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Command Module Owner`s Manual

1. delay 2000 Wait for Create s bootloader to run iRobot Command Module Owner s Manual 23 iRobot The 100 ms delays are included in the code above so that fast transitions aren t missed by Create The following code turns off Create s power if PINB amp 0x20 if power is on PORTD amp 0x80 set D7 low delay 100 delay so new state is seen by Create PORTD 0x80 set D7 high to turn power off delay 100 delay so new state is seen Create 4 19 Putting the Command Module to Sleep The Command Module processor has a low power sleep mode You can put the module into this mode to conserve power without having to remove it from Create or turn it off Create s battery power is always available to the Command Module so the Command Module can drain Create s batteries if it is left in the robot The following code puts the processor into low power mode after first turning off Create and setting all of the Command Module pins and other hardware into the state that draws the least power include lt avr sleep h gt void powerOff void If Create s power is on turn it off using D7 if PINB amp 0x20 PORTD amp 0x80 delay10ms 50 Delay in this state PORTD 0x80 Low to high transition to toggle power delay10ms 10 PORTD amp 0x80 Configure pins and other hardware for minimum power wdt_disable disable watch dog timer ADCSR
2. 1 71 The fourth line of the code enables the timer interrupt See the ATMegai168 datasheet for more information on these control registers 2 Declare variables to store the current count of the timer and also a flag variable to let you know when the time has expired The timer counter should be a 16 bit variable to allow you to specify longer times up to 65 535 seconds You can use this variable to determine when a certain number of interrupts have elapsed Declare the variables with the following code volatile uint16_t timer_cnt 0 volatile uint8 t timer_running 0 3 Define the actual interrupt handler function code This code will get called by the microcontroller once per millisecond as specified by the timer registers above SIGNAL SIG_OUTPUT_COMPARE1A if timer_running if timer_cnt timer_cnt else timer_running 0 The first line declares that this is the handler function for the timer1A compare interrupt in the form that the AVR compiler expects See the avr libc documentation that came with WinAVR for information on how to declare other types of interrupt handlers The body of the interrupt checks to see if the timer is running and if it is running it reduces the timer counter by 1 When the timer counter has counted down to O it sets the timer_running variable to false 0 You can now put timed delays into your Command Module programs The following code allows you to do something for 2
3. WINAVR Make All WINAVR Make Clean m Taj d to run on the RDK mc d files include lt avr interrupt h gt include lt avr io h gt TIP If avrdude says cannot find the file specified check that you have the correct COM number and check all connections TIP If avrdude says not in sync resp 0x00 press reset before downloading Always press Reset on the Command Module before downloading iRobot Command Module Owner s Manual 12 iRobot Press the RESET button on the Command Module with the USB cable attached to start the bootloader In Programmers Notepad click on Tools gt WinAVR Program This starts the downloading program avrdude It communicates with the Command Module s bootloader to erase the Command Module s flash memory and then write in your new program This process can take up to a couple of minutes for a large program Avrdude outputs its status in the debug window as it erases the memory and then writes and verifies your new program On successful completion you will see text similar to the following toward the bottom of the text in the debug window avrdude verifying avrdude 2118 bytes of flash verified avrdude done Thank you If it doesn t successfully program and you get an error message similar to the ones listed below follow the suggestions that follow to fix the problem and try again avrdude p ATMegal68 P com9 U flash w input
4. net One of the best sources of information on the website is the forum where you can find answers to most of your development questions Be sure to search the forum before posting your own question because most common questions have already been answered already 3 2 Setting up a new project In this example you will set up a new project for the input example program The steps are similar for any new project you create 1 Get the source files Make a new directory on your computer and name it input Copy the files input c oi h and makefile from the examples input directory on the Command Module CD to this directory The file input c is the main C source code file oi h is the Open Interface header file and makefile contains instructions for Programmers Notepad on how to compile and download the project Programmers Notepad Wina YR 2 Start Programmers Notepad using the desktop shortcut If you don t have the shortcut find Programmers Notepad directly at C WinAVR pn pn exe if you used the default installation directory lt Programmers Notepad 2 Save AS AYR Assembler Save Al CtrleShaft 5 Batch Files Save Workspace As Ci C 3 Create a new project In Programmers Notepad go to File gt New and click on Project iRobot Command Module Owner s Manual 10 iRobot New Project Name input O CN Lox J ea 4 Click on the button to select the project dire
5. These registers must be set before using the PORTx and PINx registers Example Set pins CO C2 as inputs and C3 C7 as outputs DDRC OxF8 The hexadecimal hex value OxF8 11111000 in binary so the most significant 5 pins C3 C7 become outputs 4 6 PORTx Setting pullups on an input pin Register PORTX O pull up disabled 1 pull up enabled DDRD 0x01 enable pull up on pin BO only For an input pin a bit value of 1 in the PORTx register enables a pull up on that pin a bit value of O disables the pull up If the pin is an input with the pull up enabled it is guaranteed to be in the high state if it is not being driven low by external hardware If the pull up is not enabled on an input pin and it is not being driven then the pin is considered to be floating and you can t depend on it being in a specific state 4 7 PORTx Setting the state of an output pin Register PORTX O low 0 volts 1 high 5 volts DDRB 0x10 set pin B4 already an output to high The PORTx register sets the state of an output pin either high or low If the pin s bit is set as a O then that pin will be low O volts if it s a O then it will be high 5 volts Note that when a pin is an output the PORTx register specifies its state but when it is an input the PORTx register specifies whether its pull up in enabled To change the state of one pin at a time while leaving the other states undisturbed u
6. but it can be directed either to the Create connector or to the USB serial connector Sometimes you may want to debug your program by sending characters to the PC or sending characters to the module from your PC Pin B4 is connected to a device that can switch the UART from Create to the USB connector Make sure that this pin is always configured as an output If B4 is high 1 the UART is connected to the USB If B4 is low 0 the UART is connected to the Create connector After changing the destination of the UART wait for at least 10 bit times at your chosen baud rate before attempting to send or receive data For example at 57600 baud wait for at least 10 57600 seconds or 174 microseconds The following code provides some useful functions for sending characters out of either the USB or Create port define USB 1 define CR8 2 void setSerial uint8 t com if com USB PORTB 0x10 else if com CR8 PORTB amp 0x10 uint8 t getSerialDestination void if PORTB amp 0x10 return USB else return CR8 void writeChar char c uint8_t com uint8_t originalDestination getSerialDestination if com originalDestination setSerial com delayus 200 byteTx uint8_t c if com originalDestination setSerial originalDestination delayus 200 4 18 Powering Create You can turn Create s power on or off through the digital O lines of the Command Module If you have an a
7. 2 is on pin D6 A low signal turns the LED on and a high signal turns it off The following code sets up the pin directions and then turns LED 1 on and LED 2 off DDRD 0x60 make D5 and D6 outputs PORTD amp 0x20 turn led 1 on PORTD 0x40 turn led 2 off The LEDs on Create are controlled through the Open Interface with the four byte LED control command Note that the Open Interface must first be in Safe or Full Mode The states of the Advance and Play LEDs are set by bits 1 and 3 in the second byte and the power LED has its color and intensity set by the third and fourth bytes respectively The following code sets the power LED yellow at half intensity and turns on both of the other Create LEDs byteTx 132 Full Mode QxoA leds opcode byteTx 0x30 led bits byteTx 32 power led color byteTx 128 power led intensity You can try changing the values in the last three lines to see how they change the LEDs and refer to the Open Interface documentation for a complete description 5 4 Composing and playing songs You can use Create s Open Interface to define and play songs You can define up to 16 different songs and play them back at any time and in any sequence When you define a song you assign it a song number which you then later use to play that song You also specify the number of notes in the song and then each note and its length The notes are specified by MIDI
8. Make sure Create s serial cable is not plugged in Press the red Reset Button on the Command Module to start your program When the input program starts two LEDs should flash slowly one on the Command Module and one on Create itself Press the Play button on Create It will play a song and light the Advance LED on Create solid while the song is playing Press the soft button on the Command Module Create plays a different song and the LED on the Command Module stays lit while it s playing There are three different input output methods you can use in your programs two of which you ve just seen First you can read the state of Create s buttons and other sensors and set the state of its LEDs and motors using the Open Interface serial protocol Next you can interact with the Command Module s built in hardware by reading the state of the soft button or controlling LED 1 and LED 2 on the Command Module Finally you can add your own hardware for input and output The next chapter will walk you through adding another button and LED to one of the Command Module s input output I O ports and interacting with them with the input program A note on starting programs Normally if the USB cable is inserted in the Command Module when you press the reset button the Command Module runs its bootloader and does not start your program To run your program without first removing the USB cable press and hold down the programmable butto
