration Bug spin VAR long stack 10 PUB Go dira 5 1 cognew Blinker stack repeat PUB Blinker repeat louta 5 waitent clkfreq 4 cnt Array cog executing Blinker BUG P5 output in the wrong cog Launch a new cog to control P5 Optionally keep cog running Infinite loop Invert P5 output register bit Delay for 1 4 s
354. ghtly back to keep from falling over and to maintain to their desired position They only stay still for the short time that their center of gravity is perfectly positioned over their wheels contact point on a level ground This tendency to keep moving makes them great attention getters The human vision system is particularly sensitive to things that move This helped our ancestors to survive by finding food and keeping us safe from predators Now advertisers use this trait to their advantage by using blinking lights and images that move or change over time Builders of balancing robots can use it to their advantage too by drawing onlookers wherever they go Figure 6 2 Anja and Kyle with my DanceBot 238 DANCEBOT A BALANCING ROBOT Building the DanceBot Okay let s build our DanceBot What will we need I ve experimented with many designs and I m happy with my setup see Table 6 1 At some point I m planning to build a kit that will make it easier for others to build their own robots if you re inter ested look at my web site The following sections will describe each subsystem of the robot ll start with an overview of the system and then get into the nitty gritty details of which part I used how to interface it and how the Propeller will use it MECHANICS MAKE THE ROBOT MOVE The mechanics of a balancing bot are simple Two powered wheels control a rigid body For the body we could use everything from erecto
355. gin size Start the tv terminal term start 302 USING MULTICORE FOR NETWORKING APPLICATIONS Start the W5100 driver eth start Display a title string and indicate we are waiting for the ethernet to come up term out 02 term pstring string HydraEtherX TCP Client Test 13 13 term out 01 term pstring string Waiting for Eth 13 Wait for a while for the ethernet to come up waitcnt cnt 17d78400 Indicate that we are done waiting term pstring string Done waiting 13 13 Fill out the arrays needed for initialization Destination IP is IP we are sending to dip 0 192 dip 1 168 dip 2 1 dip 3 2 Fill out the rest of the arrays needed for initialization W5100 IP address ip 0 192 ip 1 168 ip 2 1 ip 3 100 Gateway gateway 0 192 gateway 1 168 gateway 2 1 gateway 3 1 Subnet subnet 0 255 subnet 1 255 subnet 2 255 subnet 3 0 W5100 MAC address macl 00 mac 1 70 mac 2 6e macl3 69 ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 303 mac 4 73 macl5 Qa Initialize the W510Q eth init gateway subnet ip mac Notice that the gateway subnet ip and mac arrays are byte arrays to pass the address of the pointer to the init method you use the e symbol This example would set your IP to address 192 168 1 100 your gateway to 192 16
356. given waveform v Tryit Adding Terminal Functionality to ViewPort Let s say the next task at hand is to count events and send an alarm message when 11 events have occurred The ViewPort debugger has a Terminal pane that can be used to send character events to the Propeller DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 107 chip The corresponding terminal object that the Propeller application code uses has all the same functionality as conduit but it also supports terminal communication and even includes familiar method calls like Char CharIn Dec DecIn and more from the Parallax Serial Terminal object In general additional changes that have to be made for debugging with ViewPort s terminal object include E Replace the conduit object declaration with a terminal object declaration vp gt terminal ViewPort conduit object E Add two longs for sending characters to and receiving characters from the terminal immediately before the contiguous list of long variables long vptx vprx long minutes seconds milliseconds count E Add a config method call with a string that configures the terminal vp config String start terminal terminal 1 E Update your vp config and vp share calls to include the transmit and receive variables that were added to the variable declarations in a previous step vp config String var vptx vprx minutes seconds milliseconds count vp share vptx c
357. gnals the other two thirds of the time In each case the value stored by the counter module s phase register accumulates at a rate that s proportional to the voltage input A cog typically works cooperatively with its counter module to perform Sigma Delta A D conversion The cog managing the process has to wait a precise number of clock ticks then copy the value stored in the counter module s phase register and then clear it for the next sample interval The resolution of the converter is defined by how many clock ticks the loop takes before it repeats For example if the converter takes 2000 clock ticks to repeat the number of times the input pin detected a signal above 1 65 V could range from 0 to 2000 The typical Sigma Delta ADC does not use all the clock ticks so for a range of 0 to 2000 clock ticks a voltage input of 0 V might correspond to 250 and a voltage input of 3 3 V might correspond to 1750 The actual resolution of the ADC in this case would be 1500 which is between 10 and 11 bits and would be used to describe the peripheral ADCs in the previous section The range of measurements also depends on the output impedance of the sensor If it has a high output impedance the entire measurement range might be reduced from 250 1750 to 600 1400 for example The relationship between sensor output and ADC measurement should still be linear just on a different scale that will take a few tests to determine However the testing can be w
358. gram will block which means it sits there and does nothing waiting for data to arrive Set the block argument to true if you want the RX method to block and wait for data to arrive The second thing you could do if there is no data waiting for us in the W5100 when called is to return immediately and somehow indicate to the application that there was no data available at the time In our case we would return immediately and set the return value to 0 which remember indicates how many bytes have been read from the W5100 into the HYDRA main memory pointed to by ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 311 the dataptr argument To set the RX method to nonblocking set the block argument to false BLOCKING OR NONBLOCKING Which should you use Remember that a blocking call will wait until data is available which in theory could be a long time Simply ask yourself what would happen to your application if it paused and waited around for too long Would you miss some user input i e Gamepad sample Would you be unable to update the video or the music If a method pausing for too long would cause a problem in your application use nonblocking If your application will never do anything other than look for data from the W5100 it s better to use blocking The concepts of blocking and nonblocking are important when writing code for things like device drivers and operating systems Sometimes it s helpful to
359. gt s 114 _ DEBUGGING CODE FOR MULTIPLE CORES add addr 4 Point at next long wrlong _ms addr Copy _ms gt ms lockclr sID Clear lock bit jmp timekeeper Goto timekeeper Initialized data Cog RAM ASM vars k long 1000 k 1000 Uninitialized data m res 1 More ASM variables _s res 1 _ms res 1 _dt res 1 sID res 1 t res 1 addr res 1 The code between the Debugger Kernel and the timekeeper labels is responsible for copying initial values from Main RAM to Cog RAM One important first test to run on assembly code is to make sure these values have been copied correctly To run this test with PASD Download PASD from www insonix ch propeller prop_pasd html Read the documentation and try the example code included in the download Make sure that Timestamp Dev ASM spin is in the same folder with PASDebug spin Open Timestamp Dev ASM with the Propeller Tool software If you don t know which COM port the Propeller chip is connected to for program ming press F7 in the Propeller Tool software and make a note of it v Run PASD VY InPASD click the COM menu and set the COM port to the Propeller chip s program ming port Z In PASD click File and select Upload Code F11 NNN NN F11 VERSUS F2 IN PASD File Upload Code F11 in PASD loads the code into the Propeller chip and copies the ASM code to PASD In contrast Get ASM Code F2 just copies the ASM code over It can be used if you manually upl
360. hanced tested in isolation and even integration tested as parallel processes You didn t know it but all this time we ve been building towards this moment the creation of a building block object An object is a set of code and data that is self contained and has a specific purpose Though we called our examples Propeller Applications that s only half the story A Propeller Application is an executable image made from an object which itself may be made up of one or more other objects We ve actually been designing an object all along Now we want to transform it into a building block object Building block objects are meant to be subcomponents of other objects they have a set of required inputs and deterministic outputs Propeller users love building block objects because they can swiftly combine them into one object or application that performs with all the expert skills of the collective of objects Figure 2 18 shows an analogy for this concept Take a look at the following code we rewrote the top portions of our last exercise but our core the LED_Flash method is only slightly different Can you see how v Enter and save this code Give it the name Flash spin WRAPPING ITUP_ 35 Objects A builder chooses from many premade objects to construct a bike in very little time Can you imagine having to create every object yourself Utilizing a set of high quality objects saves you an immense amount of time
361. hardware we ll use throughout this book 2 THE PROPELLER CHIP MULTICORE MICROCONTROLLER Multicore Defined A multicore processor is a system composed of two or more independent CPUs usually in the same die that achieves multiprocessing in a single physical package see Fig 1 1 Put simply a multicore chip can do many things simultaneously MULTIPROCESSING VERSUS MULTITASKING Are you thinking multitasking For computers multitasking is a method of shar ing a single CPU for multiple possibly unrelated tasks A single core device that is multitasking fast enough gives the illusion of things happening at once A multicore device however achieves true multiprocessing performing multiple tasks simultaneously In comparison a multicore device can run at a slower speed con sume less power and achieve better results than a fast running single core device can In this book we will usually refer to tasks functions and processes in the context of multiprocessing rather than multitasking It may seem quite daunting to get multiple processors all working together in a single coherent application In fact once upon a time the task was notably treacherous since it was unclear exactly how to apply multicore technology Many complex systems were devised that either stripped developers of power or burdened them with unruly multithread obstacles Eight individual processors on same silicon die dad Wla
362. hat in mind here is a list of the common microcontroller sensor interfaces introduced in this chapter On off Resistive capacitive diode transistor and other Pulse and duty cycle outputs Frequency outputs Voltage outputs Synchronous serial Asynchronous serial To further simplify sensor measurements the Propeller Object Exchange web site obex parallax com shown in Fig 4 1 has prewritten objects for many sensors that can serve as building blocks for an application These building block objects can take care 2 Propeller Object Exchange Windows Internet Explorer g v E http fobex parallax com w de G Propeller Object Exchange i amp D dab i Page Terms of Use All objects on the Propeller Object Exchange are provided under the MIT License By dowmloading and or submitting objects you are agreeing To Submit an Object 1 Register or login to this exchange click the Register or Login link at the top right corner of this page 2 Click on the Upload an Object link that appears to the right after you login and fill out the required fields Data Storage Tool RAM EEPROM flash hard drive Helpful function language development aid DE Human Input He Keyboard mouse joystick game pad j Protocol gt eS SPI 1 Wire I2C asynchronous serial pa Floating point PID trigonometry physics yon Motor Control AER Sensor Servo stepper standard mo
363. he Propeller chip vZ Click the Parallax Serial Terminal s Enable button V Watch the display as you press and release the pushbutton and verify that it displays the correct binary values stored by ina 16 for the pressed and released button states 126 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES gt Parallax Serial Terminal Disabled cli EDK Com Port Baud Rate in come 115200 OR a Prefs Clea Pau Figure 4 6 P16 input state display Keep in mind that the pushbutton is just one example of an on off sensor Also keep in mind that once the code has acquired that 1 or 0 measurement it s up to the applica tion designer to decide what to do with the information and write code to make it so The Spin language has lots of flexibility Pushbutton Decisions spin shows a simple next step that calls different methods depending on whether the sensor is sending the on off signal In Fig 4 5 the pushbutton is the circuit sending those signals but again some completely different sensor could be sending on off signals While the program s Pressed and NotPressed methods just display some simple messages an application might instead acquire a timestamp move an actuator update a display start a mecha tronic calibration sequence sound an alarm make a phone call or maybe all of the above With the Propeller microcontroller all the tasks might even be performed in parallel by separate cogs Pushbutto
364. he ViewPort software introduced in the previ ous chapter can also do a great job of graphically displaying the time varying voltage signal the Propeller chip measures with the Sigma Delta ADC Figure 4 34 shows the mic s output in response to a whistle in ViewPort s analog view The Oscilloscope pane displays the ADC measurements versus time and the Spectrum Analyzer pane displays signal strength versus frequency The cursor on the Spectrum Analyzer pane can be positioned with the mouse cursor at the top of the spike in the graph to determine that the tone is 1 24 kHz at a glance Although the whistle is a single frequency which could also be measured by dividing the period of the sine wave into 1 the Spectrum Analyzer pane is exceedingly useful for displaying the component sine waves and magnitudes in signals such as spoken A ViewPort v4 1 504 Welcome code dso Isa at mixed video andy terminal limescale s5o0us 1 40 Overview click on name to configure Name Plot Edit j n Max Avg val v1 s9 21 B22 159 Cursors Show A B Diff Vert Horz Edit Variables Connection Disconnected Memory 00 00 16 Figure 4 34 ViewPort analog view 166 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES phonemes and telephone dial tones Figure 4 35 shows the phoneme aaaaahhhh pro noun
365. he fact that the time it takes a capacitor to discharge through a resistor to half of its starting voltage is At 0 693 C R If C is a fixed value and R is a resistive sensor the value of R is R At 0 693 C Likewise if R is fixed and C is variable C At 0 963 R In either case so long as one value is fixed a decay time measurement can be used to determine the other value RC DECAY EXAMPLE MEASURE A POTENTIOMETER S POSITION The Test Simple RC Time spin application interacts with the circuit in Fig 4 16 to display a number that indicates the potentiometer s position based on the measurement of its variable resistance In the previous section the potentiometer was in a circuit that caused it to provide the Propeller I O pin with a variable voltage source In this circuit P18 R Pot 10 ka T GND GND l eX eees ey e c er e e e ey J v a QO U m re rm m a Seeeeeeee Figure 4 16 RC decay test circuit 140 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES it is instead connected as a variable resistor with the A terminal disconnected which is commonly referred to as floating As the knob gets turned the wiper W terminal s contact with the resistive element inside the potentiometer moves along its length When the knob is turned in one direction the contact point will get closer to the A terminal and the resistance between B and W will get larger In the other direction the con
366. he following topics E Examining the makeup and drawbacks of central air HVAC systems E Creating the HVAC green house model E Designing the control electronics Scalability and real world considerations Software creation considerations What gets processed where E Modular programming using Propeller objects E Electronics design and implementation We ll start out by getting familiar with some inherent problems in a typical residential HVAC system and see how using the Propeller as a system management tool can be educational interesting and fun Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_11 399 400 THE HVAC GREEN HOUSE MODEL Exploring the Problem On April 23 1886 an inventor named Albert Butz patented a furnace regulator he called the damper flapper When a room cooled below a predetermined tempera ture a switch energized a motor to open a furnace s air damper so the fire would burn hotter When the temperature rose above the preset level the switch automati cally signaled the motor to close the flapper damping the fire so it burned cooler This simple yet ingenious thermostat was the seed that eventually grew into a little company named Honeywell Information To learn more about Albert Butz and Honeywell read the article referenced here at www51 honeywell com honeywell about us our history html Though the
367. he modified Test Time Counting 2 spin code initializes the m s and ms variables to 995 59 and 10 and the repeat loop is changed from unconditional to 8 repetitions The if debug KeyCheck condition is commented and the debug Vars method call is out dented so that it is part of the repeat loop block but not part of any if conditions preceding it With these modifications it displays eight steps in the sequence from 10 minutes 59 seconds 996 milliseconds through 11 minutes 0 seconds 3 milliseconds 90 DEBUGGING CODE FOR MULTIPLE CORES Test Time Counting 2 spin debug Start 115200 Start debug cog ms 995 xxfAdd 59 xxAdd 10 xxAdd repeat 8 xx Modify to 8 reps ms Add 1 to millisecond count if m 60 If minutes 60 m Q Set minutes to 0 if debug KeyCheck xxComment debug Vars m String long m s ms 0utdent Step 2 Establish Precise Time Base in Another Cog Now that we know the counting sequence is correct a next step in the development process might involve establishing and testing a 1 millisecond time base The Incorrect Loop Interval Code section explained how waitent clkfreq 1000 cnt is not precise enough for time keeping applications because it doesn t take into account how long the other instruc tions in the loop might take That section also introduced synchronized delay code for accurate timekeeping Here is a variation on the synchronized timekeeping loop
368. he motor resemble an H Let s look at what happens when we set the switches to different positions When the switches S1 and S4 are closed and S2 and S3 are open a positive voltage will be applied across the motor By opening the S1 and S4 switches and closing the S2 and S3 switches this voltage is reversed allowing reverse operation of the motor Switches S1 and S2 should never be closed at the same time as this would cause a short circuit on the input voltage source The same applies to switches S3 and S4 To control the speed of the motor we ll use pulse width modulation PWM We can t directly tell the H bridge to supply only half power to the motor because the switches can only be turned on or off However we can tell the H bridge when to turn the switches on and for how long So if we want to drive at half power we can turn the switch on for 50 percent of the time and later turn the switches off for 50 percent of the time The motors will average this out and drive the wheels at a medium speed The LMD18200 implements an H bridge that can deliver up to 3 A of continuous output at up to 55 V It has a low on resistance of 0 3 Q per switch and can be driven directly from the Propeller s outputs Besides implementing an H bridge it also protects our robot with an undervoltage lockout an overcurrent detector and a thermal shutdown These features BUILDING THE DANCEBOT 241 VDD GND nteg rated H Bridg es PWM OUT 2
369. hen channel is 0 the expression stores the channel 0 ADC measurement in adcVal Q When channel is 1 the expres sion stores the channel 1 ADC measurement in adcVal 1 and so on Test MCP3208 fast spin CON _clkmode xtali plli6x _xinfreq 5 000 000 Crystal and PLL settings 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal adc MCP3208 fast PUB go channel adcVal 4 pst Start 115200 adc Start 1 0 2 1 repeat channel from to 3 Serial communication object ADC object Start Parallax Serial Terminal Start MCP3208 mode is legacy Initialize display pst Str String adceVal pst Dec channel pst Str String eae pst NL repeat Main loop waitent clkfreq 10 cnt Refresh display at about 10 Hz pst Home Home position on PST repeat channel from to 3 Get measurements adcVal channel adc In channel pst Position 12 channel pst Dec adcVal channel pst ClearEnd Display measurements Figure 4 29 shows the values Test MCP3208_fast spin displays in the Parallax Serial Terminal Each of the two potentiometers connected to MCP3204 channels 0 and 1 in Fig 4 28 has 4096 possible values 0 to 4095 which represent voltages from 0 to 4095 4096 5 V Another way of looking at 4095 is that it s about 1 22 mV below 5 V Twist each potentiometer knob to adjust its voltage and monitor the results in the Parallax Serial Term
370. her common question that comes up is how to transfer information to a PC application HOW DO I SYNCHRONIZE MY SLOWER APPLICATION CODE WITH A HIGH SPEED PROCESS Let s say that the ADC object samples the signal at 40 kHz but an application needs the information at a rate of 1 kHz This might happen because an example algorithm is available that is designed for 1 kHz or maybe other peripherals in the system can only respond at 1 kHz Suffice it to say that one object needs the information at 1 kHz but the building block object samples at 40 kHz A common mistake is to try to slow down the building block object which is simply not necessary Instead the application should have a loop that repeats at 1 kHz and grabs the most up to date measurement from the building block object Remember the convention for a loop with waitent t dt to synchronize the loop to repeat in dt clock ticks Immediately after the waitcnt QUESTIONS ABOUT PROCESSING AND STORING SENSOR DATA 183 command store the latest sensor measurement from the building block object A low speed 10 Hz example of this was demonstrated by the Test Sigma DeltaADC spin object in the section on Sigma Delta ADC HOW DO I STORE DATA FOR LATER RETRIEVAL AND KEEP IT FROM GETTING ERASED The portion of the Propeller s external EEPROM not used for storing the program can be useful for storing small amounts of data The PE Kit Tools EEPROM Datalogging article features a Propeller EE
371. his chapter we have shown how to take an off the shelf Ethernet chip interface that chip physically and electronically to the HYDRA game development platform and write an API in both assembly and Spin to communicate with it We showed how to write code for a simple network application while making use of the multiple cores available to us and managing resources using semaphores We even explored a little how this multicore solution is preferable to low power cheap microcontrollers Hope you enjoyed the chapter Exercises 1 Modify the Button Masher game to stream UDP packets at a constant rate as opposed to only when the player or opponent pushes a button This way even if a packet is lost it won t matter too much because another packet will be along shortly This will turn Button Masher into an actual real time game 2 Modify the Button Masher game to communicate via the HY DRA Net port instead of Ethernet 3 Use the last cog to add sound to Button Masher This can be as simple as a sound that is played when the game ends 4 Make Button Masher more time efficient Currently the MonitorButtons and MonitorEthernet methods are Spin methods that are interpreted This means that they execute one Spin instruction every time the Hub comes around to that cog which is slow Rewrite MonitorButtons and MonitorEthernet to be assembly instructions that fit within one cog they must be fewer than 512 bytes PORTABLE
372. his project out of the box it was decided to use a standard piece of hardware the Propeller Demo Board Rev C Revisions A and B will work as well with slight changes to connections Referring to Fig 10 1 the project requires an NTSC TV VGA monitor PS 2 key board an audio amplifier the NTSC TV s audio input will work fine and the Parallax Demo Board Rev C or better In addition you are going to need a PC to run the serial communications software on Technically any PC that supports the FTDI VCP USB to serial drivers connection will work The project simply needs to be compiled and downloaded to the Propeller NTSC TV VGA Monitor PIL VIDEO AUDIO VGA RPC commands from PC VT100 terminal USB Propeller Demo Board Rev C D Figure 10 1 Overall system block diagram of what s needed for the setup OVERVIEW SETUP AND DEMO 355 Board once this is accomplished you don t need to use the Propeller Tool anymore which is only officially targeted to PCs running Windows Nonetheless this project requires a standard RS 232 communications via a USB to serial connection And since the USB chip on the Propeller Demo Board is an FTDI chip your PC must support the driver You can find out more and download the latest FTDI drivers from the Parallax and FTDI sites here www parallax com usbdrivers www ftdichip com FTDrivers htm To compile and upload the code into the Propeller Demo Board you must have a c
373. his section we will equip a remote Propeller XBee system with a couple of sensors and then transmit the data from the sensors back to the base XBee to send the data to SENDING DATA FROM THE PROPELLER TO THE PC 205 the PC for monitoring The base can be the Propeller using serial pass through using the Prop Plug to the XBee or using a dedicated XBee to PC board as previously mentioned The sensors used for testing are Parallax s HM55B compass module and the PING ultrasonic range finder These devices will eventually assist in our robot project but you are free to modify the code to use any of the sensors previously explored in this text Additional equipment E HM55B Compass Module E PING Ultrasonic Range Finder E Or other sensors as desired with appropriate code Figure 5 10 is an image of the nodes Even though we don t need to just yet we will use this opportunity to set the DL address of the remote unit to 0 to ensure it is sending data to the base unit V Connect the PING sensor and HM55B compass on the remote unit as shown in Fig 5 11 If a different I O pin is used update the pin numbers accordingly in the CON section of the code Connect the LEDs as well we will use them shortly v For the base unit XBee open and clear the X CTU Terminal window Open the COM port if closed Having that port in use will help ensure the correct Propeller is programmed Download Simple_PC Monitoring_from_Remote spin to the
374. ications E Configuring the XBee manually and with the Propeller 189 190 WIRELESSLY NETWORKING PROPELLER CHIPS NODE 0 Bot Tilt Controller NODE 2 Bot Graphics Propeller Demo Board 3 Node Bot Network 5 Range 310 dBm 60 Angle 7270 Networked Bot Propeller Proto Board on Boe Bot Chassis Figure 5 1 Three node network for monitoring and control E PC to Propeller and Propeller to Propeller communications with the XBee E Transparent and API data modes of the XBee E Forming a multi node Propeller network for robot control and monitoring This chapter will work through several examples of communications but really the intent and focus is on how to perform the communications with the Propeller It is left to you the reader to take the principles discussed combine them with your imagination or needs and develop a Propeller network of your own Many other projects and informa tion from this text can be combined with this chapter for truly amazing projects OVERVIEW OF NETWORKING AND XBee TRANSCEIVERS 191 Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_05 Overview of Networking and XBee Transceivers The ability to communicate wirelessly has had such a significant impact on personal and data communications that many today cannot envision life without the use of cell phones Wi Fi networks and Bluetooth features in pe
375. icular I O pins see the Propeller Education Kit Lab Propeller PC Applications with ViewPort available from the Downloads amp Articles link at www parallax com Propeller Also www mydancebot com has a 60 page PDF manual and a Videos link with some great video tutorials that demonstrate how to configure ViewPort for a variety of applications ASCII stands for American Standard Code for Information Exchange Each time you press one of your computer keyboard s printable character keys it transmits the information to your PC as an ASCII code The ASCII codes 0 33 are nonprintable characters that are used for terminal control and configuration The Parallax Serial Terminal uses 16 of these for commands such as ClearScreen and NewLine The ASCII code for space is 32 and 33 126 are displayed by the Printable Ascii Table spin program and listed in Fig 4 44 178 _ SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Parallax Serial Terminal Disabled Click Enable button to Com Pott Baud Rate TX M DTR FT ATS come 115200 v o RX DSA CTS Prefs Clear Pause Figure 4 44 Printable ASCII characters Printable Ascii Table spin CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object ASYNCHRONOUS SERIAL 179 PUB go c pst Start 115200 Start Parallax Serial Terminal
376. ightly modified the GPS_IO_Mini spin object to add methods that return the degree and minute portions of the latitude and longitude separately so that it is easier to convert within a spreadsheet program The modified source for the GPS_IO_Mini spin object can be found here ftp propeller chip com PCMProp Chapter_09 Source GPS_IO_mini spin BAROMETRIC PRESSURE SENSOR A barometric pressure sensor measures atmospheric pressure which is the pressure exerted on a unit of area from a mass of air above the surface of Earth When submerg ing into water the deeper you travel beneath the surface the greater the pressure will be built up from the water overhead When rising from far down in the depths of water toward the surface the pressure is alleviated This is not at all different from the pressure felt from air when going from sea level to higher altitudes or vice versa In fact air does have mass and a considerable amount of it A cubic yard of air at sea level when the temperature is at 70 F weighs almost two pounds Since the air pressure diminishes as you travel into the upper atmosphere we can use this knowledge to compute a reasonable altitude measurement This is where a barometric pressure sensor is useful because it can measure the pressure felt upon it and produce a reading we can then use There are many different applications for a pressure sensor one of which is an altimeter for a large or small aircraft Many people wonder Why
377. igital card is attached for data logging purposes As you can see from Table 9 1 we have only one data connection to the GPS This is because on startup the GPS is wired to output raw data at a constant rate that the Propeller will read in serially 324 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER Next the Propeller is connected to an SD card using an SPI interface meaning there is a Serial Clock Data Out and Data In connection from the Propeller to the SD card The barometric pressure sensor uses a slightly modified SPI interface but it also contains all of the same communication pins as does the SD card One additional input into the barometric pressure sensor is the Master Clock pin input Since the barometric pressure sensor contains its own built in microcontroller for sampling the pressure sensor and communicating with outside devices i e the Propeller it requires an input clock for the CPU operation The required clock rate is 32 768 kHz and we will synthesize that frequency using the Propeller s counter regis ters and output it from a pin on the Propeller into the input pin on the pressure sensor This saves us from having to purchase an oscillator chip WHY DO WE USE 32 768 kHZ The 32 768 kHz signal is a common clock frequency that you may see often espe cially in designs that call for a real time clock RTC The reason why is that with a real time clock we are interested in keeping track of the time of da
378. ike making calls to another running program and using its resources subroutines Thus there is a client server relationship here and you can think of the RPC call as message passing as shown in Fig 10 9 There are various forms of the technology and it s more of a concept than a specific algorithm or methodology For example in some RPC setups the RPC call mimics the actual binary footprint of the function call Assuming the C C programming language here s a solid example float DotProduct float ux float uy float uz float vx float vy float vz Looking at this function depending on the compiler directives the parameters are passed by value on the stack from right to left if we assume six floats each four bytes there is a return value requiring another four byte float thus we need to pack the parameters up into a single record and pass it along and then wait for a single float four byte result RPC Call Overview DLL Call Overview Process 1 Process 2 Process 1 Process 2 RPC call from process 1 to 2 Local 7 a subroutines amp subroutines amp NOTEY Se memory void foo DLL call process s dynamically R gt ES links to common code in DLL library code is loaded and executed by process s However code is not part of a seperate Call across process process but rather simply loaded into a boundaries into other common memory space and executed by proces
379. il you get experienced with sizing the stack we recommend reserving 128 longs initially and optimizing it later Why should you optimize and when is the best time to do it You should optimize the size of stack space so your object does not waste precious memory for all the applications that use it Only when you re absolutely done with your object should you consider optimizing stack space doing so beforehand could be disastrous as you make final tweaks to your code To determine the optimal stack size needed for your object we recommend using the Stack Length object that comes with the Propeller Tool 42 INTRODUCTION TO PROPELLER PROGRAMMING Tip Many objects come with the Propeller Tool software To find demonstration code for them choose Propeller Library Demos from the drop down list above the Folder View To find the actual building block objects choose Propeller Library instead V Load the Stack Length Demo object see the previous Tip and read its comments o If you want to learn even more load the Stack Length object itself and read its top comments and its Theory of Operation section We ll use the Stack Length Demo object as a template for our test As it suggests we copy and paste its temporary code above the existing code in our Flash object as shown here CON _clkmode xtal1 plli6x Use crystal 16 for fast serial _xinfreq 5 000 000 External 5 MHz crystal XI amp XO OBJ Stk Stack Leng
380. ilters repeat a i2c readLocation ACC3D_Addr 28 8 8 lt lt 8 outxh at i2c readLocation ACC3D_Addr 29 8 8 outxl if a gt 32000 accel 800 a 65536 else accel 800 a Excerpt from i2cobject spin Copyright c 2006 James Burrows The code object that we will use to measure tilt for our robot is called tilt spin It measures the gyroscope and accelerometer sensors and fuses the result with a Kalman filter which is implemented as fixed point math in Spin code See Fig 6 8 for a sche matic on how to connect the accelerometer and gyroscope to the Propeller FUZZY LOGIC CONTROL THE BRAINS I ve spent a lot of time optimizing the DanceBot s control logic At the highest level the problem is quite simple We steer and the robot balances Our high level interface LIS3LVO2DQ Accelerometer aa a G gg f o VDO GNO 3 i vyp VDD u ISDA 1 vpo a z2 Pv Tia 4 a vse 2 t y5 6 Propeller anpe 5 sony a GWS PG 03 Gyro 8 J a2 CND ig VDD Figure 6 8 Schematic of tilt circuit BUILDING THE DANCEBOT 249 should be as simple as those of a car s remote control requiring us to provide just the speed and steering inputs The robot should do all the hard work of analyzing inputs and adjusting the speeds of the two motors However a balancing bot drives differently from a car steering is easier while managing speed is much more difficult Let s start by seeing what we need to do to steer the robot Since the
381. imerMs vars debug ListHome Display values debug Vars m String minutes seconds milliseconds debug break 92 DEBUGGING CODE FOR MULTIPLE CORES PRI TimerMs t cnt dt clkfreq 1000 repeat waitcnt t dt mst t if ms 1000 ms 0 StF if s 60 s 0 MEF if m 60 m 0 Current clock counter Ticks in 1 ms Infinite loop Wait for the next ms Add 1 to millisecond count If milliseconds 1000 Set milliseconds to 0 Increment seconds if seconds 60 Set seconds to 0 Increment minutes If minutes 60 Set minutes to 0 Judging from the Parallax Serial Terminal in Fig 3 18 it s working great isn t it Even with modifications similar to the previous code that test at times like 10 minutes 59 seconds 999 milliseconds it is unlikely to expose a hidden memory collision bug in Test Timestamp from the Other Cog spin Parallax Serial Terminal COM15 Com Port Baud Rate Tx DTR ATS coms z 115200 7 RX DSR CTS I Echo On Initial timestamp test DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 93 Step 4 Remember that Multiple Processors Are Involved and Test Going back to the Common Multiprocessor Coding Mistakes list we can check off a few possible bugs already The timing interval is correct and it doesn t miss the waitent boat The two cogs are using global variables to exchange values and appear to be doing so c
382. in Vars s 59 ms 999 dt clkfreq 1000 DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 113 if not semID cognew entry m ve gt locknew dbg start 31 30 entry Repeat DAT Entry entry timekeeper loop org Check out a lock lt Add for Debugger Keep cog running DAT block ASM address reference Debugger Kernel add this at Entry Addr long 34FC1202 6CE81201 83C120B S8BCOEGA SE87COEQ3 S8BCOEQA long SEC7COE 5 AQBC1207 5C7CQ003 5C7C0003 S7FFC S7FF8 if_z if_z if_z if_z if_z if_nz mov rdlong add rdlong add rdlong add rdlong add rdlong mov add waitcnt add cmp mov add cmp mov add cmp mov lockset jmp mov wrlong add wrlong addr par _m addr addr 4 _s addr addr 4 _ms addr addr 4 _dt addr addr 4 sID addr t ent te dt t _dt s s 60 s 0 m 1 m 60 m 0 sID loop addr par _m addr addr 4 _s addr WZ WZ WZ WZ Copy par gt addr Copy m gt m Point at next long Sais Point at next long ms gt _ms Point at next long dt gt dt Point at next long semID gt sID Copy ent gt t Add dt tot Wait for tt dt mst if _ms 1000 _ms 0 stt if _s 60 _si 0 mt _m 0 if _m 60 if not lockset sID Copy par gt addr Copy m gt m Point at next long Copy s
383. in some cases with an object from the Propeller Object Exchange the raw sensor mounted on the PCB based modules can be monitored directly by the Propeller chip PUSHBUTTONS Figure 4 4 shows two example pushbutton contact sensor circuits one with a pull up resistor and the other with a pull down resistor When a Propeller I O pin is set to input pressing the button in the circuit on the left causes a cog s ina register to store a binary 1 in the bit that holds that I O pin s input state For example if a pushbutton circuit is connected to P21 ina 21 would return a 1 if the button is pressed or a 0 if it is released The circuit on the right will result in the opposite values 1 if released 0 if pressed Caution Always include that pull up or pull down resistor do not leave it out If the pull up or pull down resistor is left out the I O pin becomes an antenna when the button is not pressed So the binary 1 0 result would depend on nearby electric fields or in some cases nearby I O pin states which can fluctuate In other words without the pull up or pull down resistors there s no telling what the I O pin will detect when the button is not pressed This is why pull up and pull down resistors are incorporated into circuits involving electrical contact ON OFF SENSORS 123 Figure 4 3 Examples of sensors with on off outputs When the button on the left side of Fig 4 4 is pressed the I O pin detects the short circuit
384. in the variable After repeating this 16 times the entire measure ment has been shifted right three extra digits because of those two zeros and one tristate at the end of the timing diagram So the command adcVal gt gt 3 shifts the entire value right by three binary digits to correct this before returning the ADC measurement Test Gyro spin SCLK 16 I 0 pin Assignments SDATA 17 DOUT in the schematic nCS 18 70S in the schematic PUB Init outaLSCLK SCLK amp CS gt output high outaLnCS dira SCLK dira nCS PUB Measure adcVal Get gyro ADC value outaLnCs CS gt low repeat 16 16 clock pulses outaLSCLK Clock pulse falling edge outaLSCLK Clock pulse rising edge adcVal adcVal lt lt 1 ina SDATA Get data bit from DOUT outaLnCS CS gt high adcVal gt gt 3 Shift right to get rid of last three digits ViewPort s lsa tab makes it possible to examine the synchronous serial signaling to verify that it s correct Figure 4 41 shows the communication signaling on lines 16 through 18 Line 18 is nCS and it does indeed go low for the entire exchange Line 16 is SCLK and the Propeller sends 16 pulses to it line 17 is SDATA the binary values the ADC transmits in response to each clock pulse Remember that the last three SDATA that accompany the last three rising edges are discarded With that in mind the binary value is 0111111101 decimal 509 The ViewPort package
385. inal In Fig 4 28 the MCP3204 s channel 2 input is tied to 3 3 V and the Parallax Serial Terminal in Fig 4 29 shows a measurement of 2719 Since 2719 4096 is approximately 3 3 5 this measurement is correct and indicates that the system is functioning properly The input voltage for channel 3 is tied to ground 0 V in Fig 4 28 and the result of adcVal 3 in Fig 4 29 is 0 so that measurement provides a second indication that the system is functioning properly 160 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Parallax Serial Terminal Disabled Cli E BR M DT oO s Figure 4 29 MCP3204 test measurements SIGMA DELTA ADC As mentioned earlier a counter module is a configurable state machine that s capable of performing a variety of tasks independently for its cog The On Off Sensors that Depend on Signaling section demonstrated an object that used a counter module to transmit 38 kHz square waves Another application of the counter modules built into each cog is Sigma Delta analog to digital conversion Figure 4 30 shows how a cog s counter module interacts with a Sigma Delta ADC circuit When in POS detector with feedback mode the counter module opposes the state it detects at the input pin with 3 3 V Voltage Saw 1 65 V inet Input Pin 27 Ri Feedback Png 3 3 V R CERTEN p GND Figure 4 30 Sigma Delta ADC circuit and signals VOLTAGE OUTPUT 161 the feedback pin and keeps a running count of
386. increases the voltage at the lower plate drops since the upper plate is connected to the 3 3 V supply and its voltage cannot move So the microcontroller measures the time it takes for the voltage at the lower plate to drop from 3 3 to 1 65 V The code for this behaves identically to the RC decay measurements discussed earlier since it starts by applying a high signal Then the I O pin changes to input and waits for the voltage to drop from 3 3 to 1 65 V RC measurements with a photodiode can be slow The RC Time object s default measurement timeout should be adjusted to a larger value with a call to its TimeOut method Figure 4 20 shows a schematic of the QTI module which measures infrared reflectiv ity of surfaces It s popular with robotics hobbyists for determining whether the robot 3 3 V 0 01 uF 1 0 Pin Photodiode 4 GND Figure 4 19 Photodiode and circuit 144 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES 3 3 V 470 9 I O Pin lt gt QRD1114 Figure 4 20 The QTI is above a black surface which absorbs infrared or a white surface which reflects it The letter q denotes charge and the product name QTI was chosen as an abbreviation of charge transfer infrared The module has a built in infrared LED circuit that emits infrared light If the infrared light reflects off a nearby about one eighth of an inch away white surface and strikes the infrared transistor s light collecting surface it will
