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1. 17455 68th Ave NE Suite 304 Bothell WA 98011 USA 206 486 8086 fax 206 486 0253 130 The Computer Applications Journal issue 26 April May 1992 5 5 AN AAY v svym usua TOTAL PACKAGE PERFORMANCE QUALITY PRODUCTS RESPONSIVE SERVICE RELIABLE DELIVERY SOLID STATE DISK 124 Y Card 2 Disk Emulator EPROM Flash and or SRAM 1 Meg Total Bootable TURBO XT WITH FLASH DISK 266 2 Serial 1 Parallel Port Up to 2 Flash Drives 1 Meg Total Software Included 2 Meg DRAM 20 MHz AT CPU CARD 536 4 Meg DRAM 0 to 60 C 2 Serial 1 Parallel Port CMOS Low Power Surface Mount All Tempustech VMAX products are PC Bus Compatible Made in U S A 30 Day Money Back Guarantee Qty 10 Ok Call for Quantity Pricing TEMPUSTECH INC TEL 800 634 0701 FAX 813 643 4981 Fax for 295 Airport Road fast response Naples FL 33942 Listing 2 continued do get character the main loop accept input char action output_ac
2. 98 Issue 26 April May 1992 164 The Computer Applications Journal 2 13 05 39th Ave Bayside NY 11361 Canada 4 16 756 9477 FAX 416 756 4118 U S 1 80066344605 16 SOIT OT IME is cocoon The Circuit Cellar BBS 300 1200 2400 bps 24 hours 7 days a week 203 871 1988 Four incoming lines Vernon Connecticut In this installment of ConnecTime we re going to look at sensing current in an AC line the ins and outs of halogen lamps and some issues surrounding CRCS You might think sensing current in an AC power line to determine whether a motor is running is a simple matter Think again Msg 50778 From RICHARD PFEIFFER To ALL USERS am using an RTC52 to control a train horn need to monitor the status of a 1 HP AC compressor motor The AC is always on but the motor turns off based on the pressure in the tank The control switch is a sealed unit and cannot get in between it and the motor What need is a way of sensing current in the incoming AC line thought that wrapping a thin wire around one lead in the AC cord could sense the current status but it is too low Help don t do op amps and such If were rich would just whip out a PC and a GPIB voltmeter and all this would be simple but just need a simple TTL level on off signal If anyone can help would appreciate it Msg 50788 From DALE SINCLAIR To RICHARD PFEIFFER There are a few companies th
3. 10Mb Drive 50 gt j Hoff Height 51506 Compaibie FLOR MY DRM 20Mb Hard Drive 100 2 360 K 35 2 1 2 Mb 552 40Mb Hard Drive 180 2 730 K 358 144 Mb 602 CDC 94166 141 300 2 L bracket for 720K of 4 44M drives 7 exta 115Mb Ful Height ESD interface 640 x 200 LCD 29 he unit ae dispi My the Toshiba 1100 loptop Omputer Driver boord to generate text ond graphic 1t inchided This 0 serial tate LCD You Lite ay Tamia with wiring when attempting to use this unit 340 x 400 LCD 50 skopnine POWER SUPPLYS 380 WATT 29 00 Non encosed Oupa SV 507 HOGA AN 15A Dimensons 12Lx5 Wx 4H Nwar SHITCHING 19 00 ord to 30 00 2 4 pin power connectors attached 115 230 Volt Dimensions 8 5 L x 45 WaZ H Ouput SV 29 75A H12V 045 NQ 0 04 A INO OSA eneunwvanesaunuuvvanaonunenun 40 amp 50 WATT NONENCLOSED 2 for 25 00 HeNe Laser Tube 10vw tras cuut 99 Proteon ProNet 4 Model p1347 Token Ring Board 09 2 16 bit 4 Mbps JEEE 802 2 and 8025 YYY compatible twisted pair interoperable with IBM Token Ring network The Spy In The Sky ZEA 1728 element CCD 9 00 o gt H 4096 clement CCD 29 00 A DC 300 XLP and DC600 tape cartridges 20 and 40 Mb IDE drives call for price Non Enclosed TTL Monitors Comer with pinout 12V at 4 Amp input Hwhor frequency 15 Khe Ablity to do 4 ond 80 coum eaS inch Sole out 29 9 inch feat 29 95 Graphic a Alphanume
4. Call for more information 916 924 8037 FAX 916 972 9960 coo CO Zz 14 The Computer Applications ournal 14 DEPARTMENTS Firmware Furnace From the Bench Silicon Update Practical Algorithms ConnecTime Ed Nisley Infrared Home Control Gateway You can already control your TV VCR and CD player from the comfort of your chair using a hand held infrared remote Why not control your home as well Ed shows us the firmware involved in doing just that 70 issue X26 April May 1992 The Computer Applications J ournal ome folks have problems in places where most of us don t even have places Consider the fate of the poor chap who fixed Steve s furnace last week he didn t move around enough to keep the motion sensing lights turned on The house was on manual lighting control while the repairman was at work if you can imagine that Now suppose everybody in Steve s house wore a badge that broadcast a unique ID The HCS II could then track each person and adjust the room lighting sound system volume security defenses and so forth depending on who was where Finally he d have a truly personalized automated house that would work without manual adjustments Of course the system can only track people or suppose dogs wearing IR badges But consider what the HCS II s response might be should the basement door open without a valid badge ID on either side
5. SPA No moving parts NON VOLATILE B ked SRAM No IC Sockets Used Counters corrosion and shock ANG E E ET warm RAM string the program number and revision level Program revisions will ensure an orderly start up would also suggest providing an external means to force the program to cold start the system in the event of a catastrophe This function could be invoked via a jumper switch or by keyboard from a system configuration mode Having a clean way to restart the system is nice should your defen sive coding and elaborate recovery mechanisms fail Believe me you don t want to talk your customer through the procedure of shorting out RAM power with a paper clip a John Dybowski has been involved in the design and manufacture of hardware and software for industrial data collection and communications equipment 428 Very Useful 429 Moderately Useful 430 Not Useful i SRAMDISK S MI Robust amp Reliable ZNO SOFTWARE JANEEDED Take it out of the box and plug it in IDEAL FOR HARSH ENVIRONMENTS Humidity dust vibration shock e Seek time less than 0 2 millisecs e Data retention at least 2 years e Device driver on board Business Machine Interfaces Inc AUTOMATION DATA LOGGING HOBBY HOME PROJECTS e 4 to 64 Mbytes OEM APPLICATIONS e Standard AT ISA bus Paip e Fully DOS Compatible BOARD BLUE EARTH OFFER 7 RESEARCH
6. includes 256K RAM Supports 640K BIOS ROM Parallel Port 8087 Socket Model XT 640R Includes 8 Slot Passive Backplane Plugs into PC XT AT e 2716 27010 ERPROMS 16K 1Mega Bit EEPROMS NMOS CMOS Includes Software e Read Write Verify Copy 195 00 quantity 1 MAGNUM OPUS CUSTOM ELECTRONIC ENGINEERING XT M SINGLE BOARD COMPUTER CLOSE OUT SPECIAL 1 65 00 10 63 00 25 60 00 100 55 00 4 77 MHz 8 MHz Operation e Clock e Keyboard Port e Speaker Port EP 1 EPROM PROGRAMMER BASIC SBC BASIC Interpreter 8K 32K RAM 8K 24K EPROM On Board EPROM Programmer Serial Port RS232C 24 Parallel VO Lines Timers Interrupts e 197 00 quantity 1 908 283 4925 Engineering Manufacturing Analog Digital Microprocessor Standard Custom Semi Custom 284 Kennedy St Iselin NJ 08830 137 The Computer Applications Joumal INDUSTRIAL STRENGTH SINGLE BOARD COMPUTER JAS OPTIMUM FEATURES FOR DATA AQUISITION AND CONTROL PROFESSIONALLY DESIGNED AND BUILT FOR TOUGH APPLICATIONS WITH A 2 YEAR WARRANTEE AND A 30 DAY MONEY BACK GUARANTEE PROGRAMMING SA SNAP IN EITHER MULTI TASKING BASIC FORTHoR ANSI C FE Atures NCLUDE 80PTICALLY COUPLED DIGITAL INPUTS 8 HIGH DRIVE BUFFERED DIGITAL OUPUTS 16 PROGRAMMABLE DIGITAL I O LINES 16 THIRTEEN BIT ANALOG INPUTS 2 OPTIONAL TWELVE BIT ANALOG OUTPUTS 4 SERIAL RS232 485 SERIAL PO
7. IRGATE also includes calibration routines Steve s description of his IR hardware explains how the various IR remote units and badges work He has the advantage of using the MC145030 chip directly on the firmware end of the signal there is essentially no hardware at all As a result must discuss the MC145030 data format in some detail before explaining how the firmware transmits and receives it IR I O Figure 2 shows the MC145030 data format adapted from the data sheet The chip uses Manchester encoding which defines two comple mentary signals for each data bit Motorola calls the pair of signals a bit frame to indicate a single data bit A complete message requires 39 5 bit frame times 24 frames hold data or framing bits while the remainder provide silent periods before during and after the real frames Motorola calls the contents of the message address bits because they think of the MC145030 as a widget to control a device at a specific address refer to them as data bits because our messages convey information to the HCS rather than selecting an address Fortunately the bits don t care what they are called and do the same thing regardless of their labels Steve chose the bit frame time to work correctly with the Sharp IS1U60 receiver which specifies a 600 ps minimum On and Off time Because a Manchester encoded bit frame uses both states the minimum frame time is 1200 ps Stev
8. A Simple RS 485 Network Exploit the Nine Bit Serial Communication M odes of the 805 1 8096BH 68HC11 68HCOS and 2180 Microcontroller Families Circuit Cellar INK issue 21 Ken Davidson CEBus Update M ore Physical Details Available Circuit Cellar INK issue 19 Ken Davidson CEBus A New Standard in Home Automation Circuit Cellar INK issue 10 Harv Weiner ed New Product News CEBus Power Line Interface Products Circuit Cellar INK issue 25 The Best LAN May Be Found off the MAP EDN Nov 7 1991 Also mentions Ethernet and ARCnet FieldBus An Emerging Communications Standard Microprocessors and Microsystems Dec 1988 Ken Davidson Domestic Automation CEBus Goes Coax Circuit Cellar INK issue 25 Get Byte the MUL Byte BOS Multitasking integrated multitasking o preemptive task sched o task management a event management u message management o timer management Add these multitasking Ofixed block memory Our technical support is today and see how easy 10s Integrated Systems Box 3067 Del M ar CA 92014 Why spend months designing documenting coding and debugging a multitasking kernel when you can have Byte BOS a widely used multitasking operating system on your desk tomorrow libraries and development tools that run on a PC Only 995 buys our multitasking kemel with all these features o on chip serial YO manager
9. DUP 1 lt SWAP 8 gt OR RANGE makes a copy of the top of the stack and if it s not 1 through 8 lt need 2 numbers 1 to 8 gt Position and or Velocity oton Gontro LL DCX PC fi 8 Axis Programmable Motion Controller State of the art Digital Muhifunction Controller can be configured in minutes using off the shelf components DCX motherboard contains intelligence memory firmware and 8 sockets for plug in Modules 1 to 8 plug in DC Servo Stepper or Special Purpose Control Modules can be mixed matched on same DCX board Install in any PC XT AT compatible or use stand alone with RS232 and or IEEE 488 interface Modules High level interface libraries in C and BASIC with examples and source gt 116 ee Er easyto use and fast Hypertinked On line help g emulotion process iceMASTER is FAST The 1 keeps typical dow nlood times to u stondord COMM port Rental And 1 0 Day Tri iceMASTER delivers productivity easy to learn Precision Micro Control Ge V0 OR als Availab ides you through t 5 2K baud serial link der 3 seconds usi iceMASTER is Versatile iceMASTER 51 iceMASTER 68HC1 land iceMASTER COP8 support family derivatives Call today for FREE DEMO DISK Call today to ask about FREE 8051 Macro Assembler 800 METAICE 800 638 2423 MetoLink Corporotion PO Box 1329 Cha
10. If the serial interrupt source is SBU F which will start the serial from a transmitted character clear the transmission set up the next address interrupt and check for the end of and do aRETI RAM If the end is flagged then exit the interrupt without sending any P START Parallel Routine data otherwise retrieve a byte of data Once thrown into the P START from the memory card place it into routine a check of the function mode Photo 1 A 9600 bps character transmission top trace is shown in relation to the chip select used to enable he SRAM memory card CE bottom trace in he serial record mode Photo 2 The parallel playback mode requires hardware handshaking between the Bit Bucket and a PC s parallel interface Characters are grabbed CE1 top trace from the SRAM memory card and placed info the output register INT1 middle trace is lowered signaling We PC that a character is ready The PC reads its parallel port and acknowledges by lowering and raising ifs strobe line INTO lower trace The Bit Bucket raises INT and the cycle is repeated for each additional character The Computer Applications Joumal Issue X26 April May 1992 81 directs execution into the parallel record mode or the parallel playback mode Like the serial record mode an endless loop is entered at P RECORD Photo 3 Al the arcuitry for the Bit Bucket minus he wail wart power Supply fits into a small 5 inch square Pactec enclo
11. Issue 26 April May 1992 9 A CASE HISTORY Comparing the state machine technique with a more conventional approach to building a microprocessor program is interesting The case history describe here is a special purpose terminal which uses the 68705P3 microprocessor containing a 16 x 1 LCD character display and a4 x 3 keypad Pressing keys causes the processor to select or edit displays or to send messages out a serial RS 232 port originally wrote the code for this project using the brute force get an input compare and branch approach However the result contained a great number of conditional and uncondi tional branch statements Alarmed at what looked like a massive debugging effort then rewrote the code using the state machine approach Both programs required about the same amount of RAM 24 versus 25 bytes The compare and branch method required 1540 bytes of EPROM for the entire program tests branches and subroutines The state machine NBS 10 Interface Card provides gateway ta network RS 485 twisted pair controlier 2 J 68HC11 which contained eight states and nine possible inputs was 121 bytes smaller This decrement is not a great saving but it does indicate that a problem of this magnitude will be smaller if the state machine approach is used The benefit from the state machine method would probably increase with larger programs The big advantage of the state machine approach s
12. Fij Usually resolving such an issue isn t this simple Note the X register can only accommodate 8 bits which limits my total table offset to 255 bits maximum THE OUTPUT ACTION MACHINERY First define the various actions by numerical codes and construct the output action table shown in Listing 4a This time have to retrieve an action code from the table and act on it The offsets into the two tables will be identical because the next state and action code tables are the same size and structure Once the offset into the next state table is calculated can also use it to retrieve an action code Now wish to jump to an action routine based on the value of the action code retrieved from the table The 6805 indexed JSR instruction together with a jump table will accomplish the task assume that the action code routines exist somewhere in memory The preface AR_ indicates an action routine See Listing 4b Why you may ask bother with the no action routine when all it containsisaNOP Because if you ever want to add something to the system you simply replace the NOP in the action routine with the desired code The routine makes the system much easier to maintain Now need to make a jump table out of the addresses of these routines putting them in the order of their action codes as shown in Listing 4c You access the action routine with a four step process 1 Determine the index into the action
13. room blaster interface for the IR Link uses multiple IR LEDs ensure all badges in the mom will held remote control can actually do quite a bit As easy as the concept might be to synthesize the IR Link functions in software still found it difficult to give up soldering something Having the ability to network together enough Photo 4 Unbelievably this is the same wall that was shown inthe last issue The additional features built info the HCS fl and ifs expandability allow a much cleaner setup with more capability than was possible with he original HCS The Computer Applications Joumal FAST COMPLETE ACCURA TE DRAM TEST DIPs SIMMs SIPs 64K 256K 1M 4M RAMSTAR Ins RESOLUTION ACCESS SPEED VERIFICATION 80 ns thru 180 ns Std 5249 01 45 ns thru 110 ns Fast 349 0 4MEG Option Add 89 01 AUTO LOOP Continuous Test 6 25 MBits sec ADAPTERS SIMM SIP ADAPTER 189 01 Tests 64K 256K 1M amp 4M Devices 8 or 9 Bit versions NTX ADAPTER Tests 64 Pin Dual Edge 149 00 Laserwriter Type SIMM s Toe m 4X ADAPTER 89 010 Tests 64K amp 256K By 4 Bit Devices AC ADAPTER Regulated 5V 1 Amp FREE RAMFACTS DRAM NEWSLETTER 1 800 RAMSTAR COMPUTERDOCTORS 9204 B Baltimore Boulevard College Park Maryland 20740 18 99 MADE IN U S A U S PATENT No 4 965 79 s 113 issue 26 April May 1992 25 IR Links to cover a whole house or of
14. Dirt 1S DMed 70 20 IN Quantity of Dirt Dirt IS DMHigh 100 20 IN Quantity of Dirt Dirt IS DHigh 127 20 IN Ouantity of Dirt Dirt IS NotDLow 0 30 EX Ouantity of Dirt Texture IS TSmooth 0 25 IN Texture of Floor Texture IS TMed 30 20 IN Texture of Floor Texture IS TRough 60 30 IN Texture of Floor OUTPUTS Vacuum 50 AC Vacuum Control IF Pressure IS PLow AND Dirt IS DHigh AND Texture IS TRough THEN 50 IF Pressure IS PLow AND Dirt IS DMHigh AND Texture IS TRough THEN 30 IF Pressure IS PHigh AND Dirt IS DMLow AND Texture IS TSmooth THEN 10 IF Pressure IS PHigh AND Dirt IS DLow AND Texture IS TSmooth THEN 40 IF Pressure IS PVHigh AND Dirt IS DLow THEN 50 Height 50 AC Beater Brush Height IF Dirt IS DHigh AND Texture IS TSmooth THEN 40 IF Dirt IS DMHigh AND Texture IS TSmooth THEN 30 IF Dirt 1S DMHigh AND Texture IS TMed THEN 10 IF Dirt IS DMLow AND Texture 1S TMed THEN 30 IF Dirt IS DLow AND Texture IS TSmooth THEN 50 IF Dirt IS DMHigh AND Texture IS TRough THEN 20 IF Dirt IS DHigh AND Texture IS TRough THEN 50 IF Dirt IS DMLow AND Texture IS TSmooth THEN 10 Speed 50 AC Beater Brush Speed IF Dirt IS DLow AND Texture IS TSmooth THEN 50 IF Dirt IS DLow AND Texture IS Med THEN 10 IF Dirt IS DMHigh AND Texture IS TMed THEN 10 IF Dirt IS DHigh AND Texture IS Med THEN 20 IF Dirt 1S DMHigh AND Texture 1S TRough THEN 30 IF Dirt IS DHigh AND Textur
15. The Computer Applications Joumal through A5 go to U3 and select one of 64 addresses and DATA comes from the HC 11 s DO line The RESET pin of the MT8809 is tied to the F68HC11 board s RST line so the whole system is reset at once U4 and U5 are the Maxim quad 5 volt only receivers and drivers The receivers are connected to the X I Os of the crosspoint switches and the line drivers are connected to the Y I Os THE PHYSICAL DESIGN The New Micros board uses a vertical stacking type connector for the expansion jack so it was natural for me to piggyback my board on top of theirs used modular phone type jacks for my RS 232 O and found that eight of these jacks side by side are exactly the same width as the control ler board These connectors are taller than the distance between the boards so just hung them over the edge Now when I say RS 232 what really am describing is the two serial lines and signal ground I ve been blissfully living my life without ever using the other signals that are part of a real RS 232 connection and I ve Issue 26 April May 1992 35 avoided most of the confusion associ ated with this messy standard How ever realize not everyone can avoid doing so used 4 pin jacks for this project and just made up the way they are wired because there is no standard for wiring RJ 11 jacks in RS 232 applications In retrospect should have used 6 pin RJ 11 s just in case nee
16. can t wait for the system to have a voice and telephone privileges too
17. still think the concept has more entertainment than control value but the idea is intriguing nonethe less Unfortunately this idea is one that is still waiting for technology to advance to a point where there is a cost effective solution How long this module remains on the drawing board depends on such an evolution So ask you to bear with us while we take some time before delivering these designs to you After all wed like them to work first unfeasible were it not for the unique defined as the number of the IR Link located in the solarium eg 2 When the condition is true a list of actions will be performed The only concern is finding a cost effective method to identify an individual While possibly suited more for an office than the home our solution was to use an electronic ID badge We have already described that the IR Link s primary function is to sit passively and monitor the ether for 38 kHz Manchester coded IR transmissions Take the circuit in Figure 2 add a lithium battery replace the manual transmit switch with a slow 0 1 Hz oscillator and build it into a small pocket clip container Every 10 seconds this portable beeper transmits a coded signal just like you were pressing the button on a hand held remote Provided it is aimed in the vicinity of an IR Link more about increasing coverage later the SC will receive that transmission as it would any other By selecting a unique code for each b
18. OFF END GEND The Computer Applications Journal HallTimer OFF whole portions of a program depending on some condition Check out some of the example programs present later if you re still not clear about G F Finally comments are preceded by an exclamation mark All text following the up to the end of the line is skipped COMPILE TIME The program actually run by the SC is made up of binary representa tions of the keywords described above presented the basic format of that binary in the last issue In order to translate from the English like program developed by the user to the binary used by the SC a compiler is necessary Simply named C OM P I L E the compiler runs on an IBM PC compatible and takes as input straight ASCII text entered with any text editor does a syntax check and generates a file called EVENTS BIN containing the raw binary code used by the SC When the user running HOST presses the L key HOST looks for EVENTS BIN loads it into memory and sends it to the SC The SC imme diately starts running the new program and the HOST screen reconfigures itself assuming the transfer went all right PROGRAMMING CONSIDERATIONS A key idea to keep in mind is that a program is made up of a series of event equations The SC continually runs through the list over and over again Any action that takes place near the top of the program could affect the evaluation of equations