9. Module is powered by an Atmel AVR ATMega168 microcontroller All of the code that you run and download to the Command Module runs on this processor Below is a list of the microcontroller s features including memory size and fuse setup For more detailed information on the ATMega168 see the datasheet on the Command Module Product CD The Command Module comes with a pre installed bootloader to allow you to easily download your own programs to the Command Module The bootloader is described in more detail in the Bootloader reference section Command Module s ATMega168 specifications e Architecture 8 bit RISC e Crystal frequency 18 432 MHz 18 432 000 Hz e Available Flash memory 7168 words 14336 bytes e EEPROM memory 512 bytes e Features o Two 8 bit timer counters o One 16 bit timer counter o 6 PWM channels o 8 channel 10 bit ADC o One serial UART o SPI interface o 2 wire serial interface o Watchdog timer o Interrupt and wakeup on pin change Reference e Fuse and lock bits are set to their defaults except as follows o Boot Flash section size 1024 words BOOTSZ 00 o Boot Reset vector enabled BOOTRST 0 o Brown out detection level at VCC 4 3V BODLEVEL 100 o Clock NOT divided by 8 CKDIV8 1 o External Crystal Oscillator Frequency 8 MHz CKSEL 1111 SUT 11 o SPM not allowed to write to the Boot Loader section BLB1 mode 2 BLB12 11 10 e Therefore fuse and lock byte value
10. PINx register and then use the bitwise and operator to check only the associated bit The following code branches your code according to the state of pin D7 if PIND amp 0x80 if D7 is high run this code else otherwise if D7 is low run this code If D7 was connected to a button you could use this code to perform different actions depending on whether the button was being pushed 4 10 Command Module Internal Pins The Command Module s ePorts only expose pins BO B3 and CO C5 See the Hardware Reference in chapter 9 for the details and locations of these pins on the ports The remaining pins are reserved for the Command Module s own hardware and the Create Cargo Bay Connector on the underside of the Command Module Pin Description Direction PB4 Serial port select 1 connect serial 1 O to USB Output port a0 connect serial I O to Create PB5 Create Power Detect High if Create is on Input PDO Serial Rx Input PD1 Serial Tx Output PD2 Create Device Detect Input Change Create s baud Output rate to 19200 by toggling this pin 3 times with 200 ms pulses or use the Baud command see the Open Interface documentation PD3 USB Detect Input PD4 Command Module Soft Button Input PD5 Command Module LED 1 Output PD6 Command Module LED 2 Output PD7 Create Power Toggle Turn Create on or off witha Output low to high transition For these pins only use the
11. The first line above waits in a while loop until the serial transmit buffer is empty and the second line loads the value to be sent 128 in this example These operations can be combined into a function named byteTx which will be used in the rest of the software examples in this chapter void byteTx uint8 t value while UCSROA amp 0x20 UDRO value 3 To receive a byte over the serial port wait for a byte to be available and then read the byte from the serial receive buffer The following code combines these operations into a function called byteRx uint8 t byteRx void while UCSROA amp x80 wait until a byte is received return UDRO This function will wait until it receives the next byte so don t call it unless you know a byte is being sent or you could end up waiting forever You can check if a byte is available with the following code if UCSROA amp 0x80 a serial byte is available You can also set up a serial receive interrupt to receive bytes in the background and store them for you to look at later in your program The drive example program uses this method to receive sensor information from the Open Interface You can copy this functionality by adapting your program from the drive example iRobot Command Module Owner s Manual 22 iRobot 4 17 Using the USB Port for Serial Debugging The Command Module processor only has one UART serial hardware device
12. are connected to the Command Module s four ePorts There are three ports on the top and one on the side facing the cargo bay The top three connectors are positioned so that you can attach sensors on the right left and center and compare their values to steer the robot TIP If you attach a light sensor to the analog input of each top connector you can program iRobot Create to follow a flashlight by turning toward the sensor that receives the most light The Cargo Bay ePort has extra I O lines for Create s Low Side Drivers which you can use to run motors without any additional hardware For a complete list of all of the Command Module s I O and connectors refer to the Hardware reference section in chapter 9 Some of the I O pins are connected to the Create CargoBay Connector located on the underside of the Command Module iRobot Command Module Owner s Manual 15 iRobot 4 4 The Digital 1 0 control registers The Command Module s ATMega168 microcontroller has three I O ports labeled B C and D Each of these ports contains 8 pins numbered O to 7 The Command Module s ePorts expose pins B 0 3 and C 0 5 See the Hardware Reference in chapter 8 for a table of which microcontroller pins are connected to which ePort pins The digital 1 O pins on each port are controlled and accessed by three built in registers per port You need to set the value of some of these registers before using the I O pins The regist
13. custom hardware to expand Create s capabilities without tethering the robot to a PC The Command Module plugs into Create s Cargo Bay Connector and it has four expansion ports that provide additional inputs and outputs for your custom hardware Three of the connectors are on the top surface spaced to provide easy attachment points for an array of sensors and one connector is on the back for easy access from the cargo bay The Command Module is powered by an Atmel AVR ATMega168 microcontroller which can be reprogrammed by downloading programs from your Windows XP computer with the included USB cable Your programs can use the iRobot Open Interface serial protocol to control Create s motors lights and speaker and read its sensors At the same time the microcontroller can directly interface with your own custom hardware through its I O connections Start with one of the example programs and expand and change it to add your own functionality Updates and more information are available at www irobot com create This manual assumes intermediate knowledge of the C or C programming languages including bitwise operators If you don t know either of these languages pick up a book on C from a library or bookstore You can also find a lot of good reference materials and tutorials online by searching for C language in an internet search engine Power LED Cargo Bay ePort Hold Down Screws Power Switch Top Right eP
14. hex c stk500 avrdude ser_open can t open device com9 The system cannot find the file specified e Make sure Create has a full set of charged batteries e Make sure that the Command Module is securely seated in Create e Make sure that the USB cable is firmly plugged into both the Command Module and your computer e Make sure that the COM number of the Command Module matches the com number listed in your makefile e Make sure that you installed the USB serial port for your Command Module as described in chapter 2 e Make sure that no other device is using the COM number in the makefile avrdude p ATMegal68 P com9 c stk500 U flash w input hex avrdude stk500_getsync not in sync resp 0x00 e Make sure Create has a full set of charged batteries e Make sure that the Command Module is securely seated in Create e Make sure that the USB cable is firmly plugged into both the Command Module and your computer e Press the reset button on the Command Module being sure not to press the soft button at the same time avrdude p ATMegal68 P com9 U flash w input hex c stk500 out then nothing happens e Make sure that the USB cable is firmly plugged into both the Command Module and your computer e Press the reset button on the Command Module being sure not to press the soft button at the same time 3 5 Testing the input example program Remove the USB cable from the Command Module
15. note number and the lengths are specified in multiples of 1 64th of a second The following code defines song number 3 to be the first seven notes of Mary had a Little Lamb byteTx 140 song opcode byteTx 3 song number byteTx 7 song length byteTx 71 note 1 number B byteTx 24 note 1 length 24 64 seconds byteTx 69 note 1 number A length 24 64 seconds number G length 24 64 seconds number A byteTx 24 note byteTx 67 note byteTx 24 note byteTx 69 note byteTx 24 note byteTx 71 note byteTx 24 note byteTx 71 note byteTx 24 note byteTx 71 note length 24 64 seconds number B length 24 64 seconds number B length 24 64 seconds number B PP RP RP PP BP BP BP Be byteTx 48 note m length 48 64 seconds To play back the song send the play command byteTx 132 Full Mode byteTx 141 play opcode byteTx 3 song number You can define all of the songs at the beginning of your program or right before you play them Note that the Open Interface must be in Full or Safe mode to play a song For more information about the song interface including a reference of all of the note numbers that Create can play refer to the Open Interface documentation iRobot Command Module Owner s Manual 26 iRobot 5 5 Moving Create The Open Interfa
16. takes a light measurement when it first starts to calibrate the sensor and when it finds an area with significantly more light it stops and beeps so that you can locate it and turn off the light The light example program uses the ADC to measure the analog voltage from a CDS light sensor When more light hits the CDS sensor you will measure a higher voltage at the ADC input and vice versa The example program then uses this information to search for and identify lights left on To try the light example program you need to make your own light sensor Buy a CDS light sensor a 10 K resistor and a male DB 9 connector to allow you to easily plug the sensor into the Command Module Please see Appendix A for several sources where you can buy these components Once you have the components assemble them as shown in Figure 5 CDS Light Sensor 10K Transistor Create Figure 5 Light sensor assembly for the light example program iRobot Command Module Owner s Manual 19 iRobot Your light sensor is now ready to use Insert it into the top center ePort Now create a new project build the light example program and download it into the Command Module using the process explained in chapter 3 Download the latest source files from www irobot com create Look through the code to see that the program takes one ADC measurement when it first starts in order to set a baseline light measurement Then it continuously measures t