387. ines will result in a whisper that sounds like it could be girl or curl We can make this say burl and pearl as well For b and p sounds f1 and f2 must be set very low and swept upwards quite rapidly while f3 and f4 can be the same as the following vowel s Two changes must be made to our PRI talk method to make b and p First replace setformants 0 1350 1350 4700 with setformants 0 200 ioa 4700 Second replace v go 150 with v go 50 to speed up the transition Now you should hear burl By commenting out the first ga 30 you should hear pearl While I won t go over every consonant recipe here as I d have to rediscover them myself thereby depriving you of the pleasure we should cover the nasals m and n Let s try to say the word monster That way we can slip in the s and t sounds to uti lize the FRICATION section as well as the NASAL completing our tour of VocalTract s parameters First Pll say monster very slowly in a froggy voice see Fig 12 6 EN Depiny Wavetorm 23ms Int egral Energy at Specific Energy cn a i id A al BA dn Spectr um vs Time Figure 12 6 A spectrograph of me saying monster followed by a baby monster 438 SYNTHESIZING SPEECH WITH THE PROPELLER After I said monster our two year old daughter repeated monster unexpectedly You can
388. ing The object based nature of the language was introduced in the previous chapter and one of the most important features of building block objects from the Propeller Library and Propeller Object Exchange is that their authors usually follow con ventions established by Parallax to make their interfaces simple and trouble free Building block objects that launch code into other cogs take care of most of the multiprocessing grunt work Good objects also contain methods that simplify con figuring the process executed by the other cog and exchanging information with the top level application object By convention a building block object that launches a process into another cog has a Start method that receives configuration information and contains code that launches the new cog It also has a Stop method for shutting the process down and freeing the cog In many cases these objects also have methods that provide a data exchange inter face In other cases the parent object passes information about its variable addresses so that the object can directly write to and or read from the parent object s variables Regardless of whether a method interface a memory sharing interface or some com bination of the two gets used the building block object that manages the process keeps the interface simple For example let s consider the Propeller Library s Keyboard object After its Start method gets called its assembly language code takes care of com
389. ing colored objects something that s useful as long as we have a color camera and are looking for colored objects FINDING SPECIFIC OBJECTS Let s look at another interesting OpenCV filter the Viola Jones object detector This filter is used to accurately find objects that statistically resemble objects that the detec tor has been trained for As configured in ViewPort it s quite good at finding all types of human faces with or without glasses different hairstyles and from different ethnic groups 276 CONTROLLING A ROBOT WITH COMPUTER VISION The Viola Jones detector looks for features in the frame Specifically the detector evaluates different parts and scales of the image to match their features with those iden tified in the training set These features are rather simple when we look at them They consist of a small number of rectangular areas where pixels are darker or brighter than the surrounding area Taken by itself a single feature isn t enough to detect an object but by combining multiple features that match in the right location and at the right scale the algorithm efficiently finds objects The key to using the Viola Jones detector successfully is a good dataset of images from which the features are learned In theory the filter is able to detect a wide variety of objects when you take the time to build a clean learning set So far it has been used mostly to find human faces Unlike the color blob finder th
390. ing depending on what we picked them to be The point is that if you were using another processor or process to make the RPC calls and not a human at a serial terminal then there is no reason to use ASCII coding However that said I still prefer sending things in ASCII format during the debugging phase so I can at least look at my data strings on the other end and see what s going on COMPRESSING RPC FOR MORE BANDWIDTH The whole idea of RPC technology is to use it thus you might have a program running that makes 100 local calls with 100 RPC calls every time through the main loop You want the RPC transport process to be quick hence compression of the RPC data and or caching is in order For example if you are sending large chunks of text or data that has repeating symbols it s better to compress it locally transport it and then decompress and execute since computers are typically thousands if not millions of times faster than the communications links 370 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS In addition advanced RPC systems might use the same data over and over thus there is no need to keep sending the data to the server A caching system should be employed where on the first RPC call the caller indicates that a data structure being passed is static and cacheable Thus the server caches it after its first use Then on subsequent calls the client need not send the structure until it needs ref
391. ing Multicore for Networking Applications 281 Introduction 281 Ethernet and Internet Protocols 281 EtherX Add in Card for the Propeller Powered HYDRA 287 CONTENTS ix Creating a Simple Networked Game 312 Summary 318 Exercises 318 Chapter 9 Portable Multivariable GPS Tracking and Data Logger Introduction 319 Overview of the Sensors 322 Main Spin Object 344 Experiment 346 Summary 351 Exercises 352 Chapter 10 Using the Propeller as a Virtual Peripheral for Media Applications Introduction 353 Overview Setup and Demo 354 System Architecture and Constructing the Prototype 362 Remote Procedure Call Primer 366 Virtual Peripheral Driver Overview 370 Client Host Console Development 372 Exploring the Command Library to the Slave Server 387 Enhancing and Adding Features to the System 389 Exploring Other Communications Protocols 389 Summary 396 Exercises 396 Chapter 11 The HVAC Green House Model Introduction 399 Exploring the Problem 400 The HVAC Green House Model 402 Summary 423 Exercises 425 Chapter 12 Synthesizing Speech with the Propeller Introduction 427 Using Spectrographs to See Speech 427 Exploring the VocalTract Object 431 Summary 441 Exercises 442 Appendix A Propeller Language Reference Categorical Listing of Propeller Spin Language Elements 443 Categorical Listing of Propeller Assembly Language 449 Reserved Word List 457 Appendix B Unit Abbreviations Index 319 353 399 427 443 459
392. ing locally to the user interface experience the command is processed parameters extracted and converted to proper formats and then the handler s call down to the drivers on the other cores Let s start with the SOUND command since it s one of the simplest relatively speaking The parser is looking for SOUND to begin with Once found the parser needs to find one of the subcommands PLAY or STOP or STOPALL Each of these subcommands might have parameters as well so there is a lot going on but if you write the parsing functions cleanly in each handler it s a snap Let s take a look at the code for this handler Sound Commands snd play chan 4 freq 5000 dur in sec 0 255 Plays the note on the requested channel with sent frequency and duration snd stop channel 4 Stops the requested channel snd stopall Stops all channels elseif strcomp tokens string SOUND or strcomp tokens string SND Case PLAY if strcomp tokens 1 string PLAY SND channel 3 freq 0 4K duration 0 secs Enter handler Channel 3 argl atoi2 tokens 2 Frequency to play arg2 atoi2 tokens 3 Duration in seconds arg3 atoi2 tokens 4 Issue command to sound core if arg2 gt 0 snd PlaySoundFM argl snd SHAPE_SINE arg2 snd SAMPLE_RATE arg3 255 3579 ADEF else snd StopSound arg1
393. ing the assembly debugging functionality The left most apostrophes can be removed to comment out the debugging code or added back to uncomment them For example this code is not commented Fi dbg start 31 30 entry debugger 3 Now it s commented dbg start 31 30 entry debugger y Also an apostrophe following each brace makes it possible to use a couple of find or replace sessions to quickly uncomment and comment the debugger code TimeStamp Dev ASM spin is a test program for an assembly routine that performs the same function as the TimerMs method in Timestamp Object spin In fact the required changes to substitute the assembly routine for the TimerMs method in the Timestamp Object would be minimal The cognew command would have to be modified to launch the assembly code and the stack variable array could be removed since assembly lan guage does not require stack space in Main RAM that cogs executing Spin code use for expression calculations method parameters return addresses and return values Timestamp Dev ASM spin Supplies minutes seconds milliseconds timestamp upon request CON Constant declarations _clkmode xtali plli6x System clock settings _xinfreq 5 000 000 VAR Variable declarations long cog m s ms dt semID Counting variables OBJ Object declarations ae dbg PASDebug lt Add for Debugger Si PUB TestStart TestStart method m 10 Initialize Sp
394. ing with many things at once often a separate focused process core can address each task individually and the collective of separate processes can achieve amazing things with little work on the developer s part It s easier than you may think If you start every application with this in mind you ll be most successful Let s test this out with an example Suppose you have an assembly line that produces thousands of products per minute The machinery to do it is expensive so both quantity and quality must be high to keep the business profitable You need a system that inspects the product at various critical stages discarding the bad keeping the good and adjusting the speed of assembly along the way to maximize throughput The workers and managers can t be left out of the loop they need reports of some kind and the ability to adjust settings as the need arises And most importantly each of these things should behave consistently without any bottlenecks introduced by the activities of another LET S GET CONNECTED 17 This may sound horribly complex but breaking it down into separate problems eases the pain E First concentrate on a system that only inspects the product and gives a pass or fail response to each one E Then devise a process for discarding units deemed bad while keeping the good E Build a component whose sole task is to adjust assembly line speed based on a ratio of good versus bad product produced E
395. instruc tions found in modern processors In the following sections we ll explore how OpenCV implements several of these functions and then use them in our Propeller Spin program STATE OF THE ART COMPUTER VISION WITH OPENCV 275 FINDING COLORED OBJECTS Since OpenCV supports color video sources one useful filter we can employ is a color blob filter This filter finds the area containing the largest number of pixels that match our target color To understand the color filter however we need to understand two different color spaces Earlier in this chapter we learned that pixels make up an image and that each pixel in a 24 bit color image is typically defined by three bytes that define the red green and blue levels of the pixel This the RGB color space is the most common color space used by electronic systems like computers cameras and webcams It s an additive color model where different proportions of the three primary colors are added together to reproduce the broad array of colors we see on our monitors For example to produce a yellow pixel we would add equal amounts of red to equal amounts of green using more of both would make the pixel brighter Other color spaces exist and are appropriate for different uses For example the subtractive color space CMYK cyan magenta yellow and black is used in the printing industry and HSV hue saturation and brightness is used in televisions Video coming from a webcam is
396. ion see Fig 9 1 using three wires TX RX and ground to other forms of clocked serial communications such as Serial Peripheral Interface SPI and Inter Integrated Chip C In contrast to serial communications some sensors and peripherals may be interfaced using parallel data and control lines For example the Wiznet Ethernet Chip discussed in Chap 8 supports sending and receiving Ethernet data through a 16 bit 8 bit parallel address data bus Finally there are more exotic methods conceived by manufacturers where careful reading of the datasheet or hardware reference manual is required for interfacing Once a device is physically connected to a microcontroller software must be written to send and receive data and commands This task is generally trivial when interfacing one sensor to a microcontroller but it can grow in orders of magnitude in complexity when talking with multiple sensors The reason why is because different sensors and peripherals operate at diverse frequencies While one sensor outputs its custom data once every second 1 Hz another sensor could be transmitting its data 10 times a Full Duplex UART TX CPU 1 CPU 2 E li Bi Gnd Serial Peripheral Interface SPI MOSI MISO CPU 1 Master SCLK CPU 2 Slave B Hil Ei Gnd Inter Integrated Circuit 1 C SDA CPU 1 SCL Master CPU 2 Slave B ii iB Gnd Figure 9 1 Interface technologies INTRODUCTION 321 second 10 Hz Wh
397. ional Bit 0 123 45 6 7 B 0 123 45 6 789 5123 456789 g jM Nibble gt Byte at ae wae TCP Flags j Congestion Notification TCP Options Offset j T e e CEUAPRSF ECN Explicit Congestion 0 End of Options List Number of 32 bit words in Notification See RFC 1 No Operation NOP Pad TCP header minimum value Congestion Window 3168 for full details valid 2 Maximum segment size of 5 Multiply by 4 to get C 0x80 Reduced CWR states below 3 Window Scale byte count E 0x40 ECN Echo ECE Padest Qtiae 060 EONA 4 Selective ACK ok U 0x20 Urgent sm oo 13 8 Timestamp RFC 793 A 0x10 Ack SynAck 00 01 P 0x08 Push SE LL as Checksum Please reter to RFG 793 tor R 0x04 Reset No Congestion 01 00 E the complete Transmission S 0x02 Syn cages Ie os Checksum of entire TCP Control Protocol TCP F 0x01 Fin Congestion 11 00 segment and pseudo Specification Receive Feepomse I Ot header parts of IP header Sender Response 11 11 Copyright 2008 Matt Baxter mjb fatpipc org www fatpipe org mjb Drawings Figure 8 5 TCP header field 286 USING MULTICORE FOR NETWORKING APPLICATIONS MAC Header IP Header UDP Header Data CRC Checksum 14 bytes 20 bytes 8 bytes 18 1472 bytes 4 bytes Ethernet Type II Frame 64 to 1518 bytes Figure 8 6 Ethernet frame with IP header UDP header and data UDP Header Byte Offset 4 Length Checksum on 3 1234567899Q1 1 1234567 8 9
398. ions TABLE 10 3 SPI CLOCKING MODES CPOL CPHA MODE CLOCK POLARITY CLOCK PHASE 0 0 0 1 0 1 2 1 0 3 1 1 392 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS E Mode 1 The clock is active when HIGH Data is read on the falling edge of the clock and is written on the rising edge of the clock E Mode 2 The clock is active when LOW Data is read on the rising edge of the clock and is written on the falling edge of the clock E Mode 3 The clock is active when LOW Data is read on the falling edge of the clock and is written on the rising edge of the clock Note Most SPI slaves default to Mode 0 so typically this mode is what is used to initiate communications with an SPI device That about sums it up for SPI Of course the Propeller chip does not have any SPI hardware built into it thus if we want to talk to the Propeller chip with an SPI interface we have to write a virtual SPI interface just like the serial driver itself Therefore we have to bit bang the SPI interface Assuming we want to get each bit of information into the Propeller chip plus a little overhead maybe five instructions per bit that means that a 20 MIP core is going to be able to keep up with a 4 MHz SPI interface so something to keep in mind It s still better than the 115 200 serial connection For more information about SPI interfacing and protocols take a look at some of the docu ments located on the FTP
399. ip interfacing get maximum performance However with this setup now the command packets RPC calls would be encoded as command bytes followed by data bytes so the interface would be nonhuman readable but much faster Now the Propeller chip truly acts like a virtual peripheral and as long as the host client chip system has an SPI interface we can send commands to the Propeller In other words we turn the Propeller into a black box that can be controlled with an SPI interface that has a rich set of multimedia capabilities For example you could hook a BASIC Stamp up to the SPI interface or another processor and then leverage the power of the Propeller chip over a single SPI interface with a simple set of commands USING TCP IP TO SERIAL FOR FUN The last topic I want to discuss is more for fun than for anything else but it s kind of a cool hack Currently we are using a PC and a serial terminal program to talk to the Propeller chip but the serial terminal is running locally on the machine so at best we can put a 10 to 20 ft cable out there and connect it to the Propeller Demo Board But what if we wanted to truly be remote Well we could create a real Ethernet connection and connect an Ethernet module to the Propeller Demo Board but that would require a lot of work and time However there is a cool trick though that we can play with TCP IP and Ethernet the trick is to load a serial over TCP IP connection on two comput
400. is filter only looks at the grayscale component of the video Color frames sourced from a color webcam are first processed by a grayscale filter before the object detector is run Since only grayscale frames are needed you can use this filter on video sourced from the PropCV frame grabber FINDING SHAPES Faces are quite complex objects Let s look at a filter that finds a simple shape a circle A circle filter is quite useful because spheres viewed from any direction have the shape of a circle Also balls are quite common in many of the sports we play A technique to accurately track where they are in a robotic system can be useful It s easy to confirm the location and radius of a circle once we ve found it All we have to do is look at the pixels that are one radius away from the circle s center and make sure they mark the edge of the object we re seeking This filter typically preprocesses the frame with an edge detector filter so the circle s edge will ideally be completely white However finding the location and radius is inefficient in our traditional Cartesian system where pixel values are arranged geometrically by their x and y locations There are so many possibilities Luckily we can transform our frame data from the Cartesian system into a three dimensional space using the Hough transform where this process becomes much easier This mathematical technique is a linear transformation that maps edge points to a specific point
401. is to modify the program so that both methods exchange information through a single global variable named delay The code in Cogs Sharing Info Bug fixed spin corrects the problem by declaring a global variable named delay The Go method updates the delay variable whenever a new value gets entered into the Parallax Serial Terminal and the Blinker method uses the delay variable s value to control the rate of the loop that toggles the LED circuit on and off Cogs Sharing Info Bug fixed spin CON _clkmode xtali plli6x 5 000 000 _xinfreq VAR Blinker method Current cnt register gt t variable Set I O pin to output Repeat loop Synchronized delay Invert I O pin output state Constant declarations Crystal and PLL settings 5 MHz crystal x 16 80 MHz Variable declarations COMMON MULTIPROCESSOR CODING MISTAKES 73 long stack 10 Stack for cog executing Blinker long delay Global var for cogs to share OBJ Object declarations pst Parallax Serial Terminal Serial communication object PUB Go Go method pst Start 115200 Start Parallax Serial Terminal cog delay clkfreq 4 Initialize delay variable cognew Blinker 5 stack Launch Blinker method into new cog repeat Repeat loop pst Str String Enter delay ms Prompt user for input delay pst DecIn clkfreq 100Q User input gt delay var PUB Blinker pin t Blinker method t t ent Current cnt register
402. ith the matching address responds and then communication begins The protocol is rather complex and beyond the scope of this chapter but some good references are located on the FTP site in Chapter_10 Docs i2c directory SPI I C AND LOW LEVEL CHIP INTERFACING Now that we have discussed some of the technical details of SPI and I C let s take a moment and talk about how we might design or alter our current system to take advan tage of the technology First our current system uses a serial terminal controlled by a primate to send and receive commands and data to and from the Propeller chip which is running the CCP and the virtual peripherals Thus we need to remove the serial terminal and human out of the loop and create a tighter low level interface based on either SPI or I C Let s assume SPI for now As Fig 10 16 shows this is what we need to implement The CCP essentially works the same but now instead of an RS 232 communications driver we need to write or obtain an SPI driver Then as the SPI driver receives bytes we need to monitor it for commands execute them and return results This is all going to happen 100 times faster than the serial interface thus assembly language might need to be employed to 394 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Client processor anything with an SPI interface Propeller Cog i Virtual SPI Driver Common Ground L Figure 10 16 Chip to ch
403. ith the modifications just discussed it s now ready for ViewPort debugging The call to the conduit object s config method sends a list of variable names var minutes seconds milliseconds The code also passes the addresses of the start and end variables in the list with a call to vp share so ViewPort will monitor minutes through milliseconds Make sure to keep the names in the config method call the same as the names of the variables in your code This will ensure that you can use all of ViewPort s debugging features with those variables Test Timestamp Object with ViewPort spin Check minutes seconds and milliseconds in code tab s Watch windowpane and signal timing in the dso tab s Oscilloscope CON _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz x 16 80 MHz OBJ vp gt conduit ViewPort conduit object time TimeStamp Object TimeStamp object 104 DEBUGGING CODE FOR MULTIPLE CORES PUB Go minutes seconds milliseconds Configure ViewPort display amp share minutes through milliseconds vp config String var minutes seconds milliseconds vp share minutes milliseconds time Start 10 59 999 Start timestamp cog repeat Main loop time GetTime minutes Get a timestamp To run the program in ViewPort S Copy the following objects to the C Program Files ViewPort mycode directory o Test Timestamp Object with ViewP
404. its Kb kilobit 1024 bits KB kilobyte 1024 bytes K bytes kilobyte 1024 bytes K words 1024 words K longs 1024 longs MB megabyte 1024 KB GB gigabyte 1024 MB Rates bps bits per second kbps kilobits 1 000 bits per second Mbps megabits 1 000 000 bits per second cps cycles per second fps frames per second 459 460 APPENDIX B kHz MHz GHz MIPS ppm Time hertz kilohertz megahertz gigahertz rotations per minute million instructions per second parts per million min us ns minutes seconds milliseconds microseconds nanoseconds Power related Vv VDC VAC mV mA uA mW volts volts direct current volts alternating current millivolts ampere milliamperes microamperes watt milliwatt megawatt ohm UNIT ABBREVIATIONS 461 KQ MQ uF nF pF kilo ohm mega ohm microfarads nanofarads picofarads Distance cm km in ft yd millimeters centimeters meters kilometers inches feet yards miles Pressure mbar Pa kPa millibars pascals kilopascals Temperature K F C Kelvin Fahrenheit Celsius 462 APPENDIX B Other mol g dB dBm moles acceleration decibels decibels referenced to milliwatts INDEX Note Page numbers referencing figures are followed by an f page numbers referencing tables are followed by a t aaaaahhhh 166 166f Absolute Telnet termi
405. l turn the light on whenever the button is pressed and leave it off when the button is released repeat Repeat loop waitcnt tt delay Synchronized delay outal6 ina 21 4 BUG fixed outaLpin Invert I O pin output state There are also situations where a loop should monitor a process until just before the allotted time runs out For example let s say the application needs the P6 LED to turn off immediately when the button is released without a potential quarter second delay The previous code could take up to a quarter of a second before turning the light back off but maybe only a couple of milliseconds delay is acceptable Here is an example that monitors the P21 pushbutton and mirrors the state with the P6 I O pin until about a millisecond before the loop has to repeat repeat waitcnt tt delay outaLpin Keep repeating button LED loop until time is almost up repeat until cnt t gt delay clkfreq 100Q outal6 ina 21 4 BUG fixed The inner repeat loop continues its outa 6 ina 21 process until the current value of the cnt register minus the value stored by the cnt register at the end of the previous COMMON MULTIPROCESSOR CODING MISTAKES 71 time interval is greater than or equal to some number of clock ticks that s slightly less than the outer loop s time interval In other words current cnt previous cnt gt value slightly less than time interval The statement repeat until cnt t gt
406. l us the raw signals that are sent to and from the Propeller Refer to Fig 6 12 to see 10 traces which represent the communication with the accelerometer gyroscope motors and encoders The accelerometer clock acCL trace shows the pulses used to clock the data coming and going to the accelerometer over the accelerom eter data acDT line using the I C protocol Notice that multiple bytes are transmitted BUILDING THE DANCEBOT 253 ViewPort v4 1 64 Cie File Edit View Configuration Plugins Debug Help 4 200us sous us soe 20us Time msec Connection Disconnected Memory 00 00 08 Figure 6 12 ViewPort measurement of input output signals to from the accelerometer to first query and then read in the two bytes of the sensor The gyro out gyrOT trace shows the pulse output to the gyroscope which is returned slightly later in the gyro in gyroIn trace As the bot is rotated this signal gets both longer and shorter The next four traces mlp mlr m2p m2r are the direction and pulse width modulation lines used to control the two motors And final
407. l window and type once again You should get no response and the remote RX light on the AppBee should not blink 202 WIRELESSLY NETWORKING PROPELLER CHIPS COMMAND CODE CH MY Sleep Modes SM Serial Interfacing BD AP RO IO Settings DO D8 IR Diagnostics DB EC TABLE 5 1 SUMMARY OF PERTINENT XBee SETTINGS Networking amp Security MEANING amp USE Channel Sets the operating frequency channel within the 2 4 GHz band This may be modified to find to a clearer channel or to separate XBee networks PAN ID Essentially the network ID Different groups of XBee networks can be separated by setting up different PANs personal area networks Destination Low Address The destination address where the transmitted packet is to be sent We will use this often to define which node receives data A hexadecimal value of FFFF performs a broadcast and sends data to all nodes on the PAN The default value is 0 Source Address Sets the address of the node itself This will be used often in all our configurations The default value is 0 Sleep Mode Allows the sleep mode to be selected for low power consumption lt 10 pA While we won t use it a good choice is 1 Pin Hibernate This would allow an output of the Propeller to put the XBee to sleep using the Sleep Request pin when it is not sending or expecting data Interface Data Rate Sets baud rate of the serial data into and out of the
408. ld a custom piece of hardware for this project but to use one of the Propeller Demo Boards Rev C Actually revi sions A and B will work as well but Revision C and later versions are clean and have built in USB to serial Figure 10 7 shows the reference design for the Propeller Demo Board for reference The software is written in such a way that it assumes the connections as shown in the Propeller Demo Board but you can always change these as mentioned In any event using the schematic as a reference let s take a look at the overall system design as shown in Fig 10 8 SYSTEM ARCHITECTURE AND CONSTRUCTING THE PROTOTYPE 363 a ae are aa See er eet ey 1 USB Mini B On Board USB to Serial VddVdd 6 9 5V 3 3V l Also available separately VDC On Off LM2937IMP 5 0 LM2937IMP 3 3 I as the Propeller Clip 32 KB 10 ka o l or the Propeller Plug I EEPROM l 5 4 3 g I l L l I s I Ta I l 24LC256 I ST l l Vadvda l l Keyboard l m 3 3VOUT l PS 2 10kQ I vcclo RXD 3 3V I TXD Clock 0 1 HF TEST I 2402 bI GND DTR i Reset l FT232RQ 0ko I pan Green l l O L N 100 Q l L a l z a Va ee Ge a cs AM 100 Q VddVdd Mouse Noo Vdd PS 2 10kQ Jumper 5V 3 3V rl Vdd Clock EHI oa ee PT a PT l o el l 5 MHz 100 Q Electret Vdd Vdd N L Removable Mic N Crystal Y U LED GE 10 kQ 1nF ydd Indicators UU x 1 uF LOO AAA 0 1 uF 100 kQ de nF 10 kQ 10 kQ
409. le A to generate the 38 kHz square wave but it could just as easily have selected counter B with a channel argument of 1 After transmitting the 38 kHz signal for 1 ms the code copies the state of ina 5 to a variable named detect Before displaying the detect variable s value and repeating the loop the application code makes a second call to the Square Wave object s Freq method passing a frequency of 0 Hz to stop the 38 kHz signal to the IRLED Test IR Detect spin CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object squ SquareWave Square wave object ON OFF SENSORS 135 PUB go detect pst Start 115200 Start Parallax Serial Terminal repeat squ Freq 2 38000 P2 IR LED flicker at 38 kHz waitent clkfreq 100 cnt Wait 10 ms detect ina 5 Check IR receiver squ Freq 2 Q 0 Turn off IR LED Cursor home display label detector state clear to end of line pst Str String pst HM IR Detector pst Dec detect pst ClearEnd Information This example is an adaptation of Test IR Detect spin in PE Kit Tools Transmit Square Wave Frequencies This post is part of the PE Kit Tools series published in the Propeller Education Kit Labs sticky thread in the Propeller forum at http forums parallax com The IR receiver is an active low device meaning it sends a low
410. le counts clock ticks the cog waits until it detects the RC circuit s transition from high to low Then it copies the accumulated clock ticks from the counter module to the memory address that the parent object passed to the Time method For example the variable address was tDecay in Test Simple RCTIME spin v Try replacing the potentiometer with the photoresistor Simply remove the potentiometer and plug the photoresistor into rows 28 and 29 in Fig 4 16 When you run the test application the Parallax Serial Terminal will display smaller values corresponding to brighter light or larger values corresponding to dimmer light Since the decay time is At 0 693 C R a capacitor that s 10 times the size will result in decay times and measurements that are 10 times as large Likewise with a capacitor that s one tenth the size the measurements take one tenth the time gt Parallax Serial Terminal Disabled Cli EBR tDecay 4007 Figure 4 17 RC decay measurements in the Parallax Serial Terminal oF 142 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Try different size capacitors The RC Time object has a TimeOut method that defaults to 10 ms clkfreq 100 For larger capacitors it may be necessary to call the RC Time object s TimeOut method and pass it a larger timeout value such as 100 ms which is clkfreq 10 OTHER RC DECAY AND GROWTH CIRCUIT VARIETIES Photodiodes generate current flow in pr
411. lephone cable could be used to connect the rooms to the wiring closet In our proto type we decided to use four pair CAT 5 cable to support the possible current draw that we may see from the servo motors In addition we decided to put 12 V on one pair to drive 12 V indicator lights in each pushbutton switch Developing Control Board Prototypes At this point we decided to build a test room control board Fig 11 11 to see how well it would function The first one was YL AN Ov eb tusspioagt A ve D Figure 11 11 The first prototype room control board with LCD display temperature sensor humidity sensor servo driver and pushbutton switches 412 THE HVAC GREEN HOUSE MODEL sto USB 0000000 amma 0000006 yal NS 000 000 ee KoKo rite 990000004 he 1000 000 Q z 5 6 Keke 0002 oo O0 6 Koke K KSKS 0000 tO O00 00O PES 39t S3 A0 50600 00 stes oU000000 OOOO O0 O nO 00000000 mOG 30 ols P IDO 00035 900000355 Bers 3 a aisuerasaiag ie Serres erre 000000000 J 0 00000000 le i re re re O re O O o Q z J 000000000000000 393 000000000000000 59 00000 ARAA 000000 0000006 O000000 o Figure 11 12 The second prototype room control board built using the low cost Parallax Propeller Proto Board USB and some rudimentary code was writ
412. level chip interfacing and SPI IC 393 394 low rate wireless personal area network LR WPAN 191 nodes of 208 LR WPAN See low rate wireless personal area network Lynxmotion Geared Motor 238 MAC address 282 283 303 mac array 303 Main method 31 32 Main RAM 12 13f access by cogs 54 54f Main ROM 12 13f main Spin object 344 346 345f mapping strings 230 Martin Jeff 1 15 Master Clock pin input 324 Master Input Slave Output signal MISO SOMI 290 390 390f Master Output Slave Input signal MOSI SIMO 290 296 390 390f MCP3204 157 158f 159 160f MCP3204 ADC 168 MCP3208 157 mean sea level MSL 347 memory access collisions 54 memory addresses 57 memory collisions 73 74 74f 93 94f corrected with timestamp test 97 98f MEMS See microelectromechanical systems technology Memsic 2125 Accelerometer 144 145 148 152 149f 152f 225 225f method 24 method call with parameters 29 29f 34 34f microcontroller interfaces of sensors 119 122 networked game creation approach of 313 sensor interfacing with 320 322 microelectromechanical systems MEMS technology 148 332 INDEX 469 microelectromechanical systems MEMS technology Cont accelerometers 245 245f 247 barometric pressure sensors 332 Microsoft 284 Microsoft COM technology 372 Microsoft Excel 319 347 348 MISO SOMI See Master Input Slave Output signal mode descriptions 391 392 mode method 299 300 Modes of SPI
413. licated motions requires a sophisticated control algorithm Fuzzy logic has received somewhat of a bad rap because it was once hyped as the silver bullet to all problems It s not a silver bullet but it makes some things easier especially configuring a complex control function with human intuition We ll use fuzzy logic to create smooth continuous mapping functions defined by just two setpoints that relate the variable being mapped to human concepts Figure 6 9 shows a simple fuzzy mapping function that is used by DanceBot to monitor its speed The input to the function is a real number in this case the bot s measured speed The output is a set of five numbers indicating membership in each of five speed classes fast backwards slow backwards stopped slow forwards and fast forwards While different people might have different definitions for the fuzzy speed classes mentioned we all have a good idea what they mean It s also quite easy to talk logically about fuzzy classes for example If you re falling forward fast you need to drive forward fast Fuzzy logic allows us to tune the bot with just two numbers per transfer function the setpoints for slow and fast in the previous example The resulting function will be continuous without sudden jumps and will gracefully top out at the maximum values all without Speed 17 10 30 Peo O a Figure 6 9 Fuzzy mapping function to translate speed to fuzzy
414. ll run at the resolution and color mode of the source input Processing a 24 bit megapixel video stream on the PC is no big deal Let s look at the memory consumption for a frame of that 1 Mpixel 24 bit pixel 3 byte 24bit 3 MByte a lot for the Propeller but little of a PCs gigabytes of RAM Want to see how well OpenCV finds your face All you ll need is a webcam and Propeller connected to your PC running ViewPort When you load the previous code Tutorial 15 in ViewPort to the Propeller you ll see a color video from the camera in ViewPort s video view Your head should be marked with a red frame and the x and y variables on the Propeller should indicate the scaled position see Fig 7 12 for a screenshot It should be straightforward to drive a hobby servo with the x signal so that the servo tracks your face To find different objects or to use a different video source choose the appropriate controls in the openCV panel SUMMARY 279 ViewPort v4 1 64 DER Overview click on name to configure ax Avg Name Plo Earn pos Be 594 Cursors mor a B Streaming Video H Scanline at Y 972 Me V Scanline at X 904 Source edge face color circle Feature File 1 Feature File 2 hev haarcasca ev haarcasca d AQUBC Blob X 456 Y 483 W 6 H 8 Cursor X 904 Y 972 V
415. ller This is fine for getting started writing simple programs but I quickly determined that I needed a more powerful debugging tool to develop and con figure my robot This led me to develop an application I now call ViewPort I started by dedicating one of the eight cogs to continuously share data stored in the Propeller s memory with a PC application This let me monitor and change variables all while the other seven cogs were running at full speed When I added a module that sampled all 32 I O pins at 80 MHz other hobbyists became interested in using my application to debug their integration code and ViewPort was born Since then I ve added other capabilities to the ViewPort application to turn it into a complete debugging package In other parts of the book you ll see how you can use ViewPort to debug Spin pro grams with its visual debugger how to stream video to debug computer vision problems and how to use the virtual instruments to measure signals In this section we ll use 252 DANCEBOT A BALANCING ROBOT ViewPort Debugger Propeller with 8 Cogs DanceBot Position Encode pulse length phase uickSample Sample IO pins at up to 80 Msps E 2 Kalman O 50 Hz update to s eliminate drift Fuzzy control Measure tilt balance and keep position Monitor Change Variables Proportional fwd rev Gyro g Accelerometer Analyze Data Encoder OpenCV Vision Engine Conduit cana PhysX World Simulation Share dat
416. ller Tool software v Use Run gt Compile Current View Info F8 to compile the application v Use the upper left Object View pane to open the Parallax Serial Terminal Float32 and FloatString objects v Click the Documentation radio button to display each of the building block objects in documentation view The Parallax Serial Terminal and Float32 objects both have Start and Stop meth ods listed first in their Object Interface sections which is visible in the Propeller Tool software s documentation view This is your clue that each of these objects launches code into another cog and that your application code will have to call each of their Start methods before calling any of their other methods If an object s Start method is optional its documentation comments should state that and if it doesn t a call to the object s Start method is probably required for the object to do its job s Test Float32 spin CON _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object fp Float32 Floating point object fs FloatString Floating point string object PUB Go degrees radians cosine pst Start 115200 Start Parallax Serial Terminal cog fp Start Don t forget this pst Str String Calculate tangent pst NL repeat pst Str String pst NL Enter degrees degrees
417. lly testing the daughterboards and the master board we attached them to the Propeller Proto Boards and used aluminum standoffs on the four corners to stabilize the connections The resulting board sets shown in Figs 11 17 and 11 18 were robust compact repairable and reproducible So now that we had the hardware designed for the house it was time for some software design Figure 11 17 The control daughterboard mounted on the Propeller Proto Board THE HVAC GREEN HOUSE MODEL 417 Figure 11 18 The master daughterboard mounted on the Propeller Proto Board SOFTWARE DESIGN CONSIDERATIONS WHAT GETS PROCESSED WHERE Having processing power in each room made some functions intuitively obvious Here is a listing of the functions that could easily be handled by the single Propeller chip in each room Servo PWM generation Parallel LCD control Pushbutton detection debouncing Temperature sensor polling Humidity sensor polling Status light control Target temperature display Communications TX RX Something to remember is that the design of the Propeller chip lends itself well to providing parallel functions and services For example servo motors require a steady stream of pulses in order to maintain their position Therefore it is possible to use an object to constantly supply these pulses You need only tell the servo control object at what position the servo should be and the object takes care of the rest Th
418. lock signal is used to trans fer each binary digit in messages to and from the microcontroller For example to get a measurement from a serial ADC with synchronous serial communication the Propeller sends pulses to the ADC on a clock line with each pulse the ADC sends the next binary digit a 1 or 0 in the measurement Serial ADCs are slower than their parallel counterparts but require fewer I O pins Serial ADCs are not typically fast enough to sample high speed signals like video and radio intermediate frequency however some parallel ADCs are fast enough to keep up Some serial ADCs on the other hand are fast enough to sample audio signals while others are better suited to slower signals such as sensors that measure lower speed processes ambient light temperature etc The measurement capabilities of peripheral ADCs are described in terms of resolu tion which indicates the number of values the ADC can use to describe a range of input voltages Resolution is typically given in bits with values like 8 bit 12 bit 16 bit and so on If an ADC has 8 bit resolution it means a measurement has 8 binary digits bits VOLTAGE OUTPUT 157 in the number that describes the voltage An 8 bit value can store a number from 0 to 255 which is 28 256 different values A 12 bit value can store 2 4096 different values ranging from 0 to 4095 The digitized voltage an ADC returns to indicate a voltage measurement is typically digitized
419. lor of NISC terminal ntsc nl Print a newline to NTSC terminal ntsc out num 255 Outputs a single ASCII character to NTSC terminal ntsc sx num 39 Sets X cursor position of NTSC terminal ntsc sy num 29 Sets Y cursor position of NTSC terminal elseif strcomp tokens Q string NTSC Case PR print PR or P if strcomp tokens 1 string strcomp tokens 1 string term_ntsc pstring tokens 2 term_ntsc out ASCII_CR Case CLS clear screen elseif strcomp tokens 1 string CLS Clear screen term_ntsc out 00 term_ntsc newline term_ntsc pstring prompt Set color to normal CLIENT HOST CONSOLE DEVELOPMENT 385 term_ntsc out C term_ntsc out Q Case OUT output a single character elseif strcomp tokens 1 string OUT or strcomp tokens 1 string 0 term_ntsc out byte tokens 2 Case NL newline elseif strcomp tokens 1 string NL term_ntsc newline Case COL set color elseif strcomp tokens 1 string COL Extract color 7 argl atoi2 tokens 2 8 Send driver set color command C col 0 7 term_ntsc out C term_ntsc out argl Case SX set cursor x position elseif strcomp tokens 1 string SX Extract x argl atoi2 tokens 2 40 Send driver set x command 0A x 0 39 term_ntsc out 0A ter
420. ls to the GPS object methods that show how to use their many features PMB248 Figure 4 46 GPS propeller circuit ASYNCHRONOUS SERIAL 181 The one gotcha with the GPS Float packages at the time of this writing is that the I O pins are declared in building block objects Follow these steps to make the objects compatible with the circuit in Fig 4 46 V Download GPS Float Demo and GPS Float Lite Demo from ftp propeller chip com PCMProp Chapter_04 v Unzip each package into a folder V Open the GPS_Float and GPS_Float_Lite objects with the Propeller Tool software Z Update the _RX_FM_GPS and _TX_TO_GPS constant declarations to 22 and 23 respectively _RX_FM_GPS _TX_TO_GPS 22 23 The GPS_Float_Lite_Demo and GPS_Float_Demo objects also communicate with the Parallax Serial Terminal at 57 600 bps instead of 115 200 V Set the Parallax Serial Terminal s Baud Rate drop down menu to 57600 Figure 4 47 shows the GPS_Float_Lite_Demo object s output taken at Parallax Incorporated in Rocklin CA The latitude and longitude shown can be entered into Parallax Serial Terminal Disabied Click Fnable button to continue ComPort Raud Rae O Te M DIH M HIS come 57600 o osn ocr F 4a Prefs Olcar Pause GPS_Float_Light_Demo Where in 182 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES http maps google com After clicking the Satellite button you ll see an aerial view of Paralla