19. SOLID STATE PC FOR UNATTENDED APPLICATIONS The Solid State PC from INCAA Datacom is a compact highly reliable device designed specifically for unattended and embedded applications such as network functions data acquisition and control The Solid State PC is designed around an AMD 286 processor featuring a clock speed of either 12 or 16 MHz and zero wait states It features 5 12K of DRAM with parity expandable to 4 MB and provides hardware support for LIM EMS 4 0 A 128K flash EEPROM expandable to 768K replaces the disk drive The Solid State PC is fully compatible with the IBM AT bus but has no conventional keyboard screen or disk drives The disk drives are simulated by memory and a backlit LCD screen plus two general purpose button switches are provided for operational use but can be disabled if not required A special BIOS manages the solid state facilities so programs can access them as standard devices A control port and associated DOS software enable a conventional PC to be attached for software installation development and testing You can then transfer files between the conventional disk of the PC and the solid state memory The screen and keyboard of the PC can be used as if they were peripherals of the solid state unit This feature also allows local or remote monitoring and control of the unit by an appropriate asynchronous device or PC In addition to the control port a standard serial communication port COM
20. The topic this month is the firmware needed for an IR gateway to the new Circuit Cellar Home Control System II It receives infrared signals from remote units and passes them to the Supervisory Controller SC for action so you can control the HCS II without leaving your chair as well as transmitting IR signals that can poll Set badge response delay default 40 ticks Calibrate remote MC1 45030 bit clock 12 4 kHz n 0 3 sets report detail Calibrate transmitter oscillator connect 38 kHz output to TI input Dump program status debugging use Show and clear error flags debugging use Set badge polling interval default 190 ticks Set logging mode bit mapped L report current mode LO disable default L1 show received IR messages L2 show transmitted IR messages L4 show generated polls Set network interactive mode N report current mode NO set interactive mode N1 network mode no error messages default N2 network mode with command echo Set output bit x to n OA O setbit A OB 1 set bit B OC 0 setbitC OD 1 setbit D Set number of badges to poll default 0 no polling Query and reset received IDs a dump all 512 IDs in hex 130 chars in line ID 0 is bit 0 of first byte Qn report ID n status in format 003 1 On m report IDs n through m in hex bytes ID n is bit 0 of first byte perform power on reset must be completely spelled out Send IR ID n Figure 1 The IRGATE commands include functions to sen
21. as discussed earlier and second a routine to make use of the port s ability to read back 8 bit data did not write an interrupt routine for my PC to make use of the bidirectional port howeve did dedicate 5 minutes to writing a BASIC program to test the interface Transfer was an excruciat ingly slow 140 characters per second or about 8 minutes for the 64K bytes of data That s 13 minutes total to get a program written and data transferred don t care how much you may hate BASIC if that s the extent of the task it was cost effective Isn t that the bottom line FLEXING THE FIRMWARE Now that you can see the simplic ity of the hardware and firmware you may wish to take this project to new heights A routine to nondestructively test the amount of SRAM a card contained could be substituted for the predefined size selection Maybe a two digit hexadecimal display indicat ing the data presently being trans ferred How about the ability to use other types of memory cards such as EPROM OTP Flash or EEPROM Each has its own timing and power supply requirements Perhaps you d like to randomly place and retrieve data This aspect is a tough one for binary transfers unless your format uses a control word to define the block of data that follows This method could cause problems though if sync is lost between the control word and the data block would prefer a format in which the lower nybble holds data and
22. available Call for pricing Call for your custom product needs Free Quote Quick Response DEFINE Lampl Module Al DEFINE Lamp2 Module A5 DEFINE Stereo Module A8 DEFINE Air Horn Module Al6 BEGIN IF Steve Li vi ngRoom THEN Lampl ON Lamp2 ON Stereo ON END e9 En S a EXPRESS A IF Ed LivingRoom AND NOT Steve LivingRoom THEN Air Horn ON doch Boas CP Lampl OFF Lamp2 OFF San Diego CA 92126 END FAX 619 530 1458 619 566 1892 124 The Computer Applications Journal Issue X26 April May 1992 45 other programming languages false is simply zero while true is any nonzero value Variables may also be incre mented or decremented for use as counters When a variable reaches zero further decrementing has no effect Likewise when one reaches 255 incrementing does nothing No other math besides incrementing and decrementing is supported Text messages may be sent to any LCD Link in the system A very useful subset of the ANSI cursor control commands has been implemented on the LCD Link and the SC allows you to send any of these commands to the display module Finally the PL Link s refresh period may be set If you ll recall Ed s article in the last issue the PL Link may be set to send out on or off commands periodically to all modules it s referenced since its last reset That way any module accidentally triggered by garbage on the power line will be set back to its
23. bus operation 525 TC48 Dual Am951 3 Timer Counters 24 digital I O lines 16 bit AT bus operation with expanded interrupts 398 DIO24 High current digital I O board 24 buffered DIO lines 8254 timer Com patible with opto 22 equipment 195 AD3110 Super fast 16 channel A D board 12 bit 200 kHz A D rate Burst mode operation On board FIFO memory Programmable gain Timers DIO lines Supports DMA and pacer clock Optional D A outputs 665 AD3710 Low cost version of AD3110 with on board FIFO memory and 200 kHz burst mode operation 525 DA810 8 channel 12 bit D A Voltage or current loop output 8254 timer 24 digi tal 1 0 lines 589 MR16 110 VAC mechanical relay expan sion board Computer control of 16 AC BAd keruan a anin e n 215 OP16 Optoisolated 16 channel digital input expansion board 225 TS16 16 channel thermocouple expan sion board Supports J amp K types 298 Unparalleled choices for real world control Over 50 hardware and soft ware products for singleand OEM users FREE 80 PAGE CATALOG Real Time Devices Inc State College PA USA tia Tel 814 234 8087 FAX 814 234 5218 Issue 26 April May 1992 132 58 Listing 4a The action codes are defined first followed by the output action table b Next the wde to carry outeach acton is defined c in order to get to each action routine a jump table is defined d Last comes the code to retrieve he address of a given action routine and jump
24. in industrial networking BITBUS nodes generally use an Intel 8044 BEM microcontroller which is essentially an 8051 integrated with a serial communication controller and firmware Each node must also indude an RS 485 transceiver because BITBUS specifies an RS 485 interface Intel offers a wide variety of development tools for BITBUS as well as distributed control modules BITBUS cards for the PC are available allowing the PC to be a BITBUS node and you can also get board level products from other companies Echelon s LON and the Neuron microcontroller Echelon Palo Alto CA intro duced its Local Operating Network LON in 1990 Echelon suggests that its LONs see Figure 2 could be used in a wide range of distributed control environments such as automobiles twisted pair 1 25 Mbps or 78 kbps RF 4880 bps power line 9600 bps coax IR optical fiber Protocol Transmission Hierarchy Media access Error detection features serial LonTalk proprietary none peer to peer predictive CSMA optional CD optional priority message acknowledgement optional 16 bit CRC message ordering duplicate detection Application layer features network variables Figure 2 The Local Operating Network or LON was introduced by Echelon late in 1990 The Computer Applications Joumal Issue 26 April May 1992 15 Network nodes OSI layers specified Communication media cable length up to 255
25. may or may not be be more resistant to this kind of failure On one hand their fila ments are capable of withstanding higher temperatures without burnout that is the most important characteristic of the halogen lamp design and is also the one that allows production of higher light intensities and higher color temperature On the other hand most not all halogen lamps are designed as low voltage high current bulbs This might militate against long life under SCR control because it s precisely this type of low resistance filament that s most vulnerable to the initial current peak In Message 51502 Kenneth Scharf correctly stated that a linear i e gradual turn on is likely to prolong filament life whereas a digital i e sudden turn on is likely to shorten it That is precisely the case In a halogen bulb more properly a quartz tungsten halogen bulb iodine is usually a component but not necessarily the only halogen used Bromine is often also added The function of the halogen is not to condense and evaporate to from the filament that s quite impossible because the filament operates at temperatures that are immensely higher than the boiling point of any halogen including iodine What is actually happening is that the tungsten filament the halogen vapor AND the quartz envelope all form a closed multiphase dynamic chemical system In a regular bulb tungsten atoms evaporate from the hot filament and
26. remember you don t get an interrupt for each frame and you don t know what the data is Safe and effective for the whole 8051 family BCI51 Basic compl eSoothes assembly and C ination _ Long lasting relief of time and budget headaches Maximum strength error handling eThe affordable cure for long code winters i Fast integer math supplement sy BASIC 52 or stand alone outstanding technical support Assembler amp 0 nly 299 A ieee RT extensions 149 Assembly Language Toolkit 149 Call 801 487 7412 FAX 801 487 3130 SYSTRONIXinc 754 East Roosevelt Ave Salt Lake City Ut 84105 150 My first inclination was to measure the pulse produced by the first two sync bits which looks like it should be exactly one bit frame long Unfortunately the IS1U60 cannot switch instantly because it requires some time to decide that it is seeing an IR signal and more time to decide that it is not Photo 1 is a magnified view of a few IR bursts to show the IS1U60 response time finally realized that the time between successive negative transi tions of the IR signal must be 1 0 1 5 or 2 0 bit frame times so the code could extract the frame time without knowing the data values The trick is to use the length of the initial sync pulse to estimate the frame time then classify each transition time and compute the average frame time The code in Listing 2 does just that Because Micro C does not y
27. these days can sit on the couch with one IR remote control and command an entire audio visual surround sound entertainment system By now you know that the new HCS II is a reality see sidebar for more information While it contains noteworthy enhancements over the original the physical solution to producing some of these features was a far cry from the initial design tech nique IR remote control was a prime example During the design phase ap proached the task of adding remote control by looking for an off the shelf IR remote control chip that could easily interface to the HCS Since IR remote control chips usually come in encoder decoder pairs assumed the proper route would be to use the encoder chip to make a hand held device with buttons as if you really needed another IR remote and use the decoder chip with suitable IR recogni tion circuitry wired to the HCS as the receiver Press a coded key on the transmitter and presto the code is received by the HCS and acted upon Ed Ken and had already speci fied the basic configuration of the new HCS and its networked COMM Links The X 10 power line controller designated the PL Link was already up and running The IR Link was to be the next module on the system The Computer Applications ournal My initial proposal designated the Motorola MC 145030 as a suitable remote control encoder decoder chip see Figure 1 An added bonus was that the MC145030 cont
28. 00 KITS Power supplies Support and Application Software available Ss L S ELECTRONIC SYSTEMS DESIGN 2280 Camilla Rd Mississauga Ontario Canada SSS L5A 258 Phone Fax 416 277 4893 Terms Shipping US Canada 6 Check or Money Order Please 96 Issue 26 April May 1992 The Computer Applications Journal BCC72 BASIC 72 Computer Controller The BCC52Computer Controller is Micromints F1 lottest selling standalone single board microcom yuter ts cost effective architecture needs only a yower supply and terminal to become a complete de felopment or end use system programmable in 3ASIC or machine language The BCC52 uses Micromint s 80C52 BASIC CMOS microprocessor which contains a ROM resident 8K byte floating roint BASIC 52 interpreter The BCCS2 contains sockets for up to 48K ytes of RAM EPROM an intelligent 2764128 PROM programmer three parallel ports a serial erminal port with auto baud rate selection a serial yrimer port and is bus compatible with the full line of 3CC bus expansion boards BASIC 52 s full fbating point BASK is fast ard efficient anough for the most complicated tasks while its cost effective design allows it to be sonsidered for many new areas of implementation It can be used both for development and end use applications Processor Input Output 80052 BASIC 8 bit CMOS microcomputer sconsole VO RS 232 serial pat gelectable conversion to dine pints RS
29. 16 24 32 40 48 56 or 64 These numbers make up the last column on the table I put an 8 on top of the stack and ROT the in value up from third to the top of the TIRED OF WAITING FOR THE PROMPT pat up with a ROM ery ms 00S and programs instant teed to replace Nitra te sere completely in controllers or diskless workstations The only perfect protection from viruses Easy to install half size card MVDISK1 64k MVOISKe 360k MVDISK3 1 44m Quantity discounts 95 EPROM PROGRAMMER PLUGS INTO PRINTER PORT D0 ROMS FOR SBC OR MVDISK PROGRAM 2764 27010 EPROMS 8088 SINGLE BOARD COMPUTER WORLDS SMALLEST PC AOBOTS ALARMS RECORDERS DOS THREE EASY STEPS 1 Develop on PC 2 Download to SBC 3 Burn into EPROM 2 PARALLEL LCD INTERFACE 3 SERIAL KEYBOARD INPUT PC TYPE BUS AREAL TIME CLK BIOS OPTION BATTERY OR 5V FREE SHIPPING IN U S 5 YEAR LIMITED WARRANTY Box 394 Merrimack NH 508 792 9507 120 DOS IN ROM stack and subtract it from 8 Then I subtract this result from the result of multiplying the out value by 8 and Pm done This math works the same way in hex but the table looks stranger Let me illustrate what I ve just explained 3 5 CALC gt 8 5 is 40 8 ROT gives 5 40 5 35 From the table you can see that 3 in 5 out is in fact 35 Bingo Now youre ready for ON CHECK CALC XSWITCH 1 SWAP C OFF CHECK CALC XSWITCH 0 SWAP C The SWAP
30. 232 serial pat 31 80C32 func three 8 bit programmable TTL compatibie Ek bys ROM MI P interpreter parallel 1 0 ports using a 8255 PPI 256 bytes RAM salternate console RS 422 RS 485 a 16bit countar imers ines 11 MHz system dock To OrderCall pedi 1 800 635 3355 EMORY expandable to 62K bytes Tel 203 871 6170 five on board sockets up to four 6264 8Kx8 static RAM Fax 203 872 2204 either an 8K 2764 or 16K 27128 EPROM leQry 100 Ory BCC52 BASIC 52 Controller Board with BK RAM 189 00 5149 00 BCC52C Lower power all CMOS version of the BCC52 5199 00 159 00 BCC5 21 Fullindustial wmperature range 5294 00 5220 00 BCC52CX CMOS Expanded BCC5S2 w32K RAM 5259 00 159 00 MICROMINT INC 4 Park Street Vernon CT 06066 window does exist between the time the write successfully completes and the write pending flag is cleared The failure mode in this case would not be a lost record but a duplicate record The extraction of data from the ring buffer is a two stepped process in which the read function operates in a nondestructive fashion and the remove function must be used to delete a record from the buffer Also locating the outgoing services here is natural because you have already assigned a block of buffer management code to service the incoming data The process consists of continually performing reads on the buffer If data is returned it is posted for transmission to the host computer and a pending removal is indi
31. From the Bench eff Bachiochi Does it Come With a Memory Standard ym Advertiser s index Part 2 The Nitty Gritty The Computer Applications Journal Issue 26 April May 1992 3 RUUD Oa INK Battery Lore Cleared Up was just given a copy of The Computer Applica tions Journal quite a magazine In the December 199 1 January 1992 issue ConnecTime contained several messages addressing camcorder batteries Boy what a mixture of misconceptions Working in a technical support position here at Panasonic have to answer these questions day after day Here are the key points for the proper care and feeding of your camcorder batteries 1 Batteries should be charged following each and every use Charge each battery for about 30 minutes past the point where the charge indicator goes off No 24 hour charges Memory was a condition which supposedly affected NiCd batteries Virtually all camcorders today use lead acid gel cell type batteries Memory did have an effect back in the mid 1950s NiCd technology has changed drastically since those days Recently several particles have appeared which have basically written off the entire issue Battery capacity actually increased with short cycle discharge charge cycles 2 Never store your battery in a partially charged state Remove the battery when not in use as some camcorders may draw a small amount of power and thus discharge the battery over time 3 Exe
32. IR remote is sometimes necessary Using the RCODE keyword you can test whether a particular code was received by either a particular IR Link or a range of IR Links For example writing IF Reode 13 0 tests whether code13 wasreceived by IR Link number 0 You can use the informa tion to produce different responses based on which room the transmission came from When the IR Links are used as part of a people locator system knowing which IR Link received the code tells you where a certain person is located A statement like I F Rcode 13 gt 0 can be used to see if the code was received by any IR Link Steve s article in this issue covers the IR Link in more detail Finally setting up default states when the system is reset and continu ing from a Known condition is often useful The RESET keyword tests true just once on the first pass through the event equations after a reset then tests false from then on Now that you have all the condi tions under your belt it s time to combine them into useful tests Any number of conditions may be com bined in a single F statement using NOT AND OR and parentheses A NOT preceding any of the above conditions complements the result AN Ds and ORs do pretty much as you d expect Some examples of valid conditions might include IF Input 20 0N AND Modul e L11 OFF or IF Input 10 ON AND Output 21 OFF OR Timer 2 gt 30 J UST DO IT On the other si
33. Iota Systems Inc 702 831 6302 20 MHz Board Available Incline Village NV 89450 Issue 26 April May 1992 3 9 CP 1128 Combination Programmer 1295 00 v Supports AMD s v Supports upto28 pinE MACH110 210 120 130 EPROMs and bipolar 230 EPLDs Altera s 900 1800 series and MAX EPLDs Cypress CY7C361 Lattice s isp LSI1032 amp pLS 1032 National Semiconductor s 5D amp 7D devices ond MAPL devices Y Qualified and recommended by AMD Lattice National Semi conductor Signeticsond others f Utilizes only manufacturer ap proved programming algo rithms PROMs including the microwire C devices Supports Dallas Semi conductor NVRAMs and TI DSP320 Micro chip PIC microcontrollers VW Lifetime FREE software updates available via BBS and US Mail Y Call fora DEMO disk and literature pack WV Made in the USA EPROM PROGRAMMER EP 1140 E EPROM amp ucontroller Programmer 895 00 V The EP 1 140 supports NEC s 27C8001 8 Mbit EPROM all27C240 4 Mbit 16 bit EPROMs FLASH EPROMs NVRAMsandall microwire EPROMs VY All Intel AMD ond Signetics 40 pin controllers supported directly Y Qualified and recom mended by Intel Signetics Notional Semiconductor and others W Lifetime FREE software up dotes available via BBS and US Mail W Risk free thirtyday money bock guarantee W Made in the USA With lifetime FREE software upda
34. and MORE all from mithin ORE FAST e Li i f 1 ist prices from 195 ERSY TO USE MENU DRIVEN ENVIRONMENT CURTIS INC 2837 No Fairview Ave e St Paul MN 55113 999 00 2 00 P H 612 631 9512 FAX 612 631 9508 TO ORDER CALL 804 479 3893 PC DOS s a trademark of IBM MS DOS s a trademark of Microscoft LIFE FORCE TECRROLOGY 106 5477 RUTLEDGE RD VR BERCR VR 23464 10 12 Issue 26 April May 1992 The Computer Applications Journal FEATURES Embedded Controller Networking Alternatives FEATURE ARTICLE James Butler Embedded Controller Networking Alternatives Infrared Tracking and Remote Control The Frugal Networker Programming the Home Control System II Distributed control systems rely on network communica tions to exchange data and keep processes coordi nated There are numerous network ing options available the best depends on your application 14 Issue 26 April May 1992 The Computer Applications J ournal nterest in embedded control ler networking seems to be growing rapidly perhaps because of the increasing number of ways an embedded control ler network can be implemented In this article describe several methods for adding networking capability to embedded controllers including relevant hardware and software products and standards Embedded controller networks like office LANs allow embedded controllers to communicate with each other and potentially wi