17. text file in case you need to restore it later 1 Insert the Command Module product CD into your computer Start the WinAVR installation program WinAVR 20060421 install exe by double clicking on it 2 Select your language Installer Language e x amp Please select a language Cr lt a 3 Click through the rest of the install screens accepting the defaults WINAVR 20060421 Setup i 215 x Welcome to the WinAVR 20060421 Setup Wizard This wizard will guide you through the installation of WinAYR 20060421 Tt is recommended that you close all other applications before starting Setup This will make t possible to update relevant system files without having to reboot your computer Click Next to continue 4 The last screen says that WinAVR has been installed on your computer The installation is now complete Click Finish WinAYR 20060421 Setup 5 xj Completing the WinAVR 20060421 Setup Wizard WInAYR 20060421 has been installed on your computer Click Finish to close this wizard iRobot Command Module Owner s Manual iRobot 2 4 Installing the USB serial port To install the drivers for the USB serial port connect your Command Module to your PC using the provided USB cable as shown in Figure 3 Included USB Cable USB Port on PC USB Port on Command Module Command Module Create Figure 3 Connecting the Command Module to your computer s USB port The Com
18. 90 Other patents pending iRobot Command Module Owner s Manual
19. A 0x00 disable the ADC UCSROB 0x00 disable UART CLIJ disable interrupts PRR QxFF enable all power reduction modes DDRB 0x10 Set b4 as output other B pins as input PORTB OxOF set ePort pins BO 3 high DDRC 0x00 set all C pins as input PORTC x7F enable pull ups on all C pins DDRD OxEE DO rx and D4 button are inputs PORTD 0x78 configure D pins Put the command module into sleep mode These functions are defined lt in avr sleep h gt set_sleep_mode SLEEP_MODE_PWR_DOWN sleep_mode iRobot Command Module Owner s Manual 24 iRobot 5 Open Interface Reference For full details on Create s Open Interface serial protocol see the Open Interface Command Reference at www irobot com create This chapter gives an overview of some of the features of the Open Interface along with code examples for using these features 5 1 Starting the Open Interface The processor in the Command Module is an Atmel ATMegai68 8 bit microcontroller All of the operations on the processor are carried out with 8 bit registers as opposed to the 32 bit registers in most home computers For efficiency use 8 bit variables and calculations wherever possible only using 16 bit variables wherever their greater range is really necessary Make sure that Create s Mini DIN port does not have a serial cable connected or Create will not receive the serial commands from the Command Modu
20. DCSRA 0x87 enable ADC prescale 128 ADMUX 0x40 set voltage reference The first line above sets up pins C4 and C5 as inputs The second line disables the digital inputs on these pins to save power when you only want to use them as analog inputs The third line turns off a power saving feature that can t be used when using the ADC The fourth line enables the ADC and sets the ADC prescaler to a value of 128 in order to slow down the clock that controls the ADC so that it functions properly while still allowing the main processor to run at a faster frequency The last line sets up the voltage reference to be the internal processor pin AVcc which is 5V in the Command Module The next step is to set up Some variables to store the result of the measurements The following code declares two 16 bit variables needed to store the 10 bit ADC results uintl6_t meas_c4 uintl6_t meas_c5 iRobot Command Module Owner s Manual 18 iRobot 2 Select the channel as C4 and take the first measurement ADMUX amp 0x0F clear the ADC channel ADMUX 0x04 set the ADC channel to C4 ADCSRA 0x40 start the ADC measurement while ADCSRA amp 0x40 wait until it s done meas_c4 ADC save the result The low 4 bits of the ADMUX register let you select which pin to read from CO C7 So the first two lines of the code clear the ADC channel and then set it to a value of 4 for
21. Port Settings Driver Detais B s per second a00 xj Dase x Barty Noe Stopb s f xl Elow contot Noe z Select the Port Settings tab and then click on the Advanced button Advanced Settings for COM4 3j xj COMPotNunbec MEYN r USB Transfer Sizes Cancel Select lower settings to correct performance problems at low baud rates Select higher settings for faster perfomance Odan Recesve Bytes faoss Transmit Bytes fias r BM Options Miscalaneous Options Select lower settings to correct response problems Serial Eruenseator F Senal Prever r Latency Ta fis o Cancel It Power Off r Timeouts Evert On Suprise Remova I Set RTS On Cose r Mirena Read Timeout msec fo Minium Wite Timeouttmeec 0 Change the COM Port Number to COM9 or another unused port between COM1 and COM9 using the pull down menu Using a high port number will reduce the chances that the port setting will interfere with other hardware that you may install on your computer in the future All of the example programs assume that you are using COM9 If you use a COM port other than COMQ you will need to update the example program s makefile before you download to the Command Module The installation is now complete iRobot Command Module Owner s Manual iRobot 5 Your First Project The example programs are a good place to start using the Command Module The program that came preprogrammed on y
22. ake sure it is firmly Turn on Create and wait two seconds until Create s Power seated LED stops flashing which indicates that Create is now running its main code Press the reset button on the Command Module and listen for a series of fast beeps The LEDs on the Command Module and Create will blink slowly Place Create on the ground and press the black soft button on the Command Module The robot will play another song and then start driving around and flashing its LEDs in sequence beeping and turning when it bumps into something To stop the robot press the soft button again or pick the robot up Troubleshooting e After turning on Create always wait until Create s Power LED stops flashing rapidly before starting a Command Module program Create Figure 1 Inserting the Command Module into Create connector e Make sure the Command Module is securely seated e Make sure that your iRobot Create has a full set of charged batteries See Create documentation for more Tighten the two hold down screws on either end of the information on batteries Command Module with a Phillips head screwdriver as shown in Figure 2 e Ensure that Create s serial cable is not connected to its Mini DIN connector e Disconnect the USB cable from the Command Module Command Module Philips head Hold Down Screws Screwdriver Command Module we Create J L D Create Figure 2 Securing the Command Modul
23. ashing including the one on the assembly you just installed If you press the button on your assembly the input program will light the LED solid and play a third song 4 12 Taking an analog measurement using the ADC The I O pins on PORTC of the Command Module can be used to take analog measurements with the processor s 10 bit Analog to Digital converter ADC For full details on the ADC see the Analog to Digital Converter section of the processor datasheet included on the Product CD The 10 bit ADC uses a 5V reference so the result of an analog measurement on the Command Module is an unsigned 10 bit number with a value from O to 1023 representing input voltages from O V to 5 V For instance an input voltage of 1 V gives you an ADC reading of 205 according to the formula ADC reading Vin 1024 Vref 1 V 1024 5V 205 To take an analog measurement you need to set up the ADC start the measurement and then store the result when it is done Each of these operations uses registers which are predefined in the WINAVR environment in the lt avr io h gt header 1 Set up the ADC The following code uses predefined registers to set the processor up to take analog measurements on pins C4 and C5 located on pint of the Cargo Bay and top center ePorts respectively DDRC amp 0xC30 set C4 C5 as inputs DIDRO 0x30 disable digital input on C4 C5 PRR amp 0x01 disable ADC power reduction A
24. ccezces ste tacsciceeccactee ters viesucecceee targreeeds 7 2 4 Installing the USB Seta DOM ssc csrescecszcstacsneceeccachesdere eben tcecaece tars ceenes 8 3 Your First Project wiccciscscsicice ssec snes eescemscuncmssseneusemscantenesadinndumccacteceucmaccesiew 10 3 1 Developing for the Command Module g acciccc cececcescrco recs ccezestestesteeaceen ds 10 3 2 Setting UN a NEW ONO OCU rice cate ccsccrdtecusmertvonseceseciseesincataee de USETE 10 3 3 Compiling your DIOlECT ics serichcatacusnesde caster ien ie NEA EEEE DAER RA ENESA 11 3 4 Downloading your project over the USB link cscsseeeseeeeeseeeees 12 3 5 Testing the input example POG FAIN wise cseinccesnsenstectetentsetecseceesedseeanees 13 3 6 Creating your OWM PIOlOCE oicg sec cdcenteanc sacred rae EEE EEE ERTETEK EREE 14 4 SoftWare Referente ion cnccciiecescnsensnsictnncinssnninmensanincwnscnsencenentnenancnsneannenines 15 4 1 Declaring and using variables and registers on the ATMega168 15 4 2 1 0 Pim aS eiren EEE E REEERE 15 4 3 The Command Module s connectors s s sssesessssrssrenrrsrrrrenrrerenrenenne 15 4 4 The Digital I O control registers s ssssessserensrrrrsrennrsrrrrenrnerrnrenrnnne 16 4 5 DDRx Setting the direction of a piNn ssssssssssessrsrssrerrrsrrrrenererrsrrnerne 16 4 6 PORTX Setting pullups on an input pin siscsssicesuscsadeseesacdmadediveursinanes 16 4 7 PORTx Setting the state of an output pin s sesssssserersrrrrrrr
25. ce drive command to move Create is five bytes long The opcode is followed by two signed 16 bit values specifying the velocity in mm s and the radius in mm Each 16 bit value is sent as two bytes high byte first The following code makes Create drive straight forward byteTx 132 Full Mode byteTx 137 drive opcode byteTx 0x01 velocity high byte byteTx 0x2C velocity low byte byteTx 0x80 radius high byte byteTx 0x00 radius low byte The first line puts the Open Interface in Full Mode Note that the Open Interface must first be in Safe or Full Mode for the Drive command to work Combining the value on the third and fourth lines above you can see that the velocity sent was a 16 bit value of OxO12C 300 which makes the robot drive forward at 300 mm s about a foot per second The fourth and fifth lines combine to send a radius value of Ox8000 which is the special case value indicating that the robot should drive straight The following code makes Create drive backward slowly 100 mm s at a radius of 500 mm byteTx 137 byteTx OxFF velocity high byte byteTx 0x9C velocity low byte byteTx 0x01 radius high byte drive opcode byteTx OxF4 radius low byte The velocity value of 100 as a signed 16 bit hex number is OxFF9C is sent as the second and third bytes The radius of 500 becomes Ox01F4 as a 16 bit hex number Refer to the Open Interface documenta