421. ltafADC spin CON _clkmode xtall p1ll16x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz FB PIN 7 Sigma delta ADC feedback pin IN PIN 6 Sigma delta ADC input pin SAMPLE_TICKS 2000 Clock ticks per measurement VOLTAGE OUTPUT 163 OBJ adc SigmaDeltafADC Spin Declare Sigma Delta ADC object pst Parallax Serial Terminal Serial communication object PUB go adcVal t dt Go method pst Start 115200 Start Parallax Serial Terminal Start adc object pass pins the number of clock ticks in a sample and the address of adcVal The SigmaDeltaADC object stores the latest measurement in adcVal once every SAMPLE_TICKS adc start FB_PIN IN PIN SAMPLE_TICKS adcVal t t ent dt clkfreq 10 repeat waitent tt dt pst dec adcVAl Display current measurement pst Str String pst CE pst HM adcVal The SigmaDeltaADC Spin object nicknamed adc in the test object has a Start method with four parameters feedback pin number input pin number clock ticks per Sigma Delta sample and the address of a variable in which to store the latest A D conversion Check the CON block for the IN_PIN FB_PIN and SAMPLE_TICKs dec larations The IN_PIN and FB_PIN declarations match the I O pins in the Fig 4 31 schematic After these constants and the address of the adcVal variable get passed to the SigmaDeltaADC Spin object s Start method with adc Start FB_PIN IN_P
422. ly the encoders encA encB show the pulses received from the quadrature encoder remember their frequency and phase tells us how quickly and in which direction the wheel is turning Refer to the Fig 6 13 to see the sensors and the Kalman filter in action The screenshot of ViewPort s oscilloscope shows the values of three variables while I tilt the DanceBot back and forth The blue trace shows the raw signal from the gyroscope it s a clean signal that indicates how quickly I m rotating the bot and the signal is highest when the bot is being turned The red trace shows what happens when I integrate the signal 254 DANCEBOT A BALANCING ROBOT ViewPort v4 1 64 Ce analog fuzzy mixed video terminal 200 sol Q0us ZTE Sods 1k oy 8 600 DC AC _ Off wa DC AC _ Off Avg 231k Ey 42 53s gyr 1 gyri 5 s 240k 2 895k Time sec gyrolnt M Connection Disconnected Memory 00 01 18 Figure 6 13 ViewPort measurement of the tilt system from the gyroscope here the signal is highest when the bot is turned all the way to one extreme At first the red trace accurately reflects the bot s tilt However over time the integration errors add up and the signal has drifted so far as to be useless The green trace shows the raw signal from the accelerometer notice ho
423. m between a master left and a slave right SPI device and the signals between them which are E SCLK Serial Clock output from master E MOSI SIMO Master Output Slave Input output from master E MISO SOMI Master Input Slave Output output from slave E SS Slave Select active low output from master SPI is a full duplex protocol which means that as you clock data out of the master into the slave data is clocked from the slave into the master This is facilitated by a transmit and receive bit buffer that constantly recirculates as shown in Fig 8 13 TABLE 8 1 ETHERX INTERFACE TO HYDRA EXPANSION SLOT ETHERX CARD PIN HYDRA PIN FUNCTION O_0 Pin 1 P16 Pin 21 OPMODE 2 O_1 Pin 2 P17 Pin 22 OPMODE 1 1 0_2 Pin 3 P18 Pin 23 OPMODE 0 1 0_3 Pin 4 P19 Pin 24 SCLK SPI Clock 1 0_4 Pin 5 P20 Pin 25 SCS SPI Chip Select 1 0_5 Pin 6 P21 Pin 26 MOSI Master out Slave in 1 0_6 Pin 7 P22 Pin 27 MISO Master in Slave out O_7 Pin 8 P23 Pin 28 RST W5100 Reset 3 3V Pin 14 POWER 3 3 V Power GND Pin 20 POWER Ground ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 291 Figure 8 12 SPI electrical interface Courtesy of Andr LaMothe Master Slave Memory SCLK Memory o 1 2 3 4 5 6 7 MOS lafoj 2 3 4 5 6 7 t MISO Figure 8 13 Circular SPI buffer Courtesy of Andr LaMothe
424. m value of 5 Multiply by 4 to get byte count Figure 8 3 Total length of IP datagram or IP fragment if fragmented Measured in bytes Header Checksum Checksum of entire IP header Copyright 2008 Matt Baxter mjb fatpipe org www fatpipe org mjb Drawings IP header field Please refer to RFC 791 for the complete Internet Protocol IP Specification 284 USING MULTICORE FOR NETWORKING APPLICATIONS Now that we have IP addresses we know where to go but we need some more information about what to do with the data Think of your computer right now Lots of Internet data comes and goes There s your web browser mail client instant messaging BitTorrent and so on How does your computer know that a piece of data it received from the Internet came for your web browser and not your e mail The answer is a number called a port number Your web browser works on a specific port your e mail on a different port and so on Another header is added to help tell Internet devices about the port number and this layer is a TCP or UDP header Once again these headers contain much more data than just the port numbers but for the purposes of working with the EtherX card this is what we will focus on NOTE As a side note the layer following the IP header doesn t need to be TCP or UDP It could be something else such as Address Resolution Protocol ARP Domain Name System DNS or PING What s the difference between
425. m2cnt m2w add sub m2Cnt 1 m2Cnt 1 wrlong m2Cnt m2w jmp loop long 1 long 1 BUILDING THE DANCEBOT 245 it long 1 m2W long 1 mAEnc long 40100 0000 0001 0000 0000 0000 12 mABEnc long 41100 0000 0011 0000 0000 0000 12 13 00011 miCnt long 0 m2Cnt long 0 The code object that we will use to both drive and measure the motor is motor spin It lets us control the motor s speed and direction and keeps track of where the wheel is using the pulses from the quadrature encoder MEASURING TILT WHICH WAY AM I FALLING We humans have an inner ear that tells us which way we re tilting This mechanism relies on fluid moving in a channel where it is sensed by small hairs When we drink alcohol the alcohol changes the properties of the ear s fluid and our sense of balance is affected Apart from this our sense of balance is good and helps us to balance quite well A good sense of balance or rather a sensor that will tell us which way we re tilt ing is critical to building a robust balancing robot How do we best teach our robot to measure its tilt One technique is to measure the distance to the ground from a sensor offset from the wheels Measuring the distance can be done either using ultrasound or measuring the amount of light reflected from a beam This can work in some environments but the surface has to be absolutely flat otherwise the robot will fall because it s not able to accurately me
426. m_ntsc out argl Case SY set cursor y position elseif strcomp tokens 1 string SY Extract y argl atoi tokens 2 30 Send driver set x command 0B y 0 29 term_ntsc out B term_ntsc out argl Look through the code carefully if you understand this handler you can create any additional handlers you need Once again you will notice there is virtually no error handling or value range testing These things must be added if you need them As an example let s take a look at the OUT subcommand which is copied here and high lighted in the previous listing for reference Case OUT output a single character elseif strcomp tokens 1 string OUT or strcomp tokens 1 string 0 term_ntsc out byte tokens 2 386 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS The OUT command connects directly to the NTSC driver s PUB out c method which is listed next All we need to do is extract a character from the user input and pass it directly to the PUB out c method on the driver side PUB out c i k Output a character 00 01 08 09 SQA QB SC 0D others case flag 00 case c 00 01 08 09 SOA 0D 0A col 0B row C color flag 0 In fact through the PUB out c command the user can set the cursor change colors and clear the screen However since thes
427. me An example of a capacitive voltage output sensor is the condenser microphone A condenser mic has built in capacitors that translate air pressure fluctuations across a diaphragm into voltage fluctuations that can be measured by a microcontroller Since the voltage fluctuations are low amplitude and change rapidly with time they are referred to as small signal and AC Microcontrollers use analog to digital converters to measure and digitize sensor voltage outputs Both A D converter and ADC are common shorthand names for analog to digital converter Propeller applications that require voltage mea surements can make use of peripheral ADC chips or a technique called Sigma Delta analog to digital conversion PERIPHERAL ADCs Peripheral ADCs typically use two means of transmitting digitized voltage measure ments to a microcontroller parallel and serial An ADC that transmits its measure ments with parallel communication has a number of output pins connected to a number of Propeller I O pins For the sake of example let s say that there are eight ADC output pins connected to eight Propeller I O pins With this scheme the ADC can transmit eight binary digits at once to the Propeller chip This arrangement makes it possible to report measurements quickly but it takes a lot of I O pins In contrast serial ADCs typically use two to four lines for communication The most common variety of serial communication for ADCs is synchronous serial where a c
428. me from the robot s camera This can require significant computer processing power and memory to manipulate all the bytes that make up each image Also while it s easy to code a filter that will brighten an image designing a filter that will find a bottle of beer in a cluttered room is much more difficult Decades of research have been spent trying to understand how the human brain processes vision We ve learned that the brain s vision system has many parts each of which is specialized for some task For example some cells in our eyes are active only when we re looking at lines at a certain angle and further along the chain neurons are arranged to decode three dimensional information from our two eyes Some researchers have even found a neuron that recognizes just the subject s grandma Almost half of the human brain is dedicated to processing vision It takes that much processing power to do what we take for granted Luckily modern desktop computers and even the Propeller are getting to the point that we can apply them to computer vision PropCV A Computer Vision System for the Propeller In the next sections we ll build a complete computer vision system that will run entirely inside the Propeller I originally built PropCV so that my kids could dance with my DanceBot but it s now a part of ViewPort so people can use it for all sorts of projects One of my customers is even working on a project to make industrial robots wel
429. means we will receive serial GPS data at a baud rate of 4800 bps with 8 bit ASCII no parity and one stop bit To read in the serial NMEA sentences we will make use of Parallax s Object Exchange OBEX Web site portal http obex parallax com The Object Exchange Web site contains hundreds maybe even thousands by now of user submitted Spin assembly or C code objects for use by the general public under the MIT license When searching the keyword GPS a number of NMEA parsers are already listed on the Web site We elected to use a simple Spin language GPS parser that initially displays the GPS information on a VGA terminal This file was originally created by Perry James Mole The two files of interest to us for our experiment are E GPS_IO_Mini spin E FullDuplexSerial_Mini spin The FullDuplexSerial_Mini spin is a slightly modified version of the Parallax full duplex serial driver with the only modifications being that some of the transmitter components are removed to save space in main memory The parsing of the NMEA strings takes place in the GPS_IO_Mini spin object spe cifically in the routine readNMEA listed here PUB readNEMA Null 0 0 repeat longfill gps_buff 20 0 repeat while Rx lt gt Wait for the to ensure we are starting with Rx uart rx a complete NMEA sentence cptr 0 repeat while Rx lt gt CR Continue to collect data until the end of the NMEA sentence Rx uart rx
430. mmunications Also to demonstrate control action the two LEDs on the remote end device provide control action You are welcome to have as many end points as you desire well up to 65 000 or just use one and change the end point s address to test Figure 5 13 is a diagram of our network and hardware NODE 1 XBee PING s 6 Compass 3 LEDs NODE 0 s gt o o END DEVICE oe My_Addr 1 o DL_Addr 0 XBee A a We a a t NODE 2 a a COORDINATOR a a My_Addr 0 a A Ea DL_Start 1 a PING DL_End 3 or higher Compass LEDs END DEVICE My_Addr 2 DL_Addr 0 Figure 5 13 Hardware for coordinator polling 210 WIRELESSLY NETWORKING PROPELLER CHIPS In this example the coordinator cycles through a range of end point addresses by changing the DL value of the coordinator s XBee It sends out codes and values to request data from each end point and to control the LEDs on each Before allowing the coordinator to have control we are going to manually test the control and responses v Add the LEDs to the remote end device V Open Acquisition_with_Control_End spin For each end device number the constant MY_Addr in the CON section of the code sequentially from 1 up skipping a few numbers to test unresponsive nodes Download Acquisition_with_Control_End spin to each remote end device Use the Propeller for serial pass through or another PC to XBee configuration at the PC
431. mperature that is read from the sensor four times a second 4 Hz For our experiment these variables will be logged to an SD card OVERVIEW OF THE SENSORS 339 SECURE DIGITAL CARD The Propeller has no built in nonvolatile memory memory that doesn t get erased when power is removed The Propeller Demo Board does employ an external EEPROM used for programming the device but we want to use something more portable removable and easily recognizable by a PC for analyzing the data log files For this reason we have elected to use a Secure Digital SD card connected via SPI SD cards are essentially flash memory devices that are a collection of sectors Each sector is usually 512 bytes and there can be millions of sectors on very large SD cards SD cards have no inherent file system Thus FAT16 FAT32 NTFS Linux file systems and so on have no idea how to read SD cards Therefore someone has to write a driver interface that translates if you will the SD card sectors into a file system For example the only operations you really need to implement on a FAT 16 32 file system are the abilities to read and write a sector The SD protocol and hardware supports this so to support the FAT system you have to write a driver that implements the FAT file system on the SD card and translates things like the directories boot records and so on This is a complex business and outside the scope of this book Fortunately for us an object has been upl
432. ms the red LED will begin to blink Received data ben is analyzed for either d for drive data or p to begin a mapping scan case DataIn Test accepted data dq If drive data Right_dr gt XB RxDEC Get right and left drive Left_dr XB RxDEC SERVO Set Right Right_dr Drive servos based on data SERVO Set Left Left_Dr p p pan and map command mapping true Set flag for mapping outaLgrnLED Turn on green LED Map Go map The SendUpdate method is run in a separate cog to continually send out the status of 66 the range direction and drive values led by u The value of theta is subtracted from A THREE NODE TILT CONTROLLED ROBOT WITH GRAPHICAL DISPLAY 229 8191 to allow the direction of rotation to be correct in the graphics display If a panning map is in progress updates are suspended due to mapping being true Repeat if mapping false If not mapping XB Delay 250 Range Ping Millimeters PING Pin Read range theta HM55B theta Read Compass XB TX u Send update command XB DEC Range Send range as decimal string XB CR XB DEC 8191 theta Send theta of bearing 0 8191 XB CR xb DEC Right_Dr Send right drive XB CR XB DEC Left_Dr Send left drive XB CR When mapping the value of pan is looped from 1000 to 2000 the range of allow able servo values The range is measured and the PanOffset is calculated The value of th
433. ms the video data is written into one part of memory such as bitmap_base and when the complete display change is ready it is copied into the section of memory that the graphics driver uses to display the actual display It is effectively double buffered to prevent flicker on the screen We do not have the luxury of the memory needed for that operation Instead to reduce flicker values of the old data are saved When updating the graphics are redrawn in the background SUMMARY 231 color to erase them then the new data is used to draw the graphics in the cor rect color such as in this code Draw bot vector image gr width 2 gr color 0 White gr vec 120 120 100 bearing_1 bot Erase last image gr color 1 Black gr vec 120 120 100 bearing bot Draw new image Many features of graphics spin are used including text lines arcs and vector based graphics The code is fairly well commented for adaptation TRY IT Y Add another sensor to your bot Modify both the bot and graphics code to send and display the value Summary In this chapter we looked at what the XBee is and how it can be configured and used in a wireless sensor network Using AT codes sent from the controller the XBee can be configured for specific applications such as unique addresses used in polling operations In API mode frames are sent and received with specific data Using the networking capabilities a three node
434. munication and have called it read_data_word An example of its use is as follows OVERVIEW OF THE SENSORS 337 System initialisation Basic equations Read calibration data factory calibrated from PROM of MS5540 Word1 Word2 Word3 and Word4 4x16 Bit Convert calibration data into coefficients see bit pattern of Word1 Word4 C1 Pressure sensitivity i OFFT1 C2 Pressure offset i TCS C3 Temperature coefficient of pressure sensitivity 10 Bit TCO C4 Temperature coefficient of pressure offset 10 Bit Tret C5 Reference Temperature 11 Bit TEMPSENS C6 Temperature coefficient of the temperature 6 Bit Read digital pressure value from MS5540 D1 16 Bit Read digital temperature value from MS5540 D2 16 Bit Calculate calibration temperature UT1 8 C5 20224 Calculate actual temperature Difference between actual temperature and reference temperature dT D2 D2 Tret dT D2 UT1 Actual temperature TEMP 200 dT C6 50 2 0 1 resolution Calculate temperature compensated pressure Offset at actual temperature OFF C2 4 C4 512 dT 2 Sensitivity at actual temperature SENS C1 C3 dT 2 24576 X SENS D1 7168 2 OFF Temperature compensated pressure P X 10 2 250 10 0 1 mbar resolution TEMP D2 20 dT D2 TEMPSENS OFF D2 OFFT1 TCO aT D2 SENS D2 SENST1 TCS dT D2 P D1 D2 D1 SE
435. munication with the DEBUGGING CODE FOR MULTIPLE CORES keyboard and buffers any key presses The application object can then call the Keyboard object s Key method to get the latest buffered key press or find out that there s nothing in the buffer whenever it has time Another example is the Sigma Delta ADC object which is designed to provide digitized analog voltage measurements and will be dem onstrated in Chap 4 This object s Start method is designed to receive a variable s memory address from the application object After the Sigma Delta ADC object s Start method launches its analog to digital conversion code into a new cog that cog always copies the most recently measured voltage value into the parent object s variable that was set aside for receiving the measurements In either case the end result is a simple and easy to use interface which in turn tends to be bug free because all the application code has to concern itself with using the information it has received Object Design Guidelines If you plan on designing a building block object that launches a process into another cog either for an application or for the Propeller Object Exchange the Start and Stop method conventions introduced in the previous chapter are crucial and designing a bug free interface that communicates with other objects through shared memory is equally crucial Figure 3 4 shows an example of one of the ways a building block object that ha
436. n Decisions spin CON _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object PUB Go pst Start 115200 Start Parallax Serial Terminal ON OFF SENSORS 127 repeat pst Str String pst HM inal16 pst Bin inal16 1 Display 1 binary digit waitent clkfreq 20 cnt Wait 1 20 second if inal16 1 Tf ina l16 stores 1 Pressed call pressed method else otherwise NotPressed call NotPressed method PUB Pressed pst Str String pst NL Button pressed pst CE PUB NotPressed pst Str String pst NL Button not pressed pst CE On Off Sensor Example Pushbutton Array Figure 4 7 shows a pushbutton array that includes two additional copies of the P16 pushbutton circuit These copies are connected to adjacent I O pins P17 and P18 This provides a small example of an on off sensor array The Spin language has a simple feature to check multiple inputs on any range of con tiguous I O pins in a port Instead of ina 16 which would just return the state of P16 an application can use ina 18 16 to check all three pushbuttons with one command Ina 18 16 returns a three digit binary number with each digit indicating the state of one of the pins For example if the P18 and P16 pins were pressed ina 18 16 would return 101 If the P18 and P17 I O pins were pressed ins
437. n conversion calculations The coefficients are necessary for calculating the correct pressure and temperature because the output of the sensor is affected by changes in temperature Also the sensor is affected by light especially direct sunlight so it s best to create an enclosure around the sensor when using it during the daytime or under changing lighting conditions The Spin code for reading the coefficients is show here cmd 111 010101 000 calib1 read_calib word cmd cmd 111 010110 000 calib2 read_calib word cmd cmd 111 011001 000 calib3 read_calib word cmd cmd 111 011010 000 calib4 read_calib word cmd Retrieve the calibration bits from the words c1 calib1 gt gt 1 c2 calib4 amp 3F calib3 amp 3F lt lt 6 c3 calib4 gt gt 6 c4 calib3 gt gt 6 c5 t calib1 amp 20001 lt lt 15 calib2 gt gt 6 c6 calib2 amp 3F The read_calib_word method is a private method in the abs_pressure_01 spin object and it transmits the appropriate command and returns the calibration 16 bit word After the calibration words are received we use a combination of AND bit masking bitwise ORing and bit shifting to extract the calibration coefficients The next step is to read in the 16 bit data words that contain the current uncompen sated pressure and temperature values Again we have created a private method that handles the nonstandard com
438. n executing a well behaved application the team of cogs has flexible control over the I O pins without causing conflicts between them A pin is an input unless a cog makes it an output and an output pin is low unless a cog sets it high Tip An active cog is one that is executing instructions or sleeping An inactive cog is one that is completely shut down Only active cogs influence the direction and state of I O pins System Counter The System Counter is the Propeller chip s time base It s a global read only 32 bit counter that increments once every System Clock cycle Cogs read 14 THE PROPELLER CHIP MULTICORE MICROCONTROLLER the System Counter via their CNT register to perform timing calculations and accurate delays The System Counter is not a mutually exclusive resource every cog can read it simultaneously Information We use the System Counter in nearly every exercise in the next chapter Counter Modules and Video Generators These are some of the Propeller s secret weapons Each cog contains two counter modules and one video generator They are simple state machines that perform operations in parallel with the cogs that contain them Using its video generator a cog can display graphics and text on a TV or computer monitor display Using its counter modules possibly in concert with software objects a cog can perform functions that might require dedicated hardware in other systems such as measuring pulses frequency
439. n the Parallax Serial Terminal When the pushbutton is pressed the terminal should dis play ina 16 1 and when it s not pressed the terminal should instead display ina 16 0 The state of the incoming on off signal is stored in bit 16 of the cog s ina register which is ina 16 When the pushbutton is pressed ina 16 returns 1 because the pushbutton circuit applies 3 3 V to I O pin P16 When the button is not pressed ina 16 returns 0 because the pushbutton applies 0 V to the I O pin through the pull down resistor P16 Input States spin CON _clkmode xtali1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object PUB Go pst Start 115200 Start Parallax Serial Terminal repeat pst Str String pst HM inal16 pst Bin inal16 1 Display 1 binary digit waitent clkfreq 20 cnt Wait 1 20 second Figure 4 6 shows the Parallax Serial Terminal display while the pushbutton is not pressed Of course when the pushbutton is pressed the display will instead read qna 16 1 Assuming you have already tried programs in earlier chapters you now know the steps for loading a program into the Propeller chip and displaying messages from the Propeller chip in the Parallax Serial Terminal To test P16 Input States spin follow these steps V Use the Propeller Tool software to load the application into t
440. nal measurement 252 253f plug in functionality of 276 278 synchronous serial communication 172 173f timestamp variable monitoring 104 105f Viola Jones object detector in 275 276 voltage displayed by 165 166 165f 167 Viola Jones object detector 275 virtual peripheral Propeller as 353 397 vision sensors 258 259 258f vision guided robots 257 258 VocalTract 429 consonants in 435 437 recreating vowels with 432 434 resonators in 432 sections of 431 432 431f spectrographs of 434f 437f stereo images with 439 vowels with 432 434 Volder Jack 432 voltage output peripheral ADCs 156 159 160f of sensors 156 168 Sigma Delta ADC 160 168 160f vowels spectrograph of 434f synthesizing 429 430 VocalTract code for 432 434 VT100 379 380f W5100 Ethernet Chip 288 294 307 308 buffers of 311 init method 300 interfaces 293 mode method 299 SPI assembly layer and 295 296 W5300 chip 293 waitcnt 91 timing interval errors and 68 71 tricks with RC Decay 71 waitcnt command 27 68 waveforms of speech 427 428 428f 429f Wi Fi networks 191 193 Willows Garage 274 wireless networking of Propeller chips 189 191 190f hardware 193 networking and XBee transceivers overview 191 193 192f polling remote nodes 208 214 sending data from Propeller to PC 204 208 206f 207f 208f three node tilt controlled robot with graphical display 221 231 using XBee API mode 214 221 XBee testing and configuri
441. nal program 357 abs_pressure 01 spin 338 accelerometer clock acCL 252 accelerometer data line acDT 252 253 accelerometers 148 152 dual axis 144 145f MEMS 245 245f 247 Memsic 2125 144 145 148 152 149f 152f 225 225f Tri Axis 168 169f AcceptData method 228 acCL See accelerometer clock ACK See acknowledgement acknowledgement ACK 288 AD592 temperature probe 142 142f ADC See analog to digital converter ADC101S021 timing diagram 171 171f add count command 78 add0 296 add1 296 Address Resolution Protocol ARP 284 Adobe Photoshop 258 259 Advanced Research Projects Agency ARPA 286 air bypass system 405 407 405f 406f 407f air registers 401 403 almanac 326 altimeter calibration formula 335 347 altimeter setting 347 altitude 334 335 348 348f American Standard Code for Information Exchange ASCII 177 179 178f 368 369 analog sensor conversion 131 133 analog to digital converter ADC 334 AND bit masking 336 APL See application programming interface API listing 295 295t API mode data acquisition and control using 218 221 218f data framing and 214 217 215f 217f of XBee 214 221 AppBee SIP LV 194 195f application methods layer of EtherX 299 312 init method 300 303 listen connect and connection established 305 307 mode method 299 300 open and close 303 304 receive 308 311 receive size register 311 312 socket programming 303 304 start and stop methods 3
442. nce can result in distortion of the image or no image at all Thus interrupts cannot be used while drawing an image because it will affect the video timing While there is nothing wrong with these implementations the game programmer is limited in that the only time he or she has to work with is during the vertical sync Things also start to get complicated when we consider conditions like what happens when both player and opponent have a score of four and push the button within the same video frame Remember that we won t be able to check gamepad and EtherX until the vertical sync So if both happened within the same frame we would have no way of knowing who actually won It would appear as though they both happened at the same time and the game logic would be forced to declare a tie MULTICORE APPROACH USING THE PROPELLER The Propeller by contrast would not need to wait until the vertical sync to sample the gamepad check the EtherX card play a new sound etc All of these things happen in a different cog in parallel with one another and completely independent of each other Let s see the Button Masher code and discuss some of the important points of the implementation Real quick let s break down what cogs will handle what Cog 0 Boots into the Spin interpreter by default and will start the drivers for our T O peripherals and handle our game logic Cog 1 Gamepad NES controller driver Cog 2 EtherX SPI driver Cog 3
443. nd Circuit Applications lab Additionally an extensive list of links to counter module documentation and applications for the Propeller is available from http www parallax com go counters The Propeller Education Kit Labs Fundamentals book and the PE Kit Tools section in Propeller Forum s Propeller Education Kit Labs sticky thread make use of an object named SquareWave as a tool for generating square waves utilizing a cog s counter modules SquareWave is similar to the Synth object in the Propeller Library and both Square Wave and Synth were developed from example code from the Propeller Library s CTR spin object Instead of launching another cog these objects configure a counter module to generate the square wave in the background so that the cog s code can move on to other tasks in the foreground The Test IR Detect spin application uses the SquareWave object to transmit the 38 kHz square wave signal to the IR LED circuit connected to P2 The SquareWave object does not have a Start method since it s not launching a process into another cog So the main loop calls the SquareWave object s Freq method and passes it I O pin 2 channel 0 and a frequency of 38 000 Hz The Freq method s channel parameter can be either 1 or 0 because each cog has two counter modules A and B The Square Wave object s Freq method expects a channel parameter of 0 to select counter module A or 1 to select counter module B This example selects counter modu
444. nd mode Z Hello World If all went well you should once again be getting echoes after changing the destina tion address back to 0 The waiting before and after the is called the guard time and it ensures that if a string containing is sent the unit won t flip into command mode inadvertently Tip Permanent changes Using the Modem Configuration feature of the X CTU software all changes are saved to nonvolatile memory and will still be in place after cycling power Using the AT commands the settings will revert to original values after cycling power unless the ATWR write command is sent to write to nonvolatile memory The important aspect here is that just as we sent data strings to the Xbee for con figuration changes so can your Propeller configure the XBee through code Multiple commands can be used in one line by separating them with commas For example the following sets DL to 0 and exits command mode ATDL 0 CN 204 WIRELESSLY NETWORKING PROPELLER CHIPS TRY THESE v Try changing your MY address to 1 and sending data You should see the remote unit receive and transmit but you get nothing back Why v Change your DL to FFFF This is the broadcast address any nodes on your network would receive it Be sure to set MY back to 0 for the loop back to work Use the command ATND Network Discovery After a few seconds you should see a list of other nodes in the network including their MY address two line
445. ne cog typically has a Start method which has to be called to launch the code that does its job into another cog The Test Float32 spin application object utilizes three building block objects to calculate and display the floating point tangents of integer degree values entered into the Parallax Serial Terminal s transmit windowpane Two of those building block objects have Start methods Parallax Serial Terminal and Float32 The Parallax Serial Terminal object has assembly code that gets launched into another cog that maintains full duplex serial communication with the PC and the Float32 object also has assembly code that gets launched into another cog to optimize the speed of its floating point calculations In addition to Start and Stop methods both of these objects have methods that take care of exchanging information with code running in the other cogs These methods all use the scheme shown in Fig 3 4 accepting parameters and passing them to the other cogs or returning results they got from other cogs or both The third building block object is COMMON MULTIPROCESSOR CODING MISTAKES 59 FloatString This object is a collection of useful methods for converting floating point values to their string representations but it does not use any other cogs to make these conversions so it does not have a Start method Each of these objects has documentation comments that explain how to use their methods V Load Test Float32 spin into the Prope
446. ne you use will be based on whether you want the W5100 to be a server or a client If you choose to implement your socket as a UDP socket there is no need to use the listen connect or con_est method calls because UDP doesn t establish a connection before sending and or receiving data Following is the code for the listen connect and con_est methods PUB listen This method will initiate a TCP listen Call this method for a TCP server to listen for a connection if socket_type TCP write 04 01 2 PUB connect When TCP this method will establish a connection with a server if socket_type TCP write 04 01 4 PUB con_est ret_val Call this method to determine if a TCP connection has been established The method will return true if a connection has been established if read 04 03 17 ret_val true else ret_val false If the EtherX card will be a TCP server it will call the listen method after it calls the open method This method will tell the W5100 that it will be a server and that it should wait for a client to try and establish a connection with it After you call the listen method you will need to call the con_est method which returns true if a connection has been established with a client and false if a connection has not been established Following is a snippet of code from the SimpleTCPServer code that shows how to use listen and con_est It can be found in the Chapter_08
447. ng 193 204 194f wireless sensor network WSN 189 231 WireShark 285 286 287f Wiznet 288 Wiznet Ethernet Chip 320 write method 298 300 308 wrong address passed to method 74 76 wrong clock frequency settings 64 66 65f wrong count 78 WSN See wireless sensor network Xband Motion Sensor 153 153f XB AT_Init 211 XBee 191 193 192f 231 API mode 214 221 exercise 232 234 232f sending raw ADC digital data 232 232f updating versions of 204 XBee testing and configuring 193 204 194f configuration settings 201 204 2021 203r equipment and software 194 loop back communication 198 201 199f PC to XBee communications 195 198 196f 198f 199f XBee ZigBee Mesh series 191 X CTU software 194 199 200f Xerox PARC 282 _xinfreq 66 ZOC terminal program 357
448. ng at the address pointed to by the dataptr argument to the internal buffer of the W5100 Once the bytes have been written to the internal buffer of the W5100 the EtherX driver instructs the W5100 to transmit that data Keep in mind that the default size for the internal buffer for socket 0 the socket that the EtherX driver operates on is 2048 bytes This means that you can t write more than 2048 bytes worth of data at one time using the TX method GOT A PROBLEM WITH BEING LIMITED TO 2048 BYTES No problem Check out the W5 100 data sheet it s included in the Chapter_08 Docs DataSheets directory and read about how to configure the W5100 Specifically you want to modify the size of the socket buffer Learn what register s address you need to write to and what data you need to write to get the buffer size you want then write that value to the address you need using the write method That s what it s there for Another gotcha besides the fact that by default you can t transmit more than 2048 bytes at a time is that you need to be sure you don t specify the size argument to be any larger than the buffer that is pointed to by the dataptr argument There is no automatic checking for an array that is out of bounds Receive The TX method is nice in that it operates the same no matter what your socket type is TCP or UDP It is used the same way no matter what However the RX method is called to receive data fr
449. ng for heat or cool most HVAC systems will blindly produce the hottest or coldest air that they can until the thermostat tells them to stop To make matters worse it is rare that a residential HVAC system has more than one thermostat so a single sample is used to provide the standard for the entire building Without a way to monitor the temperature in each room managing the distribution of conditioned air so that all rooms attain the same temperature requires someone to manually visit one room at a time measure the room temperature and then adjust the air register in that room in an attempt to balance it with the others TRYING TO STRIKE THAT BALANCE This balancing process would seem to be relatively simple to perform and not require much maintenance after it has been completed However there is more to this process EXPLORING THE PROBLEM 401 than you might imagine When balancing airflow in a building you enter the first room and either increase the opening of the air register to allow more airflow or decrease it to create the opposite effect As pointed out earlier in most central air systems you have a set amount in cubic feet per minute of conditioned air being created So when you reduce the amount of air allowed into one room air is then diverted to the other rooms in the building This causes unwanted and usually unpredictable changes in temperature elsewhere in the building The inverse is true as well When y
450. nsorXX log where XX is a number between 00 and 99 Once a suitable file name is found we open it for writing Now a TV terminal is great for debugging purposes for example to see if the GPS receiver has three or more satellites or whether the SD card was mounted properly and so on However for our experiment we will be taking the hardware on the road for a test drive and we will not be bringing along a TV To aid us in debugging when a TV is not readily available we will make use of a number of LEDs The following lists the LED outputs we are using along with their description E Mount SD If the SD card was mounted properly on startup this LED will be lit E GPS Satellites If the GPS has three or more satellites this LED will be lit 346 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER E Heart Beat Each time through the main object s infinite repeat loop this LED will toggle This is useful in helping the user see that all is working well E Pressure Good This LED is lit when the temperature read from the barometer is within normal operating ranges meaning we have established communication and are converting values properly E Recording This LED is lit when the Propeller is in a state that is recording data to the SD card Experiment In the experiment for this chapter we will be taking the prototype data collecting unit and traveling around a residential neighborhood This neighborhood in particular con sis
451. nt thanks to that fact that its input is the gate G terminal of a MOSFET metal oxide semicon ductor field effect transistor The first transistor s drain terminal is pulled up to Vcc the supply for the higher voltage system with a 10 kQ resistor The second transistor s drain D terminal is pulled up to the 3 3 V supply so the highest voltage it will send to the I O pin is 3 3 V Each of these transistors inverts the signal Since the two are cascaded the signal is inverted twice and the signal at the I O pin is the 3 3 V version 0 to 5 V gt AMW _L I O Pin 3 9 kQ min Figure 4 13 Protectan I O pin witha series resistor RESISTIVE CAPACITIVE DIODE TRANSISTOR AND OTHER 137 I O Pin 0 to Vcc V Vcc gt 3 3 V 2N7002 GND GND Figure 4 14 Level shifter with two FET transistors of the input signal V Vcc In other words if V Vcc is high 6 V for example the voltage at the I O pin will be 3 3 V On the other hand if V Vcc is lw 0 V the voltage at the I O pin will be 0 V Other interfaces for higher voltages include level translator ICs optoisolators and solid state relays Level translator ICs are sometimes referred to as level shifters and they provide voltage translation in a single chip Some level translators boast extra protection circuitry as well as maximum switching speeds that are significantly faster than the circuit in Fig 4 14 which is only good for switching speeds up to 20 or
452. ntains the ideal frequency not the actual frequency in this case To achieve much higher clock accuracy we need to use an external crystal To make the Propeller use the external 5 MHz crystal in our circuit our application needs to set some built in constants CON _clkmode xtali pll16x Use low crystal gain wind up 16x _xinfreq 5 000 000 External 5 MHz crystal on XI amp XO This is a CON block with the typical clock configuration The _clkmode constant is set for low crystal gain xtal1 and a phase locked loop PLL wind up of 16 times The _xinfreq tells the Propeller that the external crystal is providing it a 5 MHz clock signal The combination of _clkmode and _xinfreq means we have an accurate 5 MHz clock multiplied by 16 with the Propeller s internal PLL for a total speed of 80 MHz That s an amazing speed from such an inexpensive crystal 40 INTRODUCTION TO PROPELLER PROGRAMMING Applying this to the previous examples may not appear to make a change but if you looked at the difference on an oscilloscope it would be clear Tip The clock mode constants can only be set in the application level object Clock mode constants in building block objects are ignored at compile time SYNCHRONIZED DELAYS Despite the clock settings noted previously the timing of events will still be slightly off unless we use waitcnt in a specific way So far our loops have performed an operation and then waited for an interval of time
453. ntil the results of some test provides the necessary reminder So start your parallel processing think memory exercises as you go through this chapter by keeping in mind that segments of multicore Propeller application code get executed in parallel by more than one cog Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_03 Propeller Features That Simplify Debugging The Propeller microcontroller s architecture programming language and design conventions that object authors adhere to don t just simplify application development they help prevent a myriad of coding errors that could otherwise plague application developers ARCHITECTURE THAT PREVENTS BUGS While designing the Propeller microcontroller one of Chip Gracey s first and fore most goals was to distill its design so that the rules for accomplishing any task would be simple and straightforward Two examples where this design approach prevents a variety of bugs are in I O pin and memory access There are some multicore microcontroller designs where each processor has direct access to only its own bank of I O pins so extra communication steps are necessary for a core to interact with an I O pin outside of its bank In contrast with the Propeller chip any cog or group of cogs can influence any Propeller microcontroller I O pin or group of I O pins at any time Each cog has its own output and