35. and would like to control it with the same photoswitch Are there any reasons why shouldn t use the halogen lamp in this way And can expect to go through as many halogen bulbs Msg 51471 From PAUL PETERSEN To ANDREAS MEYER If your photoswitch is one of the cheap K Mart varieties you might be stressing the bulb s filament have one in my kitchen and have noticed in the morning the light flick ers a bit just as the sun is coming up and morning twilight is fading It s that very critical crossover point where the photodetector doesn t know if it s dark or light It only lasts a couple of seconds but while it s turning on and off very rapidly can hear the filament in the bulb twanging away I ve wondered if this was good for the filament but the bulb is a 20 watt night light and only burns out after 6 months of usage hm Msg 51502 From KENNETH SCHARF To PAUL PETERSEN have one of those photoelectric units on an outdoor porch lamp It turns the bulb on slowly because the SCR goes into partial conduction during the period that it isn t quite dark yet Instead of being digital the unit seems to be linear the photoresistor being part of a divider network that changes the conduction angle of the SCR As a result the bulb never goes abruptly on or off and while going on is preheated slowly think this extends the life of the bulb rather than limits it I got over a year out of the
36. as possible in order to minimize the amount of time the block is in an unknown state There fore all intermediate operations should be performed on copies of these Processor Ric Hc I Offering exceptional value in a single board embedded controller Micromint s RTC HC11 combines all of the most asked for features into a small 3 5 x 4 5 package at a reasonable price Featuring the popular Motorola MC68HC118 bit microcontroller the RTC HC11 gives you up to 21 lines of TTL compatible 4 lO an amp bit B channel analog to digital converter two serii ports a real time clock calendar with s Sy 2 battery backup 512 bytes of nonvolatile EEPROM andup to 64K of on board RAM or EPROM 32K j s a MS of which can be battery backed Software development can be done directly on the RTC HC11 target system using BASIC 1 1 an extremely fast integer BASIC interpreter with dedicated keywords for 1 O port A D converter timer interrupt and EEPROM support In addition a flexible Board j Q configuration system allows a BASIC program to be saved in the on board battery Oo backed static RAM and then automatically executed on power up Micromint oy LS afsooffersseveral hardware and software options forthe RTC HC11 including ia RNO the full line of RTC series expansion boards as well as an assembler ROM So S o monitor and C language cross compiler aS Q Additional features include Eo eA Wig Asynchronous serial port with full
37. available Calf or write today for more information Control Resources 19042 San Jose Unit S P O Box 8694 Rowland Heights CA 91748 818 912 5722 Voice 818 854 1439 Fax 159 LET S GET FRIENDLY Before fuzzy logic can take off engineers have to design fuzzy prod ucts At least in Japan from what understand fuzzy vacuum cleaners 8051 8096 68HCII 68332 SINGLE BOARD COMPUTERS Wefealure a series of single board computers for process control applications Each is available asa bare printed circuit board or fully assembled and tested Optional development software is also available Please contact us to discuss your requirements and receive a literature package covering technical specs and pricing ALLEN SYSTEMS 2346 Brandon Road Columbus OH 43221 614 488 7122 The Computer Applications Journal Issue 26 April May 1992 89 Listing 1 Puttinga microprocessor in a vacuum cleaner may seem extreme but is a good example of how fuzzy logic can be used to simplify programming NLX230 Vacuum Cleaner Example TERMS Pressure IS PVLow 0 30 IN Vacuum Pressure Pressure IS PLOW 40 20 IN Vacuum Pressure a Pressure IS PMed 70 20 IN Vacuum Pressure Pressure IS PHigh 90 20 IN Vacuum Pressure Pressure IS PVHigh 135 30 IN Vacuum Pressure Pressure IS NotPVLow 0 30 EX Vacuum Pressure Dirt IS DLow 0 30 IN Quantity of Dirt Dirt IS DMLow 40 20 IN Quantity of Dirt
38. bit microcontrollers as well as a few 32 bit devices A popular communication medium is twisted pair cable to which the microcontroller is interfaced using an inexpensive RS 485 transceiver like the 75176 This approach has some potential limitations The network bandwidth is moderate typically 57 000 to 375 000 bps You have to write or purchase the software implementation of a network protocol Finally the communication Microcontrollers with 9 bit asynchronous serial communica tion capability partial list Hitachi HD64180 Intel 805 1 family 8096 80C186 188 EB EC Motorola 68HCO5 family 68HC 11 family 68HC16 68300 family Semiconductor COP884 CG CS COP888 CG CS FG HPC family Texas Instruments TMS7002 7042 National Zilog Z180 family Supers RELAY INTERFACE PROVIDES SOFTWARE CONTROL OF RELAYS Network nodes OSI layers specified Electrical specification cable length speed up to 32 physical W 485 data link application RS 485 twisted pair up to 1200 meters 9600 bps proprietary asynchronous serial master slave controlled by master node message acknowledgement optional 8 bit checksum data transfer Protocol Transmission Hierarchy Media access Error detection features Application layer features Figure 6 Micromint s MC Net allows the connection of their 8052 BASIC and HD64180 based embedded controller boards and a PC processing over
39. code table the same way as determined the index into the next state table 2 Retrieve the action code from the table using this index 3 Multiply the action code by 3 to get the offset into the jump table because each entry of the action code jump tableisa3 byte MP instruction 4 Set up the offset as an index and do an indexed J SR through the table which will send the processor to the Listing 3 a The 6805 implementation of th Retrieving he next state involves calculating an offset into the table appropriate action routine The action routine terminates with an RTS instruction sending the processor back to the main interpreter loop The code for this setup is shown in Listing 4d The SR J MP_TABLE X instruc tion sends the program to the correct entry in the jump table the jump table entry sends the program to the action routine then the action routine does what s required and does an RTS back to the main routine THE PUSH AND RTS HACK Some microprocessors do not have an indexed SR instruction The 6502 is one of these but it does have a PUSH instruction In that case I ve included a useful trick bdow 1 Setup a table containing the addresses of the action routines e next state section consists completely of definitions b a INPUT CONDITION DS 1 J CURRENT STATE DS 1 Next Reb GREEN YELLOW state definitions EQU 0 EQU 1 EQU 2 Next NEXT STATE state table EQU STATE RED
40. compiler pre processor assembler simulator printed documentation and complete library source code Requires IBM PC or compatible 5 25 360K disk PROMulator 256 189 95 An EPROM emulator lets you avoid Bum and Test development cycles In circuit emulation of 2K 32K 27xx series EPROMs ABS Plastic case Assembled or compiled code is downloaded directly to the target hardware Cottage Resources Corporation Suite 151 10271 South 1300 East Sandy Utah 84094 VISA MC COD Call to Order 801 268 2875 The Computer Applications Journal Issue 26 April May 1992 7 5 interval to 5 or 10 seconds to keep from clobbering yourself CALIBRATION CONSTANTS Although describe the IR signal as being either on or off when transmitting or receiving a message that is not quite accurate The IS1U60 receiver expects the IR signal to havea 38 kHz modulation so an on signal is actually a burst of 38 kHz IR pulses Producing the modulating fre quency with firmware isn t feasible at least not while monitoring a serial network connection so Steve added some hardware to chop the output signal But he insisted on a way to calibrate the oscillator against the 803 l s 11 0592 MHz crystal rather than use a frequency counter or scope So IRGATE includes a transmitter calibration routine that displays the frequency of that modulating signal To use it just connect the oscillator to the 8031 T1 input pin enter the
41. connector and DB 25 connector no enclosure is available for 130 Cross Assemblers from 50 00 Simulators from 100 00 Cross Disassemblers from 100 00 Developer Packages from 200 00 a 50 00 Savings Make Programming Easy Our Macro Cross assemblers are easy to use With powerful conditional assembly and unlimited include files Get It Debugged FAST Don t wait until the hardware is finished Debug your software with our Simulators Recover Lost Source Our line of disassemblers can help you recreate the original assembly language source Thousands Of Satisfied Customers Worldwide PseudoCorp has been providing quality solutions for microprocessor problems since 1995 Processors RCA 1802 05 Intel 8051 Motorola 6801 Motorola 6809 Intel 8080 85 Mot 68k 8 10 Intel 8048 Motorola 6800 Hitachi 6301 Rockwell 65C02 Hitachi HD64180 Zilog 280 New Zilog Z8 Zilog Supers 55 TMS 7742 27210 5701024 and memory s y All products 716 Thimble Shoals Blvd Suite E cards require an IBM PC Made inUS A EMPDEMO EXE available BBS 916 972 804 or compatible 68 Issue 26 April May 1992 Motorola 68HC11 MOS Tech 6502 Intel 8096 196kc For Information Or To Order Call PseudoCorp Newport News VA 23606 804 873 1947 FAX 804 873 2154 connect the RS 232 port to COMI on the PC Make sure the board power is off and insert the MC68HC705 in the ZIF socket Next turn on the programme
42. current_ s t at e equal to that value Now how do handle outputs In BASIC and assembly language use two arrays each two dimensional each addressed by current state and input condition a next stote array and an output action array The output action array contains numbers that are codes for various output actions The processor looks up the action code corresponding to the current state and input condition and then uses it to determine what action routine it should call The pseudocode provided in Listing la now becomes that in Listing lb Of course in assembly language you don t usually have instructions to access entries of an array and a great deal of singing and dancing is required to simulate the effect of a two dimensional storage array with sequential lists If use C to design the state table data structure each entry has a two part structure consisting of a next state and an output action The program enters the table with current state and input condition and reads the next Listing Z a Interpretatonof the state machine ignoring outputs can be reduced to a five line program b Adding output Support increases the size of he pseudocode by two lines a do read input condition next_state state_table current_state input_condition current state next state loop b do read input condition output_action_code action_table current_state input_condition procedure output_action_cod
43. duplex uh RS 232 and halfduplex RS 435 drivers 1 MHz synchronous serial port CPU watchdog security Low power sleep mode 5 volt only operation RTC stacking bus R 162 Special Devel opment System Price RTC HC11 DEY 300 00 Board w B bit ADC EEPROM 32K battery backed RAM Clock Calendar BASIC 1 1 ROM monitor utility diskette with assembler and complete manual set Other configurations also available starting at 239 MIC ROMINT INC 4 Park Street e Vernon CT 06066 203 871 6170 e Fax 203 872 2204 To Onc er Call 1 800 635 3355 The Computer Applications Joumal Issue 26 April May 1992 95 dements Also setting a limit on the maximum size for records that can be written to and read from the ring buffer is helpful in case the storage region somehow gets corrupted and the end of record marks get scrambled You don t want to move a huge block of data on a read that could overflow the destination buffer destroying adjacent areas This method of han dling the ring buffer uses some common sense techniques to reduce the chance for errors but further steps can be taken to maximize the ring buffer s integrity As in the simpler data structures you can use dual redundant blocks with checksum verification and a primary secondary flag to determine whether a block is intact and contains valid information The implementa tion details are basically the sa
44. editor and a member of the Computer Applications Journal s engineering staff He holds aB S in computer engineering and an M S in computer science from Rensselaer Polytechnic Institute SOURCE Please see page 3 1 for more information about the availability of HCS II components 410 Very Useful 411 Moderately Useful 412 Not Useful issue 26 April May 1992 49 State Machines in Software A Design Technique for Single Chip Microprocessors by Peter Hiscocks Programming the Motorola MC68HC705C8 by Edward Oscarson The Computer Applications Journal Issue 26 April May 1992 51 State Machines in Software A Design Technique for Single Chip Microprocessors State machines are commonly built in hardware using discrete logic Explore the use of similar techniques for embedded software 52 Issue X26 April May 1992 FEATURE ARTICLE Peter Hiscocks hen you design a digital control system you may find viewing it as a machine with a number of states useful The classic example is a traffic light it has ared state a green state and a yellow state It may also have other states left turn advanced green flashing pedes trians only crossing all stop and so forth The state machine is particu larly effective at detecting preventing and signaling errors in input from a human operator For that reason you should always seriously consider a state machine as the basis for a user i
45. enough That s not for a CPU chip but for a complete tanoLiNK Controller board in a typical application The automatic power cycliry technology that makes that possible is standard and built in Wat development if we write the device drivers for you And the timing critical low level code And throw in a complete BIOS And a full monitor with source code And what if the hardware includes all the real world interfaces you ll probably need like A Ds buffered digital O and high power switching And low cost What if the standard board package includes a macroassembler An integrate editor A communications interface Complete illustrated technical references What if the hardware includes a switching supply and even the serial cable What if you don t even need an EPROM programmer There is a better way For information call 1 800 GET DATA 4383282 or 602 996 0255 FAX The Computer Applications Journal nano Power Devices A division of AirDigital Corporatio Issue X26 April May 1992 73 74 IMAGENATION VIDEO FRAME GRABBERS Simplicity Functionality Affordability Accuracy Cortex l Real Time Capture Half Slot XAT 512 x 484 x 8 Bit RS 170 CCIR Extemal Tigger Dual Video input Opt XMS Mapped Low Power Options STD 80 or 32 Bus External Trigger Vidmux 4 4to1l MUX Half Slot XVAT Includes Software C Library amp Source I
46. for both The Computer Applications Journal ADIO Link modules Since these modules must be polled over the network system response to a net work input is somewhat slower than to a direct input Similarly the current state of any output may be tested for either on or off As with inputs there are local outputs tested with OUTPUT and network outputs tested as with network inputs with N ETB T The same issue of response time applies to outputs as to inputs Analog inputs may also be tested using theADC keyword A single keyword is used for both local and network ADCs because there are far fewer potential analog inputs than ether digital inputs or outputs Issue 26 April May 1992 43 AllLightsOn h AllUnitsOff h DAC n c LCD n string Module m ON OFF Module m DIM n Module m BRIGHT n NetBit n ON OFF Output n ON OFF Refresh r Timer n ON OFF Variable n TRUE FALSE h housecode A P h housecode A P n digital to analog channel c constant O 255 n LCD Link number O 7 string any ASCII text string m module A1 P16 m module A1 P16 n dim level l 31 m module A1 P16 n bright level l 31 n network output bit O 239 n output number O 239 r refresh interval 0 99 minutes 0 off n timer number O 63 n variable number O 15 Figure 2 XPRESS action keywords give you plenty of control over your living environment The current state of any X 10 module may be
47. how a state machine approach can be used in a next_state green a green next_state green b yel low next_state green c green 6805 microprocessor Implementing a state machine in assembly language on this type of processor presents some next_state green d red digital voice VOICE MODULES VM 1410A 75 w o EPROM Plays natural sounding voice sound Holds up to 10 messages Max length 5 12 seconds 32Kbps Built in 1W power amplifier Single 6 12 VDC operation Voice digitization VP 880 495 Demostration EPROM available Other models available For security alarms P O S promo tions amusement parks elevators VOICE IC CHIPS VCS 1870 voice chip set 29 50 Includes a CVSD codec chip VP 1870 and a filter module SF 700 Sampling rate is adjustable from 9 6 to 128 Kbps Universal 8 bit uP uC interface Advanced CMOS technology Single 3 6 VDC operation Other models available For digital recorders digital answer ing machines PC voice boards continued PC VOICE BOARDS V Link l voice board 145 Single line IBM PC compatible Connects to telephone line or PBX Records and plays messages Automatic answering and dialing Touch tone dial tone detection Requires additional programming Software developer s kit 150 for Microsoft C Turbo C and Clipper Multi line models available For voice mail voice response Eletech Electronics 1262 East Katella Ave Anahe
48. keywords allow you to configure your system on he fy and make programs more readable The Computer Applications Journal Listing 1System actions may be based on any number of input conditions making complex control scenarios realizable t t Example HCS Il Program l CONFIG PL Link 1 DISPLAY Modules A DEFINE Lampl Module Al DEFINE Lamp2 Module A5 DEFINE MotionA Input 2 DEFINE Motion6 Input 6 DEFINE Door Sensor Input 10 DEFINE Basement Timer Timer 38 BEGIN IF MotionA EDGE OR MotionB EDGE THEN Lampl ON Lamp2 ON Basement Timer ON END IF Door_Sensor ON THEN Lampl ON Lamp ON END IF Basement_Timer gt 5 AND Door Sensor OFF THEN Lampl OFF Lamp2 OFF Basement Timer OFF END Listing 2 As Steve and Ed describe elsewhere in his issue IR badges may be used with IR Links to track people throughout a house and base decisions on where people are located Demonstrate use of IR badges for tracking t t Be nice to Steve but razz Ed if he walks inthe room without Steve l CONFIG PL Link 1 CONFIG IR Link 3 DISPLAY Modules A B C DEFINE Steve IRcode 0 Badge number 0 DEFINE Ed IRcode 2 Badge number 2 DEFINE LivingRoom 1 1 IR Link number 1 8051 Family Tools In Circuit Emulators The DrylCE Plus is a modular emulator designed so you can get maximum flexibility from your emulator purchase The base unit contains all the hardware necessary to support po
49. local inputs and outputs and what network modules are in use HOST allows you to set a new time and date it actually reads it from the host PC so be sure you ve set it correctly before running HOST and allows you to load a new program into the SC I ll cover where that program comes from next THE LANGUAGE OF HOMEOWNERS The original HCS that Steve presented about seven years ago had a simple menu driven interface and control scheme It gave the user several programming options including turning an X 10 module or direct output on and off at specific times in response to an input or after a specific time period While that scheme is easy to use and allows a good degree of control it falls well short of meeting the needs of a more sophisticated control system that may be applied to both industrial and home environ ments Suppose have an area with two lights two motion sensors and a door sensor want the lights to come on if either of the motion sensors is tripped then go off 15 minutes after no motion is detected also want the lights to come on if the door is opened and to stay on as long as the door is open regardless of motion When you have a system like the old HCS where you could only key actions on a single input such a scenario is impossible to realize without additional circuitry to combine the sensors external to the HCS Remember this situation for later and you ll see how easy it is to do with the new
50. m module A1 P16 n network I O bit number O 239 n output number C 239 True after reset hh hour O 23 mm min O 59 dd day SU MO TU WE TH FR SA DY daily unu nuna lt Op gt n timer number o 63 n timer number 031 Timer n ON OFF Timer n lt op gt s sts gt ee lt Op gt gt n gt lt s O 65535 seconds Timer n lt op gt s n timer number 32 63 lt 0p gt Me Se Boe es s O 65535 minutes Variable n TRUE FALSE Variable n lt op gt c lt Op gt n variable number O 15 n variable number O 15 gt tc gt Mes c constant g 255 Figure 1 XPR SS condition keywords a low the testing of a wide range of sensor inputs and system variables CONDITIONAL CONTROL Figure 1 shows a summary of valid F statement conditions I ve done a lot of work on the system since the last article was written and have expanded on what was presented there l Il quickly explain how each of the conditions works I know a laundry list of mostly self explanatory com mands can be dry so l Il try to be brief Note as you go through the list that many systems on the market allow you to base actions on time or on inputs but rarely allow you to combine the two as we do here Inputs may be tested for a high state on a low state off or an edge either rising or falling To test for a rising edge you simply check
51. modulated signal A 2N2907 transistor pulses a pair of single element or a dual adement IR LEDs The schematic of the 803 1 based COM M Link circuitry explained in the last issue is shown in Figure 4 Figure 5 outlines the additional circuitry specific to the IR Link Photo 1 shows an assembled IR Link board Finally in viewing the schematic some of you might ask why havea 3 volt LM317 regulator in the circuit have already suggested that the 38 kHz modulation frequency is critical A shift in frequency affects the IS 1U60 s receiver s response and hence the distance over which the IR Link could receive commands A remote control sending a coded signal at 38 kHz will be received at a much greater distance than one sending the same code at 39 kHz for example After going through so much effort to reduce training errors frequency shift in the oscilla tor itself had to be minimized A CD4047 oscillator chip with polycarbonate or mylar capacitors is a relatively stable 24 Issue 26 April May 1992 clock source However the major error causing influence is the power supply voltage Set the oscillator when the supply is at 4 9 V then use it at 5 1 V and there will be a frequency shift To minimize power supply variations the CD4047 chip has its own regula tor Since we can t know what voltage will be used to power the IR Link 5 V or 9 12 V even possibly up to 35 V the LM3 17 operates from the 5 V supp