26. ctory where you saved the project code in step 1 Fill in a name for your new project such as input and click the OK button Programmers Notepad 2 File Edt view Tools window Help 5 Addfilestoyourproject Yournewproject shouldnowshow up inthe upper left hand window of Programmers Notepad Right click on the name of the project under New Project Group and select the Add Files option In the dialog box that opens find your input project directory select the file input c and click the Open button to add it to your project The file you just added will now show up beneath the project name Repeat these steps to also add oi h and makefile to your project 3 3 Compiling your project File Edt view Tods Window Help 2 bb CP une endines v Use Tabs G New Project Group a adra Wina VR Make Clean makefile WinAyR Program ih oih Sop Took Grt gg Projects E Text Cips In Programmers Notepad double click on one of the source files that you added to open it Click on Tools gt WinAVR Make All Text will appear in the output window at the bottom of Programmers Notepad showing the results of your compilation This output window will also list any errors and the line numbers where they occur in your files You should not get any errors with the provided example programs but errors may occur as you develop your own code If there are a
27. d to compile download and test your program 3 6 0 The example programs By looking at the source code of the example programs you can get a sense for the kind of code you can write for the Command Module Below is a brief description of the three example programs 3 6 1 Drive The drive example program comes preprogrammed into the Command Module It demonstrates the basic capabilities of the Command Module and the iRobot Create Open Interface by driving around reacting to sensors and using various inputs and outputs It makes a series of rising beeps when it is first powered to let you know the Command Module is alive and blinks Create s LEDs note that the program makes Create s power LED orange Then if you place Create on the floor and press the Command Module s soft button it starts driving on the floor backing up and turning when it runs into something with its bumper and blinking all LEDs in a pattern To stop the program press the button again or simply pick it up The code provides useful function to initialize the Command Module and iRobot Create continuously read Create s sensor values drive Create turn on Create and change the baud rate You can add capabilities to the main function of the program using the software examples in chapter 5 3 6 2 Input The input example program illustrates the three types of input and output that you can use with the Command Module You can interact with hardware on iR
28. direction stated in the table above The remaining pins B6 7 C6 7 are for Command Module internal use only Their direction is set in hardware and cannot be changed with software iRobot Command Module Owner s Manual 17 iRobot 4 11 Adding a button and LED to the input example program In chapter 3 you saw that the input example program looks for button presses on Create and on the Command Module and plays a song and lights an LED when a button is pressed The program is also looking for button presses on atop center ePort input pin and setting an ePort output pin to drive an LED Buy a standard pushbutton and an LED from one of the sources listed in Appendix A Solder them onto a male DB 9 connector as shown in Figure 4 The button is connected to pin 3 B1 and pin 5 GND and the LED is connected to pin 2 C1 and pin 4 5V with the flat side toward pin 2 and the longer lead connected to pin 4 This makes the LED active low lit when low Longer leg of LED Flat side of LED Pin 4 5 VDC meato M EEA Back side of male DB9 connector Pin 3 B1 Pin 2 C1 Create Figure 4 Button and LED assembly for the input example program Plug this assembly into the top center ePort Install the Command Module in Create Reload the input example program onto the Command Module if necessary and restart it by removing the USB cable and pressing the Command Module s reset button You should notice three LEDs fl
29. e Command Module s hardware For full details on the ATMega168 s registers and features please see the ATMeta168 datasheet included on the product CD 4 1 Declaring and using variables and registers on the ATMega168 The processor in the Command Module is an Atmel ATMegai68 8 bit microcontroller All of the operations on the processor are carried out with 8 bit registers as opposed to the 32 bit registers in most home computers For efficiency use 8 bit variables and calculations wherever possible only using 16 bit variables wherever their greater range is really necessary Do not use floating point numbers or division in your Command Module code The ATMega168 doesn t have hardware to handle floating point numbers or divide operations If you use these your compiled code gets big very fast Instead use integers and use right shifts gt gt instead of divides The example programs use explicit type notation so that you can easily tell the size of a variable This notation is recommended for all of your own code The example code declares variables with the following types uint8_t variable_a unsigned 8 bit variable int8_t variable_b signed 8 bit variable uint16_t variable_c unsigned 16 bit variable int16_t variable_d signed 16 bit variable To use these variable types include the stdlib h file at the beginning of your program include lt stdlib h gt The microcontroller s built in registe
30. e with the hold down screws iRobot Command Module Owner s Manual 6 iRobot 2 3 Installing the development tools The development tools provided on the included CD ROM allow you to create your own Command Module programs The Command Module uses the WinAVR set of open source development tools to let you write your own programs in the C or C languages The development tools include an editor compiler and a downloader for loading your program onto the Command Module For more information on WinAVR please check the project website at http winavr sourceforge net To install WinAVR on your Windows XP computer perform the steps below If you have a previous version of WinAVR installed on your computer please uninstall it before proceeding NOTE WinAVR places its access paths at the front of Window s PATH environment variable This can cause conflicts with application that use executables or dlls that are also in WinAVR e g make exe tclsh84 dll To fix this after installing move WinAVR s paths to the end of the PATH environment variable Open Settings gt Control Panel gt System click on Advanced click on Environment Variables Select Path under System Variables click on Edit move C WinAVR utils bin and C WinAVR bin to the end of the list after a semicolon and click OK 3 times On one occasion installing WinAVR wiped out the installer s entire path For safety copy the value of your path variable to a spare
31. en continuously low for 50 ms and can be considered pressed If the button is ever high the counter is reset so that the debouncer will reject any short pulses You can add this or similar code to your programs to ensure reliable button input iRobot Command Module Owner s Manual 21 iRobot 4 16 Setting up and using the serial port To control Create you communicate with it through the Open Interface serial protocol In order to do that you need to set up and use the Command Module s serial port Note that Create requires that data sent at its highest baud rate 115200 be sent a minimum of 200usec apart This requires using registers that are defined in the lt avr io h gt header that is included with WinAVR See the processor datasheet on the CD for more details on the serial port registers 1 Configure the serial port at the beginning of your program The following code sets up the serial port to communicate at 57600 baud UBRRO 19 UCSROB 0x18 UCSROC 0x06 The first line of the code above selects the baud rate according to the formula UBRRO processor_frequency 16 baud_rate 1 UBRRO 18432000 16 57600 1 19 Also see Changing the baud rate below The second line enables the transmit and receive functions of the serial port and the third line selects 8 bit data 2 To send a value over the serial port use code such as while UCSROA amp 0x20 UDRO 128
32. en though you think it should To make sure that no intermediate files generated by the compiler are causing a problem click on Tools gt WinAVR Make Clean and then try compiling again 3 4 Downloading your project over the USB link The next step is to download your compiled hex file into the Command Module Before downloading check that e The Command Module is turned on e You have pressed RESET on the Command Module to force it to run its bootloader e There is a full set of charged batteries in Create e Create is turned on and its Power LED has stopped flashing e Create s serial cable is not plugged in e The Command Module is securely seated on Create cargo bay connector e The Command Module is connected to your computer with the supplied USB cable and you have installed the USB serial port drivers as described in 2 4 e The COM port of your Command Module matches the COM port listed in the makefile The example programs assume you are using COM9 If you installed your Command Module on a different port number update your makefile Open the makefile in a text editor and search for where the variable AVRDUDE_PORT is set on line 204 in the input project makefile Change the value from COM9 to your desired port number for example AVRDUDE_PORT com4 programmer connected to serial device Endings gt Joelia _ v Use Tabs New Project Group 5 input C input c j makefile h oih