454. ntinuously apply vision filters tvptr points to the video buffer tmode set to O for a 6000kb buffer gt 1 for a 1500kb buffer if tmode gt 1 len 1500 len4 6000 llen 60 vptr tVptr cognew doEdit cmd pub filter tDest tSrc tFilter add a filter to the filter chain tDest destination frame tSrc source frame tFilter filter number cmd cmdNum tFilter cmdLcmdNum 1 vptr tDest len4 cmdLcmdNum 2 vptr tSrco len4 cmdNum 3 268 CONTROLLING A ROBOT WITH COMPUTER VISION pub filterValue tDest tSrc tFilter tVal add a value filter to the filter chain tDest destination frame tSrc source frame tFilter filter number tVal parameter value cmd cmdNum tFilter cmdLcmdNum 1 vptr tDest len4 cmdLcmdNum 2 vptr tSrc len4 cmd cmdNum 3 tval cmdNum 4 The following Spin code integrates the vision filter chain with the frame grabber we ve developed previously This time we ll allocate 6000 longs for our vision data and select the VIDEO4 mode from the PropC VCapture object to capture lower resolution video into the upper left quadrant This allows us to use the other quadrants to view filtered versions of our data To filter the video we ll make several calls to ve filter to configure and set up the filter chain We ll use the invert threshold difference and max filters that come with PropCVFilter Once set up the filters will run in their own cog periodically updating the video
455. ntinuously in 1 cog up to 2 Msps pst Parallax Serial Terminal Serial communication object ASYNCHRONOUS SERIAL 177 PUB Go yawAde vp register qs sampleINA frame 1 sample INA into lt frame gt array vp config string var io bits Serial TX 24P24 vi vp config string start lsa dso timescale 10ms vp config string vp config string lsa view io trigger io 23 r timescale 500us vp share yawAdc yawADC share the lt freq gt variable Start Parallax Serial Terminal on I O pins RX P25 and TX P24 pst StartRxTx 25 24 4800 Baud rate 4800 bps dira 23 Set P23 to output repeat Main loop pst Char A waitent clkfreq 200 cnt outal23 Toggle P23 with each A After the display was configured as shown in Fig 4 43 ViewPort s Configure gt Copy to Clipboard menu item was selected which copied a number of vp config calls to the Clipboard The resulting vp config calls were then pasted into View Serial Character with ViewPort spin between the vp register and vp share calls The vp config calls make the Propeller chip send the configuration information to ViewPort so that it can duplicate the settings that were in effect at the time you selected Configure Copy to Clipboard VIEW MORE VIEWPORT For more information on topics like configuring the Logic State Analyzer to display the activity of part
456. o Sander s ViewPort software provides a powerful set of tools for developing Propeller applications ViewPort s Spin language Debugger offers familiar features like runtime stepping breakpoints and flyover variable display and update options shown in Fig 3 15a VIEWPORT WHERE TO GET IT The latest version of ViewPort is available for a 30 day free trial from www parallax com Just type ViewPort in the Search field and click Go ViewPort was developed by Hanno Sander and extensive application information and tutorials are available from Hanno s www mydancebot com web site ViewPort also takes advantage of the Propeller chip s multicore design to provide a more advanced set of instrumentation and diagnostic tools with no extra hardware required These tools are listed in Table 3 1 and shown in Fig 3 155 and they make it possible to analyze Propeller chip programs and application circuits with instruments that transform your Propeller chip into its own electronic workbench PASD THE PROPELLER ASSEMBLY LANGUAGE DEBUGGER Propeller Assembly Language can be especially useful for applications that require higher speed processing precise timing or both There are already many published objects with assembly code and Spin language interfaces for common tasks like com munication sensor monitoring motor control a variety of math algorithms video display and more The Propeller Assembly Source Code Debugger PASD software
457. o be careful of what you send for your IO values AUTOMATIC POLLING WITH THE PROPELLER In this next exercise the Propeller will operate as the coordinator polling each of the end devices in succession V Ensure you have downloaded Acquisition_with_Control_End spin to your end device s using F11 with sequential MY_addr values while skipping a few values Y In Acquisition_with_Control_Coor spin modify the values of DL_Start and DL_End in the CON section to match the range of your end device addresses Y Download Acquisition_with_Control_Coor spin to the coordinator Propeller V Once downloaded open the Terminal window v Wait and watch you should see results similar to Fig 5 15 Note that in this test only an end device with a MY_addr of 2 is responsive In Pub Start once configured the code loops through the range of defined end device values passing the address to the Poll method Pub Poll accepts the address sets the DL address and informs the user It then goes through a series of steps for acquisition and control Calling Control_I0 the I O number and state are passed to turn on the LEDs This method will send the correct i instruction to control the end device IO The returning value with a timeout is accepted passed back and displayed POLLING REMOTE NODES 213 X CTU COM6 x About PC Settings Range Test Terminal Modem Configuration Line Status Assert Close Assemble Clear Show
458. o make a call to the sound driver send the message and make the RPC call The actual call is made with the other highlighted fragment copied here 384 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS Issue command to sound core if arg2 gt 0 snd PlaySoundFM argl snd SHAPE_SINE arg2 snd SAMPLE_RATE arg3 255 3579 ADEF lt Note The call to snd PlaySound should be on a single line but due to the restraints of this book s layout we had to put the code on two lines Spin does not allow this in most places and code must be on the same line Comments can be on multiple lines with the or syntax The call is made to the sound driver with the parameters and presto it generates the sound Thus the entire process of typing into the serial terminal user input tokeniza tion parsing and finally command execution are complete Before moving on let s look at the most complex of the commands which are the graphics commands to the video drivers Again it s more of the same test for the com mand string then test for subcommands parse out the appropriate parameters from the tokens array and make the calls to the driver Here s the code NTSC Commands These commands are processed and issued to NTSC terminal core ntsc pr string This command prints a single string token to the NTSC terminal ntsc cls Clear and home the NTSC terminal ntsc col num 0 7 Set co
459. o the video to clear the display when map mode exits While driving the bot will transmit updates u of right and left drive values PING range and direction of travel from the HM55B compass 0 8191 This node has a MY address of 1 and sends data to ffff all nodes on the network for a broadcast Bot Graphics Shown in Fig 5 24 drives the graphics TV display showing The bot bearing as a rotating triangle and text Distance to object as a red point in front of the bot and text Yellow range marker circles at 0 25 m 0 5 m and 1 m Left and right drives as bar indicators Signal strength for RSSI dBm as bar and text The update packets contain information for much of the display and the RSSI is pulled from the received frame through API mode When the bot is in mapping mode mapping A THREE NODE TILT CONTROLLED ROBOT WITH GRAPHICAL DISPLAY 227 Figure 5 24 BotTV graphics controller packets contain data to plot the range map It also accepts clear codes from the bot to clear the mapped display This node has a MY address of 2 and sends out no data The output display of the graphics controller is shown in Fig 5 25 in both normal driving and with the bot performing a panning map operation Note The PING range finder has a wide angle of emission and reception Do not expect pinpoint accuracy when mapping 3 Node Bot Network G Range 366 Range 310 Figure 5 25 TV displays for normal and panning
460. oaded the code with the Propeller Tool using either F10 or F11 You can then just use F2 in PASD to make a copy of the ASM code since it has already been loaded into the Propeller Chip Each time you make a change to the ASM code with the Propeller Tool make sure to load the modified code into the Propeller chip and get the latest copy into PASD either with F11 from PASD or a combination of F10 or F11 in the Propeller Tool and F2 in PASD DEBUGGING TOOLS APPLIED TO A MULTIPROCESSING PROBLEM 115 PASD then finds the Propeller Tool software loads its code into the Propeller makes a copy of the assembly language code and loads it into PASD When PASD reappears in the foreground the address to the left of the first assembly instruction at Addr 00C near the upper left corner of Fig 3 24 should be highlighted V Use the Debug menu to open the Main RAM Cog RAM and Pin viewers Z In the Main RAM viewer select L dec to display the long value stored at each address as hexadecimal and then as decimal v In the Cog RAM Viewer scroll to Addr 02C It should show the label k You may also need to make the Value column wider to see the decimal equivalent to the right of its hexadecimal value Z Inthe PASD window select the check box to the left of the timekeeper label Addr 018 to set a breakpoint there v Click the Debug menu and select Run F5 The highlighting should advance from Addr 00C to Addr 018 indicating that the
461. oaded to the Parallax Object Exchange Web site that allows the Propeller to read and write files among other things to an SD card using the FAT16 file system Before we discuss this SD card object however let s first talk about what would be required if you were to write your own SD card interface Let s start by looking at how SD commands are formatted The first thing to remem ber is that everything is sent to and received from the SD card over the SPI interface one byte at a time all commands data etc are composed of single or multiple byte transactions Thus all the communications take place over the SPI write and read byte methods The SD layer is on top of this The complete SD card specification is a monster of a document not because of its length but because of its lack of clarity For those interested you can read all about it in the SD_SDIO_specsv1 pdf located here Chapter_09 Docs SD_SDIO_specsv1 pdf Luckily we aren t using the SD protocol mode but rather the SPI protocol mode which is much easier to deal with Of course it s not as fast as SD mode nor does SPI mode have all the features of SD But SPI mode allows us to read and write sectors of the SD card and that s all that matters Also in SPI mode both SD cards and MMC cards work in the same way so the software drivers and our experiment discussed later would theoretically work with MMC cards as well In any event all communication with
462. objects 275 face detector 278 279f filter and Viola Jones object detector 275 276 finding shapes 276 finding specific objects 275 276 Propeller integration and 276 279 277f OpenOffice org 319 open source 274 optoisolators 137 OUT command 384 386 outa 24 P16 Multiprocessing Example spin 129 130 P18 to P16 Input Decisions spin 128 129 P18 to P16 Input States spin 127 128 131 Parallax 1 Axis Gyro Module 169 174 170f 171f Parallax CO sensor 133 Parallax Digital Compass 168 169f Parallax GPS module 174 174f Parallax Mini LCD A V color display 418 418 Parallax Object Exchange 79 329 351 Parallax Propeller Forums 45 47 47f Parallax Serial Terminal 43 45 44f 45f 57 59 61 debugging development with 86 102 PST Debug LITE display in 81 83 82f pushbuttons 125 126 126f RC Decay measurement in 141 141f timing interval for 64 65f Parameters 29 PASD See Propeller Assembly Source Code Debugger PASD Debugger Kernel 111 PASDebug object 111 PASDebug spin 110 111 PC to XBee communications 195 198 196f 198f 199f Peltier devices 402 403 404f 422 peripheral ADCs 156 159 160f example with MCP3204 157 158f 159 160f Philips 290 photodiodes 138 142 143 143f photo editing software 258 259 photoresistor 119 138 141 as on off circuit 132 132f physical address 282 PID See proportional integral derivative controllers Piezo Film Vibra Tab 153 153f Pin 29 30 pin des
463. oblems such as collecting measurements in parallel can be overcome with programs that make different cores cogs monitor different sensors or arrays of sensors Other cogs can also be pro grammed to process and store the sensor measurements and in most designs there will still be cogs left over for communication display and other application specific tasks This chapter breaks sensors down into their most common microcontroller inter faces and then demonstrates how to measure an example sensor from each interface With this approach the chapter introduces a wide variety of sensors with just a few examples For instance a photoresistor is a sensor whose resistance varies with light This light sensor can be replaced easily with sensors whose resistances vary with other quantities such as rotation salinity temperature or surface reflectivity These four examples are still just the first few entries in a long list of resistive sensors It turns out that the list gets even longer because the same circuit that is used to measure resistive sensors can also be used to measure capacitive sensors and the technique used to mea sure those sensors also applies to certain diode transistor and conductivity sensors So the simple light sensor really represents an entire class of resistive capacitive and other sensors that can be used to measure a wide variety of physical quantities With 119 120 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES t
464. ocks Variable assignment PUB PRI blocks Add Subtract Multiply and return lower 32 bits signed Multiply and return upper 32 bits signed Divide signed Modulus signed Limit minimum signed Limit maximum signed Shift arithmetic right Bitwise Shift left Bitwise Shift right Bitwise Rotate left Bitwise Rotate right Bitwise Reverse Bitwise AND Bitwise OR Bitwise XOR Boolean AND promotes non 0 to 1 Boolean OR promotes non 0 to 1 Boolean Is equal Boolean Is not equal Boolean Is less than signed Boolean Is greater than signed Boolean Is equal or less signed Boolean Is equal or greater signed PROPELLER LANGUAGE REFERENCE 449 SYNTAX SYMBOLS Binary number indicator as in 41010 4 Quaternary number indicator as in 2130 Hexadecimal indicator as in 1AF or assembly here indicator String designator as in Hello Group delimiter in constant values or underscore in symbols tt Object Constant reference obj constant Object Method reference obj method param or decimal point Range indicator as in 0 7 Return separator PUB method sym or object assignment etc Local variable separator PUB method temp str Abort trap as in method parameters i List delimiter as in method param1 param2 param3 Parameter list designators as in method parameters Array index designators as in INA 2 In line multi line code comment designators
465. of the chip suppliers has offered such a wide variety of practical educational information as Parallax offers for its proces sors Anyone interested in the Propeller will find many articles application notes lab experiments and manuals on the company s Web site to ensure they get off to a good start and maintain their interest and momentum as they learn more I like the Parallax Propeller chip and have enjoyed working with it although my coding skills are still somewhat basic You ll like the Propeller too even if you only have a basic curiosity about how computer chips can easily control things in the real world As you learn how to measure things such as voltage temperature sound and so on you ll get hooked The Propeller chip is not only powerful and capable it s easy and fun to work with Jon TiTus Friend of Parallax Inc and microcomputer inventor Herriman Utah INTRODUCTION Parallax Inc brought together nine experienced authors to write 12 chapters on many aspects and applications of multicore programming with the Propeller chip This book begins with an introduction to the Propeller chip s architecture and Spin programming language debugging techniques and sensor interfacing Then the remainder of the book introduces eight diverse and powerful applications ending with a speech syn thesis demonstration written by the Propeller chip s inventor Chip Gracey We hope you find this book to be informative and ins
466. ok at this variable to determine if it should take any action As long as the variable is equal to zero it will do nothing When the variable is equal to one the SPI layer will read a byte from the W5100 on the EtherX card This will cause the SPI layer to send OxOF as a first byte to the W5100 to indicate a read operation see Fig 8 16 When the variable is equal to two the SPI layer will write a byte to the W5100 on the EtherX card This will cause the SPI layer to send a OxFO0 as a first byte to the W5100 to indicate a write operation see Fig 8 16 After reading or writing a byte the SPI layer will clear this variable back to zero If you look at the assembly code for the SPI layer the first part simply loops wait ing for the SPIRW variable to not be zero Once the variable is not zero the SPI layer determines based on the SPIRW variable if the first nibble should be 0x0 for a read or OxF for a write If the value should be 0x0 it sets the MOSI line logic low and pulses the SCLK line four times If the value should be OxF it sets the MOSI line logic high and pulses the SCLK line four times The assembly code then does the same thing for the second nibble which should be OxF for a read and 0x0 for a write This would complete the first byte sent to the W5100 to indicate whether we will read or write a byte from the W5100 Note that most SPI interfaces allow for full duplex read and write at the same time but the W5100 command str
467. om the W5100 and it behaves differently depending on your socket type UDP or TCP The RX method is shown here Note Lines marked with the b symbol should appear on the same line PUB RX dataptr size block ret_size offset startadd a0 D al counter rdptr temp tempsize Call this method to receive data via the W5100 The method will return the number of bytes read Set block true if you want the method to block waiting for data This method will return the actual number of bytes read Block waiting for the W510 to tell us that there is data Technically we are reading the number of bytes that have been received ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 309 if block true repeat temp read 04 26 temp temp lt lt 8 temp read 04 27 while temp 0 Wait as long as we have received zero bytes If the user wants a non block RX call then we will return immediately with a size of zero if there is no data to receive else temp read 04 26 temp temp lt lt 8 temp read 04 27 if temp 0 return 0 Compute the starting address rdptr read 04 28 Read the receive pointer rdptr rdptr lt lt 8 rdptr read 04 29 offset rdptr amp S7FF Socket has 2K of buffer and that determines mask here of 7FF startadd 6000 offset Add the offset to the starting address of socket 0 Determine how many by
468. om the previous example now the cog executing the Blinker method is repeating the loop with a precise timing interval of every 20 000 000 clock ticks If the commands in the loop take longer than 20 000 000 clock ticks to execute the waitcnt command will just keep waiting until the cnt register eventually rolls over and gets back around to the target value Since the cnt register is 32 bits it rolls over every 2 clock ticks That s 4 294 967 296 clock ticks which takes about 53 7 s when the Propeller s system clock is running at 80 MHz COMMON MULTIPROCESSOR CODING MISTAKES 69 The symptoms of this bug seem drastic because the cog appears to stop responding only to pick up where it left off almost 54 s later Delay Beyond Interval spin has a bug that can easily miss the waitcnt boat Let s say the pushbutton in Fig 3 9 is supposed to control a second indicator light connected to P6 The nested repeat while ina 21 1 loop prevents the outer loop from repeat ing until the pushbutton connected to P21 is released A brief tap on the pushbutton immediately after the LED changes state won t cause the cog to miss the waitcnt boat but if you are still pressing the button one quarter of a second later the PS LED will stop flashing and the cog will appear to stop responding because its waitcnt command is waiting for a time that has already passed Although the P5 LED will start blinking again within 54 s which proves that the cog is still
469. om the previous timestep is used to produce an estimate of the state at the current timestep So it s predicting the current state from the last state In the update BUILDING THE DANCEBOT 247 phase measurement information at the current timestep is used to refine this prediction to arrive at a new more accurate state estimate again for the current timestep For the math wizards here s the formula Xk FX Buk Wr where F state transition model which is applied to the previous state x 1 B control input model which is applied to the control vector u w the process noise which is assumed to be drawn from a zero mean multivariate normal distribution with covariance Q Now that we ve understood the theory let s look at the actual devices and code that we ll be using The GWS PG 03 is an inexpensive hobby gyroscope that s typically used to stabilize small remote control helicopters It has two servo connectors The first is typically plugged into an RC receiver from which it gets a pulsed signal that indi cates the desired position for the servo The second connects to the servo and provides a pulsed signal whose length is the sum of the input signal and the measured signal For our application we ll feed it with a constant input signal and measure the signal on the output This is straightforward for the Propeller The following code outputs a configurable signal on the gyro s input pin and uses CTRA to m
470. om three satellites it may then use geometric trilateration to determine its current position as the intersection of the three spheres see Fig 9 6 for an illustration A large problem arises if there are even slight differences between the receiver s and the satellite s clocks For example if there was a mismatch of 100 ns and we use the speed of light as the propagation speed of the radio signal through the ionosphere this would lead to an error of 100 ns c 100 10 9 299 792 458 m s 299 79 m of error Thus the GPS receiver either needs to have a really expensive and accurate clock onboard or it can use positional information from more than three satellites to correct its clock and accurately produce a position In practice four satellites are required for a 3 D position fix unless other information like current elevation is known a priori GPS receivers are manufactured by many different vendors This means that the infor mation communicated by them can come in a form of a proprietary protocol Fortunately OVERVIEW OF THE SENSORS 327 Figure 9 6 GPS trilateration for us most GPS receivers support a dual mode transmission that is capable of trans mitting standard human readable ASCII text This is known as the National Marine Electronics Association 0183 or NMEA for short The NMEA protocol describes a number of serial data sentences that describe the current status of the GPS Take a look at an example s
471. ommand it sends back a response along with a CRC You are free to inspect the CRC if you wish After you send the six byte command to the SD card it always responds with a one byte response code These response codes mean different things in different situations but generally are used to catch errors Figure 9 10 shows the bit encoding for the response codes CRC CALCULATION When the SD is in SPI mode it doesn t require CRC bytes therefore the CRC bytes can be anything However before the SD card is in SPI mode it does require that the CRC be correct If you re interested in how CRC bytes are computed try this link http en wikipedia org wiki Cyclic_redundancy_check Note SD and MMC cards use the CRC 7 method The next question of course is what commands does the SD card support Table 9 3 lists the complete command set for SD SPI mode OVERVIEW OF THE SENSORS 341 SD CARD RESPONSE FORMAT 7 6 5 4 3 2 1 0 IDLE STATE ERASE RESET ILLEGAL COMMAND COMMAND CRC ERROR ERASE SEQUENCE ERROR ADDRESS ERROR PARAMETER ERROR Figure 9 10 Response code binary bit encoding format Notice CMD0O This command is very important and literally the first command that we need to issue to the SD card This command tells the SD card to switch into SPI mode Therefore we are going to issue this command first after which the SD card should respond with a response byte of 01 to
472. on OVERVIEW OF SYSTEM OPERATION Tilt Controller This is used to read the Memsic 2125 accelerometer module calculate right and left motor drives based on inclination and then send drive values to the bot The tilt controller shown in Fig 5 22 also receives data from the bot and uses the PING range measurements to light the eight Demo Board LEDs showing distances of 100 mm for local range indication Pressing the pushbutton will send a panning map instruction to the bot to map the area in front of it for display by the TV graphics node This node has a MY address of 0 and a DL address of 1 the bot Bot This controls all function of the networked bot shown in Fig 5 23 including E Accepting drive values for motor drive Should no data be received for 1 5 s the bot will stop and blink the red LED Figure 5 22 Tilt controller board with Memsic 2125 Accelerometer 226 WIRELESSLY NETWORKING PROPELLER CHIPS Figure 5 23 Networked bot with range finder compass and XBee Accepting panning map instruction p to perform mapping operation When this instruc tion is received the bot will stop and pan the PING sensor from right to left measuring distances and sending map data m to the TV graphics node and the tilt controller When mapping is complete the bot will remain steady and blink the green LED until the tilt controller releases it from mapping mode user presses button again The bot will send a clear c code t
473. on 10 000 cps Encoder A _ l l Encoder B kad LJ L Time gt Figure 6 6 Quadrature encoder with disk and offset detectors 244 _ DANCEBOT A BALANCING ROBOT To measure these pulses we ll use the following assembly code to count pulses and determine the relative phase of the signals from the photodetectors The code uses bit manipulation to determine which way each motor is turning Dat count loop if_ne if_ne if_ne if_ne org mov m2w par add m2u 4 mov t ina Get ina 1011 21 instr 80 cnts 1Ms sec and t mAEnc t shows before flank what A bits are waitpne t mAEnc Wait for encoder A bits to change mov tl ina and t1 mABEnc tl shows after flank what AB bits are mov t2 tl and t2 mAEnc xor t2 t t2 shows which A bits changed mov t tl Get t ready for next measurement shr t2 12 rer t2 1 we Check if A on motor 1 changed shr t1 14 Leave both t2 t1 shifted if take jump jmp doM2 shr t1 12 rer tl 1 wc Check if A 1 shr t1 1 jmp doM2 rer tl 1 wc Check fud bkw on motor 1 rdlong miCnt par if_c add miCnt 1 sub miCnt 1 if_ne doM2 if_ne if_ne if_ne if_c t2 EE wrlong miCnt par Ready to do motor 2 t1 shifted 14 t2 shifted 13 shr rer jmp shr rer jmp rer t2 9 t2 1 wc Check if A on motor 2 changed loop t1 8 t1 1 wc Check if a 1 loop t1 1 wc Check if fwd bkw on motor 2 rdlong
474. on about this particular packet of information much of which we don t need to know for our Propeller programming As it pertains to the EtherX card the two things we care about most are the protocol fields and the IP address fields The protocol fields indicate the type of data that appear after this IP header In this chapter the two types of protocols we will focus on are Transmission Control Protocol TCP and User Datagram Protocol UDP The other key data in the IP header that we care about are the IP addresses Every computer 80 00 20 7A 3F 3E 80 00 20 20 3A AE 08 00 IP TCP Data 00 20 20 3A Destination MAC Address Source MAC Address Ether Type Payload CRC Checksum MAC Header Data 4 bytes 14 Bytes 46 1500 bytes Ethernet Type II Frame 64 to 1518 bytes Figure 8 1 Ethernet frame ETHERNET AND INTERNET PROTOCOLS 283 MAC Header IP Header TCP UDP Data CRC Checksum 14 bytes 20 bytes 26 1480 bytes 4 bytes Ethernet Type II Frame 64 to 1518 bytes Figure 8 2 Ethernet frame with IP TCP or UDP header and data connected to the Internet has a unique IP address this is not strictly true like with a MAC address but we will make this statement for now The IP address is sort of like a phone number Computers called routers have an idea or know exactly where an IP address is located on the Internet In this wa
475. on the pad repeat until pad read amp ff 0 Debounce button waitcnt cnt 10000 Wait for the player to push something on the pad repeat until pad read amp ff lt gt Q Increment player score player_score 1 316 USING MULTICORE FOR NETWORKING APPLICATIONS Determine if we have won if winloss and player_score 5 winloss 1 Grab the ethernet lock and send new score to opponent repeat while lockset eth_lock true eth TX player_score 4 lockelr eth_lock Set the score_change variable score_change 1 Debounce button waitcnt cnt 10000 PUB MonitorEthernet UDP_Header UDP_Header1 data This routine will run in another cog and monitor the network It runs as a continuous loop waiting for data from the opponent over the EtherX card repeat Grab the ethernet lock repeat while lockset eth_lock true If read_rsr gt then there is data in the EtherX card for us if eth read_rsr gt 0 We are making a dangerous assumption here that the only data to have arrived is the data from the other HYDRA and we KNOW that it will send 1 words of data Note here however that we read 3 words This is because when the W510 reads UDP data the UDP header is included in the data The UDP header is 8 bytes two longs so we read two longs of data which we junk Then we read the data we care about eth RX UDP_Header 4 false eth RX U
476. onds count milliseconds starting milliseconds count Returns if failed to start or nonzero if it succeeded longmove m minutes 3 Copy local gt global variables If checked out lock and launched new cog return nonzero else return zero if not semID locknew If checked out a lock Stop Stop if already running Launch process into new cog and return nonzero if successful success cog cognew TimerMs stack 1 PUB Stop Stop timekeeping if cog If cog is not zero lockret semID cogstop cog 1 Stop cog amp set cog to zero PUB SetTimer minutes seconds milliseconds Set the timer Parameters minutes minutes count seconds seconds count milliseconds milliseconds count 102 DEBUGGING CODE FOR MULTIPLE CORES repeat until not lockset semID longmove m minutes 3 lockelr semID PUB GetTime minfddr Get the current timestamp Parameters minAddr IMPORTANT Set lock on time variables Copy values received Clear lock on time variables Get current timestamp address of the caller s minutes variable Caller must declare long variables in this sequence minutes seconds milliseconds repeat until not lockset semID longmove minAddr m 3 lockelr semID PRI TimerMs t t cnt dt clkfreq 1000 repeat waitent tt dt repeat until not lockset semID mstt if ms 1000 ms Q stt if s 60 s 0 mt if m 60 m 0
477. ons and an example development process MULTICORE PROPELLER MICROCONTROLLER 7 Upon application launch a single cog runs the ROM based Spin Interpreter and executes the application from Main RAM From there the application can launch additional cogs on Spin or Assembly code as needed Cog2 RAM Cog7 RAM Interpreter Main RAM ANA N Creo AL go Figure 1 5 Application launch Here the application launches an additional cog to execute a subset of the application s Spin code in parallel It may also launch a cog to run assembly code not shown Interpreter Main RAM aN oN Comestor 9 mao Figure 1 6 Additional cog launched on Spin code PROPELLER HARDWARE We ll briefly discuss the Propeller chip s hardware and how it works in the rest of this chapter and then you ll be introduced to multicore programming and debugging in the following two chapters What you learn here will be put to good use in the exciting projects filling the remainder of this book Packages The Propeller chip itself is available in the three package types shown in Fig 1 7 8 THE PROPELLER CHIP MULTICORE MICROCONTROLLER 52 5 mm 40 pin DIP package for ra prototyping PALA 4 z P8X32A D40 3 AYWWXZZ 3 Pin 1 44 pin LQFP and QFN 9mm packages for surface mount Pin 1 production E PALAKA ww wu 6 P8X32A Q44 awaz P8X32A M44 AYWWXZZ Figure 1 7
478. ooth to transfer the information Just a few examples of programming environments with COM port features include Microsoft Visual BASIC Microsoft Visual C MATLAB and LabVIEW Of course the PC appli cation has to be configured for the right COM port and the PC code and Propeller code have to agree on a communication protocol A LabVIEW example is available in the Propeller Education Kit Applications section at http forums parallax com Summary Instead of grouping sensors by the physical quantities they measure this chapter grouped them into common microcontroller interfaces Some sensors had more than one interface option because the circuits that connected them to microcontroller I O pin s determined the types of outputs Resistive sensors for example can be measured 188 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES with RC decay time in an RC or resistor capacitor circuit or with an A D converter if placed in series with another resistor Each interface section represented a variety of sensors For example the RC decay interface can measure a potentiometer resistive or capacitive humidity sensors a color enhanced photodiode or an infrared transistor to name just a few This chapter also introduced a number of different resources for writing code to get information from sensors in each interface group including the Propeller Object Exchange Propeller Library and Propeller Education Kit resources The Propeller chip s
479. op xxxFix Wait for lock set Copy timestamp vars xxxFix Clear lock Breakpoint debug Vars m String minutes seconds milliseconds PRI TimerMs t t cnt dt clkfreq 1000 repeat waitcnt t dt repeat until not lockset semID mstt if ms 1000 ms Q stt if s 60 s 0 mtt if m 60 m 0 lockelr semID Current clock counter Ticks in 1 ms Infinite loop Wait for the next ms xxxFix Wait for lock set Add 1 to millisecond count If milliseconds 1000 Set milliseconds to 0 Increment seconds if seconds 60 Set seconds to 0 Increment minutes If minutes 60 Set minutes to 0 x Fix Clear lock Step 8 Incorporate into a Building Block Object Now that the code is known to work it s time to move it into a building block object Test Timestamp Object spin is an example of a top level object that utilizes the new Timestamp Object Notice it does 100 DEBUGGING CODE FOR MULTIPLE CORES not have to concern itself with any locks All it has to do is 1 declare the Timestamp Object 2 call its Start method and pass the start time and 3 call its GetTime method to get a timestamp From this application object s standpoint the code is simple and it can be oblivious to all the cog and lock bookkeeping the Timestamp object takes care of This is a typical hallmark of a Propeller Library or Propeller Object Exchange object that manages a process in ano
480. opeller Tool will scan for the Propeller and display results similar to Fig 2 7 22 INTRODUCTION TO PROPELLER PROGRAMMING Information Propeller chip version 1 found on COM4 Figure 2 7 Identification dialog showing version and port of Propeller chip Tip If the software was unable to find the Propeller chip check all cable connections and the power switch light then try the identification process again You may also verify the USB connection and driver using the Serial Port Search List select the Edit gt Preferences menu item choose the Operation tab click the Edit Ports button then connect disconnect the USB cable while watching the Serial Port Search List window When working properly your Propeller connection will appear as a USB Serial Port Your First Propeller Application Now that we can talk to the Propeller let s write a short program to test it We ll start our exercises slow and easy and accelerate into more advanced topics as we build up our knowledge v Type the following code into the blank edit pane of the Propeller Tool software o Make sure the PUB line begins at the leftmost edge of the edit pane Note that the case of letters uppercase lowercase does not matter but indention often does we indented the lines under PUB _LED_On by two spaces PUB LED_On dira 16 1 outa 16 1 repeat Tip This source is from PCMProp Chapter_02 Source LED_On spin When done your screen sho
481. opeller to a computer and power supply V Download and install the Propeller Tool software o The Propeller Tool software is available free from Parallax Inc Go to www parallax com Propeller and select the Downloads link o Install with the default options The software will automatically load the Windows Universal Serial Bus USB drivers needed for the next steps V Start the Propeller Tool software o When installation is complete start the software by double clicking the Propeller Tool icon on your desktop or follow the Start gt Programs gt Parallax Inc menu item A window should appear similar to Fig 2 3 LET S GET CONNECTED 19 Object View shows application structure Propallar Tool File Edk Run Help Unithe1 Full Source C Vondensed C Su C Documentabon Propeler Library Demos O Parallax inc Aa Propeller Tool v1 2 6 SQ Fanie 3 0 Help O Livay 1 O PE het 2 EQ lap lt 4x1 keypad Reader DEMO spin ADBA DEMU spr COIL_demo spin Delw Lel Tesi spin dither spin Fioat_Demo spin TrequencySynth spn lt Propeller Source apni Vt Inset Folder and File views provides Edit pane where you enter your code access to objects on the computer Figure 2 3 Propeller Tool software Windows Tip In addition to being a code editor the Propeller Tool is a launch point for a wealth of Propeller information The Help menu includes not only Propeller Help bu
482. oportion to light intensity and devices such as the AD592 temperature probe allow current to pass proportional to temperature Phototransistors also allow current through based on light intensity but the relationship between current and light is not necessarily linear In all these cases instead of allowing the capacitor to discharge through the element these devices conduct current either into or out of the capacitor Depending on the current direction voltage across the capacitor will either increase or decrease and the resulting growth or decay measurement can be used to quantify the current and the physical property it represents Information For more information on the AD592 temperature probe and blue enhanced photodiode featured in this section see the Applied Sensors Kit and PDF documentation available from www parallax com This is also a good source of information for fluid level and salinity sensing with RC decay The AD592 temperature probe shown in Fig 4 18 is designed to measure the tem perature of liquids For this circuit the I O pin has to apply a low signal to discharge the capacitor When the I O pin direction is changed to input the AD592 allows current to pass in proportion to temperature and the voltage at the upper capacitor plate increases 3 3 V AD592 Temperature Probe JE I O Pin GND 0 22 uF Figure 4 18 AD592 temperature probe RESISTIVE CAPACITIVE DIODE TRANSISTOR AND OTHER 143 Then the
483. opy of the Propeller Tool version 1 05 01 or better loaded on your system and the PC running Windows connected to the Propeller Demo Board over a USB A to Mini B cable HARDWARE SETUP The hardware setup for the project is rather straightforward With the Propeller Demo Board in hand make the following connections to the various media devices as shown in Fig 10 2 1 Connect the Video output of the board to your NTSC TV s RCA video input 2 Connect the Audio output of the board to your NTSC TV s RCA audio input or headphones Note Older versions of the Propeller Demo Board have RCA jacks rather than headphone jacks so you won t need a stereo to RCA converter cable with older versions 3 Connect the VGA out of the board to the VGA monitor 4 Connect a PS 2 keyboard to the board 5 Connect the Propeller Demo Board to the PC via the mini USB cable Of course you need to have the Propeller Demo Board 9 V wall adapter plugged in and powered on Also remember that step 4 is not only so the PC can ultimately com municate with the Propeller Demo Board via a serial terminal but also so you can use the Propeller Tool to program the board itself thus the single USB serial connection is used for both programming and experimenting Tip Later you might want to add another serial port to the Propeller Demo Board with an extra Parallax USB2SER adapter Part 28024 That way you don t have to play games with the single communication
484. or debugging but they may need some adjustment if you don t have the hardware handy for connecting to a TV Fortunately example programs that utilize the TV_Terminal object tend to be easy to modify for use with the Parallax Serial Terminal object since the method calls that display characters and numbers are similar Also the main clues to look for in demonstration and example objects are how method calls to the building block object are implemented Of the three demonstration programs for the Memsic 2125 module Paul Baker s MXD2125 Simple Demo spin looks the most approachable in terms of modifying for use with the Parallax Serial Terminal The first task is to examine the example program along with the MXD2125 Simple object to figure out what methods MXD2125 Simple Demo uses to get the accelerometer measurements So check the nickname given to the MXD2125 Simple object in the OBJ block and then look for nickname method calls In the case of MXD2125 Simple Demo spin the nickname is accel and the object dem onstrates two different sets of method calls the first for using another cog to take the measurements and the second for taking measurements with the same cog After declaring the MXD2125 Simple object with the nickname accel the first example in the Setup method calls accel Start to launch the accelerometer process into a new cog The Start method call is embedded in a text dec method call so the TV_Terminal object displays the result
485. or our final exploration into the Propeller XBee combination let s exercise the XBee s ability to measure and transmit analog and digital data without a controller The received data has a packet identifier of 83 the XBee needs to have firmware version 10A3 or higher to be able to this Y Apply an analog voltage of up to 3 3 V using a potentiometer or other device to ADC 0 pin 20 and ADC 2 pin 19 and a pushbutton to DIO2 pin 18 V Using X CTU software starting from the default settings configure for a MY of 6 and for I O settings such as DO mode 2 ADC D1 mode 2 ADC D3 mode 3 DIN Digital Input IR 3E8 sample rate of 1 second 3E8 1000 decimal or 1000 ms of time V Connect the Vcc pin 1 and the Vref pin pin 14 of the XBee to 3 3 V Connect Vss to GND pin 10 Do not connect anything else including the Propeller Y Download ADC Dig Output Sample spin to your coordinator board V Open the Terminal window and monitor You should see something similar to Fig 5 26 77 X CTU COM6 3 Hx About PC Settings Range Test Terminal Modem Configuration m Line Status Assert reg poy roa Close ES Clear a ora lV RTSM Break Com Port Packet Screen Hex 6 Data Received from address ADC Ch 0 60 ADC Ch 1 91 ADC Ch 6 4 Dig Ch 2 1 Data Received from address 6 ADC Ch 0 52 ADC Ch 1 82 ADC Ch 6 4 Dig Ch 2 1 Data Received from address 6 ADC Ch 0 54 ADC Ch 1 84 ADC Ch
486. orrectly However memory collisions have not been ruled out Remember from the Memory Collisions section that cogs using groups of variables to exchange information can end up exchanging a combination of new and old values if locks are not used to give commands executed by different cogs exclusive access to the group of memory elements Since Test Timestamp from Another Cog spin is now executing code in two separate cogs accessing the same group of variables it stands to reason that the longmove command might copy values at unexpected instants such as when the ms variable stores 1000 or when the s variable stores 60 Since the ms variable should only store 0 999 and the s variable should only store 0 59 this would be a bug that could in turn cause other bugs in the application If there really is a potential memory collision problem in this code the best way to expose it is to initialize the values to a point where they are about to roll over and then run the code in slow motion with long delays The long delays make windows of opportunity for memory collisions to occur The cog making copies of the group of variables can also sample it more quickly than the timekeeping cog updates it which should expose the bug if there is one In Find Hidden Bug in Timestamp spin the dt variable is assigned the number of clock ticks in one second instead of the number of ticks in a millisecond and there are quarter second delays after each timekeeping