52. o external serial YO manager Develop and debug Byte BOS applications on a PC with these tools OBOSPCX for target prototyping Byte BOS is available for a wide range of microcontrollers and the PC B0S and leave TITASKING to us Operating System consists of a complete set of components including a robust kernel add on u resource management o application code amp user manual o configured to your C compiler Ono royalty c source code o 1 year of tech support amp updates uling ibraries to suit your application multiple message buffer manager o multiple timeout manger manager o dynamic task manager OBOSVIEW multitasking debugger responsive friendly and knowledgeable Call us multitasking can be with Byte BOS 800 788 7288 or 619 755 8836 al 112 The Computer Applications ournal Issue 26 April May 1992 21 Infrared Tracking and Remote Control Meet the New HCSII IR Link Module Images of Big Brother accompany the idea of your house following your every move Put Steve s people tracking system to good use as part of the new Circuit Cellar Home Control System 22 Issue 26 April May 1992 FEATURE ARTICLE Steve Ciarcia ver since built my first home control system presented in April 85 one of the improvements I ve wanted to incorporate into any new HCS was an ability to extend control of the system by remote means After all
53. other solutions to the WOM problem mentioned earlier There will be times when you won t want to disturb a connection by using A L L 0 F F What you can do is declare a 64 byte variable to store an image of the crosspoint matrix Then you modify ON OF F and ALL 0 FF towriteto both places You could write a neat little routine to display the results in say an 8 x 8 The Computer Applications Joumal matrix Another way would be to work out a compression and decompression scheme and store an image in only 8 bytes because there is really only 64 bits of data involved This method is good if you want to store a lot of complicated prerecorded setups hope you find the Frugal Networker interesting and that it leads you to other ideas using the MT8809 family Also hope I ve convinced you to use Forth as a small systems language Just so don t leave you with the impression that I m a monomaniac concerning this subject let me explain that I intend to use Pascal and C in upcoming projects but as long as have the Frugal Networker won t forget my Forth a Frank Cox is back as a full time student studying science and engi neering with an emphasis on electron ics after spending many years in industry SOFTWARE Software for this article is avail able from the Circuit Cellar BBS and on Software On Disk for this issue Please see the end of ConnecTime in this issue for downloading and ordering
54. porting to custom hardware only 39 e ROMable Run Time Engine wey LLL e Programming tools On line debugging lt Target library _ CPU s 8051280 8086 Eval _Kit_contains Parallel Port I O or On Screen Simulator EE Programming amp Debugging modules GHAL MO PC TSR Target Excellent for jadder language _taini Se EEE were FAX 513 874 3684 CALL 513 874 4665 ELECTRONIC R amp D 4850 Interstate Dr Cincinnati OH 45246 114 The Computer Applications Journal Issue 26 April May 1992 27 MCIR Link TIM Link and TREK Link Generally speaking we at Circuit Cellar INK ike to be remembered for our achievements so we rarely speculate and try not to discuss vapor hardware or software Unfortunately the immediate success of the Circuit Cellar HCS II has caused quite a number of you to ask about other COMM Links beyond those presently available Our policy has always been to design and build interfaces before announcing them Too many unscru pulous businesses float vaporware before actually producing anything However we are often guilty of sitting on a design until all the pieces are complete before we present it A certain compromise may be in order The success of the HCS II deluged our offices with questions about pending designs Our merely answering No to the potential existence of other COMM Links could give you the impression that the HCS II is a dead end design rather than
55. proper state Setting the period equal to zero turns refresh off BELLS AND WHISTLES Besides the basic language build ing blocks discussed above there are additional commands and features that are used for configuration or to make the programmer s job easier Figure 3 lists these extra keywords The SC must know what COMM Link modules are connected to the network so it doesn t waste its time polling modules that aren t there The CON FI G keyword is used to define how many of each of the COMM Link modules are out there If the program contains no CON FI G statements at all the SC simply doesn t access the network HOST displays the current state of any X 10 module local input or local output you ask The D SPLAY keyword is used to define just what housecodes you want displayed DEFINE is the key to making programs more readable Instead of using keywords like I nput 2 and Modul e L3 when writing a program DE F IN E lets you give such keywords descriptive labels like Kitchen_Motion and Bathroom Light 46 Issue 26 April May 1992 After all the definitions a single BEG I N is used to denote the start of the program One last keyword used in pro gramming is the global F or GI F Global probably isn t quite the right word but it seems to fit the best GI F allows a single level of nesting of F statements The G F keyword is followed by any valid combination of
56. short circuit The first conduction cycle s after turn on may therefore allow a very high peak current which then quickly normalizes in 8051 MULTITASKING EXECUTIVE Develop Real Time Applications FAST DCE51 Executive provides Preemptive Scheduling 4 Priority Levels Up to 8 Tasks Memory Management Message Passing Interrupt Management Dynamic Task Creation Small Efficient Kernal 4K Monitor Task Available lota Systems Inc 702 831 6302 FAX 702 831 4629 POB 8987 Incline Village Nevada 89452 166 The Computer Applications Journal Issue 26 April May 1992 101 SOS TIME subsequent cycles as the filament heats up In an unlucky circuit the filament can and does fail instantly during that first surge without ever getting a chance to start working as intended In a three way lamp one of the filaments has a lower resistance to start with it s the one that probably would tend to burn out first during the initial high current peak Is this the effect that s been observed In the case of low voltage high intensity lamps with compact filaments the phenomenon is exacerbated A 6 or 12 V high intensity lamp can easily burn out instantly when turned on via a simple SCR controller whereas it would not do so if activated via a mechanical rheostat or variable transformer arrangement The failure is caused by the very high initial current peak allowed by the SCR So called halogen lamps
57. simply outputs the complement of the distance between the input and center location Thus if the input is a perfect match with the center location 31 is output remember width is 5 bits while if the input isn t in the fuzzy set at all i e outside the width a0 is output A type bit specifies whether the defined fuzzy set is considered inclusive or exclusive as shown in Figure 7 width is 13 in this example The combination of a fuzzifier including specified center and width and its input is known as a term Thus with 16 fuzzifiers the NLX230 handles 16 terms At this point each fuzzifier associated with a given input will compute the membership value 0 31 nonmember to ideal member in parallel 2 x 4 EMBEDDED PC SPPPEBEP ICT hihhip n Microcontroller Wildcard 88 e CPU clock to 10 MHz Replaces full PC motherboard Co processor and BIOS socket e DMA Bus DRAM Keyboard controllers TaT Bie petii Multi 10 On board SCSI Host Adapter supports up to 7 devices Floppy Controller 1 44M 1 2M e 2 RS 232 Parallel RS 485 multi protocol serial port All Wildcards are low power single 5 volt operation 125 Wendell Ave Weston Ont MON 3K9 Fax 416 245 6505 Wildcard 88 and Megatel are trademarks of Megatel Computer Corp Hercules is a trademark of Hercules Corp IBM is a trademark of IBM Corp 158 The Compu
58. status on the screen as each operation completes blank check program and verify When program ming is complete the final status is displayed on the screen Board power must be off prior to removing the programmed part from the socket FINALLY The PGMHCOS5 is a valuable and inexpensive tool for the microcontrol ler designer It has proven very useful when devdoping microcontroller programs for my projects as wal as for small production runs of programmed parts Now many more system architects can add a new dimension to their designs Q Edward Oscarson is a senior design engineer with Hamilton Standard and holds a B S E E from the University of Connecticut 416 Very Useful 417 Moderately Useful 418 Not Useful EPROM PROGRAMMERS 3750 Completely stand alone orPC driven rr roms l E PROMS legabit of le upgradable to EY 2 Megabit IF Socke Paral valle a an N 9 32Kinternal F acn FFPROM for easy ilmware upgrades Quick Pulse Algorithm 127256 in 5 sec 1 Menabit in 17 sec e2year warranty Made inthe USA Technical sungort by phone Complete manualandschematic Single Socket Ho a also available 550 0 Split and Shuffle 16 amp 32b t 100 User Definable Macros 10 User Definable Configurations Intelligent Identifier Binary intel Hex and Motorola S 2716 to 4 Megabi Splitting 2 ft Cable 40 pin ZIF
59. system The HCS II programming language is called XPRESS expandable Pro grammable Real time Event Supervi sory System and is based on what call an event equation The equation consists of an F section followed by a THEN section If thel F section is true theTH EN section is executed If not the action is skipped It s as simple as that Much of the power comes from being able to combine any number of conditions in the F portion and have any number of actions initiated in theTH EN portion ADC n lt op gt c lt op gt ahigh state and an edge A falling edge is tested by checking for both a low state and an edge Inputs are broken into two categories local inputs and network inputs Local inputs tested with thel N P UT keyword are those connected directly to the SC and are the fastest to test Any device that needs quick action like a motion detector at the top of a flight of stairs should be connected to one of the local inputs Network inputs tested with theN ETB T keyword are those found on the LCD Link DIO Link and n analog to digital channel gt te gt c c constant g 255 Input n ON OFF EDGE IReode c lt op gt n n input number O 239 c received IR cede O 255 lt Op gt gt lt gt lt n IR Link module number O 7 Module m ON OFF NetBit n ON OFF EDGE Output n ON OFF Reset Time lt op gt hh mm dd
60. that can t ma RL el afford a fulltime engineering staff a Sv LDN y for once in a while designs Steve Ciarcia and the Ciarcia Design Works staff may have the solution for you We have a team of accomplished programmers and engineers ready to design products or solve tricky engineering problems Need an infrared remote controller multi channel data logger or 7 axis drill controller The team has the talent to design and manufacture it Whether you need an on line solution for a unique problem a product for a startup venture or just plain experienced consulting the Ciarcia Design Works stands ready to work with you J ust send me a fax discussing your problem and we ll be in touch Remember a Ciarcia design works Call 203 875 2199 Fax 203 872 2204 Msg 51669 From STEVE LANGER To ANDREAS MEYER In message 5 1464 Andreas Meyer describes an unusually high incidence of filament failure when using bulbs controlled by a photo switch assume that s an SCR which in turn uses a photocell to generate its trigger signal When cold a tungsten filament has a much lower resistance than when it is incandescent 300 K 5 6 micro ohms cm 1000 K 249 2000 K 56 7 3000 K 92 0 3600 K 115 0 A ten fold increase in temperature results in a twenty fold increase of resistivity This means that at turn on the SCR is initially seeing a load that more nearly approaches a
61. the memory card first the medium pins connect all signals second and the shortest pins CDland CD2 are used to signal the card is fully in serted BVD1 and BVD2 indicate the state of the battery and whether the data held within the memory card could be corrupt WP reflects the status of the write protect switch on the card RDY BSY is used by pro grammable memory devices to relate the status of the programming cycle The Computer Applications Joumal Two 74LS374 amp bit registers are used as address latches for the address lines above the stock AO A15 64K space Address lines Al6 A23 are held in the first latch and A24 A25 in the second latch The remaining 6 bits of the second latch are used for LED status indicators The LEDs reflect the status of the battery in the SRAM memory module the write protect switch the memory card insertion detection inputs the address pointer end of RAM and storage or retrieval activity See Figure 2 for an explana tion of each LED A 74LS365 6 bit input buffer reflects the output logic levels from the PCMCIA s interface adapter The status outputs include battery status write protect switch position memory issue 26 April May 1992 79 card insertion detection and ready or busy for programmable devices The two remaining latches set up a Cen tronics compatible parallel I O port Two external interrupt lines are used as handshaking for the port Note most PC pa
62. the calling routine via a return code so the caller can take the appropriate action The fundamental operations the ring buffer must perform are write record read record and remove record Addition ally an initialization function allows the buffer to be allocated dynamically at run time A check function is useful to return the empty or full error status of the buffer without actually doing a read or write operation The ring buffer as described requires two control blocks in order to operate First a static block written once at initialization time that defines that start point and end point of the buffer area the total amount of bytes available for storage and the largest record allowed on a read or write operation Second a dynamic block that contains the read and write pointers and the bytes used counter which is modified on each operation that writes to or removes data from the buffer You can obtain a certain degree of security simply through the order of actions you perform when affecting the ring buffer For the write operation proceed by making a copy of the write pointer and free space counter check if the record will fit and then move and delimit the record The new values are written into the dynamic control block once the new value of the write pointer has been determined and the free space counter has been recalcu lated Monkey with the pointers and other values in the actual control blocks as little
63. to 146 degrees F TOUCH TONE DECODER and other serial interfacing roducts available Call for free information packet FULL TECHNICAL SUPPORT Provided over the telephone by our staff EACH ORDER INCLUDES A FREE DISK WITH PROGRAMMING EXAMPLES IN BASIC C AND ASSEMBLY LANGUAGE A detailed technical reference manual is also included HIGH RELIABILITY engineered for continuous 24 hour industrial applications All I Gs socketed Use with IBM and compatibles Tandy Apple and most other computers with RS 232 or RS 422 ports All standard baud rates and protocols may be used 50 to 19 200 baud Use our 800 number to order FREE INFORMATION PACKET Technical information 614 464 4470 24 HOUR ORDER LINE 800 842 7714 Visa Mastercard Ameiican Express COO ELECTRONIC ENERGY CONTROL INC 360 South Fifth Street Suite 604 Columbus Ohio 43215 110 Issue 26 April May 1992 19 uses network bandwidth more effi ciently Industry standard protocols that use synchronous serial communi cation include HDLC ISO standard 4335 and SDLC A few microcontrollers have synchronous communication capabil ity appropriate for networking includ ing the Intel 8044 similar to the 8044 BEM previously mentioned in the BITBUS section the Zilog Z80 181 a Z80 variant and the National Semi conductor HPC16400 These chips have hardware that assists you in the implementation of the HDLC or SDLC like protocols Detection
64. to 50 times faster than the MCS BASIC 52 interpreter E Includes Binary Technology s SXA5 1 cross assembler amp hex file manip util E Extensive documentation E Tutorial included E Runs on IBM PC XT or Compatible with all 8051 variants BXC51 295 603 469 3232 FAX 603 469 3530 Binary Technology Inc PRODUCTS Main Street P O Box 67 e Meriden NH 03770 152 The Computer Applications ournal Ed Nisley is a Registered Professional Engineer and a member of the Com puter Applications journal s engineer ing staff He specializes in finding innovative solutions to demanding and unusual technical problems SOURCE Please see page 3 1 for more information about the availability of HCS II components SOFTWARE Software for this article is avail able from the Circuit Cellar BBS and on Software On Disk for this issue Please see the end of ConnecTime in this issue for downloading and ordering infor mation 419 Very Useful 420 Moderately Useful 421 Not Useful ADVANCED COMMUNICATIONS PRODUCTS SEALEVEL SYSTEMS PROVIDES THE EXACT COMMUNICATION CARDS YOU NEED e 1 2 OR 4 PORT AS 232 AND RS 422 485 BOARDS e CURRENT LOOP SERIAL INTERFACES e HIGH SPEED SYNC HDLC SDLC AND ASYNC WITH DMA e RS 530 AND V 35 INTERFACE BOARDS e DIGITAL AND RELAY 1 0 BOARDS e DISKLESS EPROM BOARD WITH PROMKIT SOFTWARE BY ANNABOOKS e NEW LAP TOP ADD ONS MADE IN USA e DELIVERY FR
65. tracking system The basic HCS II IR Link utilizes a single IR LED and IR receiver because it s supposed to be used with a trainable hand held IR remote control Unlike a hand held remote that can be directly aimed at the IR Link s IR receiver a badge attached to a pocket or belt may not be in direct line of sight with the IR Link As a result to properly implement the badge tracking system I ve described additional IR LEDs and IR receivers must be connected in paralla with those on the IR Link There is a 6 pin header designated for this off board expansion The IS 1U60 IR receivers are open collector devices that can be directly connected in parallel but aimed in Adjust for 38 kHz 5 470 i 1000uF 318 ca LD273 K 2 w FET IRFOS120 HEXFET LD2 73 Sharp IS1LU6O ENC 61 9k OUT 20 15k 19 AA lan Ad just gk for 12 4 kHz BEC ENC es OUT ENABLE MC 145030 Figure 6 An intelligent IR badge has a unique code set on its switches and transmits its code on y when it hears the same code sent to it a g O02 2uF Mylar EXPRESS CIRCUITS MANUFACTURERS OF PROTOTYPE PRINTED CIRCUITS FROM YOUR CAD DESIGNS TURN AROUND TIMES AVAILABLE FROM 24 HRS 2 WEEKS Special Support For e FULL TIME MODEM e GERBER PHOTO PLOTTING e TANGO PCB e TANGO SERIES II e TANGO PLUS e PROTEL AUTOTRAX e PROTEL EASYTRAX smARTWORK HiWIRE Plus WE CAN NOW WORK FROM YOUR EXI
66. turns off all the crosspoint switches One thing to note is that the control memory is a WOM for Write Only Memory The control latches can be written but not read If software needs to know the state of the switches some method of remember ing all the writes since the last reset is needed I ll talk about some ap proaches to this problem later Figure 2 lists some of the MT89809 s specs Notice the switches have good frequency response and low distortion They should have no problem handling any speed RS 232 signal They would also make a good sound switcher In fact other members of this chip s family have a third power supply pm so they can be used with bipolar analog signals Designing an automated sound mixing board using this type of chip might be fun Another interesting application shown in the Mitel handbook is a Test Equipment Switching System which connects a rack of electronic test equipment to a number of points in a circuit under test You could use these chips to make an automated test setup See Mitel s Analog Communi cations Handbook for more informa tion on this and other telephone oriented chips THE DESIGN My first thought was to run the RS 232 signals right through the crosspoint switches This arrangement would make a neat little one chip plus glue design and would work fine as long as the signals didn t exceed the power supply voltage to the transmission gates Unfor
67. use HLL maybe they should call it C for the NLX230 An example of an NLX230 program is one to drive a fuzzy vacuum cleaner The goal is for the vacuum to automatically adjust to varying operating conditions In particular the vacuum design monitors three inputs Pressure Dirt and Texture and drives five outputs Vacuum Height Speed Clean and Bag The program Listing 1 starts by defining 15 of the 16 terms or fuzzifiers The format specifies the input eg Pressure followed by a Classification name eg Pressure Very Low orPVLow associated with a center and a width value eg 0 30 and finally whether an Nclusive or an Exclusive membership should be used Notice how the latter feature allows easy definition of mutually exclusive sets For example P V Lowis defined as Press u r e with a center of 0 and a width of 30 inclusive while NotPVLow isdefinedas Pressure with a center of 0 and a width of 30 exclusive Next each of the rules associated with the five outputs is defined Note INCLUSIVE N Ae EXCLUSI VE Figure 7 A type bit going into the Alpha Cut Calculator specifies whether he defined fuzzy set is considered inclusive or exclusive that each output can have a different number of rules in this example a total of 25 of the 64 rule memories are used The format of a rule is IF input ISclass AND input IS class THEN output The first line of each output definitio
68. used a physical circuit containing the encoder chip to create the signal source How ever if we had some way to simulate Oscillator with Enable Encoder 10 Enable AO 1 Al 3 A2 4 A3 5 mo aS Address Generator R Address oun Manchester Comparator Decoder the M anchester encoded IR signals without actually using an MC 145030 then we could use a trainable remote and eliminate the cost of making a unique hardware transmitter The obvious answer was that if the IR Link processor could decode the serial data it could also generate and encode it In effect the transmitter could be reduced to nothing more than an IR LED controlled by a processor output bit and a software routine Ed and discussed the possibility of indeed reducing the transmitter to Pin 14 VDD Pin 17 Vss Decoder Figure The MotorolaMC 145030 is a remote control encoder decoder chip that handles up to 512 unique IR codes The Computer Applications Joumal Photo l Any trainable held held remote may be used fo send commands to the HCS Il The JR Linkis a gateway responsible for directing IR codes to the Supervisory Controller just an LED but some practical limitations intervened While a 12 4 kHz data rate was easily accommo dated the 38 kHz modulation fre quency was not as easily synthesized Because the COMM Link uses an 11 0592 MHz crystal the software generated 38 kHz could not be pro duced exactly on frequency I