33. ers are predefined as 8 bit variables in the lt avr io h gt header file which is installed with WINAVR The I O registers are Summarized in the table below and more information on setting their values is included in the sections that follow DDRB Port B direction register Bit values O input 1 output DDRC Port C direction register Bit values O input 1 output DDRD Port D direction register Bit values O input 1 output PORTB Port B data register Output bit values O low 1 high Input bit values O pull up disabled 1 pull up enabled PORTC Port C data register Output bit values O low 1 high Input bit values O pull up disabled 1 pull up enabled PORTD Port D data register Output bit values O low 1 high Input bit values O pull up disabled 1 pull up enabled PINB Port B input register Bit values O pin is low 1 pin is high PINC Port C input register Bit values O pin is low 1 pin is high PIND Port D input register Bit values O pin is low 1 pin is high 4 5 DDRx Setting the direction of a pin Register DDRx O input 1 output The DDRx registers Substitute B C or D for the x control the direction of the eight pins in a port If the bit associated with the pin is set to a O then that pin is an input for example a sensor or button if it s a 1 then it s an output for example a motor or LED
34. eset The bootloader loads programs using the STK500 version 1 protocol This protocol is designed into the avrdude downloading software and is selected using the c stk500 command line option Avrdude is called automatically by Programmers Notepad when you download code into the Command Module using the Tools gt WinAVR Program option as explained in chapter 3 If desired you can run avrdude directly at a command prompt enter avrdude at the command prompt to get a list of avrdude command options iRobot Command Module Owner s Manual 30 iRobot Hardware Reference 8 1 ePort Pinouts The Command Module has a total of four Expansion Ports ePorts that allow you to add external electronics to the Command Module These ports provide e 4 analog inputs e 3 general purpose input output pins e 3 three high current low side drivers The ePorts use a standard female DB9 connector The following diagram shows the location of the 4 ePorts on the Command Module Top Center ePort Top Left ePort Top Right ePort USB Connector Command Module Cargo Bay ePort iRobot Create The ePorts have pin number connections as shown in the following diagram The numbers are shown looking down on to the ePorts OOOO 99006 8 2 ePort I O connections The tables below show the signal connections for the each of the ePorts All of the ports have similar electrical connections allowing ePort add on modules to be insta
35. f an electrical fault Only experienced users should attempt to design and build their own circuitry Prebuilt ePort modules are available from a supplier listed in the Appendix A and are suitable for users who lack the experience to design their own circuitry e Always use care when wiring custom circuitry to an ePort e Never run your iRobot Create unattended e Always fully test your new designs under close supervision e Always remove the battery from Create or remove the ePort add on circuitry from Create before handling it e Never touch the circuitry with the power turned on e Enclose your add on circuitry so it is not inadvertently shorted during operation e The Vcc and Vpwr supplies are protected by a self resetting fuse within Create If you exceed the current ratings power Create off for 30 seconds to reset the fuse iRobot Command Module Owner s Manual iRobot Table of Contents lnt rod ction senicncacntinescpnnaiunetwtiunnatmmnnenanamnamannewaeaacebaumcsewanereniwenumeapmeniwaaywie 5 LL Pe ONIN earo eens scbensus aces E a a EE 5 TZ OVE 2 2a Rn ene e a a eer rere eae 5 1 3 Example applications wc 5siascaccnsesdssensancacanectcanascaecisaneadsaataennananancasanne 5 2 Getting Started ee EE 6 2 1 Plugging in the Command Module ceeceeeeeeeeeeeeeeeeeeeeeeeeneees 6 2 2 Running the preinstalled drive demo program eeeeeeeeeeeeeeees 6 2 3 Installing the development TOONS c
36. he light level in the main loop of the program while running and compares the current value with the baseline You can set off the alarm early by shining a flashlight on the light sensor Try running the light example program and changing some of the parameters to see how it changes the behavior 4 14 Using a timer You can use timers to control Create s motions generate signals or time events This section will show you how to set up a countdown timer with 1 millisecond ms accuracy using one of the ATMega168 s timer interrupts This section assumes basic familiarity with microprocessor interrupts The frequency of the processor in the command module is 18 432 MHz 1 Set up an interrupt to occur once every millisecond Toward the beginning of your program set up and enable the timer interrupt with the following code TCCR1IA 0x00 TCCR1B OxOC OCRIA 71 TIMSK1 0x02 The first two lines of the code put the timer in a mode in which it generates an interrupt and resets a counter when the timer value reaches the value of OCR1A and select a prescaler value of 256 meaning that the timer runs at 1 256th the speed of the processor The third line sets the reset value of the timer To generate an interrupt every 1ms the interrupt frequency will be 1000 Hz To calculate the value for OCR1A use the following formula OCR1A processor_frequency prescaler interrupt_frequency 1 OCRIA 18432000 256 1000
37. iRobot Command Module OWNERS MANUAL iVRobots www irobot com iRobot Important Safety Instructions GENERAL SAFETY INSTRUCTIONS e Read all safety and operating instructions before operating iRobot Command Module e Retain the safety and operating instructions for future reference e Follow all operating and use instructions e Refer all non routine servicing to iRobot COMMAND MODULE USE RESTRICTIONS e The Command Module is for indoor use only e Do not sit or stand on this device e Keep the switch in the off position otherwise the Create robot battery will drain when iRobot Command Module is on Do not pour or spray water onto iRobot Command Module Do not expose iRobot Command Module to anything hazardous or anything that is burning or smoking iRobot Create has built in safety sensors to keep it from falling down stairs and bumping hard into walls iRobot is not responsible for any product issues that may arise if you disable those sensors using the Command Module Never handle the Command Module with wet hands Only experienced users should attempt to design and build their own circuitry ePort SAFETY INSTRUCTIONS The maximum voltage available on the ePort is 21V so the ePort pins will not shock you if they contact your skin However the ePort can supply over 20 watts of electrical power In the event of an electrical fault this can generate enough heat to burn you or start a fire in the event o
38. in 4 or Analog Input 4 PC4 ADC4 2 Digital I O Port C pin O or Analog Input O PCO ADCO 3 Digital 1 0 Port B pin 0 PBO 4 Regulated 5V voltage when Create is on Vcc 5 Create Battery Ground Gnd 6 Not Connected NC 7 Create Battery Voltage when Create is on Vpwr 8 Low Side Driver 1 LD1 9 Low Side Driver 2 LD2 iRobot Command Module Owner s Manual 31 iRobot Processor 1 0 Pins Pin Description Location Name PBO Digital 1 0 Cargo Bay ePort pin 3 PB1 Digital 1 0 Top Center ePort pin 3 PB2 Digital 1 0 Top Right ePort pin 2 PB3 Digital 1 0 Top Left ePort pin 3 PB4 Serial port connector select 1 USB port Internal O Create PB5 Create Power Detect High if Create is on Create connector pins 10 13 PB6 Clock line Internal Use only PB7 Clock line Internal Use only PCO Digital I O or Analog Input Cargo Bay ePort pin 2 PC1 Digital I O or Analog Input Top Center eport pin 2 PC2 Digital I O or Analog Input Top Right ePort pin 2 PC3 Digital I O or Analog Input Top Left ePort pin 2 PC4 Digital 1 O or Analog Input Cargo Bay ePort pin 1 PC5 Digital I O or Analog Input Top Center eport pin 2 PCG Reset Line Internal Use only PDO Serial Rx Create connector pin 2 or USB PD1 Serial Tx Create connector pin 1 or USB PD2 Create Device Detect Input Create connector pin 15 PD3 USB Detect USB port PD4 Comma
39. le After configuring the Command Module s serial port see section 4 16 start the Open Interface by sending the startup and full commands to Create as follows byteTx 128 start opcode byteTx 132 full opcode The start opcode on the first line turns on the interface and should always be the first thing you send At this point the Ol is in passive mode in which you can read the sensors but not send commands The second line gives you full control over Create and turns off the safety features If you send the safe command instead 131 Create will be in safe mode and will stop and revert to passive mode if it detects a cliff with its wheel drop sensors or cliff sensors 5 2 Changing the baud rate Create starts up with the serial port listening for commands at 57600 baud With the Command Module it is recommended to run at a lower baud rate such as 28800 baud to ensure that no data gets lost or corrupted This section shows you how to change the baud rate both on Create through the Open Interface and locally on the Command Module 1 Switch the baud rate on Create by sending the baud opcode followed by the baud code for 28800 byteTx 129 baud opcode UCSROA 0x40 byteTx 8 baud code for 28800 while UCSROA amp 0x40 The second line in the above code sets up a transmit flag and the fourth line waits in a while loop until the flag is cleared This is necessary s
40. lled in any of the ports depending on your needs The metal shields and screw jacks on the ePorts are connected to ground The ePorts are not RS 232 serial ports Do not connect an ePort to a PC Top Left ePort Pin Description Name 1 Analog Input 7 ADC7 2 Digital I O Port C pin 3 or Analog Input 4 PC3 ADC4 3 Digital 1 0 Port B pin 3 PB3 4 Regulated 5V voltage when Create is on Vcc 5 Create Battery Ground Gnd 6 Not Connected NC 7 Create Battery Voltage when Create is on Vpwr 8 Not Connected NC 9 Low Side Driver O LDO Top Center ePort Pin Description Name 1 Digital I O Port C pin 5 or Analog Input 5 PC5 ADC5 2 Digital I O Port C pin 1 or Analog Input 1 PC1 ADC1 3 Digital 1 0 Port B pin 1 PB1 4 Regulated 5V voltage when Create is on Vcc 5 Create Battery Ground Gnd 6 Not Connected NC 7 Create Battery Voltage when Create is on Vpwr 8 Not Connected NC 9 Low Side Driver O LDO Top Right ePort Pin Description Name al Analog Input 6 ADC6 2 Digital I O Port C pin 2 or Analog Input 2 PC2 ADC2 3 Digital 1 0 Port B pin 2 PB2 4 Regulated 5V voltage when Create is on Vcc 5 Create Battery Ground Gnd 6 Not Connected NC 7 Create Battery Voltage when Create is on Vpwr 8 Not Connected NC 9 Low Side Driver O LDO Cargo Bay ePort Pin Description Name 1 Digital I O Port C p