487. ort spin o TimeStamp Object V Open ViewPort Z Click the code tab V Set the drop down menu above the Spin Files list to the mycode directory VY Open the program Test Timestamp Object with ViewPort spin v Click the Start Debugging button The Start Debugging button looks like the trian gular play button on most music and video players v Examine the variables listed in the lower left Watch windowpane The Watch windowpane in Fig 3 21 will show the minutes seconds and milliseconds variables and their values While the program is running the repeat loop repeatedly updates the minutes seconds and milliseconds variables Meanwhile the conduit object uses another cog to stream those variable values to the PC where the ViewPort software updates its display with their values As you watch these variables counting upwards it provides a quick verification that the Timestamp Object is provid ing the current times as expected ViewPort has a variety of graphical analysis tools and one that s exceedingly useful for evaluating this object is the digital storage oscilloscope dso view This view can graphically display the minutes seconds and milliseconds variables The dso view shown in Fig 3 22 also has measurement tools for quickly verifying that the minutes seconds and milliseconds variables really are keeping time according to minutes seconds and milliseconds Follow these instructions to perform the test shown in Fig 3 22
488. orthwhile since a couple of capacitors and resistors are inexpensive and don t require a lot of circuit board real estate in a project Test Sigma Delta DC Signal Measurements Figure 4 31 shows a schematic of the DC signal version of the Sigma Delta ADC along with an example circuit and Parallax Serial Terminal output for the Test Sigma Delta ADC spin object Try running the program and then twisting the potentiometer Plotting the potentiometer voltage versus ADC value should result in a linear graph Test Sigma Delta ADC spin displays the ADC measurements in the Parallax Serial Terminal The Sigma Delta ADC object 162 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Parallax Serial Terminal Disabled Cli BEE 7 adcVal 1346 10 kQ Com Port Baud Rate TX DIR coms 115200 orx o poe lt BN Figure 4 31 DC Sigma Delta ADC example circuit takes care of all the interactions with the circuit in another cog and constantly updates the top file s adcVal variable Information The Test Sigma Delta ADC and Sigma Delta ADC objects are included in the PE Kit Tools Sigma Delta A D Conversion article It s available through the PE Kit Labs Tools and Applications sticky thread at www forums parallax com Also if you are using the Propeller Education Kit to try these programs and circuits use the 100 pF capacitors included in the kit instead of the 1 nF capacitors shown in the schematic Test Sigma De
489. ou open a register more fully you may steal air from rooms that were otherwise already comfortable Determining the amount that an adjustment in one room may affect other rooms is further complicated by factors including air duct size the distance from the air production source and the size of the return air path for the rooms If this room to room balancing process is completed by a competent HVAC professional this complex interrelationship between air register settings can result in reasonably consistent air temperature between all rooms However the adjustments are based on the readings taken at a specific point of time and assume that the entire system of rooms is static Unfortunately in real world HVAC environments this is just not the case The reality is that a room s heating and cooling needs will change over time as many variables come into play For example sunlight shining on an exterior wall through a window or on the roof will likely increase the room temperature The contents of a room can also have a considerable impact on the room temperature Consumer elec tronic equipment such as stereo systems televisions and computers all create heat when operating Other typical household devices such as clothes dryers refrigerators stoves and coffee makers all release heat as well Even if a room is relatively devoid of heat producing equipment it is extremely likely to have some type of lighting system with low vol
490. ount Test Timestamp Object with ViewPort Events spin incorporates those changes into the test program along with some code that waits to receive a character from ViewPort s Terminal The Test Timestamp object s Go method s repeat loop checks repeat edly for a character in the terminal object s input buffer When the RxCheck method returns something other than 1 it indicates that there s a character waiting in the buffer which in turn indicates that a character was typed into ViewPort s Terminal The Test Timestamp object waits for this event with if vp RxCheck lt gt 1 When the event occurs code in the if statement block clears the input buffer by calling vp RxF lush and then it gets a timestamp from the Timestamp object Next if count 10 compares the count variable to 10 and then post increments it If the count variable is equal to 10 code in the nested if block calls the Alarm method The Alarm method sends the string Alarm to the terminal While the actual event might be triggered by a sensor and the alarm might be a signal to a speaker this application is useful for prototyping For example if the sensor sample is still on its way in the mail you can still make progress and have application code under way before the sensor arrives Test Timestamp Object with ViewPort Events spin Use ViewPort to get events from the keyboard and test to make sure the alarm occurs after eleventh event 108 DEBUG
491. ounted Propeller chip as shown in Fig 11 13 THE HVAC GREEN HOUSE MODEL 413 p amp P 0000000000005 is 5 0000 oo00000 a OEE a4 0000 emmma ooog a JOOOQ a 0000 O0000000 00000006 O000000000060 0000c 0000 J00 2000 a JOOO0OQE 9 a J0000 wy 4 000000 O00G0Vv000000 000000000 tetsssedert 900000000000 an 00000000006 is 000000000000 8 NANNAN gt e A000 a 3797978 300 00000 00000 mh 9 0040 o00000000000 2000 O SGO eRe we ooo oO00 ooo 00o ooo ooo 000 0O00 ooo 00O 00O 00O 000 ooo ooo ooo ooo ooo ooo ooo 2929 lee Xe O re re O Q Q Q re QO re re re o Q fe o00000000000 o00000000v00 Lo of of oj of oli 000000 los eh eli elie 00000 00000 oo0oo000 oo0o000 00000 od oh oh ok e 00000 ooooC oo000 oo0o000u o00000Cn Figure 11 13 Female 100 headers soldered onto the Propeller USB Proto Board We then laid out a schematic for the room control board Fig 11 14 where all the components would be populated on the daughterboard and would connect to the underlying Propeller Proto Board through standard 100 spaced pins Not only would this design allow us to create multiple room boards it would also allow us to use the PC board mount RJ 45 jacks This design had the added benefit of being repairable In the event of a failure of the surface mount Propeller chip we could simply swap
492. our real information is Figure 12 2 shows a spectrograph of me counting from 1 to 10 What you re looking at is called a spectrograph This is a 3 D representation of a time varying signal From left to right you have time From bottom to top you have fre quency The intensity at each point is the energy of that frequency at that time Looking at speech from this perspective gives us the insight we need to go about synthesizing it In fact this is what your ear sees rather than a sputtering waveform Note the horizontal bands of darkness in the spectrograph Those are harmonics of my voice s glottal pitch I tend to talk at about 110 Hz so there s nominally about 110 Hz of separation between each band You can see the bands spread out and compress as my voice deviates up and down in tone ts Spectrum Disptay Magnit ied Waveform 46ms DUOT ove ww YU 1922 Specific Energy E os ah ates A ote 11025Hz rum vs La Spectrum vs Time Anaki 990Hz 3094ms Figure 12 2 A spectrograph of me counting from 1 to 10 USING SPECTROGRAPHS TO SEE SPEECH 429 Now notice the concentrations of dark bands distributed vertically Those are the result of resonances within my vocal tract As I talk and change the shape of my vocal tract they move around some up some down Each is a formant The key to speech synthesis is synthesizing these formants Information These spect
493. pace for cog Propeller Objects and Resources We encourage you to learn more about the Propeller Besides reading the rest of this book and exploring outside resources we ve shown you study other developers objects Dozens are included with the Propeller Tool software and hundreds more are in a central location called the Propeller Object Exchange obex parallax com see Fig 2 26 There s an active user forum full of Propeller users with ideas questions answers and genuine motivation to share see Fig 2 27 Visit the Parallax Forums 46 INTRODUCTION TO PROPELLER PROGRAMMING Object Exchange Windows Internet Explorer The Propeller Object Exchange is where developers go to share their objects with others It s free You can quickly download try out experiment with and learn from other Propeller Propeller me objects Object Exchange Objects are organized by category for easy locating Drill down through lists for more detail including user ratings and reviews Hetptul function language development sid 7 Se a 3I2 eastHar Uae Tool Object List Figure 2 26 Propeller Object Exchange obex parallax com PROPELLER OBJECTS AND RESOURCES 47 Propeller Chip Parallax Forums Windows Internet Explorer IS LE hipio parallax s omjfinns bef at a rde rK Gouge w amp 4 Propeler chp paratax Forume Do SRO http forums parallax com Log Off Control Panel
494. peed spin 98 99 Test Timestamp Bug Fix spin 96 98 98f Test Timestamp from Another Cog spin 91 92 93 Test Timestamp Object with ViewPort Events spin 107 108 109f Test Timestamp Object with ViewPort spin 103 104 Test Timestamp Object spin 99 100 Test Gyro spin 172 thermostats 400 32 768 kHz signal 324 three code network for monitoring and control 189 190f three node tilt controlled robot with graphical display 221 231 bot network code 228 231 overview and construction 221 225 222f 223f system operation overview 225 227 225f 226f 227f tilt 245 248 245f 248f ViewPort measurement of DanceBot 254 254f time 40 41 41f time method 140 141 timekeeper label 114 timekeeping code test 91 92 92f TimerMs method 100 TimeStamp Dev ASM spin 112 114 Timestamp Object spin 101 102 Timestamp test 93 95 95f 98f timestamp variable monitoring 104 105f time varying signals 428 timing 38 41 39f 171 171f synchronized delays 40 41 timing diagram ADC101S021 171 171f for clock phase polarity 0 291 292f for clock phase polarity 1 291 292f serial 171 171f SPI 291 292f timing interval errors 64 71 code that missed the waitcnt boat 68 71 incorrect loop interval code 67 68 wrong clock frequency settings 64 66 Token Ring 282 Top File spin 74 75 transistor transistor logic TTL 410 Transmission Control Protocol TCP 282 284 283f UDP differences from 284 transmit method 307
495. pirational For more Propeller related resources visit www parallax com propeller and to join in the conversation with the Propeller community visit forums parallax com ADDITIONAL RESOURCES FOR THIS BOOK The software documentation example code and other resources cited in the follow ing chapters are available for free download from PCMProp directory at ftp ftp propeller chip com About the Example Code Code listings for projects in this text come from diverse sources The Propeller chip s native languages are object based and many prewritten objects are included with the Propeller Tool programming software or are posted to the public Propeller Object Exchange at obex parallax com Copyright for Example Code All Spin and Propeller Assembly code listings included in this book including those sourced from the Propeller Object Exchange are covered by the MIT Copyright license which appears below Copyright lt year gt lt copyright holders gt Permission is hereby granted free of charge to any person obtaining a copy of this software and associated documentation files the Software to deal in the Software without restriction including without limitation the rights to use copy modify merge publish distribute sublicense and or sell copies of the Software and to permit persons to whom the Software is furnished to do so subject to the following conditions The above copyright notice and this permission noti
496. ply power ground and TX RX lines for digital communication Second we would be able to reduce costs by moving away from the more expensive intelligent periph erals and substituting a standard parallel LCD display for the serially controlled unit and replacing the 1 wire temperature sensor with an inexpensive DS 1620 chip Having the Propeller in the room placed it in close proximity to the RC servo motor eliminating worries of signal degradation affecting performance Also driving the LCD from the Propeller eliminated concerns of long wire runs corrupting serial TTL signals to the LCD As we mentioned earlier because the Propeller has 28 available pins we have the option of adding items such as the inexpensive HS 1101 humidity sensor more indicator LEDs and even a speaker for acoustic feedback and or alarms The one Propeller per room design also lent itself to using a network protocol and having multiple units share a single cable This eliminated the need for star type THE HVAC GREEN HOUSE MODEL 411 wiring allowing all the units to be daisy chained on a single cable from room to room This reduces wiring cost in new construction and greatly simplifies installation in existing buildings So using our one Propeller per room design our new cable pair consumption would simply be Pair 1 5 V GND Pair 2 TX RX This new reduced wiring consumption also means less expensive two pair wire i e te
497. pment may require more cooling in order to be comfortable 402 THE HVAC GREEN HOUSE MODEL The sad reality is that in most cases a single thermostat in a multiple room building just isn t up to the task of creating a balanced comfortable temperature for everyone If the thermostat in the building decides to make it cooler or warmer based on its single sample and that causes some rooms to be too hot or cold that s just too bad In some situations it s the worst case room that controls the temperature for the whole build ing A good example would be cranking up the AC to deal with one hot room in the house and wasting lots of energy freezing out other rooms So given such an extremely variable and dynamic environment to deal with is it possible to design an upgrade to a standard HVAC system by adding some technology smarts to deal with all these situations To find out we built a scale model HVAC green house on which we could experiment The HVAC Green House Model Two main considerations were taken into account when building the model house for this project First of course we wanted to have a test bed to experiment with mechani cal electrical and software designs to deal with the HVAC problems outlined previ ously Second we hoped to end up with an attractive and educational display piece we could use to showcase the concept of a dynamically managed HVAC system We wanted to visually demonstrate that a sm
498. port the core needs to release the semaphore so that another core can use the serial port if it needs to IF A CORE GRABS A SEMAPHORE IT MUST RELEASE IT AT SOME POINT This is important because if another core is blocking not running anything else while waiting for that semaphore to be available and that semaphore never becomes available because the previous owner never released it you have a problem The Propeller calls these semaphores locks Although they have a different name the concept is the same Notice in the code that when a button is pressed we need to send the updated score to our opponent via the EtherX card But we need to make sure the MonitorEthernet method is not talking to the EtherX first So we wait to grab the eth_lock which is a lock that we created specifically for managing communication with the EtherX card We know we have grabbed the lock when lockset returns true Also notice that when we are done sending the updated score to the opponent we immediately release the lock with lockelr Similarly in the MonitorEthernet method we grab the lock before we check to see if there is any data from the opponent and release it as soon as possible to give the MonitorButtons method an opportunity to access the EtherX if needed 318 USING MULTICORE FOR NETWORKING APPLICATIONS Summary So now we can see how to effectively use the multiple cores of the Propeller to imple ment a network application In t
499. pst str String ASCII Table repeat c from 33 to 126 Place cursor for each character in table case c 33 52 pst Position Q c 31 53 72 pst Position 8 c 51 73 92 pst Position 16 c 71 93 112 pst Position 24 c 91 113 127 pst Position 32 c 111 Display ASCII code next to ASCII character pst dec c ASCII code decimal pst Char Print a space pst Char c ASCII character GPS MODULE EXAMPLE An example of a synchronous serial sensor is a global positioning system GPS receiver These receivers calculate the time difference between the arrival of a number of satellite signals to determine geographic position and they typically report the posi tion information using one of the National Marine Electronics Association NMEA protocols Although NMEA has a new protocol named NMEA 2000 the older NMEA 0183 protocol is still widely used and the receivers are inexpensive NMEA 0832 receivers communicate at 4800 bps 8 bits no parity and 1 stop bit with no handshake This is the same serial configuration the Parallax Serial Terminal software and object would use if they were both configured to communicate at 4800 bps and it s also the protocol that was used to transmit the letter A with P24 that was just displayed by View Port in Fig 4 43 Parallax carries two different GPS receivers for prototyping shown in Fig 4 45 The Parallax GPS Receiver Module on the left h
500. pter s Sigma Delta A D conversion examples The blink ing light example programs have two potential sources of bugs that contribute to an inexact timing interval First they do not use a precise external clock and second code in their vaitcnt commands does not compensate for the time it takes other commands in the repeat loops to execute Both of these bugs are easy to spot and easy to fix Wrong Clock Frequency Settings When a Spin top file does not specify the clock settings the Propeller uses its internal RCFAST setting by default Although this oscillator is nominally 12 MHz the actual frequency can vary anywhere from 8 to 20 MHz In contrast crystal oscillators are much more precise with variations measured in parts per million or ppm which indicates how many cycles per million the oscillator might vary A typical value for the 5 MHz crystal that comes with the many of the Propeller kits and boards is 30 ppm Since this oscillator is only off by at most 30 signal cycles per million the Propeller will be off by at most 30 clock ticks per million At 80 MHz that s at most 2400 clock ticks off which is quite a bit better than 8 million or 4 million Applications that require accurate timing tend not to function correctly when the clock settings that are supposed to specify the external crystal included on most Propeller kits and demo boards are omitted One example of symptoms this coding error can cause is garbled mes
501. ption and response to the embedded application Each cog has its own RAM called Cog RAM containing 512 registers of 32 bits each Cog RAM is used for both code and data except for the last 16 special purpose registers see Table 1 3 that provide an interface to the System Counter I O pins and local cog peripherals TABLE 1 3 COG RAM SPECIAL PURPOSE REGISTERS ADDRESS NAME TYPE DESCRIPTION 1F0O PAR Read Only Boot Parameter 1F1 CNT Read Only System Counter 1F2 INA Read Only Input States for P31 PO 1F3 INB Read Only lt reserved gt 1F4 OUTA Read Write Output States for P3 PO 1F5 OUTB Read Write lt reserved gt 1F6 DIRA Read Write Direction States for P31 PO 1F7 DIRB Read Write lt reserved gt 1F8 CTRA Read Write Counter A Control 1F9 CTRB Read Write Counter B Control 1FA FRQA Read Write Counter A Frequency 1FB FRQB Read Write Counter B Frequency 1FC PHSA Read Write Counter A Phase 1FD PHSB Read Write Counter B Phase 1FE VCFG Read Write Video Configuration 1FF VSCL Read Write Video Scale 12 THE PROPELLER CHIP MULTICORE MICROCONTROLLER When a cog is started registers 0 000 through 495 1 EF are loaded sequentially from Main RAM ROM its special purpose registers are cleared to zero and it begins executing instructions starting at Cog RAM register 0 It continues to execute code until it is stopped or rebooted by either itself or another cog or a reset occurs Hub The Hub maintain
502. r Hint Axis acceleration measurements vary with tilt 4 Design an application that uses the SD Card Reader to datalog GPS coordinates WIRELESSLY NETWORKING PROPELLER CHIPS Martin Hebel Introduction This chapter looks at how your Propeller can be part of a wireless sensor network WSN to share data through wireless communications WSNs are not intended for large data transfers such as files but small amounts of data back and forth The Propeller is an amazing controller and its ability to perform parallel processing makes data com munications fast and simple for use in a WSN While the main task is being carried out other cogs can be sending or receiving data on the network With a lot to discuss and learn along the way the final completed project of this chapter depicted in Fig 5 1 will be a three node network that has E A tilt controller node transmitting drive and control data E A robot bot node that receives the data has a compass and ultrasonic range finder and is transmitting data on drive range and direction It also has the ability to map what is in front of it for remote display E A node that accepts data from the bot and displays the information graphically on the TV This chapter highlights communications to from and between Propeller chips using XBee transceivers from Digi International Topics covered in this chapter include E Networking and XBee overview E PC to XBee commun
503. r application programming interface Instead of sending or receiving the data alone the entire frame is manually constructed for transmission and manually parsed on reception The frame consists of sender s address RSSI level options frame IDs and the data or message itself Depending on the frame type different types of data are carried Some benefits to using API mode include USING THE XBee API MODE 215 Pull sender s address directly from received frame Pull RSSI level from certain received frame types Place the destination address for the packet directly in the frame Use frames for local XBee configuration as opposed to AT mode Use frames for REMOTE XBee configuration firmware version 10CD required Pass analog and digital data from the XBee s I O pins without a controller on the remote firmware version 10A3 or higher required Use frames that provide delivery notification to the sender E Data is received in a single frame up to 100 bytes ensuring it is from a single source As you can see using API mode opens many doors to fast and powerful commu nications but it can be a little complex The XBee Object supports the means for constructing and retrieving data for many of the API frame types Let s look at how a packet must be framed to be accepted for transmission as shown in Fig 5 16 taken from Digi International s XBee manual This frame type is for sending strings between units such as our data
504. r hits lt RETURN gt the CCP tries to tokenize the input line and make sense of it In other words does the input have commands in it Are they valid And so forth If valid commands are found they are passed to the various device drivers running on the multiple cores and the com mands are executed Thus the CPP has three major components E User input handing editing line input echoing E Parsing and tokenization of the user input E Execution of the requested command messages are passed to the drivers We will cover the CCP in more detail in the following sections SELECTING THE DRIVERS FOR THE VIRTUAL PERIPHERALS The drivers for each of the media devices were selected based on functionality and popu larity There are definitely better drivers for many of the devices for example more robust graphics drivers more advanced sound drivers and so on However this project isn t about using the best but more about system integration Thus it needs drivers that 366 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS are easy to interface to and easy to control with a simple subset of commands In the sections that follow we will cover the exact drivers used but the point is that they were chosen more or less for ease of use and user base COMPLETE DATA FLOW FROM USER TO DRIVER Now that you have seen all the pieces of the puzzle from a hardware and software point of view let s review exactly how these pi
505. r related coding mistakes and building block object 58 62 Start method calls 61 62 start switch 322 322f state of the art computer vision with OpenCV 274 276 finding colored objects 275 finding shapes 276 finding specific objects 275 276 INDEX StereoSpatializer 439 Stop method 36 37 300 stop switch 322 322f subnet array 303 subtractive color space 275 synchronized delays 40 41 synchronous serial 156 synchronous serial communication 172 173f synchronous serial sensors 168 174 169f Parallax 1 Axis Gyro Module 169 174 Synth object 134 synthesizing algorithms for 430 formants vowels 429 430 System Clock Cycle 13 14 27 System Counter 13 14 41 system level modular schematic 362 394f task fidelity 3 TCP See Transmission Control Protocol TCP header 285 285f TCP socket 303 305 308 TCP IP 282 EtherX card and 288 to serial 394 395 394f television HSV in 275 NTSC 324 remotes 144 145 temporary workspace See stack space terminal programs 357 358f test code remove 98 99 Test Float32 spin application object 58 61 Test Gyro with ViewPort spin 173 174 Test IR Detect spin 134 135 135f Test MCP3208_fast spin 159 Test Missing Clock Settings spin 66 Test MXM2125 Simple Object 152 Test Ping Sensor and Object spin 148 Test Sigma DeltaADC spin 162 163 Test Simple RCTIME spin 140 Test Time Counting 2 spin 90 Test Time Counting spin 87 90 Test Timestamp Bug Fix Full S
506. r set parts like VEX to a small sec tion of large diameter transparent acrylic pipe see Fig 6 3 for inspiration The pipe solution looks clean and lets you keep all the electronics inside while still letting people see what you ve done It s also easy to drill mounting holes for the motors For the motors we ll use the Lynxmotion Geared Motor GHM 16 It runs on 12 VDC and has a 30 1 metal gear for an impressive stall torque of 4 6 kg cm At 12 V with no load it turns the axle at 200 RPM This combination of high torque and good speed enables your robots to recover from hard pushes or uneven terrain Lynxmotion also sells rubber wheels for this motor so let s use the 3 6 in diameter Dirt Hawg tires Before we dive into the details of the DanceBot let s look at an overview of how to allo cate the Propeller chip s 32 I O pins to the various sensors and actuators see Table 6 2 Luckily the Propeller s input and output pins are all general purpose We can configure the behavior of each pin through software TABLE 6 1 DANCEBOT PARTS PART DESCRIPTION Parallax Proto Board Prototyping board with Propeller power supply circuitry and crystal GWS PG 03 Gyro Piezoelectric ceramic gyroscope 2 GHM 16 Motors Geared robot motor LIS3LV02DQ Accelerometer Acrylic tube Frame for the DanceBot 2 LMD18200 H bridge motor controller 3 6 in diameter tires Robot tires Motor Encoder QME 01 Quadrature encoder to sense position 12
507. raightforward difference We fuzzify that result with the velocity map and defuzzify the result with the tilt map to get t2 Now we come to the top PID controller where we use t1 t2 and tilt to calculate a target tilt for the inner PID controller For the inner PID controller we can calculate the proportional tilt error tilt the integral tilt error tiltI and use the gyroscope turn signal as the derivative tilt error Finally we can calculate the output to drive the motor by summing the PID components of the inner controller posE postposT posE positive if on right of target f fuzzifyf2 posE FposE A fuzzy posE velT f defuzzify2 FvelT velT positive if need to move right t1 f defuzzify2 FtiltT velE vel velT velE positive if going slower than target f fuzzifyf2 velE FvelE A fuzzy velE t2 f defuzzify2 FtiltT t1 t2 is a pi controller need d which is acceleration use tilt tiltT t1 t2 tilt 6 f share fuzz tiltE tilt tiltT tiltE positive if tilted right of target tiltI tiltE 200 tiltI positive if tilted right for too long tiltI tiltI lt maxTI gt maxTI f fuzzifyA2 tiltE FtiltE A fuzzy tiltE t1 f defuzzify2 Fmotor f fuzzifyA2 turn Fturn A fuzzy turn positive if turning right t2 f defuzzify2 Fmotor motor t1 t2 2 tiltI 1500 ACHIEVING BALANCE WITH VIEWPORT Parallax built a great tool to load programs written in assembly or high level Spin language to the Prope
508. ram using the Propeller s Spin language It s a fully functional program called a Propeller Application Go ahead and try it out V Download your application to the Propeller by pressing the F10 key or by selecting the Run gt Compile Current gt Load RAM menu item o A message like Fig 2 10 will appear briefly indicating the download status After downloading the LED connected to the Propeller s I O pin 16 should turn on If you check the I O pin with a voltmeter you ll measure a little more than 3 volts DC EXPLANATION As you may already realize all this program does is make the Propeller set its I O pin 16 to output a logic high 3 3 V Don t worry we ll do more exciting things in a moment but first take a closer look at how the program works The PUB LED_On statement declares that the block of Spin code under it is a public method named LED_On A method is a container that holds code of a specific purpose and the name of the method indicates that purpose Without testing it you probably could have guessed what our LED_On method does The term public relates to how we can use the method which we II discuss later A Propeller Application usually contains multiple methods and all executable Spin instructions must be grouped inside them to compile and execute properly All instructions below the PUB LED_On declaration are indented slightly to indicate that they are part of the LED_On method like subitems in an
509. re are 100 black white lines on the disk turning the disk by one rotation will produce 100 black white cycles The photo detectors are offset by 90 degrees relative to each other when one sensor is on the middle of a black line the other will be on the transition from white to black see Fig 6 6 for an illustration By looking at the relative phase of the signals coming from the detectors we re able to determine if the wheel is moving forwards or backwards To balance my DanceBot I use just one quadrature encoder to measure the position of one of the wheels this simplifies the control logic To track where the robot has traveled after it has made turns you ll need to use an encoder on each wheel Lynxmotion sells the Motor Encoder QME 01 which registers 100 cycles per revolu tion Since the encoder is mounted to the motor you ll get 100 cycles motor rev 30 motor rev wheel rev 3000 cycles wheel rev On a 3 6 in diameter wheel this means you get 3000 cycles n 3 6 in 265 cycles in This lets us measure both the speed and position of the wheel quite accurately In the real world our wheel will slip and suffer from accumulated error as the robot drives over different surfaces like linoleum and carpets so we can t actually measure our actual position that accurately When the wheels are turning at their top speed of 200 revolutions min the processor will need to count and process 200 RPM min 60 s 3000 cycles revoluti
510. remote unit Y Monitor the remote unit s LEDs they should blink rapidly a few times after several seconds as the XBee is configured Y Monitor the base unit s Terminal window A ready message should be displayed then the readings of the sensors should be reported every half second V Test the compass bearing It should read 0 to 8191 roughly as you rotate it with 0 being approximately magnetic north Z Test the range finder by placing an object in front and moving it in and out The PING sensor will report distances from roughly 30 to 3000 mm 3 cm to 3 m v If either sensor fails to respond properly check your connections and code S Tip The range finder has a fairly large angle of emission and detection Test this by putting an object to the side of range finder and going in and out to determine how wide the angle is at different distances After initializing the XBee and compass there is a three second delay is sent followed by another three second delay and the string of ATDL 0 CN Finally a byte of 13 representing a CR or ENTER key is sent The destination address is set to 0 and command mode is exited CN in exactly the same fashion as you did in the Terminal window 206 WIRELESSLY NETWORKING PROPELLER CHIPS ILs P gt gt PPPppe Base and remote nodes Figure 5 10 SENDING DATA FROM THE PROPELLER TO THE PC 207 100 Q A Be P4 5 5 Red gt T Vss Lt Vss
511. remotely adjust the amount of air delivered to each room This was a key concept in allowing us to experiment with balancing how much air was delivered to a given room Though commercially available air registers used in residential construc tion consist of a series of adjustable louvers we decided that a simple sliding panel would allow us to adjust the size of the entry port to the room while also making it clear to an observer exactly how much of the air vent was occluded We fabricated brackets and used servo motors with linkages to adjust the sliding port cover as shown in Fig 11 4 404 _ THE HVAC GREEN HOUSE MODEL Figure 11 2 12 volt Peltier solid state thermoelectric heat pump Figure 11 3 Clear polycarbonate cooling tower with external and internal blower fans mounted THE HVAC GREEN HOUSE MODEL 405 Figure 11 4 Servo conirolled air register prototype The Air Bypass System One of the last things to be implemented was an air bypass system Fig 11 5 that would allow us to either recirculate the existing air in the house for normal operation or draw air from outside the house pass it through all rooms and then exhaust it out the opposite end of the house for fresh air mode of operation The idea behind this feature was twofold First in the event that the external ambi ent air temperature was sufficient to cool or heat the inside of the house engaging this Figure 11 5 Photo of cooling tower
512. res the address of the Spin asmCt variable the command wrlong count addr copies the contents of the cog s register named count to the object s asmCt Spin variable in Main RAM The command jmp loop causes the next instruction that gets executed to be add count 1 Again remember to use the literal indicator with the jmp command to make the program jump to a particular line of assembly code For more information on assembly language see the Propeller Manual s Assembly Language Reference METHOD IN A NEW COG OUTGROWS STACK SPACE This topic was already discussed in the previous chapter If you add code to a method that was launched into a new cog and you can t see anything wrong with the code that was added check to make sure you allotted enough stack space Survey of Propeller Debugging Tools This section focuses on four commonly used software tools for debugging Propeller applications E TV Terminal E Parallax Serial Terminal E ViewPort E Propeller Assembly Language Debugger Some of these tools are simple text displays for checking variable values and text mes sages at certain points in the program while others are more full featured debuggers In addition to these tools numerous debuggers of varying functionality and cost are avail able Some are objects others are objects combined with software The best place to find the latest Propeller application debugger links along with other software and application
513. reset button or switching power off and on again Did the LED ever light up again No it didn t because we downloaded our applica tion to random access memory RAM only RAM contents are lost when power fails or a reset occurs so when the Propeller started up again our application was missing What if we want our application to start up again the next time the Propeller starts up We need to download to the Propeller s external EEPROM to preserve our applica tion even without power 28 INTRODUCTION TO PROPELLER PROGRAMMING Propeller Communication Programming EEPROM ocedd Figure 2 13 Communication dialog Programming EEPROM Y Download your Propeller Application again but this time by pressing the F11 key or by selecting the Run Compile Current Load EEPROM menu item o Once again a message will appear indicating the download status but this time it lasts longer as it programs the Propeller s external EEPROM chip see Fig 2 13 v After successful download press the reset button or switch power off and on again This time after a short delay your application restarts and the LED blinks again This will continue to happen after every reset or power cycle When you re ready for your Propeller Application to live forever you should download to EEPROM instead of just to RAM WONDERING ABOUT THAT POWER ON RESET DELAY It takes about two seconds for the Propeller to complete its bootup procedure
514. reshing For example say you have a 3 D database that you want an RPC to perform calculations on The database never changes so there is no need to keep sending it over and over once it s in the server s memory space you can save the bandwidth OUR SIMPLIFIED RPC STRATEGY Considering all these interesting methods the method used for our project is human readable ASCII encoded noncompressed RPC calls This way you can connect a serial terminal up to the Propeller chip on two pins and start calling the virtual periph erals running on the Propeller and get them to do work and return results Therefore our RPC calls all look like ASCII strings starting with a command maybe a subcom mand followed by parameters and then a NULL terminator This is the basic unit of information the CCP running on the Propeller interprets as an RPC call Later you might want to make a pure binary version of the protocol that is not human readable and much faster Also you might want a high speed chip to chip version based on SPI serial peripheral interface or IC inter integrated communica tions More on this idea later in the chapter Virtual Peripheral Driver Overview There isn t much to say about the drivers used on the project other than I went to the Parallax Object Exchange Web site located here http obex parallax com objects and hunted around for appropriate objects to use for this project based on my experience
515. rform several tasks simultaneously Then why do we need a new type of eight core processor developed by Parallax a small company in Rocklin California The reasons are many The Propeller chip takes a different approach and offers developers eight processors with identical architectures That means any 32 bit processor or cog can run code that could run on any other cog equally well You can write code for one cog and simply copy it to run exactly the same way on another cog This type of copy and paste operation works well if you have say several identical servos sensors or displays that run on one Propeller chip And unlike many multicore devices a Propeller chip needs no operating system so you don t have to learn Linux Windows CE VxWorks or another operating system to jump in and write useful code Code development tools are free and you don t need add ons that cut into your budget The many projects in this book will help you better understand how to take advantage of the Propeller chip s capabilities The Propeller chip also simplifies operations and coordination of tasks because it offers both shared and mutually exclusive resources The former includes the chip s 32 T O pins and its system counter which gives all cogs simultaneous access to infor mation used to track or time events Any cog can control any I O pin which means you can assign I O pins as needed and easily change assignments late in a project schedule A c
516. rly Let s add another method to the top of our application so it appears as follows PUB Main LED Flash 16 30 5 Flash led LED Flash 19 15 15 Then another LED Flash 23 7 26 And finally a third A MORE POWERFUL BLINK 31 PUB LED_Flash Pin Duration Count Flash led on PIN for Duration a total of Count times Duration is in 1 10 th second units Duration clkfreq 100 Duration Calculate cycle duration dira 16 23 Set pins to output repeat Count 2 Loop Count 2 times outa lPin Toggle I O pin waitent Duration cnt Delay for some time Tip This source is from PCMProp Chapter_02 Source LED_Flash spin Now our application has two methods Main and LED_Flash Logically our Main method is now our application s director giving commands to guide the nature of our application The LED_Flash method is now a support method obeying the Main method s commands Information What makes Main so special It s not its name it s the position it holds Main is special only because it s the first method in our application the one the Propeller activates automatically when the application is started Main calls LED_Flash a number of times each with different values for the param eters What do you think is going to happen Try it out and see Y Download this application to the Propeller As you may have predicted our application blinks pin 16 s LED 5 times slowly then pin 19 s
517. rographs are made using the Spectrum Display software written by the author It is included in the Chapter_12 Tools folder and the sample programs are in the Chapter_12 Source folder SYNTHESIZING FORMANTS AND VOWELS AND MAKING SPEECH SOUND LIKE SPEECH Synthesizing formants was very challenging for me and I spent a lot of time trying to do it The first and most obvious approach was to synthesize individual sine waves for each harmonic of the glottal pulse This was way too much work and computationally impractical I did much later come up with one approach that was really simple but falls into the hack category as it generated discontinuities in the output signal Just generate sine waves at the center frequency of each formant and reset their phases at each glottal pitch interval like magic the sine waves diffuse and the pitch harmonics distribute nicely around the formants centers giving you instant vowel sounds Good enough for a talking watch but not a musical instrument Let s look at some vowel sounds In Fig 12 3 I will make my glottal pitch very low like a frog so that the pitch lines will be highly compressed making it easier to see ta Spectrum Display 12784 Magnified Waveform Af yt Poe aaan A Aana 15147 V 46ms ix Integral Energy 3408 Specific Energy 11025Hz Spectrum vs Time 3229Hz 3500ms Figure 12 3 A spectrograph of me making some vowel sounds 430 SYNTHESI
518. roller 228 Brad s Spin Tool BST on Macintosh 20 breakpoint marker 110 breathing sounds 435 BST See Brad s Spin Tool building block objects 34 35f 55 56 code moved to 99 102 design guidelines 56 57 Propeller programming 37 38 start method and multiprocessor related coding mistakes 58 62 Building Block spin 75 76 built in languages 5 Burrows James 247 bus interface 293 Button Masher game 281 312 317 Butz Albert 400 byte arrays 303 byte limitations 308 bytemove 331 colon equals 24 cable runs 409 410 Cadmium Sulfide CdS 133 capacitive sensors 138 139 153 156 188 in RC decay circuits 138 139 Carrier Detect Multiple Access Collision Avoidance CDMA CA 209 CAT 5 cable 410 412 CCA See Clear Channel Assessment C Cam 2A camera 259 260f CCP See Command Console Program Console Command Program CDMA CD See Carrier Detect Multiple Access Collision Avoidance CdS See Cadmium Sulfide charge transfer infrared 144 chatting 284 chip s packages 7 8f chip to chip interfacing 393 394f circular SPI buffer 290 291f civilian GPS receivers 326 Clear Channel Assessment CCA 209 clear screen CLS command 381 386 client host console development 372 386 command line interface 379 380 initialization 375 376 issuing commands to drivers 380 386 serial communications parsing and tokenization 377 379 clkfreq 27 68 _clkmode 66 clock ticks converting 143 clock
519. rom other objects should be declared as private especially those that threaten the object s integrity if misused Since LED_Flash is our core method we re making it private just as a matter of principle We re making this object automatically handle cog launching memory man agement and LED blinking with one simple interface so there s no need for outside objects to call LED_Flash directly In the VAR block we declared a variable Cog to hold the ID of the cog this object will launch We ll use this to stop that cog later if necessary We also declared a single Stack variable of 32 longs the same size as before We replaced our Main method from the previous example with two new methods Start and Stop The Start method launches a cog to flash our LED The Stop method stops the cog launched by Start if any Information By convention whenever you create an object that launches another cog you should have methods named Start and Stop that manage the cog This provides a standard interface that gives users of your object a clear indication of its intention Our Start method includes the same parameters as our LED_Flash method Other objects will call our Start method to launch another cog to flash an LED with the given parameters Ironically it seems the first thing Start does is call Stop This is because we want each instance of our object to maintain only one cog at a time We don t want users calling our objec