69. variant of Artificial Intelli gence Al which is widely known as that which cannot be done by computer The simplest way to grasp fuzzy logic is to realize it is quite like the Boolean logic we know and love except that the two values allowed in that scheme True and False are extended to encompass multivalues such as Could Be or You re Ridding That sounds good but the next levels of detail membership func tions singletons alpha cut and so forth are usually what causes eyes to glaze over I m going to skip all the theoretical stuff which is well covered in the NeuraLogix literature and academia and proceed directly to a real world example Consider the ubiquitous PID controller PID which stands for Proportional Integral Derivative is a closed loop control scheme commonly used to set a control output depend nu Issue X26 April May 1992 85 ing on the state of an error input For example in a disk drive with an analog head positioner i e voice coil the power applied to the positioner control output is determined by the error input i e the distance between the current track and the track being sought PID refers to the three aspects of the error that should factor into the output They are as follows The P term says the output is simply a function of the current error For instance when using the disk example if the track sought is far
70. 1 and a parallel port LPT 1 are supplemented by two extra serial I O ports which can operate synchronously or asynchronously DMA channels assigned to these ports can provide very fast throughput The Solid State PC features a ruggedized completely closed aluminum housing measuring 2 6 x 8 9 x 11 2 The absence of a ventilator reduces noise and improves reliability while permitting use in environments nor mally considered unsuitable for a PC One AT expansion slot is provided for a card up to 9 4 inches in length Optional hardware and software items include a math coprocessor ROM DOS protocol drivers emula tion packages network adapters and a communications coprocessor The Sold State PC starts at 1900 NCAA Datacom Inc 233 Peachtree St N E Ste 404 Atlanta GA 30303 404 523 1 109 Fax 404 522 7116 moo ANAAO NEWS Edited by Harv Weiner LOW COST SINGLE BOARD COMPUTER A new single board computer designed for use as a stand alone system or as a user interface to an existing control system has been announced by Applied Logic Engineering The RS 232 SBC is an 80C32 based design that includes an on board 1 x 16 LCD and 20 key keypad to provide you with input and output capability The board also includes a full RS 232 serial communication port for connections to other embedded control systems or PCs The board accommo dates a27C256 EPROM for program storage and a 32K static RAM for memor
71. 1993 As of January 1992 LonWorks Transceivers were not available Echelon will be selling media interface modules or they will provide technical data from which you can design your own LON interface boards for desktop and industrial PCs are also available CA C3 Ls JRS u3 COmMzeozo AONMUX XTALZH LAN CONTROLLER CHIP SETS Another way to add networking capability to an embedded controller is to include a LAN controller chip set Chip sets are available that interface to a wide range of microprocessors and some microcontrollers This approach is advantageous because you can construct a moderate to high bandwidth network while using industry standard protocols The main disadvantage is the chip set is likely to increase the cost of your controller hardware significantly Another disadvantage is regard less of the chip set you choose you will probably have to write software that implements an application layer high level network commands of your own design as well as having to write microcontroller code to talk to the chip set Datapoint s ARCnet ARCnet was originally introduced in 1977 by Datapoint Corp and has since become a de facto standard Over 3 000 000 ARCnet nodes have been installed in everything from industrial LANs to office PC LANs U4 HYCSe6B S5TsasLe 50 PH A PH B TPA TPBHS TecHs PULSEL PULSE2 RXDATA REF _V Figure 4 The Standard Microsystems COM20020 is an ARCnet controller
72. 30 1 2 3 4 5 6 7 8 9 Figure 4 The NeuraLogix NLX230 Fuzzy Microcon troller can be used in applications where traditional microprocessors lack the speed or memory to do the job know Laplace isn t some kind of yuppy bar We whose heads are less egg like usually resort to various PID tuning procedures Often in the haste to get it working intricate PID tuning schemes quickly devolve into play around with the dials and see what happens To start understanding the fuzzy approach to a microapplication like PID first consider the ultimate brute force approach Instead of using an Euzzitier g 8 Fd 8 a N rg algorithm control is made using a look up table i e a predefined memory Let me see Even using only Sbit integers need a memory with 24 bits of address 8 bits each for the P I and D terms and an amp bit output The bad news is 16 megabytes of memory is over 500 even with falling memory prices The good news about the look up table approach is it is fast the loop time is the same as the memory cycle time i e millions of loops per second The procedure to initialize the memory with the proper output data for all 16 million possible input states is left as an exercise for the reader The promise and hope of fuzzy is to combine the concise representation of an algorithm with the speed and simplicity of a look up table To see how it works take a look the N
73. AVIDSON To STEVE LANGER picked up a book on interior lighting and it explained almost what you just did Running the lamp dimmed will indeed allow the inside of the quartz to begin to blacken but running the bulb at full intensity every so often will allow the complete reaction to take place and will restore the lamp Msg 51997 From STEVE LANGER To KEN DAVIDSON By the way my source for info on halogen bulbs was the horse s mouth itself some few hrrrmmpphhh years ago we were looking to replace a conventional bulb in an instrumentation light source with a halogen bulb and were dealing with GE directly got to spend a couple of very interesting hours with two of the fellows on the develop ment team that worked on halogen bulb technology there CRCs are very often used in checking communication data streams for errors Might there be more to them than meets the eye Msg 52670 From KENNETH SCHARF To ALL USERS We use the CRC 16 polynomial equations to checksum data on a transmission scheme on several of the products work on From what have read this polynomial equation will produce a unique number for a string of bytes of up to 4096 in length The idea behind this is there are 32K bits in 4K bytes and each bit may be a one or a zero That adds up to 64K which is represented in a 16 bit number The polynomial is both data and position sensitive interchang ing bytes will produce a different result Now if this i
74. Atlanta number is 404 248 2565 In this catalog you will find exactly what you are looking for What is the current range you are looking to measure I may have an extra sample laying around Also do you just need a comparator output when a preset threshold is exceeded or do you want a binary output scaled to the current Either way it s in 20 Also included are the Hall Effect devices that others are suggesting Msg 51089 From PELLERVO KASKINEN To RICHARD PFEIFFER A word of warning you may not really benefit from plain AC current sensing The current in a motor with an idle compressor changes very little when the compressor is loaded What changes is the phase angle power factor In other words there is plenty of current sloshing through the motor windings even when the compressor is idle but it is practically 90 degrees out of phase with the supply voltage When the compressor turns on the phase angle gets much more in line with the voltage when real work is being performed The Computer Applications Joumal Issue X26 April May 1992 99 AON OTIME You might need just an old fashioned CT current transformer available from your local electric contractors or their supply houses for a few bucks The problem with them is that they generally produce a 5 ampere secondary while you would benefit from a 1 ampere or even better 0 1 ampere secondary You can make one yourself You actually indicated you have tried but the
75. CRCUIT CELLAR x THE COMPUTER APPLICATIONS JOURNAL 5 rei LA A _ i 3 aT S aiis e PAA eh MTT j 04 mai tata R Ara ee k a I S ana aa a pity eek al lt 7 il no A LRT EA ot t NT Ht JEn A r koet TER 2 oe X POR 7 ee el te p ERS YF i ify AOR Sok AR ay Tee a aod os yee eee Or Ssh oO Fry est Soe ten aaa ene oy hte t Se ES AIS Soy SELE lg ED E o E e i i a OAE DISTRIBUTED CONTROL SPECIAL SECTION Embedded Programming Infrared People Tracker Programming the MC68HC705 Software State Machines Apri May 1 992 Issue 26 Ey DIU KO AT INK Divide and Conquer hat s the best way to approach a large control or data collection application You can hit it with a big hammer and use lots of computing power in a central location or you can break the problem into smaller pieces and spread the load around When we designed the Circuit Cellar Home Control System Il we opted for the latter approach We put the burden of deciding when what should happen on one central controller but we distributed the tasks of power line interfacing infrared interfacing and individual input and output bits onto other processors spread out around the house I d like to be able to say we purposely followed our Building Automation issue with a Distributed Control issue because of the HCS Il but can t It was a coincidence buta nice one It gives us the opportunity to point out the HCS M s dis
76. CT command and tune the frequency You even get a simple tuning graph try it and see Al 9 ss He he ae LES SS SESE A second calibration routine mea sures and displays the remote unit s bit frame time The nominal value is 1290 us but if you study Figure 2 Dra Rantral E ll el cll i Bd blind Introducing the Most Expandable 3 7 2 Board Available MCU 31 2 On Board Options Include 16 Channels 10 bit A D 14ps w S H Dallas 1287 RTC Flexible mem config s RAM 8 32KB ROM 8 16 32 64 KB RS 232 or 485 jumper selectable Watchdog timer w jumper sel reset source Pre decoded extemal bus for very easy user interface directly compatible with other ADS boards see back issues of Circuit Cellar INK More I O modules are availble Call for our FREE catalogue today 404 352 4788 Design from 149 95 W Advanced lt Solutions 1920 Moores Mill Road Atlanta GA 303 18 14 76 Issue X26 April May 1992 The Computer Applications Joumal ee ae a e 3 H e 7 43 V 139 5 a mE DH gt s esssssrsososte AAAA A n Adua 8 a a A a ia f Peeetooounnere Photo The U60needs some time to decide that it is seeing en JR signal end more time to decide that if is not The fp trace shows he raw IR signal while the bottom trace shows the 1S1U60 s output again you ll see how difficult it is to determine this value
77. DB GREEN DB RED DB RED DB RED STATE GREEN DB GREEN DB YELLOW DB GREEN DB RED STATE_YEL DB YELLOW DB YELLOW DB RED DB RED CURRENT STATE I NPUT_CONDI TI ON NEXT_STATE X CURRENT STATE Current Get Multiply by number of conditions Add Move table offset Next Jump to the next variable state variable in RAM nput Name the start of the table Input A Input B Input C Input D Input Input Input Input Input A Input B Input C Input D the current state input in this case 4 input condition to X register now in A state in the state is The Computer Applications Journal REALIZE THE POWER Issue 26 April May 1992 5 7 Real Time Devices Accessing the Analog World Exciting New Products AD1200 359 12 bit 125 kHz A D Conversion 16 Analog input Channels 3 Timers and 16 DIO Lines Supports DMA amp Pacer Clock AT Bus Version Available for AMPRO CPUs DM200 12 bit 40 kHz 8 channel analog input board 8254 timer and 16 digital 1 0 lines 295 DM406 12 bit 100 kHz 16 channel analog I O board 2 D A outputs 8254 timer 16 digital I O lines Supports DMA and pacer clock 449 DM806 High current digital I O board 8254 timer opto 22 compatible 195 PC XT AT Boards AD2700 16 channel 12 bit 150 kHz analog input board Supports DMA pacer clock and programmable gain 8254 timer 16 digital I O lines 16 bit AT
78. Forum MicroDesign Resources Inc 874 Gravenstein Hwy So Suite 14 Sebastopol CA 95472 707 823 4004 Fax 707 823 0504 Tom Cantrell holds a B S and an M B A from UCLA He owns and operates Microfuture Inc and has been in Silicon Valley for ten years working on chip board and system design and marketing 425 Very Useful 426 Moderately Useful 427 Not Useful Issue 26 April May 1992 91 Writing Code to Support Nonvolatile Memory Designing a system to survive an unexpected power loss may seem as easy as adding a battery backup to the RAM However making a truly bullet proof system often requires more safeguards 92 Issue 26 A pril May 1992 PRACTICAL ALGORITHMS John Dybowski our system has been running flawlessly for weeks Now you ve made the final code tweaks and you know you re going to blow the competition out of the water At your presentation everyone waits expectantly as you plug in the new production PROM and power up the system Quickly you realize that something is wrong The system is now making funny noises and scrolling strange characters across the display Sheepishly you reach over and reset the system Same result What could be worse A call comes in from the computer room the entire network is down choked by a rash of gibberish from your demo unit Your findy tuned well crafted creation resembles some cheap dime store novelty Beads of sweat for
79. ID codes carefully suggest you put all your control codes in the range 256 511 so the high bit distinguishes badges from remote controls and the low byte holds the entire ID code If you are using passive badges you must allow enough dead air between polls to accommodate remote control inputs set the polling Affordable 8031 Development Single Board Computers Assemblers Compilers Simulators and EPROM Emulators Control R Series Single Board Computers Two modes of Control R series computers make prototyping one of a kind products or small production runs easy and economical Both feature RS232 compatible serial ports single 5 volt supply operation and direct access to Ports 1 and 3 of the 8031 Additional features are as follows Control R Model 1 49 95 Fully populated board with I O header for Ports 1 and 8 serial port and 8K EPROM socket 3 0 x 4 0 Control R Model 2 79 95 Same features as the Control R 1 plus 8K of SRAM and expansion bus with data address RST INT1 WR RD PSEN ALE and T1 3 5 x 4 5 148 Software and Hardware Development Tools Control C 8031 Cross Compiler 200 00 The Control C 8031 cross compiler is a full featured K amp R style C development system available at an affordable price Optimized for embedded system use it will produce ROMable code for any 8051 based system including designs using only the 128 bytes of internal RAM Package includes
80. INQUIRIES WELCOME BARAN HARPER GROUP LOS ANGELES TORONTO BBS 416 471 677 139 VOICE 416 294 6473 not use a supply over 12 VDC because you won t be able to properly adjust the Vpp voltage The 5 volt supply is regulated with an LM78L05 regulator intended the programmer s circuit design to be as simple as possible Low cost and available parts are used throughout Most parts including the zero insertion force socket are available from Digi Key designed the PEMHC05 me chanical layout to simplify the construction of an enclosure All active parts are mounted on what would be considered the component side of a two sided PC board After they are soldered in place the pro gramming socket is mounted on the solder side I usually mount the programming socket in a standard IC socket to get a little extra height above the component leads protruding from the board This arrangement allows the board to be mounted in a plastic enclosure that has a square cutout for the programming socket and four mounting holes for the board A couple of additional holes for the power switch power jack and LEDs and the enclosure is complete Connections for two status LEDs are provided on the board These LEDs provide a visual indication of program mer operation when the PRO G7 software package is used They are provided for compatibility with the Motorola board and may be left out if you d like because the BURN 0 5 program provide
81. LX230 Fuzzy Microcontroller FISC Imagine you had a computer with an instruction set including gems like Branch Maybe and Output Approxi mately should make for exciting debug sessions Fortunately the NLX230 isn t such a beast even though it is named a Microcontroller The chip is much simpler than that Indeed it doesn t have an instruction set at all Instead the NLX230 samples inputs eight channels of 8 bits each INTERLACE Timing amp Control Output Register OUTPUT x8 Minimum Comparator Maximum Comparator Figure 5 Each of the 16 fuzziliers on the NLX230 may be assigned to an input either one of he eight input channels of a loopback from the output The Computer Applications Joumal and generates outputs ditto according to rules and terms Interfacing the NLX230 is simple Figure 4 The DIx and DOx pins are the process inputs and outputs respectively The ability to multiplex eight channels worth of data onto each of the DIx and DOx buses is provided with the three MA pins which encode which of the eight channels are using the pins The STB pin times the DIx and DOx transfers X1 and X2 are crystal connections while OSC is a TTL compatible square wave output of the on chip clock generator The NLX230 has been designed to run at up to 30 MHz which translates to 30 million rules per second RIPS in FuzzySpeak Before the chip can start fuzzing the definition of t
82. M able re entrant GOFAST floating point Replace 80x87 MATH COPROCESSORS Drop in IEEE SOURCE LIBRARIES Link and Go with C compilers Intel Microsoft Borland WATCOM Zortech Metaware and more 1992 US Software Corporation GOFAST and MuttiTask are trademarks of US Software Corporation All other trademarks belong ta their repective owners 140 The Computer Applications Joumal Solutions for 80386 486 PROTECTED MODE 80x86 amp V Series Z80 180 64 180 8085 68xxx 68HC16 68HC1 1 6801 6809 8051 80196 1960 R3000 SPARC and more Call for free information diskettes today PHONE 503 641 8446 FAX 503 644 24 13 USA TOLL FREE 800 356 7097 14215 NW Science Park Drive Portland OR 97229 US SOFTWARE Issue 26 April May 1992 67 found in its little brother Among them PRO G7 can transfer the micro controller s EPROM contents to the PC which can be useful for comparing the contents to a data file or for making copies of the part PROGRAM SOME PARTS Setting up the programmer and programming parts is easy First Complete kits of parts and assembled PC boards are available from Single Chip Solutions P O Box 680 New Hartford CT 06057 203 496 7794 Kit includes all parts less optional resistors and LEDs wall transformer and mating connector DB 25 connector and PC board no enclosure is available for 100 Asy Assembled PC board with wall transformer mating
83. MHz 595 ID161 100 MHz 695 High Speed 8K Trace Buffer 16 timing channels expandable to 32 state channels M ulti Level Triggering State Pass Counting Event Timer Counter Performance Histograms Hardcopy Output Disassembles S bit micros Supports VGA EGA HGA_ Demo diskette available 30 Day Money Back Guarantee INNOTEC DESIGN INC 6910 Oslo Circle Suite 207 Buena Park CA 90621 Tel 714 522 1469 FAX 714 527 1812 1 66 Issue 26 April May 1992 The Computer Applications J ournal 4mA which is enough to force Q1 into saturation when itis on Figures 2 from any wall transformer or power and 3 show the timing of the program supply capable of providing 9VDC at ming voltage with respect to Vcc during power on and power off se Power for the board may come 150 mA I puta series diode on the board to protect the circuitry against reverse voltage on the supply line Do X 10 TW523 DEVELOPERS KIT AT LAST Now you can TRANSMIT amp RECEIVE X 10 COM MANDS under control of YOUR application program We supply you with the I O SOURCE CODE Be up and running in MINUTES Write your own CLIPPER BASIC program We also have comple application packages Shipped within 24 hours worldwide Phone our BBS for complete pricing and details X 10 TW523 Transceiver e Serial OR Parallel RJ 1 1 DB25 Interface e Microsoft Turbo C 1 0 Drivers source 6 foot cable Each Kit contains Technical Reference M anual DEALER
84. OM STOCK e EXCELLENT TECHNICAL SUPPORT i COMMUNICATIONS amp 1 0 e SATISFACTION GUARANTEED SEALEVEL SYSTEMS INC PO BOX 830 LIBERTY SC 29657 803 843 4343 issue 26 April May 1992 17 Does It Come With a Memory Standard Part 2 The Nitty Gritty In the last issue Jeff introduced us to the PCMCIA memory card standard This time he shows us how to build an interface that should stand the test of time assuming the standard does too 78 Issue 26 April May 1992 FROM THE BENCH Jeff Bachiochi roblem logging data over any period of time whether it be tempera ture patterns device status or caloric intake often requires more storage space than an inexpensive micro controller has to offer needed a simple way to extend the amount of data could gather and provide a semipermanent record of that data Solution Although disk storage is not rugged enough for many environ ments it does have the advantage of a removable semipermanent medium Nonvolatile memory devices over come the environmental problems associated with disk storage yet still provide shirtpocket transportation and archiving of data In my last column revealed the arrival of a new interface standard for solid state memory cards Although it had its start back in the 8Qs this standard never took off like it should have due to a lack of interface specifi cations After a bit of refin