41. mand Module product CD Install the drivers manually by double clicking on CDM_Setup_32 exe if you have 32 bit Windows XP or CDM_Setup_64 exe if you have 64 bit Windows XP iRobot Command Module Owner s Manual iRobot The New Hardware Wizard window will then pop up a second time showing that it has found a USB Serial Port Repeat the above procedure again selecting the Install the software automatically option Once the driver installation has completed click the Finish button and proceed to the next step Next find the COM port number which was assigned to the Command Module On your PC go to Start gt Settings gt Control Panel gt System Go to the Hardware tab and click the Device Manager button Scroll down and expand the Ports COM amp LPT category by clicking on the sign Ele Action Yew Help e PSS R ARa 8 Device Manager mi x B IDE ATAJATAPI controllers E IEEE 1394 Bus host controllers gt Keyboards E 5 Mice and other pointing devices H Monitors EEP Network adapters g Other devices Ports COM amp LPT F Communications Port COM1 a Communications Port COM2 E Processors amp SCSI and RAID controllers w Sound video and game controllers Ei System devices ica Universal Serial Bus controllers T Double click on the USB Serial Port line to launch the properties window USB Serial Port COM4 Properties 2 xj General
42. mand Module should be automatically detected and the New Hardware Wizard window will pop up Select Yes to allow Windows to connect to Windows Update Found New Hardware Wizard Welcome to the Found New Hardware Wizard Windows wil search for current and updated software by looking on your computer on the hardware installation CD of on the Windows Update Web site with your permission Bead our privacy policy Can Windows connect to Windows Update to search for software C Yes this time only Fes now and every time connect a device C No not this time Click Next to continue Select the Install the software automatically option Found New Hardware Wizard Welcome to the Found New Hardware Wizard This wizard helps you install software for FT232R USB UART If your hardware came with an installation CD lt gt or floppy disk insert it now What do you want the wizard to do G instal the software automatically Recommended Install from a list or specific location Advanced Click Next to continue It should install the driver and return without errors saying that the hardware is installed and ready to use Found New Hardware Wizard Completing the Found New Hardware Wizard The wizard has finished installing the software for USB Serial Converter Click Finish to close the wizard If the wizard says that it is unable to find the software quit the wizard and open the Com
43. n on the Command Module as you press the reset button TIP To run your program with the USB cable attached hold down the soft button while pressing the reset button iRobot Command Module Owner s Manual 13 iRobot 3 6 Creating your own project The easiest way to start a project is to copy one of the example programs and modify it for your own application For instance the framework for sending commands and reading sensors provided by the drive example can be useful for most applications To create your own project based on the drive example perform the following steps 1 Copy drive c oi h and makefile from the drive example directory over to your new project directory 2 Inthe new directory rename drive c to the desired name for your new program such as myapp c 3 Edit the makefile to reflect the new name of your application Specifically you need to change the value of TARGET to the name of your new application On line 59 of the drive makefile you ll see the line TARGET drive Change this to the new name of your application For instance TARGET myapp Next change the behavior of the program to suit your new application by changing the C code In drive c the behavior of Create is defined in the main function Refer to chapters 5 and 6 for examples of the different functionality that you can add When you re ready with your code repeat all of the steps in this chapter to set up a project an
44. nd Module Soft Button Left button PD5 Command Module LED 1 Left green LED PD6 Command Module LED 2 Right green LED PD7 Create Power Toggle on rising edge Create connector pin 3 ADC6 Analog Input Top Right ePort pin 1 ADC7 Analog Input Top Left ePort pin 1 8 3 ePort connection types and interfacing The ePorts include several different types of connections including ADC inputs Digital Os low side drivers and power supply lines The connections labeled as Digital O or ADC Input can be configured in software to be either type see sections 4 5 and 4 12 The ePorts Digital I O and ADC input lines have the electrical circuit model shown in the following schematic The connector s pins are connected to the Command Module s internal processor through an electrical protection network to protect against electrostatic shock damage To Processor 5V 5V ps To ePort me A NWN la i A R H The RPU pull up resistor shown in the schematics is internal to the processor and is only available on the Digital 1 0 lines and not the ADC input lines It can be enabled or disabled by setting or clearing the appropriate 1 O configuration registers When configured as an output the Digital I O lines are capable of sinking more current than they can source An output is considered to source current when current follows out of the pin through an external component and into the ground
45. nstead of counting every transition you only want to consider the button as pressed once it has settled down To add this type of filtering to the button you ll want to keep sampling the input periodically and only consider the button pressed once it has been in the pressed state continuously for a certain number of samples For a button input debouncing for 50 milliseconds ms is plenty of filtering 1 Toward the beginning of your program set up the input pin B1 in this example and declare the variables needed Connect the button between B1 and ground Then when the button is pressed B1 will go low uint8 t button_pressed Q uint8 t button_cnt 0 DDRB amp 0x02 make B1 an input PORTB 0x02 activate B1 pull up 2 Add the following code in your program where you are looking for a button press It will debounce the button for 50 ms button_pressed 0 while button_pressed if PINB amp 0x02 check the button button_cnt 0 if not pressed else button_cnt if pressed if button_cnt gt 50 button_pressed 1 delayMs 1 delay for 1 ms using timer function The code above waits in a while loop counting the number of times that the button input is low Since there is a 1ms delay in the loop each increment of button_cnt represents 1 ms of time Section 4 14 describes how to implement the delay functionality When button_cnt reaches 50 the input has be
46. ny errors fix them and compile again You can edit your text files in Programmers Notepad see the File menu or you can use any other text editor to change your files and just use Programmers Notepad to compile and download your projects iRobot Command Module Owner s Manual 11 iRobot ta Projects B Text dips mon sa Fie E ER e input sym avr nm n input elf gt input sym Size after input elf section size addr data O 8388864 ie DSS 8388864 noinit o 8388864 eeprom o 8454144 stab 876 o stabstr 132 o debug_aranges 20 debug_pubnames 139 e debug info 517 0 debug_abbrev 299 0 debug_line 1073 ie debug_str 286 o Total 4332 gt Process Exit Code 0 gt Time Taken 00 08 efa f11 327 fansi CR LF INS Project selected When your compilation is successful the size of your compiled file in bytes will be listed toward the bottom of output window on the line labeled text outlined in the picture above your statistics may be slightly different The maximum size program that fits in the Command Module s flash memory is 14336 bytes 7168 words The top 1024 words of the flash memory are taken up by the bootloader and can t be used When your compilation is successful it creates a hex file input hex in this case in your project directory that you can load into the Command Module Sometimes when developing your own code the compilation may not work ev
47. o set the low side drivers to output intermediate voltages using pulse width modulation PWM with the PWM Low Side Drivers command 144 The pwm period is 128 The following code turns on low side driver O at 25 low side driver 1 at 50 and low side driver at O off byteTx 144 pwm low side drivers opcode byteTx 32 low side driver at 25 of 128 byteTx 64 low side driver 1 at 50 of 128 byteTx 0 low side driver 2 at 0 of 128 Note that both of these commands require the Open Interface to be in Full or Safe Mode iRobot Command Module Owner s Manual 27 iRobot 5 7 Sending an Infrared Character Low side driver 1 can also be used to send an infrared character in the format that Create recognizes the same format that is used by the Home Base and Remote Control Since the Open Interface also provides the value of such characters see section 5 8 you can use this to allow one Create to communicate with another Create robot Connect an infrared LED to low side driver 1 located on pin 8 of the cargo bay ePort in the following configuration IR LED Longer leg E of LED o Flat side of LED Back side of male DB9 connector 100 ohm resistor The following code sends the value 20 from the LED that you have connected byteTx 151 Send IR opcode byteTx 20 For more information on this command including the characters sent by the Home Base and remote control
48. o that you don t change the baud rate on the Command Module until you ve completely transmitted the serial bytes at the old baud rate 2 Change the baud rate on the Command Module to match Create using the following code cli disable interrupts UBRRO 39 sei enable interrupts delayMs 100 The first line above disables interrupts while you change the baud and the third line re enables them The second line sets the new baud rate You can compute the correct value of UBRRO for the baud you want from the formula UBRRO processor_frequency 16 baud_rate 1 UBRRO 18432000 16 28800 1 39 All of Create s baud codes are also defined as constants in the oi h header file included in each of the example programs The last line of the code above is a 100 ms delay to allow for the baud change to take effect in Create before sending any more serial commands See section 4 14 of the example programs for details on setting up this delay functionality To make it even easier to change the baud rate a function named baud has been included in the drive example program which you can use to change the baud rate to any of the available baud codes listed in the Open Interface documentation iRobot Command Module Owner s Manual 25 iRobot 5 3 Controlling Create s LEDs To control either of the Command Module s two LEDs set their associated I O pin LED 1 is on pin D5 and LED