520. ronment Each wheel is driven by its own motor which makes the robots highly maneuverable Since the robots maintain their own balance they can be quite tall while maintaining a small footprint They can turn on a dime navigate precisely and are a pleasure to watch while they keep their balance See Fig 6 1 for a picture of my DanceBot and this link for videos of the DanceBot in action http mydancebot com dancebot videos 235 236 DANCEBOT A BALANCING ROBOT Figure 6 1 DanceBot balancing on two wheels Building a robot that balances and maintains position robustly in any environment is not easy Balancing robots are complex in that they require input from multiple sensors and must react quickly to changing conditions A related problem typically taught in physics classes is the classic inverted pendulum problem Unlike a normal pendulum which hangs downward and is stable the inverted pendulum has its mass above the pivot point and is therefore quite unstable To keep the mass from falling it must be actively balanced by moving the pivot point horizontally as part of a feedback system For our balancing robot we need a high performance microcontroller to process the sensor input and calculations The Propeller s multiple cogs allow you to split your complex project into simple parts that can be built and tested one at a time We re now blessed with wonderful hardware that makes it much easier and cheaper to build a balan
521. rs 283 CON constant variable declarations 24 block 39 Conduit cog 252 Conduit object 277 Console Command Program CCP 357 consonants 435 437 436t context switch 322 ControlPin method 220 cooling tower 403 404f coordinator nodes 208 copy_buffer method 331 CORDIC 432 core grabbing semaphore 317 Correct Loop Interval spin 67 68 Count 29 30 count a cog RAM register 78 counter modules and video generators 14 CRC See cycle redundancy check CRC checksum byte 340 CRC32 checksum 282 crystal circuit 38 39f crystal settings 65f 66 cycle redundancy check CRC 340 damper flapper 400 DanceBot balancing robot 235 255 254f building 238 242 2387 239f 239t 240f 241f challenge of 235 237 236f 237f controlling 255 following line with camera 270 272 271f fuzzy logic control the brains 248 251 249f H bridge schematic 240 240f measuring position 243 245 243f measuring tilt 245 248 245f 248f mechanics 238 242 239f parts 238 238t PropCV and 259 Propeller pinouts 238 239 state of the art computer vision with OpenCV 274 276 system diagram 273 273f track pattern 272 274 273f ViewPort and balance of 251 255 252f ViewPort measurement of tilt system 254 254f DARPA See Defense Advanced Research Projects Agency DARPA Grand Challenge 2005 274 DAT data and assembly code 24 block in Spin programs 78 data framing API mode and 214 217 215f 217f data logger 3
522. rs are all registered to the musical scale with 48 steps per octave making every fourth value a chromatic tone Note that the ASPIRATION and GLOTTAL sounds are summed before feeding into the formant resonators F1 F4 that make vowel sounds The NASAL section is an anti resonator used for M N and NG sounds Lastly the FRICATION section is for white noise sounds like T TH SH S and F that occur at the tongue teeth and lips or after the resonators Vocal Iract vl 1 by Chip Gracey C 2006 Parallax Inc 28 October 2006 Ihis object synthesizes a human vocal tract in real time Lt requires one cog and at least 80 MHz The vocal tract is controlled via 13 singlo byute parameters which must reside in the parent object VAR byte aa ga gp vp vr fl 7 3 f4 na nf fa FF vocal tract parameters AA ASPLRAI LON GLOTTAL t OUTPUT FRLCATLON VIBRATO parameter description unit notes aa aspiration amplitude 255 breath volume silent loud linear ga glottal amplitude 255 voice volume silent loud lincar ap glottal pitch 1 48 octave voice pitch 100 110 00Hz musical note A2 vibrato pitch 1 48 octave voice vibrato pitch 48 gt 1 2 octave suing vibrato rato 0 0763 Hz voice vibrato rate 52 4 Hz formanti frequency 19 53 Hz ist resonator frequency 40 781 Hz formant frequency 19 53 Hz 2nd resonator frequency 56 gt 1094 Hz formant3 frequency 19 53 Hz 3rd resonator frequency 128 2500 Hz formant
523. rsonal devices The ability of these devices to communicate on their respective networks even your Bluetooth headset forms a network with the player relies on key features E The use of addressing to send data to specific destination devices and to identify the source of the data E The use of framing and packets to encompass the data itself in a package with necessary information such as the destination address E The use of error checking to ensure the data arrives at the destination without errors E The use of acknowledgements back to the source so that the sender knows the data arrived correctly at its destination Simple two device or two node systems may not need all these features It s really dependent on the needs of the network but if ensuring data arrives correctly to an intended destination is vital then these features are a must The XBee uses a fully implemented protocol and communicates on a low rate wireless personal area network LR WPAN sometimes referred to as a wireless sensor network WSN with RF data rates of 250 kbps between nodes For the seasoned network readers LR PANs operate using IEEE 802 15 4 a standardized protocol similar to Wi Fi IEEE 802 11 and Bluetooth IEEE 802 15 1 The XBee is currently available in the XBee 802 15 4 series and the XBee ZigBee Mesh series The 802 15 4 series often referred to as Series 1 is the simplest and allows point to point communications on a network The ZigBee
524. s in Propeller Tool Help or the Propeller Manual The repeat instruction is a flexible looping mechanism that we ll learn more about as we experiment As written in this example repeat makes the Propeller do nothing endlessly What s the point of that Without repeat our program would simply end leaving nothing for the Propeller to do it would terminate and reset the I O pin to an input direction In other words the LED would light up for a small fraction of a second and then turn off forever giving the appearance that our application did absolutely nothing Most applications have an endless amount of work to do in one or more loops For simple tests like this one however we need to include a do nothing repeat loop in order to see the intended result Challenge Try changing the application s numbers and downloading it again to see the effects What happens when you change both occurrences of 16 to 17 How about setting outa to 0 instead of 1 A Blinking LED Admittedly our first example is an expensive alternative to a simple wire and light but now you know a way to control the Propeller s I O pins Here s a more exciting example using the techniques we learned plus a little more v Create a new application with the following code Tip Press Ctrl N to start with a fresh edit pane PUB LED_Blink dira 16 1 Set I 0 pin 16 to output direction repeat Loop endlessly outa 16 1 Set I 0
525. s is in the Propeller Chip forum s Getting Started and Key Thread Index at http forums parallax com SURVEY OF PROPELLER DEBUGGING TOOLS 79 TV TERMINAL The Propeller Demo Board in Fig 3 11 was the first Parallax board available with a built in Propeller chip and it highlighted the Propeller chip s multiprocessing capabilities with microphone PS 2 mouse and PS 2 keyboard inputs along with stereo headphone VGA and RCA video outputs The two PS 2 connectors are shown in the upper right of Fig 3 11 and the microphone is in the middle to the right of the P3 and P4 labels Along the bottom the stereo headphone RCA and VGA connectors are shown from left to right The Propeller Tool software that accompanied this board included example objects to demonstrate all these features and early Propeller designers made use of the RCA video output to debug their code with a TV using the TV_Terminal object More recent Propeller boards and kits also have built in audio video connectors kits and boards that do not have them typically offer inexpensive adapter options so that just about any Parallax Propeller kit can run demonstration objects that utilize the TV_Terminal object A number of Propeller Object Exchange Obex objects utilize the TV_Terminal object and hardware to demonstrate the object s functionality To evaluate these objects either the Propeller chip can be connected to a TV or the demonstration object can be ported to use th
526. s launched a process either a method or some assembly code into another cog can provide an information bridge between the two cogs This figure shows a call to one of its methods after the object has launched a cog as a result of a call the application object made to the building block object s Start method To exchange information Application Object Building Block Object Call Start a OTN a Start Launch into Method lt Method Other Cog Return Value Global Variables Parameter s x 7 N Method gt Public Method Call lt Method or ASM Return Value Public Method Cog Main RAM Other Cog Figure 3 4 Cog information exchanges with object method calls OBJECT DESIGN GUIDELINES 57 with the other cog the application object calls one of the building block object s public methods Code in those public methods is executed by the same cog that is executing the application object s method call Those public methods can exchange informa tion with the method s or assembly language ASM code executed by the other cog through the building block object s global variables Propeller Library examples of objects that use this approach include the Parallax Serial Terminal Keyboard and Mouse objects Another common design for building block objects that manage processes in other cogs involves a Start method with one or more parameters that receive one or more memory addresses
527. s are controlled by servomotors they may be commanded to hold the doors in any position from 100 percent open to 0 percent open So it would be possible to set a mixture amount if you want to assure a certain amount of fresh air is moved through the building on a scheduled or regular basis to reduce odors and to remove stale air from the building Error detection and alerts If a room fails to reach the desired temperature in a reasonable amount of time the master board could show an alert or trouble condi tion Another possible error detection function could be if the room board has not been polled by the master board in a specific period When this timeout has been reached the board could show a trouble message on the LCD to alert the room occupant that the board needs diagnostics and repair Alert required preventive maintenance The master board is able to track the run time for the blower fans so it would be possible to alert the user when filter replace ment intake cover cleaning and other maintenance may be required Go wireless As was shown earlier in this book it is possible to forgo the use of CAT 5 cables for communication altogether If the room boards master board and control board were all equipped with ZigBee modules and powered by a small wall wart type power supply it may be possible depending on the distances involved to retrofit an existing home HVAC system without the additional cos
528. s are then calculated for each room based on its need according to its temperature reading Again the Spin code to accomplish this is straightforward THE HVAC GREEN HOUSE MODEL 421 Calculate Vent positions totalvent 0 repeat count from to 4 temp LONGLRoomTargetTemp1 X count 4 J lt LONGLRoomCurrentTemp10X count 4 if temp gt 10 temp 10 temp temp 10 LONG RoomCurrentVentPosPercent count 4 temp totalvent totalvent temp Next using the calculated average internal air temperature compared to the external air temperature allows us to automatically determine if the Peltier solid state heat pump should be operating in a cooling or heating mode so ut HEATING TTT if OverallAverageDesiredTemp10X gt OverallAverageTemp10X Heating if OverallAverageDesiredlemp10X lt outsideTemp Fresh LONG BlowerFanPower POWER_ON LONG PeltierPower POWER_OFF LONG PeltierDirection PELTIER_HOT_INSIDE LONG AirSupply FRESH_AIR if OverallAverageDesiredlemp10X gt outsideTemp Recirc LONG BlowerFanPower POWER_ON LONG PeltierPower POWER ON LONG PeltierDirection PELTIER_HOT_INSIDE LONG AirSupply RECIRCULATE ee a COOLING 77 if OverallAverageDesiredTemp10X lt OverallAverageTemp10X Cooling if OverallAverageDesiredlemp10X gt outsideTemp Fresh LONG BlowerFanPower POWER_ON LONG PeltierPower POWER_OFF LONG PeltierDirection PELTIER
529. s equation Yaw rate adcVal 512 300 degrees second 512 4 4 Figure 4 40 shows the synchronous serial communication timing diagram for the Gyro Module s ADC101S021 A D converter This timing diagram is an excerpt from the ADC101S021 datasheet The steps for this communication are 1 Initialize the nCS and SCLK high 2 Set the I O pin connected to the nCS pin low 3 Apply 16 clock pulses and record the SDATA after each rising edge 4 Set nCS high FIGURE 1 Timing Test Circuit SDATA 3 leading zero bits 10 data bits 2 trailing zeroes 20145306 FIGURE 2 ADC101S021 Serial Timing Diagram Figure 4 40 ADC101S021 timing diagram Reprinted with permission of National Semiconductor Corporation 172 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES In Test Gyro spin a call to Init followed by a call to the Measure method implements the timing in the diagram The call to Init covers step 1 making nCS and SCLK output high Measure takes care of the rest of the steps It sets the nCS pin low and then takes the SCLK pin low then high After each transition from low to high the command adeVal adcVal lt lt 1 ina SDATA does two things First it shifts whatever is in the adcVal variable left by one leaving a 0 in the rightmost binary digit Then it copies the value 1 or 0 that the ADC101 s SDATA pin is sending to the Propeller chip s I O pin SDATA 17 in this case to the empty rightmost bit
530. s from 100 to 111 or decimal 4 to 7 which includes 100 101 110 and 111 If any of those conditions is true the TopButton method gets called Upon return a waitcnt command executes and then the loop repeats The case statement does not continue down through the other conditions after the first true condition is detected the code executes commands in the case block and then exits the case statement Also case statement conditions do not necessarily have to contain single method calls The other condition in the case state ment has a code block with two method calls though it could also contain expressions commands and so on v Test P18 to P16 Input Decisions spin with the Parallax Serial Terminal P18 to P16 Input Decisions spin CON _clkmode _xinfreq xtali pll16x Crystal and PLL settings 5 000 000 5 MHz crystal x 16 80 MHz ON OFF SENSORS 129 OBJ pst Parallax Serial Terminal Serial communication object PUB Go states pst Start 115200 Start Parallax Serial Terminal repeat states ina 18 16 pst Str String pst HM ina 18 16 pst Bin states 3 Display 3 binary digits case states Evaluate case by case 4100 111 TopButton Method calls for buttons 010 011 MiddleButton 001 BottomButton other Otherwise clear line pst Newline pst ClearEnd waitent clkfreq 20 cnt Wait 1 20 second PUB TopButton pst Str String pst NL Emergen
531. s had a lifelong relationship with electronics computers and entertainment encompassing multiple fields including animatronics performance art computer control network systems design and software integration As president of The Robot Group Inc Vern s work has been featured at Maker Faire First Night Austin SxSW Linucon Dorkbot Armadillocon and even in SPIN magazine In 2007 he was awarded The Robot Group s DaVinci Award for his contri butions to the arts and technology community Though some of his writings have been featured in SERVO magazine he is currently best known for his regular contributions to Nuts and Volts magazine as the author of the monthly xi xii ABOUT THE AUTHORS column Personal Robotics He currently is employed as a senior software engineer in Austin Texas e Martin Hebel holds a master of science in education MS and bachelor of science in electronics technologies BS obtained from Southern Illinois University Carbondale SIUC following 12 years of service as a nuclear technician on submarines He is an associate professor in Information Systems and Applied Technologies at SIUC instructing in the Electronic Systems Technologies program where he teaches microcontroller programming industrial process control and networking His research in wireless sensor networks using controllers including the Propeller chip has led to agricultural research with SIUC s agricultural sciences
532. s of the physical address like a MAC address and the RSSI level in hexadecimal Use the command ATED Energy Detect You should see a list of about 11 hexadecimal values This is the energy level seen on the various channels Higher values are less noisy a value such as 5A hexadecimal for example converts to a level of 90 dBm V Use the Configuration tab to restore the XBee to its default values when done testing or use the AT command ATRE followed by ATWR to save to memory UPDATING THE XBee VERSIONS Just a note about the version of the XBees In the Modem Configuration tab you can see the version of firmware on your XBee such as 1083 10A5 or 10CD Later versions are more capable The majority of this chapter requires at least 1083 The firmware on the XBee can be updated by selecting a new version checking Always update firmware and clicking Write but this requires more data lines than we have available with our configurations A board such as the XBIB U from Digi International or the WRL 08687 the XBee Explorer from www sparkfun com which can also double as a carrier board is recommended These boards can be used for direct USB access to the XBee as well as changing the firmware and they supply power to the XBee Now that we can send and receive data and configure the XBee we are ready to start using Spin and the Propeller to communicate via the XBee Sending Data from the Propeller to the PC In t
533. s port for both programming and serial communications and you can simply connect the extra serial port on another pair of free Propeller pins The problem is that both the Propeller Tool and serial terminal programs like to hold the serial line The Propeller Tool seems to release it after programming but early versions didn t However most serial terminal programs must be closed before releasing the serial line even though they are not connected 356 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS b Power c Keyboard e NTSC Video f Audio g USB serial Figure 10 2 Making the hardware connections OVERVIEW SETUP AND DEMO 357 SOFTWARE SETUP AND INSTALLATION If you haven t installed the Propeller Tool do that now You can download the latest version of the Propeller Tool from the Downloads link at this Parallax site www parallax com Propeller Assuming you have the Propeller Tool installed and set up refer to Chapter 2 for detailed instructions confirm you have communications with the Propeller Demo Board with the Propeller Tool s Run gt Identify Hardware command and you can compile and download code to the board Once you have that set up the only remaining piece of the puzzle is to load a serial terminal program the Parallax Serial Terminal doesn t support VT100 emulation so we need something a little more complete since this is what is used to communicate with the
534. s system integrity by ensuring that mutually exclusive resources are accessed by only one cog at a time Mutually exclusive resources include things like Main RAM ROM and configuration registers The Hub gives each cog access to such resources once every 16 clock cycles in a round robin fashion from Cog 0 through Cog 7 and back to Cog 0 again If a cog tries to access a mutually exclusive resource out of order it will simply wait until its next hub access window arrives Since most processing occurs internally in each of the cogs this potential for delay is not too frequent Information The Hub is our friend It prevents shared memory from being clobbered by multiple cogs attempting simultaneous access which would lead to catastrophic failure In Chap 3 you will see examples of how the Propeller s programming languages allow the developer to coordinate read write timing among multiple cogs Search for Hub in the Propeller Manual or Propeller Tool Help www parallax com to find out more about the Hub Memory There are three distinct blocks of memory inside the Propeller chip E Main RAM 32 K bytes 8 K longs E Main ROM 32 K bytes 8 K longs E Cog RAM 512 longs x 8 cogs Both Main RAM and Main ROM are shared mutually exclusively by all cogs each able to access any part of those two blocks in turn Main RAM is where the Propeller Application resides code and data Main ROM contains support data and functions see Fig 1 10
535. s until multicore processors appeared When using a multicore processor such as the Parallax Propeller we can dedicate one core or cog in Parallax terms to each individual sensor This alleviates the burden of a single processor from being interrupted to handle different data rates It also makes it easier to communicate to sensors that use nonstandard communication protocols because the entire cog can dedicate 100 of its time to reading in the data This is especially beneficial for slow devices such as PS2 protocol keyboards and mice Finally debugging the communication is easier since the program operation will not randomly jump to an interrupt routine and instead will execute sequentially within each cog Overview of the Sensors As discussed in the introduction we will be connecting a GPS receiver module and a barometric pressure sensor which also contains a built in temperature sensor to the Propeller Data will be read in and displayed on a TV screen and it will also be stored to a SD card for post processing Figure 9 3 shows the overall hardware connections and Table 9 1 shows the descriptive pin connections Barometric Sensor Q Data In Out Sclk ee Master Clock Switches Start Stop Figure 9 3 Hardware connections overview OVERVIEW OF THE SENSORS 323 TABLE 9 1 PROPELLER PIN CONNECTIONS PROPELLER PIN PERIPHERAL SIGNAL NAME DESCRIPTION P1 GPS TX Receive pin from the GPS transmit P2 SD nCS SD c
536. sages displayed by the Parallax Serial Terminal Without the more precise timing provided by the external oscillator the Propeller can end up communicating at a baud rate that s slightly different from the one specified in the code Figure 3 8 shows the results with the correct system clock settings above and without them below The incorrect clock settings bug is easy to create observe and fix Try this vZ Make a copy of the Parallax Serial Terminal QuickStart object in the Propeller Library Examples folder and rename it Test Missing Clock Settings spin V Open Test Missing Clock Settings spin with the Propeller Tool and change its pst Start 115200 method call to pst Start 9600 COMMON MULTIPROCESSOR CODING MISTAKES 65 gt Parallax Serial Terminal COM15 Convert Decimal to Hexadecimal Enter decimal value Com Port Baud Rate 1x T DTR F ATS com15 3600 PX DSR CTS NV Echo On Prefs Clear Pause Disable gt Parallax Serial Terminal COM15 Bao 41 8800 8 6 4a4 j4 T4ida Baa ao V Echo On Com Port Baud Rate TX DTA ATS COM15 x 3600 Rx DSR CTS Prefs Clear Pause Disable Figure 3 8 Serial communication with and without the external crystal settings This will change the baud rate the Parallax Serial Terminal uses from 115200 bps to 9600 bps Z Change the Parallax Serial Terminal s Baud Rate drop down menu to 9
537. sed of the possibility of such damages This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract tort or otherwise For Ellie my lovely wife S A To my wife Kym my children Nic and Sami and my Mom and Dad for all the support V L G For BJ and Kris thanks for being so supportive M H For my wife Crystal and son Hunter J M H To inventors everywhere For Stacy Kaitlin and Kaylani who were wonderfully supportive despite being deprived of my attention J M For Mami and Papi thanks for everything H S This page intentionally left blank CONTENTS About the Authors Foreword Introduction Chapter 1 The Propeller Chip Multicore Microcontroller Introduction 1 Multicore Defined 2 Why Multicore 3 Multicore Propeller Microcontroller 3 Summary 14 Exercises 14 Chapter 2 Introduction to Propeller Programming Introduction 15 What s the Secret 16 Ready to Dive In 17 Let s Get Connected 17 Your First Propeller Application 22 A Blinking LED 25 RAM versus EEPROM 27 A More Powerful Blink 28 All Together Now 32 Wrapping It Up 34 Timing Is Everything 38 Sizing the Stack 41 Propeller Objects and Resources 45 Summary 48 Exercises 49 Chapter 3 Debugging Code for Multiple Cores Propeller Features That Simplify Debugging 52 Object Design Guidelines 56 Common Multiprocessor Coding Mistakes 58 Survey of Propeller Debugging Tools 78
538. sed this way is a set assignment operator it sets the bit s of the variable to which it is attached to high 1 It s shorthand and without it we d have to say dira 16 23 11111111 Note We re setting all eight of these pins to outputs only because the Propeller Demo Board shares them with the VGA circuit which causes certain LED pairs to light simultaneously when only one is actually activated This would not happen if they were wired as in Fig 2 9 Did you notice that our repeat loop has changed It now says repeat Count 2 Previously repeat was always an infinite loop but now it is a finite loop that executes only Count 2 times The contents of our loop changed as well In the outa Pin statement the is a bitwise NOT assignment operator it toggles the bit s of the variable to which it is attached It makes the I O pin s output state toggle to the opposite state high if it was low low if it was high It s shorthand for outa Pin NOT outa Pin Tip You can learn more about these and many other operators by searching for Spin Operators in Propeller Tool Help or the Propeller Manual So now our LED_Flash method takes three parameters Pin Duration and Count calculates the actual duration in clock cycles in 100ths of a second units sets the pin directions and loops Count 2 times toggling Pin each time for the calculated duration But it really won t do anything for us if we don t call it prope
539. see from those pitch lines how shrill her voice is Looking at the spectrograph you can see the initial m followed by the open mouth o and then the n After those nasal vowel nasal sounds you can see the tall noise burst of the s followed by silence then the brief t burst going into the r The m and n sounds are enhanced by using the nasal anti resonator It sucks up in band energy rather than accumulating it like the formant resonators do This creates a limited spectrum vacuum which can make things sound nasally By studying the spectrograph and incrementally building the word I made a new PRI talk method to say monster see Example4 spin PRI talk setformants 170 1100 2600 3200 nf 2900 100 1953 na 255 v go 1 aa 10 ga 30 v go 150 setformants 700 900 2800 4500 na 0 v go 50 v go 150 setformants 200 1550 2500 4500 nf 1550 100 1953 na 255 v go 100 v go 100 aa 0 ga 0 v go 100 na 0 ff 120 v go 1 fa 10 v go 150 fa 0 v go 75 Set formants for M Set nasal for M Ramp up M Set formants for 0 Nasal off Transition to 0 Sustain Set formants for N Set nasal for N Transition to N Sustain Ramp down N Nasal off Set frication for S Ramp up S Ramp down S EXPLORING THE VOCALTRACT OBJECT 439 fa 10 v go 20 setformants 580
540. separated by commas the ParseDEC method is used to pull out and display the range and bearing The signal strength RSSI is accessed and displayed PC str string 13 Ping Distance lt Range XB ParseDEC XB RxData 1 PC DEC Range PC str string 13 Compass bearing theta XB ParseDEC XB RxData 2 PC DEC theta PC str string 13 RF Signal strength PC DEC XB rxRSSI Display RSSI level The ControlPin method is used to send data back to the end device It is passed the address to send the packet to the source address of the incoming packet the IO pin number and the state 0 or 1 In order to packetize the data a new packet is constructed and then passed to be transmitted Pub ControlPin destAddr pin state XB API_NewPacket Clean out packet of old data XB API_AddStr string i Add an i to packet XB API_AddBute pin Add a byte of pin number XB API_AddByte state Add a byte of pin state Send the packet XB API_txPacket destAddr XB API_Packet 3 In ControlPin the packet string in which the data will be sent is cleared out API_NewPacket All bytes in the packet are set to 0 when cleared The string and byte values of i pin number and state are added to the packet API_AddStr or AddByte API_txPacket is used to send the data to the correct address the pointer for the packet is given and the number of bytes to be sent is provided A THREE NODE TILT C
541. servo controlled bypass doors 406 THE HVAC GREEN HOUSE MODEL bypass and activating only the blower fan would allow the house temperature to be brought to a comfortable level without expending energy operating the heat pump This part was a key piece of making our HVAC system more green Second in the event that the air inside the house was found to be unhealthy or danger ous i e a natural gas leak or a buildup of carbon monoxide the system could react by sounding an alarm moving the bypass doors into fresh air position moving every room air register to 100 percent open and activating the blower fan thereby purging unhealthy air from the entire house To implement this bypass system two servo controlled doors were added to the cooling tower that when open allow air to recirculate normally through the system see Fig 11 6 When closed they block the return air plenum path to the fan while opening side vents in the cooling tower These side vents allow external air to be drawn in to the fan from outside the cooling tower a source outside the house pushed through all the rooms in the house and then exhausted via a vent flap at the opposite end of the house as shown in Fig 11 7 If you look closely at the CAD drawings of the house you may notice that when the bypass doors are placed in the fresh air mode i e the return air duct pathway is blocked the air delivered to each of the rooms has no pl
542. ses subroutines calling processes DLL Library Figure 10 9 RPC call from process to process in contrast to a DLL call 368 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS So we might do something like this to pack the parameters up into a contiguous memory space This is used as transport buffer for RPC calls CHAR RPC_input_buff 256 Now pack the parms into the array one at a time memcpy RPC_input_buff 4 ux sizeof float memcpy RPC_input_buff 4 uy sizeof float memcpy RPC_input_buff 4 uz sizeof float memcpy RPC_input_buff 4 vx sizeof float memcpy RPC_input_buff 4 vy sizeof float memcpy RPC_input_buff 4 vz sizeof float Finally a call would be made to the RPC interface RPC_Interface DotProduct RPC_input_buff RPC_output_buff Now that the parameters are packed into a single data structure we simply call the RPC interface and pass the starting address of the structure The RPC interface in this case takes a string as the function name and then two pointers one to the input param eters and one to where the output results are stored There is obviously an agreement and a set of conventions between the caller and receiver on this function and how it works so the client can make RPC calls and the server can respond to them In this case the server or other process reads the first string determines the
543. signal carries the navigation message a course acquisition C A code and an encrypted precision P code L2 contains another P code transmission Civilian GPS receivers can only decode the course acquisition code and without further augmentation can only achieve a positional accuracy of around 3 m under low atmospheric error conditions The P code can achieve ten times better accuracy or 30 cm without additional help Since the military controls the GPS satel lites they could potentially disable the C A code in times of war or other extenuating circumstances leaving only P code receivers that contain the correct decryption keys capable of operating A civilian GPS receiver geolocates itself by receiving the L1 signal through its antenna and then it demodulates and decodes the data stream Upon receiving a mes sage it records the current time and compares it to the original time that the signal was sent encoded in the message If T s is the time the message was sent and T r is the time the message was received we can use the following to calculate the distance the GPS receiver is from the satellite Distance T r T s c where c speed of light We can think of the position of the GPS receiver as a point on a sphere with the center of the sphere being the position of the satellite and the radius of the sphere equaling the distance calculated from the previous equation If the GPS receiver is currently receiving transmission fr
544. signal to indicate that it is receiving a 38 kHz infrared signal or a high signal to indicate that it is not receiving the signal To test this program and circuit v Build the IR LED Detector circuit shown in Fig 4 11 V Load Test IR Detect spin into the Propeller chip vV Enable the Parallax Serial Terminal V Verify that the Parallax Serial Terminal displays IR Detector 1 when an object is not detected Fig 4 12 and IR Detector 0 when an object is detected Com Fort Baud Rate I DIF COMe 115200 Figure 4 12 Object not detected 136 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES SENSORS WITH OUTPUTS GREATER THAN 3 3 V Sensors that transmit voltages outside the 0 to 3 3 V range should never be connected directly to a Propeller I O pin Lots of circuits are available for making a sensor s higher voltage level output compatible with the Propeller chip s 3 3 V input Some examples of circuits to protect a Propeller I O pin from higher voltage signal levels include series resistor circuits transistor circuits level translator integrated circuits ICs optoisola tors and solid state relays Series resistors are the quickest and easiest solution especially for prototyping Fig 4 13 shows an example of a 3 9 kQ resistor in series between a 5 V sensor output and a 3 3 V Propeller I O pin This circuit provides adequate protection and a 10 kQ resistor would also be fine for most applications Note that
545. simple vision processing in a single cog with its own memory however we need more power to perform more sophisticated computer vision So let s use our knowledge to tackle the state of the art vision system that s included in ViewPort the OpenCV plug in OpenCV is a library of computer vision functions that was originally developed by Intel in 1999 It s now available to everyone as an open source project on sourceforge net and has corporate support from Willows Garage It s been used successfully in video surveillance systems video games and robotics Stanley an autonomous car created by Stanford University used OpenCV to find its way through 132 mi of California desert to win the 2005 DARPA Grand Challenge The goal of the OpenCV project is to advance vision research by providing open and optimized code for vision infrastructure Rather than reinventing the wheel researchers can reuse and complement vision algorithms contained in OpenCV Developers can add features to OpenCV and even develop commercial applications The library is written in the C language and includes more than 500 functions that cover the entire space of computer vision Besides image manipulation functions the library can be used to find objects like human faces understand gestures construct 3 D models from stereo cameras track motion and even do statistical based machine learning The functions are performance optimized to take advantage of advanced multimedia
546. sistant B PLL I O Assistant A PLL ai a lt E 5 4 3 3 lt g 1 0 Assistant A PLL 1 0 Assistant B PLL 1 O Assistant A PLL 1 0 Assistant B PLL 512 X 32 RAM y 512 X 32 RAM 512 X 32 RAM Processor i Power Up Detector VSS 10 ms F333 Brown Out Detector PARALAX SOFTRES P8X32A Q44 PLLENA Crystal Oscillator Cog 3 T O Output Register 5 A o 2 5 o o Ei z gt I O Direction Register I O Assistant B PLL 512 X 32 RAM Reset Delay 50 ms RC Oscillator 12 MHz 20 KHz Clock PLL 1x 2x 4x 8x 16x 16x must be 64 128 MHz Cog 4 1 0 Output Register 5 S E o o o 3 gt I O Direction Register I O Assistant A PLL 1 O Assistant B PLL I O Assistant A PLL 512 X 32 RAM RESET CLKSEL 3 3 Clock CLOCK Selector MUX SOFTRES PLLENA OSCENA DC 80 MHz 4 8 MHz with Clock PLL OSCENA OSCMODE Figure 1 9 Propeller block diagram OSCMODE CLKSEL I O Assistant B PLL Cog 5 Cog 6 Cog7 Pin Directions Pin Outputs 512 X 32 RAM 512 X 32 RAM 512 X 32 RAM a 32482 D L L C jis SIEG sis P27 el Ola KH Sila ajella HIA FET S 21 3 aa S23 Ca pall ajes e aesae sji ejje a ea ed ea aele CP25 A Peal Fe SHE all sls SET SSS ez vo alls zioz dia E E k AE SISI sll Sie BIBI De Pins Silos alal al ea
547. so kHz Optoisolators also come in IC packages and they provide the I O pin with a high degree of protection because the high and low signals are transmitted optically instead of electrically With an optoisolator the sensor s output gets connected to an infrared LED that s inside a small enclosure If the sensor sends a high signal the infrared LED emits light The infrared LED is right next to an infrared transistor in the enclosure with a pull up resistor that is connected to the lower voltage system s supply So the transistor s output will pass either 3 3 or O V to the Propeller I O pin depending on whether the sensor s output turned the LED on or off Since an optoisolator circuit uses light to carry the signal the two systems can be kept electrically separate not even requiring a common ground Solid state relays SSRs are designed to either pass a signal from a higher voltage system to a lower voltage system or take a signal from a lower voltage system to control a higher voltage system One of the low voltage options is 3 3 V some of the more common higher voltage options include 12 or 24 VDC 110 or 220 VAC Resistive Capacitive Diode Transistor and Other This category features lots of different analog sensors that can all be measured with the same technique commonly referred to as RC decay or RC time measurement The list of different sensors that can be measured with this technique is extensive For example 138
548. sors we sketched one of the first designs using a single Propeller to operate the entire system This would require a star wiring design where each room would have a separate line running all the way back to a central wiring closet When planning an installation of technology such as this in a new home or retrofit ting an existing home for something similar wiring requirements are a substantial issue and the downside to a star design is the cost There is both the cost of the wire itself and of the associated labor to run all the lines Though the star wiring scheme was inherently expensive it wasn t a deal killer in and of itself However the second strike against this design had to do with the length of the cable runs from each room back to the wiring closet Typically the distance between a Propeller chip and devices such as the 5 V transistor transistor logic TTL level serial LCD unit or pulse width modulation PWM controlled servo motors would be on the order of a few inches to maybe a couple of feet At real world distances of 50 ft or 410 THE HVAC GREEN HOUSE MODEL more there was a very good chance these devices would become unstable or completely fail to operate due to voltage loss over distance and or wire capacitance rounding the edges of the square wave signals The final nail in the coffin for this design was that a single Propeller chip simply did not have sufficient pins to support many rooms
549. speed classes 250 DANCEBOT A BALANCING ROBOT cluttering our code with a slew of if statements ViewPort comes with a fuzzy logic object called fuzzy spin which implements a complete fuzzy logic engine and a control panel which graphically displays the transfer functions and rule maps Now that we ve understood enough about fuzzy logic for our application we need to understand one more concept to build our balancing bot controller the cascading PID loop Basic PID proportional integral derivative controllers attempt to correct the error between a measured variable and a desired setpoint by calculating and then outputting a corrective action that adjusts the process to minimize the error The PID controller has three parts that are summed to yield the output The proportional part makes changes proportional to the error The integral part eliminates the residual steady state error in the system but might lead to overshoots And finally the derivative part reduces the magnitude of overshoot and improves stability but is sensitive to noise in the input signal In a cascading PID control two PIDs are arranged with one PID controlling the set point of another In our case the outer loop controller will control the speed of the bot while the inner loop controller which reads the output of the outer loop controller as a setpoint controls the speed of the motors driving the wheels This type of control logic will let o
550. stop bit View Serial Character with ViewPort spin uses the Parallax Serial Terminal object to repeatedly send an A character out P24 with the 4800 bps 8N1 serial communication settings The example program also uses ViewPort s QuickSample object to monitor the T O pin activity from another cog The repeat loop in the example program uses P24 to transmit an A character approximately once every 1 200th of a second P23 sends alternating high low signals with each successive A character which makes it con venient to set the ViewPort Logic State Analyzer s trigger to make the serial messages stay still in the display The reason the application transmits serial messages with P24 instead of with the Parallax Serial Terminal object s default P30 I O pin is because the Conduit object needs P30 to stream I O pin data to the ViewPort software running on the PC P30 is connected to the Propeller programming tool s USB to serial converter along with P31 for programming and bidirectional serial communication with the PC These two pins are also used for communication with the debugging software packages introduced in the previous chapter View Serial Character with ViewPort spin CON _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz VAR long frame 400 Stores measurements of INA port OBJ vp Conduit Transfers data to from PC qs QuickSample Samples INA co
551. t Next we need to copy the data from the Excel spreadsheet to the CSV file When creating the CSV file you will most likely start off with a separate spreadsheet and when you are finished save the output as a comma separated values file When you have finished your file should look similar to the following snippet of data Type Latitude Longitude T 30 35233833 97 90491333 T 30 35233833 97 90491333 T 30 35233833 97 90491333 T 30 35233833 97 90491333 V Save your Excel spreadsheet as a CSV file It is now time to load the data into the Web site for display On the home page there is an edit box for a file upload see Fig 9 13 Get started now Browse Choose an output format Google Maps Upload a GPS file Figure 9 13 File upload box 350 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER v Click the Browse button or click in the edit box and a file browser window will open Z Navigate and select your CSV file In the Web site under Choose an output format select Google Maps Y Now click the Go button and after a few seconds the Web site will update with a GPS track overlaid onto an aerial photograph The aerial photograph is an interactive control that allows you to zoom in and out and pan around the GPS track In the upper right corner of the map you can select between different map types You can even save the map and share it with others using another Web site called www Every
552. t s Start method multiple times and running out of cogs The next line Cog cognew LED Flash Pin Duration Count Stack 1 is a combined expression and cognew instruction If you look carefully you ll see that the cognew instruction launches our LED_Flash method with the parameters originally given to Start and assigns it some workspace Stack But why do we set the Cog variable equal to cognew 1 As it turns out cognew returns a value equal to the ID 0 to 7 of the cog it actually started or 1 if none were started We ll use this to keep track of the cog we launched so we can stop it later if desired We add 1 to the ID to make the code in Stop more convenient as you ll see in a moment WRAPPING IT UP_ 37 In Stop we check if a cog was started by us and if so we stop it The if is a deci sion command If its condition Cog in this case is true it executes the block of code within it the indented cogstop command The condition if statements evaluate can range from simple to elaborate expressions but the result is always the same it s either true or false In this case our decision is simple it means If the value in the Cog variable is not zero execute a cogstop statement Remember that Cog was set to cognew 1 giving us a value of 0 if no cog was started or a value of 1 through 8 if a cog was started Our cogstop Cog 1 command if executed stops the cog whose ID is the value