85. RS 232 switch ABORT will send the message to the terminal empty the stack and return to the prompt averting the danger CHECK will RANGE the top two numbers on the sack If either is out of range or if there is only one of them then it s ABORT time If all is wal need to take these two numbers and make one number that can add to the base address of our crosspoint switcher to turn on the desired switch CHECK DUP RANGE OVER RANGE 68332 68HCI16 HIGH NOISE IMMUNITY then they are left as they were found The matrix of numbers need to add to EI _ ONE MEGBYTE RAM EPROM Ecm 68332 UL UL ERE 595 QUANTITY ONE Our FOUR layered CPU and I O boardsare designed for tough factory floor environments Custom design and board mfg available Please call for specifics ard Computer TEL 510 475 8147 FAX 510 489 5356 33476 Alvarado Niles Blvd Suite 6 Union City CA 94587 prevevevyrey BCC I EXPANSION CONNECTOR 5 VOLT MONITOR MONITOR FRESE aed theres terete et Peepers tities f L 118 38 Issue 26 April May 1992 The Computer Applications Journal The 595 Solution to 8051 System Development PDK5 SIBEC H microcontroller board 805 2ATLBASIC CPU with 16K RAM BASIC interpreter source on disk SIBEC H hardware manual with schematic Monitor debugger ROM plus manual Monitor debugger h
86. RTS 6 TIMER COUNTERS Up TO 512K MEMORY PLus EEPROM E PAC 3000 G2 COST 389 00 QTY 1 ENAC inc 618 529 4525 P O BOX 2042 CARBONDALE IL 62902 Fax 618 457 0110 Issue X26 April May 1992 65 2V_0 033 A 0 010 A Cr pF 32 ps 15V 17 pF From the equations above the calculated value for C8 is 17 pF I used a 56 pF electrolytic capacitor to ensure a low ripple under all conditions In addition to the electrolytic also used a0 1 pF ceramic capacitor on the V pp output to provide additional filtering of any high frequency switching transients from the supply The Vpp switching is controlled via the microcontroller s RESET line and a two transistor switch Q2 is used to turn Q 1on when the MC68HC705 is brought out of reset which switches the programming voltage to the microcontroller A 3 6 volt zener diode 0 05 v Figure 2 Programming voltages must be applied in sequence during power up The fop trace shows Vpp while the CR3 on the emitter of Q2 ensures Q1 bottom shows Vec In both cases the vertical scale is 5 volts per division and the horizontal scale is 50 ms par and Q2 are off when the 5 volt supply division drops below 4 volts want to be sure the programming voltage is off when the 5 volt supply is not in regulation and when programmed devices are removed from the programmer R10 limits the current through Q2 to about quencing PC Based Logic Analyzers New Prices for 1992 ID 160 50
87. STING ARTWORK BY SCANNING CALL FOR DETAILS ye 115 HiWIRE II EE DESIGNER EE DESIGNER III ALL GERBER FORMATS Express Circuits 314 Cothren St FIO Box 58 Wilkesboro NC 28697 The Computer Applications ournal Quotes 1 800 426 5396 Phone 919 667 2100 Fax 919 667 0487 Issue 26 April May 1992 29 12 12 L0273 LO273 kl Ml L0273 LO273 Ca Ka LD273 tD2 3 Ka Adjust for 1A 1Q LED current LD273 LD273 IRF 83 IS1U60 IS1U6 S uo Figure 7 n order to cover a who e mom with R transmissions and receive badge responses a group of IR LEDs is used with several IA receivers These extra components are connected to the basic IR Link board to boos its transmitting and receiving power different directions to cover a wider area However as a practical matter additional IR LEDs should not be connected in parallel with the LD273 on the IR Link board because there is only a single 2N2907 driver Instead the 6 pin header brings the raw PCM signal out This feature should be used to drive a separate external transistor or FET Photo 3 shows a prototype expansion transmitter receiver that built It contains three IR receivers and The following is available from Circuit Cellar Kits 4 Park St Vernon CT 06066 Tel 203 8752751 Fax 203 872 2204 12 dual dement LEDs Using the prototype s own power supply and an IFR830 FET driv
88. Software is available for writing assembling and converting 805 1 programs including a program editor assembler disassembler and a hex to binary con verter Suncoast Technologies P O Box 5835 Spring Hill FL 34606 504 888 one 28838835 883 tiie rt DO oe DO on o i baca ome bag O kad eg Cad The Computer Applications ournal 2400 BPS ON BOARD MODEM A high speed modem designed for enbedded applications has been introduced by Western DataCom The 224 OEM is compatible at speeds from 300 to 2400 bps is easy to interface to TTL level serial ports and is tunable to support the V 22 and V 21 international specifications It features automatic adaptive equaliza tion to achieve bit error rates of better than 10 even over poor quality lines and its speed and small size make it perfect for terminal applications The 224 OEM also features FCC registered direct connect DTMF tone or pulse dialing compatibility with the AT command set manual or automatic operation storage of 32 digit phone number and originate answer operation Control functions include Abort Timer Disconnect Loss of Carrier Disconnect Long Space Disconnect and Failed Call Time out Board placement and connection is simplified with its compact 3 5 x 2 75 size and power requirements of 5 volts at 180 mA NMOS or 30 mA CMOS The 224 OEM DTE interface is a standard 20 pin connector with standar
89. TUS LEDS VPP 1 5 UPP2 51 52 UCC UPP UCC UPP2 24 A25 D15 A24 D14 A23 013 H A22 2 a21 1 Azo St A19 d REG RFSH GND GND GND GND i yaa Js Jes SERIAL PORT 3 0090909000000 020000 000000 PARALLEL PORT madi ig EE Figure The Bit Bucket is based on an 8751 with built in EPROM and several latches that make it possible to address more than 64K of card memory Data may be exchanged with the unit through either a serial or a parallel interface SECRET INGREDIENT There are no secrets here The PC Memory Card International Associa tion has the hardware well docu mented The interface to the PCMCIA card socket consists of 26 address lines 16 data lines I ve chosen to only use an 8 bit data path 5 control lines into the socket and 6x status lines out of the socket The five control inputs are as follows CEl and CE2 are chip enables one for the lower 8 bits of data and the other for the upper 8 bits when using a 16 bit path OE is the output enable and WE is the write enable PGM for programmable devices REG is the alternate memory area normally set aside for device recogni tion The six status lines are configured as follows CD1 and CD2 are grounded lines within a memory card used to indicate when the card is fully inserted Last time mentioned the unique arrangement of multilength contacts used in the interface socket The longest pins apply power to
90. UTERTISE inc 302 N Winchester Olathe KS 66062 913 829 0600 800 255 3739 easier to work with cheaper and able to drive LEDs directly THE FIRMWARE If you ve been follow ing this column for a while you know my language of choice is BASIC whenever possible It s quick to write easy to follow even without comments and its execution speed usually isn t a concern This time speed is top priority The serial reception won t wait for any slow code Multiple characters will be received in the time it takes BASIC to execute one line of code There are only three routines written for this project The first is initialization code to get the 803 1 ready for the task at hand Here give myself some breathing room by moving the stack pointer up to 21H I m not using all the registers below the stack but do want to use the bit 154 addressable ones starting at byte 20H for the status information The serial port is set up to use an 8 bit data word using Timer 1 in the 8 bit autoreload mode at 9600 bps The internal registers used to reflect the present state of address lines Al 6 A25 bank select are cleared and the memory card size registers used for the end of RAM detection are set up Now the first external address latch is updated from the internal register with Al6 A23 The front panel status LEDs are on the upper 6 bits of the second external ad
91. Uses only low bit of argument to simplify the calls Output is 1 for IR On and O for IR Off IRFormatFrame MsgBit pMsgFrame unsigned int MsgBit BYTE pMsgFrame if 0 oMsgFrame 1 pMsgFrame l 0 else poMsgFrame 0 pMsgFrame 1 Convert argument TRFormatBurst MsgNum pMsgBase unsigned int MsgNum BYTE pMsgBase BYTE Index IRFormatFrame 1 pMsgBase 0 1RFormatFrame 0 pMsgBaset2 pMsgBase 4 for Index 0 Index lt NUMDATABITS Index encode MsgBit amp 0x0001 into Manchester encoded burst at ptr start bits msg IRFormatFrame MsgNum pMsgBase MsgNum gt gt 1 pMsgBase 2 TRFormatFrame 0 pMsgBase trailing Convert integer into bit pattern in the transmitter buffer TRFormatMsg MsgNum WORD MsgNum memset ITrnBuff 0 sizeof ITrnBuff flush previous TRFormatBurst MsgNum lf rnBuff 24 TRFormatBurst MsgNum I TrnBuff 52 INumSend 79 SETBIT FlagIRPending pin The firmware sets up INTO to produce an interrupt for each down going edge but a little study of Figure 2 will show that the Manchester data format does not produce an interrupt for each bit frame The firmware can take advantage of the bit frame timing to anticipate The Computer Applications J our nal how many half frames in indicate ready to go bits transmission one time first repeat buffer when each bit s
92. a continuing vehicle for high tech experi mentation among the Circuit Cellar engineering staff By breaking precedence and telling you our plans risk discussing vaporware in my effort to satisfy reader demands However given this caution combined with the understanding that any projects mention here are still just ideas and that my describing them does not mean they will be automatically published as design projects let me outline some future plans for HCS Il TRceode 10 and Solarium is First of all Ed and are going back and resurrecting the Master Controller Trainable Infrared unit published in Best of Ciarcia s Circuit Cellar chapter 32 and attaching it to a COMM Link node After training the Master Controller using a PC with all your hand held remotes the Supervisory Controller can then command any individual or series of stored IR sequences to be transmitted This capability makes it possible for the HCS II to for example cue up a specific CD or tape and set the appropriate volume in response to you walking into the room Second Ken and want to build an updated version of the Touchtone Interactive Monitor TIM system that presented in issue 21 We recognize the need for outside interaction with the HCS and a more intelligent and articulate version for TIM is our goal Finally all of us have discussed a true voice interac tive interface lathe Enterprise s computer from Star Trek
93. adge different from those reserved for remote control the 28 Issue 26 April May 1992 system knows both the identity and the location of an individual Of course as with any asynchro nous transmission method like this one if too many badges are in the same area there can be message collisions The solution is to use an intelligent badge like that shown in Figure 6 In this circuit each badge has a unique code 1 of 5 72 set by the jumpers on the MC 145030 The badge is designed to transmit only after it receives its own code Using the IR Link we poll a particular area by sending out specific badge codes When the badge receives its code the circuit waits 25 ms and then sends back the same code When the IR Link receives this return transmission the system then knows the location of that ID badge The IR Link has built in commands to facilitate polling an individual badge or complete ranges of badges To prove the concept was feasible built one of these intelligent badges into a package that is the size of a small pager see Photo 2 will have to say the entire project would have been The Computer Applications J ournal size and capability of the tiny Sharp IR receivers CUSTOMIZED REALITY I want to be careful not to confuse you at this point The badge reader that built is a prototype and not a production item built it to test both the IR Link software and the concept of a people
94. after each data fidd The effect of these macros is to press the same keys that would be pressed if the data were entered manually SPECTRUM ANALYZER IN A PROBE EasyData is compatible with any software that allows data entry through the keyboard It uses standard PC serial ports as well as special serial cards Communi cation is bidirectional allowing commands to be sent to the instrument for control or to initiate data transfer EasyData will also run under Windows Modify collected data before it is sent to the key board buffer or a file EasyData can use multicharacter delimiters and filter out nonnumeric data Data can also be imported directly from a file The data will be parsed modified and macros can be added The data can then be sent to either the keyboard buffer or another file EasyData is priced at 145 Labtronics Inc 75 Rickson Ave Guelph Ontario Canada N1G 3B6 519 767 1061 The Model 107 Spectrum Probe from Smith Design converts a standard I MHz triggered oscilloscope into a 100 MHz spectrum analyzer The probe enables the scope to display logarithmic amplitude vertical versus frequency horizontal with a 60 dB dynamic range and a selectivity of 0 5 MHz The scope controls can be used to provide full zoom facilities on either axis The Model 107 Spectrum Probe offers many of the capabilities of a spectrum analyzer but at a fraction of the cost Its usefulness is primarily as a quick diagnostic and genera
95. ains both an encoder and decoder eliminating the need for two separate chips The MC145030 encodes and decodes 9 bits of information 512 combinations The chip Manchester encodes the selected address input and sends the information twice serially out via the Encoder Out pin pin 16 The transmission frequency of this data is determined by an RC oscillator This frequency can be up to 500 kHz but for reasons Ed and will explain later chose 12 4 kHz Sending a command therefore takes 5 16 ms quickly threw together the circuit in Figure 2 to test the concept This simple three chip circuit takes the Manchester encoded serial output and modulates it with a 38 kHz square wave selection of the modulation frequency depends on IR receiver used This signal then controls a pair of IR LEDs through a FET Press transmit and everything is automatic The receiver circuit shown in Figure 3 is even less complex The 38 kHz IR signal is received and demodu lated through a Sharp IS1U60 IR receiver chip Its output is inverted and connected to an MC145030 which is configured this time as a decoder When the specific 9 bit code selected on its address inputs is received the MC145030 generates a code received signal that can be easily connected to a processor interrupt OK LET S START THROWING STUFF OUT It took about three nanoseconds to realize that adding a serial decoder chip to a processor is like putting a sauce
96. ak figure average frame time and display the result AvgFrTime FrameCount sprintf CmdRespBuff Bit frame time is uus n AvgFrlime Nputstr CmdRespBuff while chkch SerFlushIn IRGATE to determine which ID codes have been seen since the last poll and it must also determine how to handle new and missing IDs The P command tells IRGATE how many passive badges require polling The default is PO or no assume interrupts discard inputs polling Polling starts with ID 0 and goes up to badges 1 so P10 will poll badges 0 through 9 inclusive Your badges must respond to those ID codes for this feature to work The I command sets the polling interval with the default being two seconds when polling is enabled You should adjust this value to suit your purposes taking into consideration battery life and response time The interval is the time between succes sive polls so polling badges O through 9 with a 2 second interval would take 20 seconds The minimum value is 20 ticks which is about 100 ms The B command sets the amount of time IRGATE waits for a badge response after sending an ID code The default is 40 clock ticks about 200 ms When polling is not active this delay determines the minimum time between IRGATE transmissions You can use remote control units as well as badges in the same system if you choose the
97. and execute it This function enables the PC to set up the microcontroller to receive data and copy it to the internal EPROM The MC68HC705 s reset line is controlled by a Maxim MAX698 POR power on reset chip This chip senses the level of the regulated 5 volt supply and provides a controlled reset active low output The reset output is delayed by an internal 150 ms timer during power up and is immediately switched to reset during power down The timer provides enough time for the programmer s Vpp voltage to stabilize before the MC68HC705 is brought out of the reset state The RS 232 interface used for downloading data uses an inexpensive MAX232 transceiver chip and four capacitors The MAX232 eliminates two power supplies and regulators from the design at the expense of the four small capacitors required for the internal switching supply The chip also provides 9 volt outputs for external circuitry The 9 volt output is connected to the microcontroller s IRQ pin to enable the programming circuitry inside the chip To generate Vpp use a TL497 switching regulator While this part may not be the latest and greatest it is inexpensive easy to find and requires only an inductor and some resistors and capacitors The TL497 is capable of supplying up to 500 mA and can The Computer Applications ournal easily supply the less than 10 mA programming current required by the MC68HC705C8 Designing with a switching re
98. and is available from Digi Key Due to the light output loading almost any value GND GND VCC GND GND GND VCC VCC GND VCC GND VCC GND VCC VCC GND GND VCC VCC VCC VCC NA NA NA o NOOA WP GND GND GND VCC Reserved Load Program to RAM and run program Reserved GND VCC GND GND Verify EPROM against external EPROM Secure EPROM amp Verify against external EPROM Dump Contents of EPROM via RS 232 interface Secure EPROM and Dump contents via RS 232 Execute program in RAM at location 0051 Tabb l The MC68HC705 has numerous programming modes selected ty pulling pins on the chip high or low at reset inductor in the range of SO 500 pH will work The current handling capability of the inductor should be at least 100 mA to prevent saturating the inductor during current peaks A 390 pF timing capacitor was chosen to provide an on time of about 32 ps This standard value is within the operating range of the part At the low current the programmer requires almost any value of capacitor in the range of 200 2000 pF should work but the value of C8 will change based on the resulting on time chose a value for C8 to provide an output ripple of less than 50 millivolts at a typical load of 10 mA To determine the value of C8 use the following SLi eho Cr WF Ton us Yo RIPPLE Assigning a typical load of 10 mA tol and substituting the calculated value of I in the equation for the output capacitor yields
99. and perhaps other upper layers 3 Make use of serial communica tion modes built in to most microcontrollers and add physical medium interface circuitry and network software 4 Interface a serial communica tion IC to the embedded controller and add physical medium interface circuitry and network software Methods 1 and 2 are hardware intensive the network protocol is primarily or entirely implemented in hardware and firmware simplifying software design Methods 3 and 4 are more software intensive allowing greater flexibility while keeping hardware costs to a minimum Method 3 can often be used to add networking capability to existing embedded controllers will describe each of these methods in detail Network nodes many OSI layers specified all Communication media MICROCONTROLLERS WITH BUILT IN NETWORKING HARDWARE AND FIRMWARE The primary advantage of using a microcontroller with built in network ing hardware and firmware is a greatly simplified design of embedded control ler hardware and software Unfortu nately there are disadvantages am aware of only two microcontrollers with relatively complete built in network protocols Also development tools for these microcontrollers are fairly expensive Intel s BITBUS solution uses the 8044 BEM microcontroller BITBUS is a serial control bus specification developed by Intel see Figure 1 It was first released in 1984 and has since gained some acceptance
100. ansmissions until could work on it in the morning One glance at the laptop monitoring the power line told a completely different story X 10 codes were still being transmitted every 8 10 seconds After pulled the power to the whole PL Link module and the transmissions still persisted my thoughts wandered lo a nearby Browning 12 Gauge Over 8 Under which could be used as a last resort if logical alternatives failed At 3 a m 1 wasn t going to call Ken and tell him we had invented an Immaculate PL Link This was so absurd it was funny Fortunately the logic of what was happening hit me soon enough to get some sleep after all It turns out that smart testing takes smarter human testers When put the second PL Link on the power line to print what it heard neglected to check its other default conditions While it was listening it was updating its own module status table The fact that some of these transmissions were logically wrong later confirmed as a wiring error didn t mean anything because they were still valid X 10 codes Because had neglected lo shut off refresh in the second PL Link the default was 5 minute refresh it was resending the bad codes Since it also listens to itself when transmitting the second PL Link dutifully reported hearing all the same codes continuing to be transmitted As one night in the life of automated home control comes to an end we can only speculate what the next night will bring
101. aranteed 20 Issue 26 April May 1992 The Computer Applications Joumal The use of a serial communication IC has the same disadvantages as the use of microcontrollers with built in serial communication features Namely this solution requires a software implementation of a network protocol One feature to look for in serial chips is the presence of FIFOs which can reduce the probability of lost characters and reduce communication processing time One popular serial communications controller with both asynchronous and synchronous capability is the Zilog 28530 the recommended chip for AppleTalk hardware For asynchronous commu nication have had good results with the National Semiconductor NS16550AF and Intel 825 10 UARTs both of which have FIFOs LOOKING AHEAD At this point the list of adopted or emerging standards relevant to embedded controller networking is expanding In addition to the standards I ve already described the four men 9 1 2 x 1 1 2 It s a complete working 486 computer on a single board Cool No fan required Use it to build Embedded video games process controllers testing instuments production controllers multiracked computers any embedded application or tiny 486 desktop computers tiny proto case included holds floppy amp hard disks this board amp two halt cards te Fully functiil with standard RC motherboard peripherals DMA clack etc included Extemal 12V powe