49. obot Create through the Open Interface use the built in Command Module hardware and add your own hardware to the Command Module s connectors This simple program flashes three LEDs one on each type of output and waits for button presses on each type of input If it gets a button press it lights the associated LED and plays a song Add your own button and LED as described in chapter 4 and try using all three types of input and output 3 6 3 Light The light example program demonstrates a possible application for the Command Module and iRobot Create It searches your house for lights which are left on and plays an alarm when it finds a light so that you can turn it off The program has all of Create s and Command Module s LEDs turned on note that Create s power LED will be orange so that it s easy to find in the dark Start it up in a relatively dark room by pressing the soft button It will sample the light level when it starts and will set off its alarm when it detects a significantly brighter room To detect the light level the program uses a CDS light sensor which you need to add to the Command Module s top center ePort as described in section 4 12 It measures the light level from the sensor using one of the Command Module s analog input pins iRobot Command Module Owner s Manual 14 iRobot wD software Reference This chapter gives code examples and explanations of how to control some of th
50. ort The manual also assumes a basic familiarity with microcontrollers including I O pins registers and interrupts as well as experience with compilers and interactive development environments IDEs For more information on how to use the Command Module s software capabilities please see the Software Reference chapter and the Open Interface reference guide found at www irobot com create 1 3 Example applications Whether you are a hacker educator or robotics hobbyist the Command Module opens many exciting possibilities The applications are limited only by your imagination e Teach robotics and programming at high schools or universities iRobot Create is a robust affordable robotic platform that enables students to each have their own robot e Add new sensors and carry out your own robotics experiments e Create a low cost swarm of robots to investigate collective behavior e Have fun with robot art exhibits song and dances or other entertaining behaviors e Add a camera and internet connection to create a low cost sentry robot iRobot Command Module Owner s Manual iRobot 3 Getting Started 2 1 Plugging in the iRobot Command Module 2 2 Running the preinstalled drive demo program Turn off Create The Command Module comes pre installed with a demo program to let you know that everything is working Plug the Command Module into the Create s Cargo Bay Connector as shown in Figure 1 M
51. our Command Module is called drive and its source code is in the Sample Projects directory on the Command Module Product CD This chapter will guide you through compiling and downloading one of the other example programs named input and will then give you directions for creating your own project The input example program is designed to demonstrate how to use all of the Command Module s input and output capabilities using buttons and LEDs 3 1 Developing for the Command Module The Command Module is built around an Atmel AVR ATMega168 microcontroller All of the programs that you write and load onto the Command Module are run on this 8 bit processor For more information on the microcontroller please see the microcontroller reference section in chapter 7 and the microcontroller spec sheet on the Product CD The Command Module uses the WinAVR suite of open source development tools to compile and download your C or C programs The WinAVR tools include the GNU GCC compiler avrdude downloader and the Programmers Notepad IDE The WinAVR installer installs a lot of useful documentation in the C WinAVR doc directory In the avr libc sub directory you ll find the avr libc user s manual which has information on many functions designed for AVR microcontrollers which you can use in your programs Another good resource for developing with AVR microcontrollers and using WinAVR in particular is the avrfreaks website at http www avrfreaks
52. pin An output is considered to sink current when current flows out of a positive power supply connection through an external component and into the output pin Generally speaking outputs source current when they are high and sink current when they are low When controlling devices that require higher currents such as LEDs always wire them so that the output sinks current as shown in the following example iRobot Command Module Owner s Manual 32 iRobot Since the Digital I O lines have built in resistors as shown in the circuit model above an external current limiting resistor is not required to drive an LED ie LED lt q Current Flow The ePorts also contain three software programmable low side drivers LDO LD1 and LD2 LDO is connected to all three of the top ePorts LD1 and LD2 are only connected to the cargo bay ePort A low side driver is special type of output which can sink a large amount of current Low side drivers are useful for controlling a motor or other power device as shown below Current Flow 8 4 ePort electrical specifications The electrical specifications for the signal lines and low side drivers are given in the following table Type Spec min max unit Analog Input Voltage In 0 5 V Digital 1 0 Voltage In and Out 0 5 V Current Out Low 0 10 mA Current Out High 0 2 mA Low Side Drivers O and 1 Voltage Out 0 21 V Current Out Lo
53. pin C4 The third line sets bits 6 in ADCSRA which starts the ADC measurement The while loop on the next line waits until the measurement is complete by watching the ADSC bit in the ADCSRA register which goes to O when the measurement is done The 10 bit result is then stored in a 16 bit variable on the last line ADC is a predefined 16 bit register Now to take a measurement on pin C5 repeat the process with the channel set to 5 ADMUX amp OxOF clear the ADC channel ADMUX 0x05 set the ADC channel to C5 ADCSRA 0x40 start the measurement while ADCSRA amp 0x40 wait until it s done meas_c5 ADC save the result The 10 bit analog voltage measurements from pins C4 and C5 are now stored in the 16 bit variables and can be used for any calculations or decisions in your program The ADC can also be set up to trigger an interrupt when it is complete if you don t want your program to have to wait while taking the measurement Please refer to the ATMegai68 datasheet and the avr libc documentation for more information on setting up an ADC interrupt 4 13 Using an analog measurement in the light example program The light example program demonstrates a possible application for the Command Module and iRobot Create With this program Create searches your house looking for lights that have been left on so that you can turn them off Start it up in a dark room by pressing the soft button It
54. pplication that requires long periods of waiting you can turn off Create and just run the Command Module in order to conserve battery power At a certain sensor event or after a given amount of time you can turn Create back on and proceed You can also shut down Create at the end of your programs to avoid draining the batteries Always check that Create is on and then wait at least 2 seconds for Create to finish running its bootloader before attempting to communicate with Create To detect whether Create s power is currently on set up the Create Power Detect pin B5 as an input with the pull up disabled If this pin is high Create s power is on The following code detects whether Create s power is on DDRB amp x20 make B5 an input PORTB amp 0x20 disable pull up if PINB amp 0x20 jRobot Create power is on else jRobot Create power is off To toggle iRobot Create s power on or off use the Create Power Control pin D7 The robot s on off state will toggle whenever there is a low to high transition on D7 The following code detects whether Create s power is on and turns it on if it s not DDRD 0x80 make D7 an output if PINB amp 0x20 if power is off PORTD amp x80 set D7 low delay 100 delay so new state is seen by Create PORTD 0x80 set D7 high to turn power on delay 100 delay so new state is seen by Create
55. rrrerereree 16 4 8 PINx Reading the state of an input or output pin s sssssssssssrsrsrsrerererse 16 4 9 Using bitwise operators to selectively change bit values ceee 17 iRobot Command Module Owner s Manual iRobot 4 10 Command Module Internal PinS icesccs ssccseressececsnckecrasspiececcs meanereezecte 17 4 11 Adding a button and LED to the input example program 0 18 4 12 Taking an analog measurement using the ADC eeeeeeeeeee ees 18 4 13 Using an analog measurement in the light example program 19 M Ee Uri seo Lo oerein A 20 4 15 Debouncing a Button INpUt siiscacsesaecancssnatssnceeadacnastineananencancassadanensnne 21 4 16 Setting up and using the Serial port cceeeeeeeeeeeeeeeeeeeeeeeeeeeees 22 4 17 Using the USB Port for Serial Debugging aessescseressrsererererrrrerrrenn 23 4 18 Powering Create 5 2 sscseacacsecs scsapancacseneebadan tecsacengiat idesneneacaagensscgesacne 23 4 19 Putting the Command Module to Sleep sesssssssessressrsrrererersrrrrererns 24 So OPS Interface Referente visio siicccisicsteiciascentecenvvsiennccneiesuacvetsecuretmannuwatanct 25 5 1 Starting tie Open Wet aCe sisisi aaa aaa iA 25 5 2 Changing the baud rate ssiri cece thee bce Sete cece aE NEE A AREENA EE EA 25 5 3 Controlling Greate SLEDS siisii giana a ENE eee aie 26 5 4 Composing and playing SONgS sssessssrensrsrrsrenrrrrrsrentrernnrennnnnnnnennn 26 5 5 M ving Create iisa
56. rs e g DDRB PORTC PIND referenced below are all declared in header files which are installed with WinAVR Include the following line at the beginning of your program include lt avr io h gt This header also declares the bit value for all named bits in the ATMega168 datasheet So you can use lines like the following in your code UCSROB 1 lt lt RXENO Set the RXENO bit in UCSROB To make it even more convenient you can use the bit value macro _BV as shown below UCSROB _BV RXENO 4 2 1 0 Pin Basics The Command Module gives you direct access to the Atmel ATMega168 microcontroller s input output I O pins so you can add any control signals sensor drivers or communication protocols necessary to interface with your external hardware The following sections explain how to use the I O pins and then gives an example of adding an extra button and LED to the input example program Another section explains how to use an analog input to measure the voltage of a light sensor using the light example program The Command Module provides digital input and output pins as well as analog input pins The Command Module uses 5V logic and a 5V reference for the analog inputs Full technical details on the Command Module s Atmel ATMega168 s I O pins and registers can be found in the microprocessor reference manual included on the CD 4 3 The Command Module s connectors The microcontroller s I O pins