553. t Xout_pin Yout_pin text str string Separate cog example QD repeat 20 text dec accel x Retrieve X axis value text out text dec accel y Retrieve Y axis value text out QD waitent clkfreq gt gt 1 cnt accel stop Stop the accelerometer driver cog Now show in same cog example accel init Xout_pin Yout_pin text str string Same cog example QD repeat 20 Get X and Y values by passing pointers to variables accel Get_XY XVal YVal text dec XVal text out text dec YVal text out QD waitent clkfreq gt gt 1 cnt text str string Demo complete Let s try developing some simple test code with the Parallax Serial Terminal that relies on the portion of MXD2125 Simple Demo spin that loads a cog with the accel erometer driver using accel Start and then calls accel x and accel y Figure 4 26 shows a schematic of the test circuit A call to accel Start 26 27 launches the accelerometer monitoring code and tells it that P26 is connected to the accelerometer s x axis output and P27 is connected to the y axis output After examining the MXD2125 Simple object it looks like the x and y methods both return the pulse measurements in terms of clock ticks Since the accelerations are measured in terms of pulses that last milliseconds and fractions of milliseconds displaying the results in terms of microseconds might make more sense Since the pulses range from 3 75 ms
554. t distribute disseminate sell publish or sublicense the work or any part of it without McGraw Hill s prior consent You may use the work for your own noncommercial and personal use any other use of the work is strictly prohibited Your right to use the work may be terminated if you fail to comply with these terms THE WORK IS PROVIDED AS IS McGRAW HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WAR RANTIES AS TO THE ACCURACY ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE AND EXPRESSLY DISCLAIM ANY WARRANTY EXPRESS OR IMPLIED INCLUD ING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE McGraw Hill and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free Neither McGraw Hill nor its licensors shall be liable to you or anyone else for any inaccuracy error or omission regardless of cause in the work or for any damages result ing therefrom McGraw Hill has no responsibility for the content of any information accessed through the work Under no cir cumstances shall McGraw Hill and or its licensors be liable for any indirect incidental special punitive consequential or sim ilar damages that result from the use of or inability to use the work even if any of them has been advi
555. t a value or its additive inverse based on C Get a value or its additive inverse based on Z Get a value or its additive inverse based on Z Limit minimum of unsigned value to another unsigned value Limit minimum of signed value to another signed value Limit maximum of unsigned value to another unsigned value Limit maximum of signed value to another signed value Add two unsigned values Add absolute value to another value Add two signed values Add two unsigned values plus C PROPELLER LANGUAGE REFERENCE 453 ADDSX SUB SUBABS SUBS SUBX SUBSX SUMC SUMNC SUMZ SUMNZ MUL MULS AND ANDN OR XOR ONES ENC RCL RCR REV ROL ROR SHL SHR SAR CMP CMPS CMPX CMPSX Add two signed values plus C Subtract two unsigned values Subtract an absolute value from another value Subtract two signed values Subtract unsigned value plus C from another unsigned value Subtract signed value plus C from another signed value Sum signed value with another of C affected sign Sum signed value with another of C affected sign Sum signed value with another Z affected sign Sum signed value with another of Z affected sign lt reserved for future use gt lt reserved for future use gt Bitwise AND two values Bitwise AND value with NOT of another Bitwise OR two values Bitwise XOR two values lt reserved for future use gt lt reserved for future use gt Rotate C left into value by specified number of bits Rotate C right into value
556. t allows users to upload their waypoint tracks and plot the data overlaid onto a number of differ ent maps including aerial photos U S Geological Survey USGS topographical maps county outlines satellite photos and much more Data is uploaded as either plaintext tab delimited or comma delimited or Excel spreadsheet data or you can even copy and paste into an edit box on the Web site EXPERIMENT 349 We are now going to go through a simple step by step tutorial on how to format and upload GPS tracking data For those who do not want to manually format their data or who want to skip to the plotting section we have supplied preformatted comma separated values CSV files located here Chapter_09 Source Logs GPS Visualizer_Lat_Long csv The GPS Visualizer Web site accepts many different data types but we will choose to stick with a simple ASCII comma separated file In order for the GPS Visualizer Web site to correlate each column of data with its respective type there needs to be a header row at the top For example to plot a simple GPS latitude longitude track we need the first row to look like the following Type Latitude Longitude Capitalization and order do not matter as long as the data on subsequent lines follow the same order The latitude and longitude fields need to be in decimal degrees and the type field needs to contain the letter T which stands for track v Organize your data in an Excel spreadshee
557. t and disruption of running cable through the building SYNTHESIZING SPEECH WITH THE PROPELLER Chip Gracey Introduction Have you ever wondered how to make a human voice in software ve always been tantalized by the idea since speech is perhaps the ultimate analog communication pro tocol It certainly predates computers by a long time In this chapter we are going to look at actual speech and then synthesize it with the Propeller using small amounts of data Here s what s in store E Using spectrographs to see speech E Synthesizing formants vowels and making speech sound like speech Exploring the VocalTract object Resources Demo code and other resources for this chapter are available for free download from ftp propeller chip com PCMProp Chapter_12 Using Spectrographs to See Speech In order to synthesize speech we need to know what s in it We could start by looking at some waveforms of recorded speech Figure 12 1 shows a partial waveform from the utterance to I found this type of analysis to be a recipe for madness as you easily fall into the morass of trying to replicate details that are not important and then missing what matters 427 428 SYNTHESIZING SPEECH WITH THE PROPELLER se Figure 12 1 A partial waveform from the utterance to Instead of worrying about waveforms we need to look at the spectrum of speech over time since that is where
558. t in relation to the master device and to the slaves on the line Electrically the I C bus consists of any number of masters and slaves on the same bus Masters initiate communication while slaves listen and respond Masters can transmit and receive from a slave but a slave cannot initiate communications In addi tion to enforce that masters are in charge the clock line SCL can only be controlled by a master furthermore placing the slave s into a passive role Multiple devices can EXPLORING OTHER COMMUNICATIONS PROTOCOLS 393 SDA SCL Figure 10 15 l C bus layout be connected to the same two signal bus from an electrical point of view so both SDA and SCL are open drain thus pull up resistors must be connected from SDA and SCL to V via a 5 to 10 K resistor on both lines Note that with the SPI bus all SPI devices share the MISO master input MOSI master output and SCLK serial clock lines however the CS or chip select lines for each device control the selection of the target device not an address as with C When a device is selected its bus is active while any other deselected devices go tristate Thus the C bus is always active and arbitration is achieved through an open drain design where SDA and SCL can only be pulled down by the master and SDA alone by the slave The addressing of devices is achieved by a seven bit address sent down the I C bus to all slave devices only the listening device w
559. t the manual datasheet schematics and educational labs as well Tip Linux and Mac software Fig 2 4 is also available but may not include the USB drivers for your system See instructions with the software to install USB drivers before connecting hardware HARDWARE PROPELLER DEMO BOARD CONNECT THIS SECOND V Connect a standard USB cable A to mini B type cable o Insert the cable s A connector into an available USB port on your computer and the mini B connector to the Propeller Demo Board s USB jack as shown in Fig 2 5 The computer will indicate that it found new hardware and should automatically configure itself since we installed the USB drivers in the previous step Y Connect a power supply 6 9 VDC wall pack with center positive 2 1 mm plug o Insert the power supply s plug into the jack next to the power switch v Turn on the power o Slide the power switch to the ON position and verify that the power light located near the switch illuminates 20 INTRODUCTION TO PROPELLER PROGRAMMING Edit pane where you enter your code A re SST brads Spin Tul m l Umie piappiranans gt gt Bveveloper binary BNetwork pBasystem gt ED Inevalumesetringsr naer puser Guices And informat wMDusers p isnared vE ynuemen gt Eavesntoo pBSoocuments Awos anker can AASS sBinkerControl sn aawe ontrormenomses s Aryo Rnkeram hA cpin minker soin niite spin wmonson AuttanAndilink spin
560. tact point will get closer to the B terminal and the resistance between W and B decreases The test application for measuring this circuit utilizes an object named RC Time which comes from the PE Kit Tools Measure Resistance and Capacitance post in the Propeller forum The article in this post demonstrates many uses and applications of the RC Time object which can be configured to take sequential measurements in the same cog or parallel measurements in one or more other cogs It can also update the parent object s variable for storing the measurement results from another cog according to a sampling rate for control systems and data logging applications The simplest application of the RC Time object is demonstrated here with Test Simple RCTIME spin which repeatedly calls the RC Time object s Time method The Time method expects three arguments I O pin starting state 1 for decay or 0 for growth and the address of a variable that the Time method should store the result in In the example program the Time method takes care of all the signaling in Fig 4 15 and places the measurement result in the tDecay variable In this particular example all the measure ments are happening in the same cog Test Simple RCTIME spin CON _clkmode xtal1 plli6x _xinfreq 5 000 000 Crystal and PLL settings 5 MHz crystal x 16 80 MHz OBJ re RC Time RC decay grouwth object pst Parallax Serial Terminal Serial communication
561. tage halogen lights and incandescent light bulbs that generate lots of heat as a by product of creating light Of course we can t overlook the inhabitants themselves Humans give off a surprising amount of heat It s generally accepted that a typical adult human being gives off about the same amount of heat as a 100 watt incandescent light bulb Then just when you thought it couldn t get more complex think of what happens to room temperatures when you open doors between rooms or worse yet open exterior doors and windows With so many different variables affecting room temperature at any given time the idea of attaining consistent balanced temperatures among all the rooms in a build ing by the application of a one time balancing of individual registers seems rather unlikely Even if you could manage to get all the rooms to reach a specific temperature the ultimate arbiter of temperature is not the thermostat or even a thermometer It s the inhabitants of a given room that decide if the temperature is right or would need to be altered to make them more comfortable Personal perceptions of warm and cold vary widely and it is rare that all of a building s inhabitants will be comfortable at the same room temperature For example a sedentary person may be comfortable in a room at 76 degrees but an active person may feel the room is too warm Even a sedentary person when placed in a room with lots of electronic equi
562. tage measurements over time The top level object then applies a noise cancellation and frequency detection algorithm to determine the signal strengths at frequency intervals specified in the code by a variable named FrequencyStep The application uses four cogs one for the TV display one for the graphics engine one for digitizing the microphone voltages and one for the top level application which does the frequency detection and then sends the data to the Graphics object This example still has four cogs available and they could be devoted to incorporating this application s features into a larger application perhaps robotic mechatronic biomedical or consumer Synchronous Serial Synchronous serial communication protocols are common for peripheral IC and module sensors The MCP3204 ADC featured in the Peripheral 4 Channel ADC Example with the MCP3204 section used synchronous serial communication and examples of sensors with built in synchronous serial interfaces include the DS1620 Digital Thermostat Parallax Digital Compass Tri Axis Accelerometer and Solid State Gyro all shown in Fig 4 37 Synchronous serial communication protocols have numerous variations examples include Serial Peripheral Interface SPI three wire four wire and Inter Integrated Circuit C Each integrated circuit that uses a synchronous serial protocol has a datasheet with timing diagrams and explanations of the signaling the microcontroller S
563. tamp cog repeat Main loop debug Str String ina 16 debug Bin ina 16 1 Display 1 binary digit debug NewLine New line if inal16 If button pressed time GetTime minutes Get timestamp amp display debug Vars minutes String minutes seconds milliseconds waitent clkfreq 20 cnt Wait 1 20 second debug Position Q 4 Figure 4 8 shows the Parallax Serial Terminal display which gives the most recent value from the Timestamp object after a button press Note that it also displays the state of P16 in the same way that the P16 Input States spin object did The P16 Multiprocessing Example object used the PST Debug LITE object instead of the Parallax Serial Terminal object to simplify displaying the list of time variables Since the PST Debug LITE object is just the Parallax Serial Terminal object with some extra features all of the Parallax Serial Terminal Parallax Serial Terminal COM6 Parallax Serial Terminal Debug LITE 0 seconds 16 milliseconds 499 Com Port Baud Rate TX DTR P ATS COM6 115200 RX DSR CTS Prefs Clear Pause Disable Figure 4 8 Customized PST Debug LITE display Echo On ON OFF SENSORS 131 methods are still available to the application The application uses debug Position to place the cursor at zero spaces over and four spaces down between each repetition of the loop Along with the str method call that displays ina
564. tarts over In each step of the way timeouts are used to ensure nonresponsive end devices do not lock up the system and that they are reported as being nonresponsive In this example we are simply collecting data and controlling LEDs for testing pur poses while displaying information for the user The returned data could be used by the coordinator for some logical decisions or to control a local output or send data to another end device for action TRY THESE Add another sensor and the code to request and respond with data Use a returned value in some way at the coordinator such as lighting an LED if the distance is within 100 mm 10 cm Rapidly collect a remote value and plot it using ViewPort Though not used in our code reading configuration values from the XBee can be done by sending the AT command and accepting returning data The XBee uses hexadecimal for all values The receiver is flushed to ensure that no data exists in the Propeller s object buffer In this example the dB level of a recent XBee reception is read and displayed XB rxF lush XB AT_Config string ATDB dataIn XB RxHex PC DEC dataIn Using the XBee API Mode API MODE AND DATA FRAMING Continual polling can take a lot of time and resources to check for data that may change infrequently It is good to have the coordinator control the communications but this requires the remote units to be awake Another mode for the XBee is called API mode fo
565. tead ina 18 16 would return 110 Or if just P16 were pressed it would return 001 vV Build the circuit shown in Fig 4 7 V Load P18 to P16 Input States spin into the Propeller chip v Test the pushbuttons by displaying their states with the Parallax Serial Terminal 3 3V 3 3V 3 3V h PBO h PB1 h PB2 P16 P17 P18 10 KQ 10 KQ 10 KQ GND GND GND Figure 4 7 Pushbutton example of an on off sensor array 128 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES P18 to P16 Input States spin CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz OBJ pst Parallax Serial Terminal Serial communication object PUB Go pst Start 115200 Start Parallax Serial Terminal repeat pst Str String pst HM ina 18 16 pst Bin inal18 16 3 Display 3 binary digits waitent clkfreq 20 cnt Wait 1 20 second With three pushbuttons controlling three different binary digits there are now 2 different combinations of binary results from 000 to 111 which is decimal 0 to 7 Case statements can be useful for picking out certain conditions For example the case Statement in the object P18 to P16 Input Decisions spin first stores the value of ina 18 16 in a local variable named states Later in the Go method a case state ment checks if the P18 pushbutton has been pressed The first condition the case state ment checks for is 4100 111 This is all the value
566. ted by the new cog can then call the Ping object s methods and wait for results without slowing down code in the other cog This is one of the beauties of multicore programming PULSE AND DUTY CYCLE OUTPUTS 147 Propeller Tool Ping BAR Fie Edit Run Help Ping C Full Source Condensed C Summam Documentation S Interface to Ping sensor and measure its ultrasonic travel time Measurements can be in units of time or distance Each method requires one parameter Pin that is the I O pin that is connected to the 2 Ping s signal line Connection To Propeller e PING e Remember PING Requires 5V Power Supply GND 5 SIG REVISION HISTORY v1 1 Updated 03 20 2007 to change SIG resistor from 10K to 1K Object Ping Interface S PUB Ticks Pin Microseconds PUB Inches Pin Distance PUB Sa opie Se Distance S2 PUB Millimeters Pin Distance 34 Program 26 Longs Variable A Longs PUB Ticks Pin Microseconds Return Ping s one way ultrasonic travel time in microseconds S PUB Inches Pin Distance Measure object distance in inches S PUB Centimeters Pin Distance Measure object distance in centimeters S PUB Millimeters Pin Distance 55 Measure object distance in millimeters iil UES Read Only Insert Compiled Figure 4 23 Ping object viewed in Documentation mode 148 _ SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Test Ping Sensor and Obje
567. ten to display current temperature and humidity the target temperature for the room and the position of the servo motor that would control the register Based on the success of the first board a second board Fig 11 12 was carefully constructed by hand based on the layout of the first prototype As we expected these boards to communicate via CAT 5 cable we needed to add RJ 45 jacks The only PC board mount RJ 45 style connectors we could find did not have 100 pin spacing making them rather difficult to install on the Proto Boards Hand routing wires also led to a couple of mistakes resulting in time being spent trouble shooting the second Proto Board At this point it was becoming clear that building each board by hand was going to be more time consuming than we originally thought and more error prone than we would like especially considering how many boards would need to be built There would be five rooms in the model house requiring a room control board and we wanted to have at least one board prebuilt and programmed as a spare to make it easy to repair the model if there were failures In addition we wanted to have some boards to use for testing and programming without having to be in possession of the entire model which at 3 ft x 4 ft in size was decidedly nontrivial to move We hit upon the idea of creating daughterboards that would attach to the Propeller USB Proto Boards via female pins soldered around the surface m
568. tern or eastern hemisphere GPS altitude GPS speed Number of satellites locked on Time Greenwich Mean Time Date DDMMYY format EXPERIMENT 347 E GPS heading E Barometer temperature 10 times Celsius format E Barometer pressure 10 times millibar format For this experiment we have already gone ahead and collected a long dataset that can be found here Chapter_09 Source Logs SENSOR_5_20_2009 csv Notice that we renamed the dataset so that it ends with a csv file extension This makes it easier for programs like Excel and Google Docs to import the data When read into a spreadsheet program all data fields will be separated into individual cells where each row of the spreadsheet referenced a sampling of data in time DATA ANALYSIS Once the data has been imported into a spreadsheet program we can condense and convert some of the fields to prepare them for plotting or graphing The first thing to convert is to change the latitude longitude format from degrees and minutes to decimal degrees For example 70 degrees 30 6 minutes 70 30 6 to 70 51 degrees 70 51 This conversion is as simple as taking the minute portion and dividing it by 60 and adding it to the degree portion Also we must take into account what hemisphere the data is collected in If the data is collected in the southern hemisphere we need to mul tiply the latitude decimal degrees by negative one Likewise if the GPS receiver was in the western h
569. ternally snapshot and queue up each frame you give it then linearly interpolate each of the 13 parameters from frame to frame over specified periods Out comes continuous speech that can be made very expressive with amazingly little input A WORD ON SYNTHESIS ALGORITHMS It used to be that synthesis algorithms were king several decades ago With the advent of big inexpensive memory however rote recording and regurgitation have become the norm for many areas in which algorithmic synthesis would be much more flexible not to mention more memory efficient Many speech synthesizers today use recorded snippets of speech which are concatenated at runtime to create continuous speech These programs and data often require many megabytes of memory In contrast VocalTract is only 0 0013 MB in size 334 longs of code 44 longs of variables per instance EXPLORING THE VOCALTRACT OBJECT 431 Exploring the VocalTract Object Figure 12 4 shows some documentation from the VocalTract object Note the schematic diagram and the parameters associated with each section The ASPIRATION section produces turbulence in the vocal tract This is for breathy sounds but is always needed for natural sounding speech The GLOTTAL section pro duces continuous glottal pulses for voiced speech The VIBRATO section modulates the glottal pitch for singing and helps regular speech sound natural as only robots are known to speak in pure monotone The pitch paramete
570. tes we need to read tempsize read _rsr if tempsize gt size ret_size size else ret_size tempsize Now we read the data from the W5100 and write it to the array pointed to by dataptr repeat counter from to ret_size 1 al startadd amp SFF a startadd amp SFFQQ gt gt 8 byte dataptr read aQ al dataptrt t of fsettt offset offset amp S7FF Socket has 2K of buffer and that determines mask here of 7FF startadd 6000 offset Add the offset to the starting address of socket 0 Need to increment the rdptr by the number of bytes actually read rdptr ret_size 310 USING MULTICORE FOR NETWORKING APPLICATIONS Then write the value of the new pointer back temp rdptr amp FF00 gt gt 8 write 04 28 temp temp rdptr amp SFF write 04 29 temp Tell the W510 that we have read the data write 04 01 4Q Issue the read command to the W5100 which just updates registers We will block waiting for the W510 to finish This takes very little time but we will check it just to be sure repeat temp read 04 01 while temp lt gt 00 As you can see this is the largest and most complex method in the EtherX driver You can see why we saved it for last Still when you boil it down all it really does is read some data from an internal buffer in the W5100 and write that data to main memory in the HYDRA This method takes in three arguments
571. text 50 60 pscore gr colorwidth 3 3 gr textmode 6 6 6 0 oscore Q 30 opp_score gr text 170 60 oscore if winloss 1 gr colorwidth 1 2 gr textmode 4 4 6 0 gr text 25 140 vic elseif winloss 2 gr colorwidth 2 2 gr textmode 4 4 6 0 gr text 40 140 edef The repeat keyword indicates the main loop of the game The score_change variable is a global variable that will be changed by Cog 5 when the player hits a button or by Cog 6 when the opponent sends us a score update because he has pressed the button All we do is clear the screen and draw the new scores on the screen We then check another global variable called win_loss which is initialized to 0 and set to 1 by Cog 5 if we won or set to 2 by Cog 6 if we lost If we won in addition to displaying the score we display Victory if we lost we display Defeat You can see in the code how we start executing methods in a new cog using the cognew keyword Both the MonitorButtons method and the MonitorEthernet method will begin executing in new cogs Actually the Spin interpreter will be loaded into two new cogs which will start executing Spin instructions in locations in main memory Here are the code listings for these two methods PUB MonitorButtons This routine will run in another cog and monitor the gamepad It runs as a continuous loop waiting for player to push any button repeat Wait for the player to stop pushing
572. th Include Stack Length Object PUB TestStack Stk Init Stack 32 Init reserved Stack space Start 16 30 5 Exercise object under test waitent clkfreq 2 cnt Wait ample time for max stack usage Stk GetLength 30 115200 Send results at 115 200 baud VAR long Cog Holds ID of started cog long Stack 32 Stack workspace for cog PUB Start Pin Duration Count Start flashing led on Pin for Duration a total of Count times Stop Cog cognew LED_Flash Pin Duration Count Stack 1 PUB Stop Stop flashing led if Cog Did we start a cog cogstop Cog 1 If so stop it SIZING THE STACK 43 PRI LED_Flash Pin Duration Count Flash led on PIN for Duration a total of Count times Duration is in 1 100th second units Duration clkfreq 100 Duration Calculate cycle duration dira 16 23 Set pins to output repeat Count 2 Loop Count 2 times outa lPin Toggle I O pin waitcnt Duration cnt Delay for some time Tip This source is from PCMProp Chapter_02 Source Flash_Stack_Test spin Note that we carefully checked and modified the code in the temporary TestStack method so that 1 Stack in the Stk Init statement is the actual name of our reserved stack space for the LED_Flash method 2 32 in the Stk Init statement is the actual number of longs we reserved for LED_Flash s stack space 3 The Start statement contains valid parameters to our
573. that prevent many multiprocessing bugs Utilizing objects to manage code that runs in other cogs is also an important way to prevent bugs Prewritten objects that perform many common tasks are available from http obex parallax com and advice on how to incorporate them into applications is also readily available from the Propeller forum at http forums parallax com Building block objects with code that runs in more than one cog follow a set of conventions for including Start and Stop methods to launch and shut down code that runs in another cog along with any methods needed for configuration or information exchange between cogs One of the most common root causes of multiprocessing bugs is our natural tendency to forget that different segments of code are executed by different processors Other common bugs relate to I O and timing For I O the most common bug is forgetting to add I O assignments at the start of a method that gets launched into a new cog If code in a cog is working with certain I O pins the method that gets launched into a new cog should initialize the I O pin settings Three common coding errors related to timing include forgetting to declare the clock settings using waitcnt delay cnt instead of synchronized delays with t cnt waitent t delay and writing code in a loop that takes longer than the synchronized waitcnt delay Although contention over an individual memory element is impossible with the Propeller chip thanks to
574. that the concepts in this short chapter serve as building blocks for many types of processes from simple to sophisticated from single core to multicore The rest of this book will show you fantastic examples of those capabilities taking full advantage of what the multicore Propeller has to offer The foundation we build in this chapter will provide you with a strong understanding of the things to come Let s Get Connected Let s get started by connecting the Propeller and testing it out You can get a Propeller chip in many different forms to suit your needs see Fig 2 2 18 _ INTRODUCTION TO PROPELLER PROGRAMMING Need instant gratification Want to wire it yourself The Propeller Demo Board is for you Use a DIP package or PropStick USB Building a permanent application Fabricate custom boards with LQFP or QFN packages or try the Proto Boards Figure 2 2 Propeller chip in different forms Tip Check out www parallax com propeller for current product offerings For demonstration purposes and ease of use we ll focus on the Propeller Demo Board in this chapter s exercises Don t worry the other products can also perform the same simple examples we show here with the addition of some simple circuitry SOFTWARE PROPELLER TOOL INSTALL THIS FIRST Now that we ve selected a Propeller product to develop applications for it we first need to install the Propeller Tool software and connect the Pr
575. the XBee and data from the XBee is sent to the PC with each method in separate cogs it allows transfer speeds tested up to 115 200 bps But for now we need to stick to 9600 bps since that is the default configuration on the XBee OBJ PC FullDuplexSerial XB FullDuplexSerial Pub Start PC start PC_Rx PC_Tx 0 PC_Baud Initialize comms for PC XB start XB_Rx XB_Tx XB_Baud Initialize comms for XBee cognew PC_Comms stack Start cog for XBee gt PC comms TESTING AND CONFIGURING THE XBee 197 PC rxFlush Empty buffer for data from PC repeat XB tx PC rx Accept data from PC and send to XBee Pub PC_Comms XB rxFlush Empty buffer for data from XB repeat PC tx XB rx Accept data from XBee and send to PC Caution Watch the I O numbers If another configuration is used modify the pin numbers in the CON section of the code If you are using the Propeller for passing serial data S Connect the hardware as shown in Fig 5 5a Download the Serial_Pass_Through spin program to the Propeller using F11 S If you are using the Prop Plug to communicate directly connect it as shown in Fig 5 5b v If you haven t yet download and install the X CTU software available in the distrib uted files or from Digi s web site There is no need to check for updates this can take a long time and the basic installation has all that is needed for now V Open the X CTU software It should look similar to
576. the 5 V output infrared detector in Fig 4 11 has a 10 kQ resistor between its output and the I O pin to provide this protection The reason a series resistor suffices is because Propeller I O pins have protection diodes that drain current to the Propeller chip s positive supply if an incoming signal is above 3 3 V or to ground if an incoming signal is less than 0 V Assuming an incom ing 5 V signal through a 3 9 kQ series resistor there will be a 1 25 V drop across the series resistor and a 0 45 V drop across the built in protection diode as the 3 3 V supply absorbs the current Voltage drop values are approximate and will vary slightly The resulting voltage applied to the I O pin is 3 75 V which is still safe for the I O pin provided the current into the diode is under the 500 uA limit specified in the Propeller Datasheet Using voltage current resistance or V IR with V 1 25 V and R 3 9 KQ the current through the resistor and the diode will be about 321 uA which is well under 500 uA limit Note Although the Propeller Datasheet specifies 3 6 V as the absolute maximum allowable voltage applied to an I O pin that value assumes no series resistance With series resistance it s the protection diode s job to make sure the I O pin can tolerate the applied voltage If a sensor is adversely affected by the current load resistor protection puts on its output Fig 4 14 shows a simple level translator circuit that draws no curre
577. the EtherX card and Fig 8 11 shows the EtherX card inserted into a HYDRA ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 289 Figure 8 10 EtherX Figure 8 11 EtherX inserted into the HYDRA 290 USING MULTICORE FOR NETWORKING APPLICATIONS ETHERX CARD ELECTRICAL INTERFACE Before we dive head first into the electrical interface of the EtherX card we ll talk about the physical interface from the EtherX to the HYDRA As previously stated the EtherX card connects to the HYDRA via the expansion header which not only provides Propeller I O and power but also USB signals HYDRA net signals and EEPROM signals so that an expansion card may be used for Propeller configuration In our case we only use the I O and power A table showing the EtherX interface to the HYDRA expansion slot is shown in Table 8 1 The interface from the HYDRA to the W5100 is SPI which stands for Serial Peripheral Interface which was originally developed by Motorola It s one of two popular modern serial standards including I C which stands for Inter Integrated Circuit by Philips SPI is a clocked synchronous serial protocol that supports full duplex communication SPI needs three wires data in data out clock ground and potentially chip select lines to enable the slave devices The downside to SPI is that every slave device connected to the SPI bus needs its own chip select also called slave select Figure 8 12 shows a simple diagra
578. the SD cards is done via the SPI interface so when we talk about writing and reading an SPI communications object interface is obviously used This differs from SD mode communications thus we want to place the SD card into SPI mode This is actually the first step when initializing the SD card Figure 9 9 shows how commands are formed for the SD card 340 PORTABLE MULTIVARIABLE GPS TRACKING AND DATA LOGGER BYTE 1 BYTE 2 5 BYTE 6 CRC 8 bit CRC not used after initial setup Figure 9 9 Format of SD card commands in SPI mode They are six bytes long and consist of the following parts Byte 1 8 bit command ID Byte 2 3 4 5 32 bit address Byte 6 8 bit CRC checksum The 32 bit address must be formatted in big endian format that is high byte to low byte This is the opposite of the Intel format which is little endian Therefore if you want to send FF_AA_00_11 in big endian you would send FF followed by AA 00 and finally 11 to complete the address Of course the address word might not be important for the particular command if not always make it 00_00_00_00 Finally the CRC checksum byte CRC stands for cyclic redundancy check is a byte that you the sender must compute based on bytes 1 5 The SD card after receiving bytes 1 5 compares the CRC you send to it and it computes its own if they are not the same the SD card will return an error Also when the SD card receives a c
579. ther bits must be set to 0 response frame Figure 5 17 API packet for received string using 16 bit address Reprinted by permis sion of Digi International identifier the XBee Object can decide how to handle the frame data and the top level code can determine what to do with that type of frame data We won t go into the details but again specific bytes have specific meanings In API mode all this data is sent out to the Propeller The XBee Object accepts the data and processes it accordingly using the RxPacketNow method This method is actually private PRI The method called is API_RX or API_RxTime ms which looks for the start delimiter 7E Once found execution is passed to RxDataNow to accept remaining data Once accepted the identifier is checked to determine the type of packet which in the case of our received string would be 81 Next the packet is parsed pulling out the data and placing it into variables that can be accessed from the top level code such as XB RxRSSI to find out the value of RSSI for the packet or XB srcAddr to get the sources address Note that the data is actually accessible through XB rxData it is not the actual data but a pointer to where the data string resides in memory Other methods can help us pull decimal data out After receiving data calling XB ParseDEC XB rxData 2 would pass the location of the string and pull out the second decimal value in the string values can be separated by
580. ther cog It takes care of any cog and lock details and provides method calls and or a memory interface for exchanging information with the application level object Test Timestamp Object spin Wait for key press and display ms since TimerMs was launched into a cog CON _clkmode xtal1 plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz x 16 80 MHz OBJ debug PST Debug LITE Serial COM object time Timestamp Object TimeStamp object PUB Go minutes seconds milliseconds debug Style debug COMMA_DELIMITED Configure debug display debug Start 115200 Start debug cog time Start 10 59 999 Start timestamp cog repeat Main loop time GetTime minutes Get a timestamp debug ListHome Display timestamp vars debug Vars minutes String minutes seconds milliseconds debug break Set breakpoint In addition to all the cog bookkeeping and stack declaration when the TimerMs method gets moved into its own building block object it should take care of all the locks Timestamp Object spin is one approach to incorporating the TimerMs method into a building block object Before launching the TimerMs method into a new cog the Start method checks out a lock Before shutting down the cog the Stop method returns the lock As with earlier examples commands in the object s other methods that get called have to wait for the lock to clear and then set it before performing any operations
581. this you just need to make the global variables SPIRW add add1 datain and dataout visible to both the application and the SPI layer However in the current version of the driver two small wrapper Spin methods called read and write are used to interface to the SPI layer we will discuss these next Information The assembly source code is omitted here in the text since assembly is a little obfuscated by its very nature Nonetheless if you truly want to understand how the driver implements SPI specifically for the W5100 check out the source code which is included every example in the Chapter_08 Source directory Use the force read the source Read and Write Layers The two main methods for interfacing to the SPI layer are the read and write methods These are two simple wrapper Spin methods that are easy to use and understand The read method in its entirety is shown here PUB read a al ret_val Call this method to read a byte from the W5100 via SPI The arguments are two bytes that contains address byte 0 and address byte 1 See W5100 data sheet for what registers these actually address The method will return the byte that came via SPI from the W510 Read data from the address specified in the arguments addQ a Set the arguments to the global addi al variables values SPIRW SPI_RD Set SPIRW to the read value 298 USING MULTICORE FOR NETWORKING APPLICATIONS Wait until the driver clears SP
582. tion We use the x posi tion of the spot to control the turning rate of the robot If the spot is in the middle we don t need to do anything However if it s on the left side of the image the algorithm APPLY FILTERS AND TRACK A BRIGHT SPOT IN REALTIME 269 ViewPort v4 1 64 File Edit View Configuration Plugins Debug i Load Connect Stop iMbps Oscilloscope Overview click on name to configure Name PlotEdit Min Max _ Avg blob 68 4M 68 4M_ 68 4M x A Horz Edit Variables Streaming Video H Scanline at Y 256 ye V Scanline at X 345 ern Source edge face color circle O WebCam Propeller O Video lmage File OShow Blob History ev ideotestipg mor Show Blob Marker Blob X 352 Y 266 W 1 H 1 Cursor X 345 Y 256 Value 12 Status ok Connection Disconnected Memory 00 01 33 Figure 7 7 Multiple video buffers showing the effects of negative edge and threshold filters tells the robot to turn left until the spot is in the center and the robot is facing the source of the spot The robot s speed is controlled using a similar technique using the verti cal position of the spot The algorithm s goal is to keep the spot s position centered in the image So when the spot is too low the robot is instructed to move forward which brings it closer to the spot s source
583. tion level object is clean and simple but can blink three LEDs at different rates simultaneously Tip The LED 3 statement in the OBJ block declared an array of three Flash objects Each one uses the same code but its own variable space After compiling you can explore the structure of your multiobject application in the Object View upper left pane of the Propeller Tool Search for Object View in Propeller Tool Help to learn more Timing Is Everything How fast has our Propeller been running all this time We have a 5 MHz crystal con nected see Fig 2 20 so it s reasonable to think it s running at 5 MHz right TIMING IS EVERYTHING 39 5 MHz crystal Figure 2 20 Propeller EEPROM and crystal circuit on Propeller Demo Board That is reasonable but incorrect The Propeller has some incredibly powerful clock ing features but as it turns out none of our examples has set the clock mode All this time our Propeller has been using its internal 12 MHz clock leaving the external 5 MHz crystal dormant Some applications will never need an external crystal because the internal clock is just fine For most applications however the internal clock is excessively inaccurate Information The internal clock runs ideally at either 20 kHz or 12 MHz but its frequency can vary by as much as 66 from the ideal Since we ve been using the internal 12 MHz clock our waitcnt delays have not been very accurate clk freq co
584. to 6 25 ms for 1 g with 5 0 ms level this would translate to 3750 to 6250 us with 5000 us level A simple way to do this is by defining the number of ticks in a microsecond Test MXD2125 Simple Object uses the expres sion us clkfreq 1_000_000 to assign the number of clock ticks in a microsecond to the local variable us Then the commands ax accel x us and ay accel y us 152 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES 3 3V Memsic Tout Vdd Yout Xout Figure 4 26 Memsic 2125 Accelerometer test schematic convert the clock tick pulse measurements into microsecond pulse measurements before storing them in the ax and ay variables Test MXD2125 Simple Object CON _clkmode _xinfreq xtali pll16x 5 000 000 OBJ MXD2125 Simple Parallax Serial Terminal accel pst PUB go ax ay us accel Start 26 27 pst Start 115200 us clkfreq 1_000_ 000 repeat Get microsecond measurements for ax accel x us ay accel y us Display measurement at 10 Hz pst Str String pst CE pst HM ax pst Dec ax pst Str String pst CE pst NL ay pst dec ay waitent clkfreq 10 cnt Crystal and PLL settings 5 MHz crystal x 16 80 MHz Memsic 2125 object Serial communication object x axis to P26 y axis to P27 Start Parallax Serial Terminal Clock ticks in a microsecond the x and y axes FREQUENCY OUTPUT 153
585. to the 3 3 V connection and causes the input register bit for that pin to store a 1 When the button is released the I O pin detects ground 0 V through the 10 kQ resistor The resistor pulls down the voltage to 0 V when the button is not pressed and thus the name pull down resistor 124 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES Pull up Resistor I O Pin 3 3 lt 3 3 V Pushbutton i WKE 1 0 Pin Pushbutton Pull down Resistor Figure 4 4 Pushbutton circuits with pull down and pull up resistors On Off Sensor Example Single Pushbutton Figure 4 5 shows a single pushbut ton connected to Propeller I O pin P16 on the Propeller Education Kit platform also known as the PE platform This pushbutton circuit utilizes a pull down resistor to keep the voltage applied to the I O pin at ground when the button is not pressed and when it gets pressed the pushbutton connects the I O pin to 3 3 V 3 w lt Pushbutton P16 10 kQ v D O v m m m m a Figure 4 5 Single pushbutton ON OFF SENSORS 125 Information Forexplanations of howto build circuits in breadboards download What s a Microcontroller from www parallax com For more information about the PE Kit PE Platform and PE Kit Labs textbook type Propeller Education into the Search field at www parallax com and then click the Go button The P16 Input States spin object displays the state of I O pin P16 i