102. ardcopy source listing e Ul listed 5V power supply Programming power supply adjustable tram 4V to 26V KERMIT communications program SXA5F 8051 8052 cross assembler BIKS BASIC programmers toolkit with tutorial 160 page BASIC Programming Manual by Systronics The PDK51 1s a fully integrated 7 Ratarahie PDK51 tutorial hardware fimware and software Optional aluminum case 45 system designed to help you develop monitor debugger source 25 your products quickly and cost battery backed real time clock 39 effectively All components are manufactured to All you need to use the PDKS1is exacting standards and warranteed for an IBM PC XT AT or compatible ery We supply therest PDK51 PLUS includes everything in the PDK51 plus Vers 3 of out popular BXC51 8051 8052 BASIC compiler 800 Call Now 603 469 3232 or FAX 603 469 3530 Binary Technology Inc Main Street PO Box 67 Meriden NH 03770 aA LVESA__ tmiorcano 119 XSWITCH or B58F is in decimal in 123 4 5 6 7 8 123 45 6 7 8 1 9 10 11 12 13 14 15 16 2 17 18 19 20 21 22 23 24 3 o 25 26 27 28 29 30 31 32 4 u 26 34 35 36 37 38 39 40 5 t 27 42 43 44 45 46 47 48 6 28 50 51 52 53 54 55 56 7 57 58 59 60 61 62 63 64 8 and I can use CALC 8 8ROT 15 Looks unfathomable Nothing to it really Remember I ll have two numbers on the stack 1 through 8 in and out CALC multiplies the out value by 8 leaving 8
103. ars later it is essential to know the variable type and the rationale for choosing the name of the variable would like to suggest a comment section in alphabetical order included in the beginning of the module that contains the name type mnemonic and what that mnemonic was derived from The alphabetical list allows easy retrieval by the reader Example in FORTRAN C CURTK real array CURtain THicKness C CURLTH real array CURtain LengTH C INIDIA real array INItial DlAmeter C STAT integer STATus of motor C 0 stopped C 1 running A final thought on comment lines First there is the usual style of commenting which includes brief comments the description of what the routine does and the compiling options Another style haven t seen used very often can also be useful in some instances Describe the current state of affairs at the instant the comment is read In other words what you have done instead of what you are going to do Information presented this way can sometimes make it easier for others to modify your code Example CThe routine has now printed C PROMPT UNITS Cwhere was null or the integer VALUE C if ALDEF was FALSE Ron Dozier Wilmington DE Want to Hear from Yoy readers are encouraged to write letters of praise Jemnation or suggestion to the editors of The Computer lications Journal Send them to Computer Applications J ournal ers to
104. ase the Beatles Despite my tendency towards cynicism truly give humble thanks for having been associated with the micro business The reason for my sentiment the simple bottom line What other business continually offers more for less Consider some analogies compar ing various products with the roughly 1000 fold improvement in microchip price and performance How about a car that goes from 0 to 60 MPH in 1 second a four pounder burger for 2 cents or a 20 000 square foot home for 1500 The cost of services is even more of a joke For example today s nonservice gas station would be replaced with the real thing a car wash engine rebuild and shoeshine while you wait Need a lawyer or doctor Just buy one for 100 a year feel sorry for those people who chose other businesses Year after year they feed their customers apologetic mumbo jumbo justifying the latest price increase the best approach whine that your customer is raising their price too Imagine if had to approach a customer with a pitch like Here s the new 8008x with 0 01 MIPS for only 10 000 Ouch No the future looks bright for me and the micro WHO S ON FIRST Currently the micro is caught in a custody battle Who are its rightful parents At the recent Microprocessor Forum the ever entertaining Nick Tredennick hosted a 20th birthday awards ceremony Nick is a well known Silicon Valley gadf
105. at sell items called current monitors for AC power control don t have any names at my fingertips but there are plenty of ads in the trade journals They work on the same principle you mentioned and look like an epoxy donut with wires or pins coming out of it They are available in a variety of current ranges and some actually have a TTL output to indicate current on Prices are more than you d think tens of dollars but it s a good price for what you get Msg 50789 From J EFF BACHIOCHI To RICHARD PFEIFFER Are there any moving parts on this compressor you can get at Use an opto interrupter or somesuch to sense movement of the motor shaft a pulley or whatever is available Msg 50805 From RICHARD PFEIFFER To J EFF BACHIOCHI No no accessible moving parts but a neat idea Someone at work suggested monitor the dam pressure change but I d need a O 200 psi sensor and RTC IO board Msg 50796 From MARC WARREN To RICHARD PFEIFFER You might also consider a Hall effect sensor These are solid state devices that can sense a small magnetic field and switch on or off depending on the field strength You could use it to sense current in the line cord or directly on the motor if enough field leaks out Sorague and Microswitch manufacture these things TTL output is available for most devices Msg 50815 From MICHAEL MILLARD To RICHARD PFEIFFER What you need is Catalog 20 from Microswitch Honeywell Their
106. ation Warm Start Initialization End Initialization Figure 1 A typical power up sequence includes checking the status of the backup battery and different initialization blocks for cold and warm starts a cold start anything goes You can perform your favorite system diagnos tics go through the rigors of a thor ough destructive RAM test and initialize the system variables to a default state before indicating the system is warm This denotation may be accomplished by writing a unique string to RAM In some cases it may not be performed until receiving the required configuration information via download from a host computer or from some other source A warm start is more restrictive Most likely you will only want to do a cursory RAM test and verify the contents of some critical control blocks Of course it s a good idea to check the state of the backup power at this time Many nonvolatile RAM controllers provide a mechanism that allows easy checking of the backup battery s state The popular DS1210 indicates a low battery condition by suppressing the second access to the RAM following power up What you actually do when you determine the backup battery is low depends to a great extent on the type of backup power source you re using If it s a rechargeable unit then making the low battery test a part of the cold warm determination logic is reason able Of course if the backup source is not rechargeable then y
107. before the first address of the Frugal Networker That way XSWITCH 1 is the first address of my switcher Actually it would be XSWITCH 1 because Forth like a Hewlett Packard calculator uses stack oriented postfix arithmetic Now to define the word ALL 0 FF ALL OFF XSWITCH 40 0 DO 1 DUP 0 SWAP C LOOP DROP For non Forthers l Il explain that the and delineate a Forth definition Typing in the above code or loading it from mass storage will compile it into memory as a word that will execute whenever called Invoking the word ALL 0 FF will zero all 64 crosspoint switches and turn them all off The 40 and 0 are the loop indices in hex The word 1 increments the address X SW I TCH which is on the stack Then 0 is put on the stack and SWAPped into proper position for the word C After performing these steps 64 times the leftover address now XSWITCH 64 is DROPped know this process is a little messy and you Forth programmers are thinking I m nuts for not using the much faster and shorter F L L or ERASE Commands Well would have used them but the MT8809 or at least the one have doesn t seem to want to take the data that fast Now l Il define some words such as 1 2 ON which will let me connect input 1 to output 2 or something similar like 1 2 OFF But first should do a reality check can only allow the numbers 1 through 8 I ll make this limit with two words RANGE ABORT
108. cated by setting a flag remove pending which inhibits further read operations The remove function is invoked after the host computer acknowledges receipt of this data and on its completion the remove pending condition is cleared Note that for this process to work properly the remove pending flag must always be set to the cleared state on power up In other words this flag must be volatile RAM VERSIONS VERSUS PROGRAM VERSIONS The situation described in my opening remark was intended to be amusing However must admit it s not entirely contrived While there weren t any witnesses it did happen to me Let me explain The tweaks made to the code inadvertently allocated an extra byte in the RAM area This byte was added after the warm RAM string right in the middle of system RAM The RAM being initialized allowed the system to warm start Of course once control was transferred to the main program most RAM references were shifted a byte and the system got mighty confused The only way to get things back to normal was to force a cold start in order fo reinitialize all the RAM variables to where they were supposed to be Actually the solution to the problem is fairly simple make the The Micro 440 is a versatile full featured controller with an on board BASIC interpreter Available with economical development packages includ ing C51 and a wide range of accessories
109. chip designed to interface with the 68xx and 80xx families of microprocessors 16 Issue 26 April May 1992 The Computer Applications Journal Network nodes OSI layers specified Communication media many physical data link 50 ohm coax or twisted pair 10 Mbps up to 1500 m separation between any two nodes on one cable length network Protocol Ethernet Transmission serial Hierarchy none peer to peer Media access CSMA CD Error detection features message acknowledgement optional 16 bit CRC sequence count Figure 5 Ethemet is perhaps the most widely used netwo rk solution at the data link and physical layers for PCs and minicomputers In the office LAN market ARCnet competes with Ethernet Although ARCnet has a data rate only one fourth that of Ethernet the perfor mance of ARCnet can be comparable to or even better than Ethernet in certain situations Of particular interest to embedded systems design ers each ARCnet node is guaranteed access to the network within a known length of time and ARCnet can out perform Ethernet for short messages Adding ARCnet capability see Figure 3 to an embedded controller design will typically require three packs a controller IC a media inter face hybrid and glue logic The ARCnet controller will handle the transmission and reception of mes sages but the software running on the microcontroller will be responsible for formatting messages to send and i
110. chunks to avoid overflowing 16 bits O FrameNum lt MAXIRFRAMES FrameNum for FrameNum FrameTimel IRTimes FrameNum 2 0 08 FrameTimel FrameTimel 12 25 FrameTime JRTimes FrameNum 100 200 0 005 IRTimes FrameNum FrameTimel FrameTi me2 1 085 set up initial frame sorting thresholds ae this is done in chunks to avoid overflows too first frame is special cased sample needs 80 derating to real time because the trailing edge is delayed by IR 7 receiver FrameTimel IRTimes 0 8 FrameTimel FrameTimel 10 IRTimes 0 FrameTimel for Index 0 Index lt NUMTHRESH Index IRThresh Index IRTimes 0 2 Index 1 1 IRThresh Index gt gt 2 now find the average frame time a determine each interrupt duration ie 1 0 1 5 2 0 bit frame times AvgFrTime 0 FrameCount 0 for FrameNum 1 FrameNum lt MAXIRFRAMES amp amp IRTimes FrameNum FrameNum if IRTimes FrameNum lt IRThresh 0 continue else if IRTimes FrameNum gt IRThresh NUMTHRESH 1 continue continued Issue 26 April May 1992 The Computer Applications Journal Listing P continued for Index 1 Index lt NUMTHRESH 1 Index if CIRTimes FrameNum lt IRThresh Index FrameTime IRTimes FrameNum 2 FrameTime Index 1 AvgFrTime FrameTime FrameCount bre
111. condense on the coolish walls of the envelope When enough of this action has taken place the filament becomes thin at some point its resistance at that point increases as does its temperature there causing a still more rapid evaporation This initiates a vicious circle which accelerates until severance burnout occurs at that point In a quartz tungsten halogen bulb the halogen vapor combines with the tungsten atoms deposited on the 102 Issue 26 April May 1992 The Computer Applications J ournal envelope wall forming a volatile tungsten halide and becomes a reverse transporter of tungsten FROM the hot walls of the quartz envelope BACK to the still hotter filament where the tungsten halogen compound is decom posed by heat with redeposition of tungsten and liberation of halogen which is then recycled This retards the thin ning of the tungsten filament thus giving increased filament life The recycling process doesn t work if the envelope walls are cold ish or if they are not made of quartz silicon dioxide Increased filament life enables operation at higher temperatures BY DESIGN and halogen bulbs indeed provide a higher color temperature as well as one hell of a lot more infrared than conventional bulbs Actually the higher filament temperature is not only a possibility but also a necessity as is the small envelope size Both factors cause the walls to be very hot which is needed for the halogen s to co
112. conditions If it evaluates true then any number of F THEN combinations following it up to the GE N D are executed If it evaluates false the whole block is skipped G F allows you to selectively execute or skip Listing 3 In a more realistic example you might contro a set of lights based not only on motion but on time of day as well Practical example of CONFIG PL Link 1 DISPLAY Modules C L 0 DY 3 00 DY 30 DY DEFINE Bedti me DEFINE Dark 16 DEFI NE 3 2 6 Morning DEFINE DEFINE BedLight Module L4 DEFINE CeilingLight Module L2 DEFINE BedTimer Timer 40 DEFINE DEFINE DEFINE HallMotion Input 10 HallLight Module L8 HallTimer Timer 41 BEGIN different depending on the time of day BedroomMotion Input 12 system behavior t Sunset Time for bed l Starting to get light out Bedroom motion detector Hallway motion detector GIF Time gt Dark AND Time lt BedTime THEN IF BedroomMotion EDGE THEN BedLight ON BedTimer ON END IF BedTimer gt 20 THEN BedLight OFF BedTimer OFF END IF Hall Motion EDGE THEN HallLight ON HallTimer ON END IF HaliTimer gt 10 THEN HalllLight OFF GIF Time lt Morning THEN HallTimer CeilingLight ON Ceilinglight OFF OFF IF Hal Motion EDGE AND Hall Light OFF THEN HaliLight DIM 12 END IF Hal Motion EDGE THEN HallTimer ON END IF HallTimer gt 3 THEN Halllight
113. controlled by master node message acknowledgement optional 16 bit CRC sequence count data transfer Many people who construct asynchronous serial networks write their own network software However at least two companies are offering microcontroller software for asynchro nous serial networking Micromint Inc Vernon CT offers network software that allows the connection of Micromint s 8052 BASIC and HD64180 based embedded controller boards and a PC see Figure 6 Cimetrics Technology Ithaca NY offers software toolkits for enbedded controller networking which support several microcontroller families 805 1 68HC11 Z180 and 80C186EB and the PC Their NSP protocol allows the master network node to read from and write to slave node memory and I O ports Figure 7 Synchronous serial communication Synchronous serial communica tion differs from asynchronous serial communication by not using start and stop bits for synchronization instead synchronization information is extracted from the data stream As a result synchronous communication Figure 7 The 9 bit multiprocessor mode supported by many popular microcontrollers is the basis of Cimetrics Technology s NSP protocol The Computer Applications Journal CONNECTS To RS 232 AR 16 RELAY INTERFACE 89 95 Two 8 channel relay output ports are provided for control ofup to 16 relays expandable to 128 relays using EX 16 expansion cards Each relay ou
114. cost stand alone EPROM d lar b f its programmers can t nish lel aI ES law E handle microcontrol consumption and reasonabe price 16 for the windowed version What has been lacking is an inexpensive pro lers with on chip patio iets se oa EPROMs What s a chip EPROM The only inexpensive programmer I ve been able to find so developer to do incentive to ty out the MC6BHIC70S Use the chip to odas board is a stand alone program itself A e S e Edward shows us E votes onl how have to manually apply the power and Vpp and twiddle the reset switch at just the right times The board is further complicated by the number of programming options supported such as copying the contents of an external EPROM into the chip or downloading and executing programs from the on chip RAM Programming the PLCC version of the processor is supported if you supply a PLCC socket decided to fill the gap by design ing and building the PGM HCO5 The PGMHCO5 is a low cost programmer 62 Issue 126 April May 1992 The Computer Applications J ournal designed for the microcontroller experimenter To keep the cost down it only supports device programming of the DIP version of the part Most experimenters will want to use the DIP version anyway because it is available in both erasable and one time programmable plastic versions The PLCC version is not erasable and therefore not useful for development although it does take much less s
115. d TTL logic levels A 2 pin 0 100 connector is provided for the telephone line interface An audio output is provided if you wish to add an op amp and speaker for aural monitoring of the call progress tones The 224 OEM Modem is priced at 179 Quantity discounts are available Western DataCom Co Inc P O Box 45113 Westlake OH 44145 0113 216 835 1510 Fax 216 835 9146 505 NASOD NEWS Random computer problems such as software errors system hang ups rebooting and even hardware damage are often caused by noise on the AC power line Eastern Time Designs has announced the availability of the Probe 100 a simple to use easy to understand toolbox sized monitor that detects and displays power problems The Probe 100 detects a wide range of power disturbances including spikes sags surges common mode noise dropouts power HAND HELD POWER LINE MONITOR failure high frequency noise and wiring problems It reports these disturbances on an easy to read LED display The Probe 100 is very simple to use The unit s power cord is plugged into an outlet It immedi ately identifies wiring problems such as hot and neutral wires reversed or an open ground Then leave the unit plugged in for 24 to 72 hours checking the The Probe 100 detects voltage impulses on the hot line from 20 to 500 V and on the neutral line from ito 50 v Impulses are mea sured from their location on the
116. d and receive IR signals as well as contol the firmware s operation Ali times are in 5 12 ms units and numeric values are decimal unless otherwise noted specific people tracker badges An HCS II system can have up to eight of these gateways on its RS 485 network so you can put a different unit in each room to ensure adequate coverage GATEWAY FUNCTIONS The overall structure of the IR Gateway or IR Link firmware resembles that of the Smart X10 controller or PL Link described in the last issue It receives and transmits serial information over an RS 485 network includes a simple decoder to handle ASCII commands from the HCS II SC and is written in Micro C 0 12 frames of silence Sync AO Al before start of bits message bit frames I ve taken a bit of heat for aban doning 80 5 1 assembly language in this column For the record about half of the Micro C source lines for the Smart X10 and IR Gateway firmware are actually assembler code written using Micro C s in line assembler As continue to point out C is good for the overall program logic but not at all suitable for high speed bit banging and interrupt handlers Figure 1 presents IRGATE s command set As with the Smart X10 controller there are commands to send and receive IR signals as well as control how the firmware operates Massage data 0 0 0 0 0 O 0 1 V Two frames of silence A2 A3 A4 AS A6 A7 AB l Trailing bit
117. d the other pins some day See ConnecTime in Circuit Cellar INK issue 24 for a good discussion on the use of RJ 11 jacks in RS 232 connec tions built everything up on 0 1 grid prototyping board with a ground plane on one side gold plated through holes and pads on the other side It probably would work without the ground plane but feel safer using it wired the circuit point to point THE SOFTWARE As mentioned previously the F68HC11 has a complete language in 8K of on chip ROM This New Micros version of Forth is called Max Forth Like most Forths it s an integrated compiler interpreter assembler and operating system won t go into its many features here but would encourage anyone who hasn t checked out Forth to do so Forth is an excel lent microcontroller language because of its power small size and ease of development l Il just present a simple applica tion program to show you how the Frugal Networker works Although suspect most readers don t know Forth think these examples will be understandable to most programmers If you try this circuit with another language hope the algorithms provide will hap you To begin have eight jacks each with an incoming and an outgoing signal line Normally would want to connect two devices together by connecting the transmitter of one to the receiver of the other and vice versa But doing so would mean turning on two switches and