57. s aa Ea aE ven tate EEA REEN RAE EA 27 5 6 Controlling Create s low side power drivers ssssesssssessrsresrererrresrenee 27 5 S nding an Infrared Character ssisisissssri sccandahestasess enasini aanwe LAERE 28 5 8 Reading Creates SenNSOrS cisdacuccuydndsisnendadsecuneddenaend Eaa aE RANEA 28 6 Microcontroller reference 2 22csesesssesesenesnsenesenenesenenesenecesensnesenesesenes 29 1 Bootlo der referente visas scrssnitnnniesietenensicnsnnsinnesnmsneninenennensannsinssennesenatanee 30 8 HardWare TETEIENCE nninnccinennsnsnesnncsnacnescnnnecenciencnnsiensnnsnnisnnsnasaasnesnmimancs 31 8 1 ePort PINOUTS seoseid eee eee ee 31 9 2 ePort 170 CONNEC S isincsrctsescsrawndscarssdeacnbarsvadarstaveansaraiess anesanReenaees 31 8 3 ePort connection types and interfacing cccracctcsarccdrccmestsesceeavnesemenverets 32 8 4 ePort electrical specifications cccccececeececeseeecesceceseceesseeeesenees 33 8 5 ePort safety and CAUTIONS c ccceeseeeecseeesesneesonessonessnearsnsensenanes 33 8 6 Component SUPPNIEMS oc cc ccsccsccscsscccssescasessnsnanassasssiesesseasasasenanassneesnacen 34 iRobot Command Module Owner s Manual iRobot D Introduction 1 1 Anatomy LED 1 Soft Button Reset iRobot Create Connector under the Command Module 1 2 Overview The iRobot Command Module works with iRobot Create giving you a way to write your own programs in C or C to control Create and to add
58. s are o Extended Fuse OxF8 o High Fuse OxDC o Low Fuse OxFF o Lock OxEF read as Ox2F by avrdude iRobot Command Module Owner s Manual 29 iRobot 7 Bootloader Reference The Command Module comes with a bootloader pre installed in the Flash memory The bootloader allows you to download your own programs to the Command Module using Programmers Notepad and avrdude and is capable of updating the rest of the Command Module s memory Flash and EEPROM The following conditions determine whether the bootloader or your program starts up on reset e If the USB cable is connected when the Command Module is reset the bootloader starts up otherwise your program starts up e Any time the USB cable is inserted the bootloader starts up even in the middle of running your program e With the USB cable connected if the soft button is held down while you reset the Command Module your program starts The bootloader code is located in the top 1024 words 2048 bytes of the Flash memory and is code protected so that it can t be accidentally overwritten The Command Module s ATMega168 microcontroller has a total Flash memory size of 8192 words 16384 bytes Since the bootloader uses 1024 words your Command Module programs can be up to 7168 words 14336 bytes in size You can also use all 512 bytes of the available EEPROM memory to store parameters and other information for your program that won t get lost with a r
59. se C s bitwise operators Section 4 9 below gives examples of this 4 8 PINx Reading the state of an input or output pin Register PINx O low 0 volts 1 high 5 volts The PINx registers are used to read the state of the pins either high or low If a pin is low the associated bit in the register will read as a O if it is high it will read as a 1 You can read the state of a pin whether it is an input or an output iRobot Command Module Owner s Manual 16 iRobot 4 9 Using bitwise operators to selectively change bit values The C bitwise operators bitwise or I bitwise and amp and bitwise exclusive or as well as the not operator should be used to change the value of one bit at a time with these registers Some examples are below The following code sets pin B2 as an output DDRB 0x04 This sets the value of bit 2 to be 1 but doesn t affect the other bits in DDRB The following code sets pin D7 as an input DDRD amp 0x80 This sets bit 7 in DDRB to be a O without affecting the other bits Once you ve set pin B2 as an output the following code sets its state to high PORTB 0x04 The following code sets pin B2 low PORTB amp 0x04 If you just want to flip the state of the pin low to high or high to low you can use the bitwise exclusive or operator The following code flips the state of pin B2 PORTB 0x04 To check whether a pin is high or low read the
60. seconds and then stop timer_cnt 2000 timer_running 1 while timer_running add code here to do something while you wait iRobot Command Module Owner s Manual 20 iRobot The first line of the code sets the counter to 2000 which sets the delay time to 2000 ms or 2 seconds The second line sets the timer_running flag variable to true 1 so that you can then watch it in a while loop on the third line When the flag variable becomes false you know that the time has elapsed You can add code in the body of the while loop to perform while you are waiting for the delay to end In some cases you just want to wait until the delay is over For that purpose you can define a simple delay function that just waits for a specified period of time void delayMs uint16_t time_ms timer_cnt time_ms timer_running 1 while timer_running This delayMs function above is used in the included software examples 4 15 Debouncing a Button Input In some cases you want to filter the digital inputs instead of using them directly The filtering will depend on the specifics of the hardware connected to the input but one common example is debouncing a button When a button directly connected to an input pin is pressed the input signal will often bounce between high and low before settling down into the correct state This can be a problem particularly if you are counting the number of button presses I
61. see the Open Interface manual 5 8 Reading Create s sensors Your Command Module program can access all of Create s sensors through the Open Interface with the sensor command When you send the command Create will reply with all of the latest sensor information in the byte order specified in the Open Interface documentation sending the result out of its serial port Create updates its sensors and replies to sensor requests at a rate of 67 Hz or every 15 milliseconds Do not send sensor requests faster than this The following code shows how to request the latest sensor information and store it in an array and then checks to see whether any cliffs are detected uint8 t i uint8_t sensor 26 array for sensor data while UCSROA amp 0x80 clear the receive buffer i UDRO byteTx 142 sensor opcode byteTx 0 send request for packet 0 for i 0 i lt 26 i sensor i byteRx read each sensor byte if sensor 2 sensor 3 sensor 4 sensor 5 a cliff is detected else no cliff detected If you don t need all of the sensor information you can ask Create to only send you a subset of the data or a single sensor See the Open Interface documentation for more information about the sensor command and the interpretation of all of the sensor data iRobot Command Module Owner s Manual 28 iRobot Microcontroller The Command
62. tion for the details of the drive command including other special case radius values The drive example program defines a function called drive which will split up and send the 16 bit values for you so that you don t have to think about the details each time 5 6 Controlling Create s low side power drivers Create includes three low side drivers which are high power output pins that can be used to drive motors or other power intensive actuators They are described in more detail in the Create documentation The three power driver outputs are brought to pins on the Command Module s DB 9 connectors Low side driver O is brought out to pin 9 on all three of the top ePorts so that you can use it from any of these connectors Low side driver 1 is brought out to pin 8 on the Cargo Bay ePort and low side driver 2 is brought out to pin 9 on the Cargo Bay ePort This allows you to connect two different actuators to the Cargo Bay ePort and run them in the cargo bay For details on the power output capacities see the hardware reference in chapter 8 To control the state of these pins use the Open Interface s low side drivers command The following code turns on all three drivers for 5 seconds and then turns them off again byteTx 138 low side driver opcode byteTx 0x07 all low side drivers on delayMs 5000 wait 5 seconds byteTx 138 low side driver opcode byteTx 0x00 all low side drivers off You can als
63. ve the battery from Create or remove the ePort add on circuitry from Create before handling it Never touch the circuitry with the power turned on Enclose your add on circuitry so it is not inadvertently shorted during operation The Vcc and Vpwr supplies are protected by a self resetting fuse within Create If you exceed the current ratings power Create off for 30 seconds to reset the fuse iRobot Command Module Owner s Manual 33 iRobot 8 6 Component Suppliers RadioShack www radioshack com 800 843 7422 RadioShack has retail stores in most major cities You can visit their website to find the closest location Jameco Electronics www jameco com 800 831 4242 Jameco is in an online web retailer that carries all of the required components Element Direct www elementdirect com Element Direct offers a low cost kit of all of the components in addition to easy to use ePort compatible prototyping sensor and expansion modules Component RadioShack Part Jameco Part DB 9 Male Solder Tail 276 1537 15747CM Connector CDS Light Sensor 276 1657 202403 5 0mm Red LED 276 209 334422CM Push Button Switch 275 1547 164566CM 10K Resistor 1 4W 271 1335 29912 2007 iRobot Corporation All rights reserved iRobot Roomba and Virtual Wall are registered trademarks of iRobot Corporation Home Base and Create are trademarks of iRobot Corporation U S Pat Nos 6 594 844 6 690 134 and 6 809 4
64. w 0 500 mA Low Side Driver 2 Voltage out 0 21 V Current Out Low 0 1600 mA Each of the ePorts has three power connections Vcc Vpwr and Gnd The ground line serves as digital and analog zero voltage reference All of the specifications given in this booklet are referenced to the Gnd line Vcc is the digital power supply line and Vpwr connects to Create s battery power supply Both Vcc amp Vpwr are switched on and off with Create s power The following table gives the specifications for Vcc and Vpwr Note that the output current specification listed is the total current for all of the ePorts combined Supply Spec min nom max unit Vcc Vout 4 5 5 5 5 V lout 100 mA Vpwr Vout 7 16 18 V lout 1500 mA 8 5 ePort safety and cautions The maximum voltage available on the ePort is 21V The ePort pins will not shock you if they contact your skin However the ePort can supply over 20 watts of electrical power which has the potential to burn you or start a fire in the event of an electrical fault Only experienced users should attempt to design and build their own circuitry Prebuilt ePort modules are available from a supplier listed in the Appendix A and are suitable for users who lack the experience to design their own circuitry Always use care when wiring custom circuitry to an ePort Never run your iRobot Create unattended Always fully test your new designs under close supervision Always remo

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