586. tor pwm is structure with bits to turn on then duty for that pattern pwm 1 5 pwm 3 5 pwm 5 5 diraV m1Dir m1Pwm m2Dir m2Pum andV diraV cognew doPWM pum To update the speed and direction of the two motors we ll use the following Spin code It limits the speed for each motor sets the output patterns to turn the motors in the specified direction and sets the time values to modulate the motors at the correct speeds pub Update speed speed2 p0 p2 t p0 mLpwm m2pwm if speed gt Q pQ midir if speed2 gt 0 pQ m2dir pumLQ pQ speed speed lt MAXSPEED speed2 speed2 lt MAXSPEED if speed gt speed2 p0 m2 pwm pwm 1 speed2 5 2505 pwum 3 speed speed2 5 2505 pum 5 5 5000 speed 15 else p0 m1pum pwm 1 speed 5 pwm 3 speed2 speed 5 pwm 5 5 5000 speed2 puml2 pQ pumL4 0 BUILDING THE DANCEBOT 243 MEASURING POSITION WHERE AM I In order to measure how far your robot has traveled you ll need a quadrature encoder A quadrature encoder is an electromechanical sensor that outputs two pulse signals which can be analyzed to determine how quickly and in which direc tion a wheel is moving The sensor typically consists of a disk covered in black and white stripes and two photo detectors that read the optical pattern coming from the disk Counting how many black white transitions are made at a sensor tells us how fast the wheel is turning For example if the
587. tor Temperature light proximity position A Signal Generation amp Processing Speech amp Sound WA Pulse pwm digital or analog output Sound generation and processing lt Fun a View All Objects Fun demo game handy trick This category contains all objects Please contact obex support parallax com with comments or questions z p a Internet 100 Figure 4 1 Propeller Object Exchange INTRODUCING SENSORS BY THEIR MICROCONTROLLER INTERFACES 121 of many difficult programming tasks They can also boil down sensor monitoring to a simple method call that returns the measurement or in some cases a Start method call that arranges for an object to keep one or more variables in an application updated with the latest measurement s Sensor intensive applications tend to examine measurements and react to them on the fly or store them for later analysis or sometimes both Figure 4 2 shows examples of audio spectrum analysis and a prototyping adapter for SD card data storage These are two examples that address processing and storage included in this chapter The treatment of processing and storage is not covered in depth here because examples will be plentiful in the project oriented chapters that follow Audio Spectrum Analyzer K K000 10 Hz Sweep Steps 4 Figure 4 2 Audio signal frequency analysis and SD card adapter 122 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES The
588. trademark owner with no intention of infringement of the trademark Where such designations appear in this book they have been printed with initial caps McGraw Hill eBooks are available at special quantity discounts to use as premiums and sales promotions or for use in corporate training programs To contact a representative please e mail us at bulksales mcgraw hill com Information contained in this work has been obtained by The McGraw Hill Companies Inc McGraw Hill from sources believed to be reliable However neither McGraw Hill nor its authors guarantee the accuracy or completeness of any information published herein and neither McGraw Hill nor its authors shall be responsible for any errors omissions or dam ages arising out of use of this information This work is published with the understanding that McGraw Hill and its authors are supplying information but are not attempting to render engineering or other professional services If such services are required the assistance of an appropriate professional should be sought TERMS OF USE This is a copyrighted work and The McGraw Hill Companies Inc McGraw Hill and its licensors reserve all rights in and to the work Use of this work is subject to these terms Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work you may not decompile disassemble reverse engineer reproduce modify create derivative works based upon transmi
589. tring Allows the user to redefine the prompt The next set of commands is remote commands that send messages to the cores running the virtual peripherals thus all the work is performed with these commands NTSC COMMANDS These commands are processed and issued to the NTSC terminal core ntsc pr string This command prints a single string token to the NTSC terminal ntsc cls Clears and homes the NTSC terminal ntsc col num Q 7 Sets the color of the NTSC terminal ntsc nl Prints a newline to the NTSC terminal ntsc out num 255 Outputs a single ASCII character to the NTSC terminal ntsc sx num Q 39 Sets the X cursor position of the NTSC terminal ntsc sy num Q 29 Sets the Y cursor position of the NTSC terminal 388 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS VGA COMMANDS These commands are processed and issued to the VGA terminal core vga vga vga vga vga vga vga pr string cls col num 0 7 nl out num 0 255 sx num 0 31 sy num 0 14 SOUND COMMANDS These commands control the sound driver core and play simple tones on up to five channels snd play channel 4 frequency 0 5000 duration in sec 0 255 snd stop channel 0 4 snd stopall This command prints a single string token to the VGA terminal Clears and homes the VGA terminal Sets the color of the VGA terminal Prints a newline to the VGA terminal
590. tring Opening returned pst Dec r pst NewLine sta cnt bytes 0 SUMMARY 187 repeat 3 repeat 39 sdfat pputc R sdfat pputc pst NL sdfat pclose pst Str string Wrote file pst NL rcs sdfat popen string newfilexr txt e pst Str string Opening returned pst Dec r pst NewLine repeat r sdfat pgetc ifr lt Q quit pst Char r pst Str string That s all folks 3 pst NL Excerpt from sdrw_test Copyright c 2008 Tomas Rokicki obex parallax com HOW DO I TRANSMIT DATA FROM THE PROPELLER TO THE PC One quick and simple way to bring data from the Propeller chip to the PC is by dis playing the values in the Parallax Serial Terminal The values can then be copied with CTRL C and pasted into a text document Provided the values the Propeller sends to the Parallax Serial Terminal are formatted so that each number on a given line is separated by a comma most data analysis and number crunching software packages can import the text file as comma delimited Tab delimited tends to be the default import setting for these software packages but they all have comma delimited option as well and it displays much better in the Parallax Serial Terminal that way Most programming environments also have COM port features that can be programmed to exchange data with the Propeller chip This makes it possible to use an actual COM port serial over USB or even serial over Bluet
591. tring_index long strtok_string_length Next up are the object includes for all of the drivers we need for our virtual RPC system NTSC VGA keyboard serial and sound OBJ serial termi term_ kbd snd ntsc FullDuplexserial_drv_Q12 spin TV_Text_Half_Height_011 spin The full duplex serial driver The NTSC driver vga keyboard _010 spin NS _sound_drv_052_11khz_16bit spin VGA_Text_010 spin The VGA driver The PS 2 keyboard driver Sound driver CLIENT HOST CONSOLE DEVELOPMENT 375 INITIALIZATION The initialization process for the program consists of initializing a few variables and then it falls into starting up each of the drivers on their own processing cores cogs As each device is started messages are printed out to the NTSC VGA and serial com munication lines Here is the initialization code Note The symbol is used to denote code that wrapped to the next line due to book layout constraints Initialize variables section for parser input_buff_index 1 Copy default prompt bytemove prompt ready_string strsize ready_string 1 Let the system initialize Delay 1_000_000 Initialize the NTSC graphics terminal term_ntsc start 12 0 0 40 15 term_ntsc ink 0 Print a string to NTSC term_ntsc newline term_ntsc pstring ntsc_startup_string Initialize VGA graphics terminal term_vga start 10111
592. trt addy16 gt gt 8 Dest Address MSB dataSet ptr addy16 Dest Address LSB dataSet ptrt 00 Options 01 disable ack 04 Broadcast PAN ID Repeat strsize stringptr Add string to packet dataSet ptr byte stringptrt csum SFF Calculate checksum Repeat chars from 3 to ptr 1 csum csum dataSet chars dataSet ptr csum Repeat chars from to ptr tx dataSet chars Send bytes to XBee As you look through the code you can see how all the individual bytes that make up a well formed frame for transmission are combined into an array of bytes the bytes are summed actually subtracted from FF one at a time for the checksum and the array of bytes is transmitted When the data is received by the XBee the frame is checked If in API mode the frame shown in Fig 5 17 is sent to the Propeller for processing Based on the API USING THE XBee API MODE 217 Start Delimiter Length Frame Data Checksum 0x 7E MSB LSB 1 Byte API specific structure API Identifier identifier specific Data 0x01 cmdData Frame ID Byte 5 Destination Address Bytes 6 7 Options Byte 8 RF Data Byte s 9 n Identifies the UART data frame MSB first LSB last 0X01 Disable ACK for the host to correlate with a subsequent ACK Broadcast 0 X FFFF 0 X 04 Send packet with Up to 100 bytes per packet acknowledgement Broadcast PAN ID Setting Frame ID to 0 will disable All o
593. ts minimum After detecting a vertical sync mark the code initializes a new frame and processes every other video line It detects the horizontal synch skips past the color burst and then samples the ADC s value every eight instructions To store the pixels efficiently into memory we pack eight 4 bit pixel values in a 32 bit long into the Propeller s global memory which is accessible by all other cogs 262 CONTROLLING A ROBOT WITH COMPUTER VISION SEE ViewPort v4 1 64 File Edit View Configuration ee Debug Help 200 sol Q0us ZOOS otha 579p5 51 9p5 40 Time usec IA Measure 3 Lodi Source Continuous Single Connection Disconnected Memory 00 01 07 Figure 7 4 NTSC waveform captured by the Propeller doLoFrame mov pixPtr par Start new frame call findVSync Find vertical sync mov fieldCtr 100 15longs line 100lines 1500 longs sampleField mov lineCtr 15 15 longs 8 120 samples call findHSync Find horizontal sync twice to skip a line waitcnt sB 0 call findHSync sampleLine mov sb 7 Pack 8 pixels long mov sL 0 PROPCV A COMPUTER VISION SYSTEM FOR THE PROPELLER 263 sample8Pix mov and add ror nop nop nop djnz mov and add ror wrlong add djnz djnz doLoFrame ret ret findVSync waitpeq mov waitpne mov sub cmp if_c jmp mov add waitcnt findVSync_ret ret findHSync
594. ts of many different inclines with varying steepness Since one of our main objectives is to compare and contrast the performance of the GPS altitude versus the barometric pressure sensor having a nonflat terrain to travel over is ideal In addition to altitudes we are interested in other measurements such as the GPS reported speed For our experiment we will be traveling between 0 and near 60 miles per hour All collected data will be stored to the SD card and then postprocessed in a spread sheet software program such as Microsoft Excel Google Docs or even OpenOffice org In order to facilitate easy importing into a spreadsheet program we are going to output data captured in the main Spin object as comma separated values With the exception to the first line that serves as a header each line of the ASCII text file log will contain a series of ASCII number strings separated by commas An example of the text log file output is shown here 30 21 1403 N 097 54 2948 W 00201 1 000 0 05 040942 210509 072 3 245 9889 30 21 1403 N 097 54 2948 W 00201 1 000 0 05 040943 210509 072 3 245 9889 30 21 1403 N 097 54 2948 W 00201 1 000 0 05 040944 210509 072 3 245 9890 An explanation of each field from left to right can be found at the beginning of the log file and for simplicity is listed here Latitude in degrees Latitude in minutes Northern or southern hemisphere Longitude in degrees Longitude in minutes Wes
595. tween the second and third lines as the code waits for the cog running the TimerMs method to clear the lock When all the extra waitcnt commands are removed and dt is restored to the number of ticks in a millisecond clkfreq 1000 the code should now resemble Test Timestamp Bug Fix Full Speed spin Placement of the lockclr command immediately after longmove in the Go method will be especially important If the lockclr command were instead placed after the debug Vars call the cog running the TimerMs method would wait so 98 DEBUGGING CODE FOR MULTIPLE CORES 5 Parallax Serial Terminal COM15 Parallax Serial Terminal Debug LITE 10 seconds 59 milliseconds 10 seconds 59 milliseconds 11 seconds 0 milliseconds 11 seconds 0 milliseconds 11 seconds 0 milliseconds 11 seconds 0 milliseconds 11 seconds 0 milliseconds 11 seconds 0 milliseconds Com Port Baud Rate TX DTR ATS COM15 115200 Rx DSR CTS J Echo On Prefs Clear Pause Disable Figure 3 20 Timestamp test memory collisions corrected long for the lock to clear that its waitcnt command would miss the target cnt register value in the next iteration of its repeat loop missing the waitcnt boat bug Step 7 Remove Test Code The next step is to remove the delays that were added for the sake of exposing the memory collisions In other words all the lines of code with comments labeled need to be reversed and th
596. typically in the RGB format Searching this stream of data for pixels that exactly match a chosen color is easy We just have to match the three bytes of each incoming pixel to our target RGB values However this solution doesn t solve our problem To accommodate changes in lighting shadows and color our filter should match colors that we humans would judge as being similar to the target color Doing this is much more efficient when we first convert each pixel s color from the RGB to the HSV color space Fortunately converting from RGB to HSV is straightforward and OpenCV provides us with a high speed filter to do that Once our pixels are in the HSV color space we can restrict our search to pixels whose HSV values lie within a specific range For example to search for bright highly saturated blue pixels we could look for pixels whose hue lies between 150 and 170 with saturation and brightness values higher than 200 We can generalize this to find all brightly colored pixels for example toys by looking for pixels with saturation and brightness values higher than 200 ignoring the hue altogether OpenCV allows us to chain filters together just like our PropCV system The first filter results in a frame where only the pixels that match our criteria are set to white Then we pass that image to a blob finding filter which finds the location and size of the best blob that fits our pixels The result is a filter that s highly robust for find
597. u use MULTICORE PROPELLER MICROCONTROLLER 5 CONCEPT Demanding jobs require a highly skilled team of workers a fine tuned force that per forms in harmony aiming for a single goal The multicore Propeller wraps this team of processors into one tiny package These processors called cogs are at your service waiting to be called upon as the need arises Both powerful and flexible they lie dormant until needed sleep and wake on a moment s notice or run continuously The flat memory architecture homogenous processor design and built in languages make for a simple architecture that is easy to learn Use in Practice Here s how you d use the multicore Propeller microcontroller in an application E Build a Propeller Application out of objects see Fig 1 3 Tip Objects are sets of code and data that are self contained and have a specific purpose Many objects already exist for various tasks you can choose from those and can also create new ones E Compile the Propeller Application and download it to the Propeller s RAM or EEPROM see Fig 1 4 E After download the Propeller starts a cog to execute the application from Main RAM as in Fig 1 5 E The application may run entirely using only one cog or may choose to launch additional cogs to process a subset of code in parallel as in Fig 1 6 Of course this performs as explicitly designed into each specialized object by you and other developers Graphics_Demo Object
598. ucture only allows one read or one write per SPI transaction thus making it half duplex The next two variables called add and add1 are the address that the SPI layer will read from or write to The interface of the W5100 is an addressable register interface This means that every read or write will be to a register in the W5100 and every register has an address As you can see in Fig 8 16 two bytes are needed to address the register you want to read or write Whether the operation is a read or write the address portion of the transaction is exactly the same Thus after sending the first byte to indicate whether the operation is a read or a write the SPI layer will read the two address variables and send them to the W5100 regardless of whether we are reading or writing The assembly code to accomplish sending the address to the W5100 acts as a shift register The assembly looks at the most significant bit of the address variable and sets the MOSI line logic high if the most significant bit of the address variable is high Similarly if the most significant bit of address variable is low the MOSI is cleared to low We then pulse the SCLK line to clock in that bit The SPI layer will shift the address variable left one bit and repeat the process until the entire address variable is clocked into the W5100 The assembly code will do this twice as there are two address variables ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 297 Note
599. uded with every HYDRA sold Figure 8 9 shows a picture of the HYDRA Game Development Kit Since this chapter deals mainly with networking we will focus on the EtherX card developed by Avery Digital While we will try our best to show how the card is inter faced to the HYDRA and how to write networked applications for it some details may be left out The complete user manual for the EtherX card is located in the Chapter _08 Docs Documentation directory The EtherX card connects to the HYDRA via the expansion slot The guts of the EtherX card is the W5100 Ethernet chip from Wiznet This chip contains a hardwired TCP IP stack which offloads a lot of the Internet protocol from the HYDRA For example if the HYDRA wants to send a simple TCP IP packet assuming the connection between server and client has already been established the HYDRA would need to send the packet and wait for an acknowledgement ACK from the receiver If the ACK doesn t come in a timely manner the HYDRA would need to resend Furthermore if the HYDRA were receiving multiple data packets the data could come in out of order which the HYDRA would need to stitch back together There is also the implementation of the sliding window protocol for transmitting and retransmitting data to deal with You get the picture The complications just go on and on The W5100 Ethernet chip handles all this for us We simply initialize the device and then send or receive data Figure 8 10 shows
600. udes things like streaming video and audio which is why you notice hiccups sometimes when streaming data on the Internet Those hiccups are the periodic packets being lost between the streaming server and your computer The time it would take to straighten out what packets were lost would take too long and would leave you way behind in the stream It s best to just ignore the hiccup and move on File transfers on the other hand need to be perfect and thus use TCP which is why when you look at a web page download an MP3 or chat with friends the data is always correct ETHERNET AND INTERNET PROTOCOLS 285 MAC Header 14 bytes IP Header TCP Header Data CRC Checksum 20 bytes 20 bytes 6 1460 bytes 4 bytes Ethernet Type II Frame 64 to 1518 bytes Figure 8 4 Ethernet frame with IP header TCP header and data Figure 8 4 shows the Ethernet frame now with the TCP header and the data Figure 8 5 shows the TCP header fields Figure 8 6 shows the Ethernet frame now with the UDP header and the data Figure 8 7 shows the UDP header fields The best way to learn about the networking fields is to actually see them WireShark is a free program that not only acts as a packet sniffer that grabs every bit of Internet traffic coming and going on your computer but also breaks down each header for TCP Header 20 Bytes ffset TCP Flags GE U A P Rs E TCP Options variable length opt
601. ul for speed optimized processes Even though the Propeller chip s architecture has eliminated the possibility of low level main memory access collisions there can still be timing issues with cogs reading from or writing to groups of memory elements during the same time period In that case one cog might get half old and half new values as the other cog is busy updating the same group of memory elements So the Propeller microcontroller s main memory has eight semaphore bits called Jocks which simplify the task of making sure that one cog doesn t try to read a group of variables at the same time another cog is updating them Communication between cogs is another design puzzle that has a variety of solutions some of which could have made coding complex and bug prone With the Propeller microcontroller cogs can exchange information through the Propeller chip s Main RAM Again since each cog gets sequential access to individual memory elements bugs as a result of low level memory contention are not possible and lock bits built into Hub and Cog Interaction Figure 3 3 Block diagram excerpt round robin main memory access PROPELLER FEATURES THAT SIMPLIFY DEBUGGING 55 main memory for updating groups of memory elements make this a simple effective and bug free means for cogs to exchange information One last but not so obvious characteristic of the Propeller chip s design that helps reduce bugs is its hardware symmetry As
602. uld look something like Fig 2 8 V Now compile the code by pressing the F9 key or by selecting the Run Compile Current Update Status menu item o If everything is correct Compilation Successful should appear briefly on the status bar If you entered something incorrectly an error message will appear indicating the problem recheck your work and compile again YOUR FIRST PROPELLER APPLICATION 23 Propeller Tool File Edit Run Help Untitled Full Source Condensed Summary Documentation PUB LED On dira 16 outa 16 repeat J 1 Propeller Library Demos X B Parallax Inc a EMG Propeller Tool v1 26 Examples H O Help O Library H H PE Kit Help lt 4x4 keypad Reader DEMO spin 408803_DEMO spin COIL_demo spin Debug_Led_Test spin dither spin Float_Demo spin FrequencySynth spin lt Propeller Source spin Sd 5 9 Modified Insert Figure 2 8 Propeller Tool with LED_On application entered LED SCHEMATIC If you are not using the Propeller Demo Board add the circuit shown in Fig 2 9 to your setup for the following exercises Pxx labels refer to Propeller input output I O pins not physical pin numbers LEDs An 240 9 Figure 2 9 Schematic for Vss LED exercises 24 INTRODUCTION TO PROPELLER PROGRAMMING Propeller Communication Verifying RAM oc eco Figure 2 10 Communication dialog Verifying RAM You just wrote your first prog
603. uld pass the current value of the delay variable in this case clkfreq 4 from the line of code just above it instead of the Main RAM address of the delay variable Top File spin CON Constant declarations _clkmode xtali plli6x Crystal and PLL settings _xinfreq 5 000 000 5 MHz crystal x 16 80 MHz VAR Variable declarations COMMON MULTIPROCESSOR CODING MISTAKES 75 long delay Delay variable OBJ Object declarations pst Parallax Serial Terminal Parallax Serial Terminal spin blink Building Block Building Block spin object PUB Go Go method pst Start 115200 Start Parallax Serial Terminal cog delay clkfreq 4 Initialize delay variable blink Start 5 delay Call start method P5 blink 2 Hz repeat Repeat loop pst Str String Enter delay ms User prompt delay pst DecIn clkfreq 1000 User input gt delay var Building Block spin has a Start method with a cognew command to launch its Blinker method passing along the pin and delayAddr parameters Each time through the Blinker method s repeat loop it uses delayAddr to fetch the current value of Top File s delay variable Since delayAddr stores the address of the application object s delay variable the expression Long delayAddr returns the value stored at that location in main memory So instead of waitent t delay the Blinker method s repeat loop uses waitent t long delayfddr If e had been omitted from d
604. up the entire Propeller system including voltage regulators EEPROM program memory crystal oscillator reset circuit and programming connection the parts in the 40 Pin DIP kit are inexpensive and easy to replace In contrast the PropStick USB version is quick and easy to wire but more expensive to replace because if a project mistake damages one part the entire module has to be replaced Test MCP3208_fast spin utilizes the MCP3208_fast building block object to acquire four channels of A D measurements from the MCP3204 ADC and it displays them in the Parallax Serial Terminal The test code declares the MCP3208_fast object and gives it the nickname adc The MCP3208_fast object s documentation comments specify the parameters for the adc Start call as Start dpin cpin spin mode where dpin is the data pins tied together with a resistor as shown in Fig 4 28 cpin is the clock pin spin is the enable pin and mode is a parameter that was used in previous revisions of 158 _ SENSOR BASICS AND MULTICORE SENSOR EXAMPLES lt i Dss Ti i psss E f Des ool oeeeses oe Mm oe ee eeee nee eee e t ne ee eee gt s s s s eolZeeweee s eelSeereee se se ee eee eoneee a a nve ee ae anaa Figure 4 28 MCP3204 test circuit schematic VOLTAGE OUTPUT 159 the object Inside the Main loop the repeat channel from to 3 loop contains the expression adcVal channel adc In channel W
605. ur bot achieve two goals driving to a specified location and staying upright while only using one output and driving the wheels a certain speed See Fig 6 10 for a diagram of the control logic The following Spin code implements the hybrid fuzzy logic cascading PID controller that keeps the bot balanced and allows us to steer and drive it like a car It starts out by calculating the position error posE by subtracting the target position from the mea sured position By minimizing this error with the top level PID controller we ll keep the bot on the desired position The posE is then fuzzified into five values stored in the A register of the fuzzy logic engine using the position error map By defuzzifying this register with the velocity map we get a target velocity velT which is proportional to Target Velocity Velocity Proportional Position Integral Acceleration Tilt Derivative Target Tilt Tilt from Kalman Filter Integrated Tilt Gyro Measurement Proportional Integral Derivative Output Motor Speed Figure 6 10 Diagram of DanceBot s control logic showing cascading PID controller BUILDING THE DANCEBOT 251 the position error We also defuzzify the A register using the tilt map This yields an angle that s proportional to position error which we ll use later as the derivative signal for the inner PID control Calculating the velocity error velE from the measured velocity and target velocity velT is a st
606. us to change direc tion easily and reduce the amount of time required to see results The Exercises section lists a small sample of the things we have considered exploring with our HVAC green house research platform As real world design criteria were taken into account when building the system it may well be possible to implement the system Figure 11 22 The Propeller powered HVAC green house hardware 424 THE HVAC GREEN HOUSE MODEL in a new home or to retrofit an existing home I would imagine it will only be a matter of time until someone implements a system such as this in an attempt to see if they can cut their heating and cooling costs as well as make their home more comfortable IN CONCLUSION At the time of this writing we are continuing to develop software and test hardware for the model We have recently obtained the liquid propane methane and carbon monoxide detectors and plan to add the emergency venting routines to the model as shown in Fig 11 23 Note If you would like to download the complete source code sets for all the boards in the HVAC green house model as well as view high resolution color pictures of the unit s construction and videos of the unit in action please visit ftp propeller chip com PCMProp Chapter_11 I would also like to take this opportunity to thank the team of amazing folks respon sible for the creation of the HVAC green house model Rick Abbot Machining and mechanical fabric
607. voltage 2 input voltage input voltage range 4 1 For example with a 12 bit ADC a 0 to 5 V input range and a 2 5 V input voltage the digitized voltage measurement would be digitized voltage 4096 2 5 5 0 2048 4 2 Some ADCs are single channel meaning they have one voltage input Other ADCs have 2 4 8 or even more channels ADC inputs typically have two flavors single ended or differential Differential measures the voltage difference between one input and another typically Vin and Vin single ended inputs measure the voltage differ ence between the input voltage and ground Peripheral 4 Channel ADC Example with the MCP3204 One highly useful ADC object on the Propeller Object Exchange is the MCP3208 object written by Chip Gracey and optimized and enhanced by Jim Kuhlman This object uses a cog to communicate with the MCP3208 and is optimized for high speed It supports the eight channel Microchip MCP3208 synchronous serial ADC and the four channel MCP3204 Figure 4 28 shows a schematic of a four channel MCP3204 connected to some voltage output test circuits and to the Propeller chip Information Other circuit examples in this chapter were built on the PE Kit 40 Pin DIP platform This one was built on the PE Kit PropStick USB platform The Propeller chip is on the module in the lower right side of the photo The 40 Pin DIP platform is recommended especially for students Aside from the worthwhile experience of wiring
608. w methods are activated most of the time We didn t need to do this in our previous examples because our applications had only one method and the Propeller naturally calls the first method in an application Not only can we call a method by name we can also demand that it take on certain attributes Suppose that we want this LED to blink that way and for so long It s all possible with the same method as long as it s written to support those attributes Take a look at this new method we based on the previous example PUB LED_ Flash Pin Duration Count Flash led on PIN for Duration a total of Count times Duration is in 1 10 th second units Duration clkfreq 100 Duration Calculate cycle duration dira 16 23 Set pins to output repeat Count 2 Loop Count 2 times outa lPin Toggle I O pin waitcnt Duration cnt Delay for some time Caution Don t run this yet Our application isn t ready until later in this exercise EXPLANATION Our method declaration looks different doesn t it PUB LED_Flash Pin Duration Count Yes we changed the name but now there are also items in parentheses The Pin Duration and Count items are parameters we made up to accept the attribute we spoke of earlier Each of them is a placeholder for values numbers or expressions when the method is called Figure 2 14 shows an example of this in action PUB SomeMethod LED_Flash 16 30 5 Call LED Flash method 1
609. w noisy it is because it s continually registering small accelerations However averaged over time it accurately indicates which way the bot is tilted The purple trace is the output of the Kalman fused signal It s clean and doesn t drift over time perfect for controlling our robot Ensuring that both of these figures are correct helps us confirm that the robot is work ing correctly With something this complex it s almost impossible to track down the source of a problem to a loose wire if we don t have a tool that shows us what s going on Now that our robot is wired correctly and we ve confirmed that our sensors and calculations are correct let s see the robot balance EXERCISES 255 Controlling the DanceBot The DanceBot is controlled like a car It requires two channels of information Channel 1 speed controls how fast the bot should travel Channel 2 turn rate controls how quickly the bot should turn about its own axis DanceBot manages its two motors to stay bal anced and to achieve the desired input Unlike a car the bot is capable of turning in place At first I controlled my robot with remote control to get the hang of it It took me much longer to get it to drive programmatically to where I wanted Here s some code that continually drives the robot in a figure 8 by driving at a set speed while turning in one direction and then the other repeat repeat 200 bal do 10 10 repeat 200 bal do 10 10
610. which behaves like a small battery to 3 3 V by transmitting a high signal Then in the middle of Fig 4 15 the code changes the I O pin to input From the circuit s point of view its voltage source just disappeared because when an I O pin is an input its high input impedance makes it invisible to most circuits Even though the I O pin is invisible to the circuit the circuit s voltage is visible to the I O pin so it can still monitor Charge Circuit Decay Circuit I O pin output high I O pin input 3 3 V Ve Ve pe i il Let t I 4 GND GND GND GND t s At at 0 693 x C x R Figure 4 15 Propeller RC decay measurement Excerpt from Propeller Education Kit Labs Fundamentals RESISTIVE CAPACITIVE DIODE TRANSISTOR AND OTHER 139 and detect when the voltage decays below the I O pin s 1 65 V input threshold Since a cog or even a cog s counter module can also measure the time between when the I O pin was changed from output high to input and when the voltage decayed below the T O pin s 1 65 V threshold it can capture that At needed to calculate the sensor s resis tance or capacitance More importantly since the sensor s resistance or capacitance varies with some physical property the microcontroller can determine the physical quantity the resistive or capacitive sensor measures by measuring the decay time RC decay is short for resistor capacitor decay and it relies on t
611. within the Propeller This layer handles the bit banging of the SPI protocol as shown in Fig 8 16 The next layer read and write provides another layer of abstraction for the driver by providing two Spin methods that will read and write data given a register address The application layer has direct access to these two methods which would allow the user application complete access to all registers within the W5100 The final layer of abstraction contains Spin methods that perform the most common operations used in applications These methods add another level of abstraction to open sockets read and write data and initialize the W5100 In truth they are unnecessary because all they do is call the read method and write method with appropriate address and data which the application could do for itself since it has access to the read method and write method They exist to make application code easier to read and write The user application needs to call a method to initialize the W5100 by providing a MAC IP subnet and gateway address After that the W5100 programming model Application Layer Application Functions open listen connect RX TX etc read write SPI Layer Figure 8 17 Simplified illustration of the EtherX software model Hardware Interface Layer W5100 ETHERX ADD IN CARD FOR THE PROPELLER POWERED HYDRA 295 TABLE 8 2 API LISTING START AND STOP FUNCTIONS start
612. x To get a similar indication of your location follow these steps Y Load GPS_Float_Light_Demo into the Propeller chip Y As soon as the Propeller Tool software s Communication window reports Loading click the Propeller Serial Terminal s Enable button The GPS receiver needs enough open sky in view to receive at least three but pref erably four or more satellite signals to calculate its position On power up in a new location the receiver may take several minutes to detect enough satellites During that time a red indicator LED on the module will blink When the receiver receives signals from enough satellites its indicator LED will stop blinking and remain on vV Take the setup to an area with plenty of sky exposure and wait for the GPS receiver s indicator light to stop blinking and remain on When the GPS receiver s indicator light stays on the Propeller will relay the date time latitude longitude and the rest of the information similar to Parallax location shown Fig 4 47 Questions about Processing and Storing Sensor Data There are several frequently asked questions about processing and storage of Propeller acquired sensor data The most common question regarding processing is how to syn chronize an application object running at a lower speed with a higher speed building block object Questions about storage typically involve long term media that cannot be erased if the application restarts and anot
613. x and y coordinates 278 CONTROLLING A ROBOT WITH COMPUTER VISION CON _clkmode xtal1 pll16x _xinfreq 5 000 000 OBJ vp gt Conduit transfers data to from PC pub findblob pos x y sum vp config string var pos x y sum vp config string dso view x y timescale 1s vp config string video source webcam0 mode face result pos source should be webcam 1000 prop or a file like cv videotest jpg mode should be face edge color circle vp config string start video vp share pos sum repeat xi pos amp S3ff y pos gt gt 10 amp S3ff sum xty Okay time to go into more detail First the result returned from the OpenCV plug in contains the location and size of the desired object all packed into a single long The x and y coordinates are stored in the lower 20 bits and range from 0 0 lower left to 1023 1023 upper right no matter what camera you use The height and width are stored in the upper 12 bits and range from 0 0 small to 63 63 the whole camera s width and the whole camera s height This makes it easy to write one program that will work for people regardless of what hardware they use Most people will use OpenCV with their computer s built in webcam or an inexpensive USB webcam However you can use the source option to set OpenCV s input to the PropCV frame grabber to an AVI file on your PC or to other video devices OpenCV filters wi
614. y and one of the easiest methods is to have an input crystal that oscillates at 32 768 cycles per second This is not a random number but rather it is 2 5 If we were to take this clock rate and input it into a 16 bit counter with outputs labeled Out 15 0 bit 15 would transition from a 0 to a 1 exactly one second after being reset The 15th bit or the most significant bit MSB could then be fed back into the reset of the counter so that the counter is self resetting Also the 15th bit could be fed into a much larger counter that keeps track of the number of seconds that have transpired since startup or last reset Even though the pressure sensor does not have any RTC circuitry at least none that we can read the developers of the sensor probably choose this as its operating speed since many circuit boards do have this clock source available and possibly to make calculations easier The Propeller is connected through a binary weighted resistor network to produce NTSC television output for data monitoring and status information However when road testing the sensors a television is not immediately available so we will make use of an array of LEDs that can signal any potential problems and toggle an LED on and off for each sample recorded to the SD card Take a look at the completed circuitry in Fig 9 4 GPS RECEIVER GPS stands for Global Positioning System It was created as part of a United States Department of Defense DOD grant and is
615. y as shown in Fig 10 6 PROMPT string This command allows you to change the actual prompt It is more of a fun command than a useful one Try redefining the default prompt by typing the following Ready gt Prompt C If successful your CCP will look like a DOS prompt now C OVERVIEW SETUP AND DEMO 361 COM27 PuTTY Figure 10 6 The help menu printing out to the serial terminal To change it back try Prompt Ready gt and you should see this READY gt Notice that all commands are case insensitive the parser capitalizes all inputs Remote Commands Sample NTSC PRINT string This command prints a single string no spaces allowed to the NTSC terminal Try printing your name to the NTSC terminal by typing this Ready gt NTSC Print Andre Of course replace my name with yours If all goes well you will see your name on the TV connected to the NTSC terminal SND PLAY channel frequency duration The command uses the sound driver to play a pure tone on the speaker audio output You control the channel 0 4 frequency 0 5000 Hz and duration 0 255 s Here s how you would start a 1 kHz tone on channel 2 that is 5 s long Ready gt SND PLAY 1000 5 362 USING THE PROPELLER AS A VIRTUAL PERIPHERAL FOR MEDIA APPLICATIONS You should hear a nice piercing 1 kHz sound coming out of the TV or whatever you have connected to the audio out port of the Propeller Demo Board
616. y these packets of data will hop along from router to router until they reach their destination address So now we have an Ethernet MAC header followed by an IP header that looks like Fig 8 2 The IP header in all its glory is shown in Fig 8 3 Byte Offset 0 1 2 3 0 Typo of Soren TOS Toa Longin IPv4 Header 4 Identification x D M 20 lt _ lt i Ii I I I Ii Ia I Ii I IM I I I I a i I I Ii i i Ia i iiiii i 8 Time To Live TTL Header Checksum Bytes as came Le td eet ee ted Ane Se Sl a a en iA ine te Soe eS Sal A LS Se sn se me tome seme IHL 12 Source Address internet Header T ee ee ee Length 16 Destination Address es a Aa nde aM A SS A SM HSS R MNN AN M aN A A aN 20 IP Option variable length optional not common r 1 2 3 Bt 0123456789 123 45767899 123 456789 6 1 ja Nibble gt Byte gt Word Version Protocol Fragment Offset IP Flag s Version of IP Protocol 4 and IP Protocol ID Including but Fragment offset from start of 6 are valid This diagram not limited to IP datagram Measured in 8 represents version 4 1 ICMP 17 UDP 57 SKIP byte 2 words 64 bits x 0x80 reserved evil bit structure only 5 OMP wh pokes pone increments If IP datagramis D 0x40 Do Not Fragment 9IGRP 51 AH 115 LOTP fragmented fragment size M 0x20 More Fragments Header Length Total Length must be a follow multiple of 8 bytes RFC 791 Number of 32 bit words in Total Length e_ee TCP header minimu
617. y Since some applications require signal analysis independent of a PC one of the Propeller microcontroller s cogs can be devoted to this task while another cog is devoted to signal acquisition This mul ticore approach greatly simplifies signal acquisition and analysis which can be espe cially challenging to implement with a single core microcontroller The next example application demonstrates the multicore approach and it uses other cogs to graphically display a spectrum analysis on a TV display for good measure TV display is another difficult task for single core microcontrollers In contrast the Propeller Library s TV 168 SENSOR BASICS AND MULTICORE SENSOR EXAMPLES 10 Audio Spectrum Analyzer Audio Spectrum Analyzer i Ee See And AT EET Pe 1000 500 1000 Hz Sweep Steps 1 Hz Sweep Steps Figure 4 36 Propeller Audio Spectrum Analyzer application and Graphics objects distill these multicore tasks down to a few method calls made by the top level application object Figure 4 36 shows TV display examples from Beau Schwabe s Propeller Application DEMO Spectrum Analyzer for Audio posted at http forums parallax com The microphone and Sigma Delta ADC circuit the application uses is similar to Fig 4 33 and the TV connection was introduced in the previous chapter The code utilizes the Propeller Library s TV and Graphics objects to draw the display and an object named Fast IO Grab to buffer digitized microphone vol
618. y the system The Spin code to implement our backpressure detection is shown here Check for Pressure Buildup pressure Reset amount of Vent Openings We assume here that at least 1 vent must be at 100 or the total sum of all open vents should add to 100 repeat count from O to 4 Calculate Total Vent Openings pressure pressure RoomCurrentVentPosPercent count if pressure lt 100 If this is true then there is not enough venting need to allocate the remainder totalvent 0 overpressure 10 pressure splitpressure overpressure 5 SUMMARY 423 pressure overpressure repeat count from O to 4 RoomCurrentVentPosPercent count RoomCurrentVentPosPercent count splitpressure totalvent totalvent RoomCurrentVentPosPercent count else pressure 0 Summary The Propeller powered HVAC green house shown in Fig 11 22 allowed us to explore parallel processing and distributed computing We delved into sensor sampling network communications servo motor control video display and data recording The simplicity of the Spin language combined with the power of objects makes it straightforward to convert theories into test cases It also allows us to avoid labor inertia that reluctance we all have to abandon a design after discovering a fatal flaw or a simpler better way to accomplish the task The Propeller chip with its multiple processors and large library of preexisting software objects allows

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