118. d with telephone lines are optional The price for the Sensor Modem base unit is 750 The Sensor Modem is designed around the HD64180 Expansion modules run 150 250 microprocessor and can address up to 1 MB of memory in the form of EPROM static RAM flash EEPROM NotaBene Technology Inc removable RAM cartridge with battery backup and OTP 11210 Arrowood Cir PROM program or data modules The 8 5 x 5 5 x 1 5 Dayton MN 55327 base unit requires 12 volts AC DC at 90 mA The Sensor 612 421 9225 Fax 612 421 9225 Modem comes standard with ten isolated digital inputs two rday or driver outputs and four bipolar 12 bit 507 OPTIMIZE YOUR ROMDISK mCU PROGRAM DEVELOPMENT INTEGRATE THE POWER OF Editors Cross Rssemblers Disassemblers Cross Compilers Data Conversion Utilities High Performance Simulators Serial dang Multimegabyte Disk Emulators ARMADILLO NEW MODELS LOWER PRICES R Unique Universal Development Communications Environment Supporting Floppy Drive and multimegabyte Bll families of bl d il emulators for ISA bus computers PE eee aoe ee ee a Communications with your target CPU 180K to 14 MB capacities User definable utilities menu EPROM Flash or SRAM technologies Pull down menus with mouse or keyboard control e Autobooting Single or Dual disk IBM PC or compatible emulation under PC or MS DOS Now you can EDIT ASSEMBLE UPLOAD DEBUG
119. data into the register to tell the inverse XORs which bit to unset in the right way or something like that But like the notion it s sort of like the classic trick of exchanging the contents of two registers without using a temporary register I ve always wanted something like that for laundry so you could swap a basket full of clothes with a washer load without either losing socks behind the dryer or soaking the front of your shirt It s been a long day Msg 52962 From MICHAEL MILLARD To KENNETH SCHARF In short no BUT IF YOU CAN CODE IT WE NEED TO TALK Because CRCs aren t perfect 99 998x how would you know that you as a receiver were reconstruct ing a correct message Somebody else had a more elegant way to express this thought but the gist is there s a possi bility of reconstructing a bogus message But have another thought on this It would seem to me that just reconstructing the original bit stream would be very rigorous for the receiver to do perhaps greatly exceed ing the receiver s resources I m going out on a limb here discussing the more common CRC implementation but the thought should apply to most other applications Remember that CRC 16 at least as normally defined is derived from the one s complement of the remainder that you get when you modulo 2 divide the original message data by the generat ing polynomial The equation for which is x x 2 x5 1 Thi
120. de of the coin is the action list following the THEN state ment Figure 2 lists all the valid actions Any number of actions may be listed either on separate lines or separated by semicolons The list is always terminated with an END statement As before l Il quickly describe each action trying not to be too arid Any X 10 module may be turned on or off dimmed or brightened Similarly an All Lights On or All Units Off command may be sent out to any given housecode Outputs may be turned on or off The same distinction is made between local and network outputs as for the F tests Analog outputs may also be set to any 8 bit value Timers may be turned on or off When a timer is turned on it is cleared to zero and starts counting If you want to clear a timer that is already on simply turning it on again will clear the count Turning a timer off forces all tests on that timer to return a false response Variables may be set to any 8 bit value or to true or false Like many Start of comment Begin Config lt link gt n n 0 7 Define lt label gt lt expr gt Start of program lt link gt PL Link IR Link LCD Link DIO Link ADIO Link lt label gt alphanumeric string up to 32 characters lt expr gt any valid program statement Display Modules lt list gt GIF GEND lt list gt X 10 module housecodes Start and end of global IF Figure 3 Additional
121. derately Useful 433 Not Useful we BAS OA A INK 112 A Night In The Life OW that there is considerable water under the bridge I don t mind telling you had certain trepidations about converting from the old home control system to the new HCS Il Granted had long ago exceeded the design capabilities of the original unit and had resorted to a number of outboard patch systems to compensate for its shortcomings But the prospect of replacing an entire wall of electronics even if it would end up considerably smarter was a genuinely frightening prospect Because we have a rule about testing what we design however the only appropriate way to observe the new HCS II was to install it and use it for real Quite understandably finding volunteers around here willing to wire their homes for science was like asking a Texan to eat sushi for the next six months The net result was that Ken and got the privilege of being guinea pigs Of course one doesn t just swap an EPROM or switch an 1 0 board when making a great leap in technology In reality converting from the old HCS to the new one meant walking up to the control board pulling the master power switch and forcefully applying a crowbar to the majority of electronics on the board After six years of blissful living found myself standing in total darkness with no idea how to turn the lights back on had remem bered to bring a manual X 10 controller and a list
122. dress latch which holds A24 and A25 A check is made on the status of the memory card The appropriate bits are masked with A24 and A25 and then latched into the second external address latch If the status is not OK a loop is taken back to recheck the status from the memory card If all is wall the transfer enable push button is checked Once the button is pushed a check is made on the transfer mode If the parallel mode has been selected a jump is made to the P START routine If the transfer mode is serial serial interrupts are enabled and a check is made on the function mode If the function is record then jump to S START other wise the function is playback so set the transmit interrupt which indicates the transmitter is empty and fall into S START S START is an endless loop where code hangs out while not in the serial interrupt routine Setting the TI bit will cause the serial interrupt to be entered in the serial playback mode as will a received character in the serial record mode START Serial Routine A check must be made to deter mine the source of the serial interrupt because there is only one serial interrupt vector If it s from a received character then clear the interrupt save the character in a temporary register and check for the end of RAM If the end is flagged then exit the interrupt without saving the data otherwise save it to the memory card set up the next address and do a RETI
123. ds containing many of the eee members of the 8051 family of embedded control microprocessors Buy one base unit and select one or all of the pods you need to do the job ata much reduced cost You get the same great functionality found in our popalir DrylCE 8031 emulator plus real time Execute to Breakpoint Line by Line Assembler and much more And the price is almost unbelievable Yes it works with the Mac too Base Unit w RS 232 IF 299 Available Pods 149 each 8031 32 80031 32 800154 800451 800535 80C552 562 800652 80C51F A 8751 52 87051 52 Call about 87 751 752 support 16K Trace Buffer option Avail 2nd Qtr 92 Standard 8031 DrylCE Still only 199 Enhanced 8031 DrylCE 269 8051 Simulation The 8051SIM software package speeds the development of 8051 family programs by allowing execution and debug without a target system The 8051 SIMulator is a screen oriented menu command driven program doubling as a great learning tool 99 Single Board Computers 8031SBC A fastand inexpensive way to implement an embedded controller 8031 32 processor 8 parallel 1 0 up to 2 RS232 serial ports 5 volt operation The development board option allows simple debugging of 8031 51 family programs 9Qea 80C552SBC 10 bit 8 ch A D 2 PWM 1 RS232 amp 2RS232 422 485 serial ports sockets for 64k ROM 64k RAM 5 volt operation optional RT Clock w battery 2k EEPROM Development board version
124. e next_state state_table current_state input_condition current state next state loop The Computer Applications Journal lssue 26 April May 1992 53 state and output action out of the structure entry in the array Listing 2 When the stoplight state machine is coded in a high eve pseudolanguage he bulk of the program consists of definitions A STATE MACHINE IN PSEUDOCODE The code in Listing 2 is the stoplight state machine coded in a sort of high level pseudolanguage This code seems like an awful lot of program to define the behavior of the stoplight but most of it is in defini tions This listing will be eliminated in the machine code for a compiled language or assembly language In return you have a very error resistant program which may be easily modi fied with the addition of states Changing the behavior of the state machine is a matter of changing the entries in the two tables define the size of the next state array number_of_states 3 number_of_inputs 4 dimension next_state number_of_states number_of_inputs dimension output_action number_of_states number_of_inputs define the array indices Next States red 0 green yellow 2 Input Conditions ane tou ue ol WN oS Define the next state array next_state red a green next_state red b red next_state red c red next_state red d red A STATE MACHINE IN ASSEMBLY LANGUAGE Now I will discuss
125. e original data back to its rightful place The actual bit patterns used in the RAM test usually have some special significance to the programmer Sometimes this preference borders close to a religious fervor so won t get in the middle of this one thanks Of course the big mistake is to believe the RAM test will run to completion Usually included as part of the power up sequence the RAM test is particularly vulnerable to power fluctuation problems Consider a system dropping in and out of brown out In this case the RAM test usually provides a pretty good window on doing some damage Thrash a table of jump vectors or a pointer block and things rapidly go down hill from there For a RAM test to be truly nondes Nondestructive RAM Test Save Test Pointer amp Test Byte Set Under Test Flag Do Read Write Test Restore Test Byte Clear Under Test Flag All Done RAM Test Complete Figure 2 A truly nondestructive RAM test must account for he possibility of apower loss in the middle of the test Issue 26 April May 1992 93 tructive enough information must be maintained to allow restoring the right data to the right location in the event the test is interrupted before comple tion see Figure 2 This information may reside in a fundamental RAM control block and consists of the address of the location under test the value stored at that location and an under test flag indicating the location is i
126. e IS TRough THEN 50 Clean 50 AC Cleanness Indicator IF Dirt IS DLow THEN 50 IF Dirt 1S DMLow THEN 10 IF Dirt IS DMHigh THEN 10 IF Dirt IS DHigh THEN 50 Bag 0 IM Bag Change Indicator IF Pressure IS PVLow AND Dirt IS NotDLow THEN 100 IF Pressure IS NotPVLow THEN 0 The Computer Applications Journal fuzzy rice cookers and so on are emerging I think the slow acceptance of fuzzy logic is inherent in the oxymo ron like nature of the term LOGICal people i e engineers often don t design warm and FUZZY i e friendly products My coffee maker can automati cally turn on at any time with crystal controlled accuracy But heaven forbid if its pot was left in the dishwasher overnight No it doesn t take a fuzzy chip to make a coffee maker that won t merrily drench the counter It does take a fuzzy mindset on the part of the designer though Same for the VCRs that take a Ph D to program The only one I ve ever been able to conquer is about 10 years old and features blessedly few buttons think few buttons is a key characteristic of a fuzzy design Hopefully fuzzy chips like the NLX230 can speed the availability of friendly products Until then I suggest you keep a close eye on your appli ances or else CONTACT American NeuraLogix Inc 411 Central Park Drive Sanford FL 32771 407 322 5608 Fax 407 322 5609 Microprocessor Report amp Microprocessor
127. e RTS returns here j ump order that a subroutine call would do it 4 Execute an RTS instruction The effect of an RTS is to pop the address off the stack and jump to it In effect this hack gives me the capabil ity of a computed jump Listing 5 a To utilize saifmodifying wde a table of the addresses of the action routines is necessary b RAM locations 40 41 and 42 are used to store the synthetic jump instruction a ADDRESS TABLE EQU DW DW DW Assume X contains the LDA STA 4 CC 40 LDX ASLX LDA STA INCX LDA STA ACTI ON_ CODE ADDRESS_TABLE X 41 ADDRESS_TABLE X 642 JSR 0040 SELF MODIFYING CODE The final method an alternative for the 6805 is similar to the PUSH and RTS hack Rather than do an indexed J SR though a jump table have the program construct a J M P instruction with an address that points at the desired action routine The address associated with theJ M P will change so the instruction must be constructed in the RAM area of the processor The addresses of the action routines are set up in a table much like the jump table The processor uses the action code to index into the action routine address table retrieves the action routine address 2 bytes and then stores the action code address prefixed by the opcode for J MP in three locations in RAM The processor then does aJ SR to the first of these three RAM locations The 6805 code that uses t
128. e picked 1290 us which means the MC145030 uses a 12 4 kHz oscillator Converting an integer between 0 and 511 as there are only nine data Message data 1 0 0 0 0 0 O10 Vv 1 5 frames of silence Figure 2 The MC145030 chip sends a sing e 9 bit number A complete transmission includes two copies of the number amid various pauses and synchronizing Ms The Computer Applications Joumal Issue 26 April May 1992 71 bits available into a message is straightforward as shown by the three routines in Listing 1 Rather than pack the output bits into bytes squan dered 79 bytes of the 8K External RAM on aC array called ITrnBuf Each byte holds one bit of the encoded message so each array element rep resents half of a Manchester bit frame Thefinallineof IRFormatMsg sets theF1 agIRPendi ng bit whichis monitored by a timer interrupt routine that ticks every 5 16 ms When it sees Fl agI RPendi ng set on it cranks the timer interrupt to 645 ps and shovels bits from the array to the output pin on each interrupt After finishing the message the interrupt handler resets the timer interrupt period to 5 16 ms The interrupt handler updates several software timers that count off intervals of a few seconds The motivation for the peculiar 5 16 ms normal rate is that it is exactly eight times the 645 ps dictated by a 1 290 ms Manchester bit frame After sending all 79 bits the code simply adds 10 counts to the software ti
129. e to select the rule whose action value drives the output Effectively this maximize the minimum operation performs a fuzzy logic sum of products so maybe they should really call it a Fuzzy PAL Intuitively what I m looking for are the inputs that least fail to be 88 Issue X26 April May 1992 Results Alpha Cut Calculator Subtracter Control Logic e 3 E 9 m ww members of a set For example say have a rule IF tall AND wide AND heavy THEN go_on_a_diet Now assume there are two candidates 1 kind of tall kind of wide kind of heavy 2 tall wide not so heavy Under the NLX230 max min scheme candidate 1 is the one that should get the message Of course 2 may get it as well unless there is another rule like IF tall AND wide AND not heavy THEN eat_before_you_die_fool SUCK IT UP Fortunately instead of endless air computing you can get your hands on some real hardware and try it yourself NeuraLogix sells a very nice develop ment system Photo 1 that includes an NLX230 based PC plug in board download and simulation software and excellent documentation The whole package is only 395 rather a bargain in my opinion So far I ve discussed the NLX230 at a machine language level i e input selectors fuzzifier numbers member ship center and width etc A key The Computer Applications Joumal portion of the software provided is a much easier to
130. ejet ScanJet for MSC QuickC Turbo C C BC Includes free copy of ZIP amp extensive examples Source avail No royal 195 ZIP Image Processing software Bright contrast sharpen outline noise removal em bossing matrix conv etc TIFF PCX GIF EPS bin Up to 4048x4048 outstanding display and printing of grayscale images EGA VGA super VGa LaserJet dot matrix Ver sions for ImageWise Idec HRT HPScanJet Source avail apture 512x512x256 NTSC or PAL live video on VGA frame veraging With Victor and ZIP Image Processing 499 Catenary Systems 470 Belleview St Louis MO 63119 Call 314 962 7833 to order VISA MC COD 105 The Computer Applications Journal Issue 26 April May 1992 11 NDA IA Xe D Leu NEWS REMOTE SERIAL COMMUNICATIONS CONTROLLER The Sensor Modem 500 Series from Nota Bene Technology is designed to provide reliable data acquisition data logging or process point control from a remote location The unit provides local RS 232 RS 485 and wide area dedicated line radio or switched dial network access for communication with up to 800 digital or analog measurement and control points per station The Sensor Modem is FCC registered 2400 1200 bps analog inputs Expansion I O modules provide fully full duplex and features autoanswering and call progress isolated O in increments of four or eight points in any monitoring DTMF and synthesized voice support used combination both locally an
131. ement and functional diversification the hard ware specifications include I O devices as well as the original memory interface Software that recognizes and takes full advantage of attached devices is still under development at the upper layers but using the inter face at its lowest levels with assorted memory cards requires little effort believe that designing with the PCMCIA interface will extend the life of any project by ensuring compatible memory cards do not become obsolete A DROP IN THE BUCKET The term bit bucket has come to mean a place where unused data is The Computer Applications ournal tossed gone forever like a write only device However this project brings new meaning to the term allowing you to retrieve all the data in a FIFO like fashion The design includes a micro 8031 with five additional latches to increase the normal 64K data space associated with most amp bit micros to a possible 64 megabytes See Figure 1 for the schematic Data I O is handled in both of the traditional methods available to most host systems serial and parallel An RS 232 serial port is supported using a MAX232 for level conversion This dual transmitter receiver 5 volt converter replaces a 1488 a 1489 and a bipolar supply Data is transmitted or received at a predetermined data rate of 9600 bps or any other rate of your choice with no handshaking necessary This rate results in a storage routine that must be c
132. en using those commands to avoid repeat transmissions LEARNING BY EXAMPLE find the easiest way to learn something new is by practical applica tion of the concepts I ve listed all the keywords and rules involved in writing a program but a few simple examples should help clear up some of the haze in the air Let me go back to the scenario cited earlier have two motion detectors two lights and a door sensor Listing 1 shows one way a program can be written to solve the control problem The first equation looks for an edge on either motion detector and turns on the lights if it finds one It also starts a timer The next equation checks the door sensor and if the lights haven t already been turned on by motion it turns them on The last statement checks the timer to find out if five minutes have elapsed If so and the door is closed the lights are turned off and the timer is stopped If the door is open the lights stay on MULTITASKING Simplify Coding CORE The TAPIR Multitasking Package offers a complete kernel for developing and debugging multi tasking code Written for speed this 100 assembly language program delivers True pre emptive multitasking A debug module to examine register status of all tasks during runtime The ability to run with or without DOS No Royalties For more information or to place an order contact TAPIR PO Box 1553 Seguin TX 78155 512 372 2587 The TAPIR mult
133. er was able to increase the radiant power output from about 20 mW on the single IR Link LED to over 4 watts A couple transmitter receiver pods like these could cover a large office or conference room quite adequately IN CONCLUSION Well this ends my part of the new Circuit Cellar HCS II description Ed will talk a little more next month about the remaining links but l Il be busy wiring up a storm If you remem ber the picture in the last issue page 32 of my old HCS you can compare it to the new layout here in Photo 4 Okay wires are wires Showing you this picture will probably create more questions because took considerable engineer ing and poetic license in the physical assembly of my system From the very beginning have claimed that HCS II Item 4 DIO Link Smart Digital 1 O Network Interface PC board and all components including 8031 processor RAM IC sockets DIO Link firmware in EPROM and user s manual Complete kit Assembled and tested order DIOLINK 1K order DIOLINK 1A 99 00 159 00 30 Hem 1 HCS II Supervisory Controller HCS II 4 layer PC board and all components including H D64180 processor ADC real time clock battery backed RAM IC sockets multitasking controller firmware in EPROM HCS event compiler on PC diskette and user s manual Complete kit Assembled and tested order HCSIIK 1 order HCSIIA 1 199 00 269 00 Item 2 PL Link Smart X 10 Powerline Transm
134. er if we suggest that as long as the system could identify me and which location am in it could channe the music to follow me as roamed about Of course this might seem an extreme example but the suggestion that a control program can be tailored to an individual person is valid On the SC the event sequence starts with IF Steve Sol ari um where Steve is defined as a specific IR response code to the system e g HIGH MEMORY Figure 4 The COMM Link is fe basis for alt the HCS If expansion modules Itis based on the 8037 and has a voltage regulator on the board so can be run from a range of power supples 26 Issue 26 April May 1992 The Computer Applications ournal T IR LEDS 3 UOLT SUPPLY LEDI LED4 TSUSSZO0 LED3 amp LED4 IR ENABLE Jes CONTROL BUS IR RECEIUER Figure 5 To make an R Link bard just add an oscillator an IR receiver and some LEDs m the base COMM Link board The basic building block r your control The PLC operating system kernel trasforms your basic microprocessor into a high performance Programmable Logic Control Just plug the PLC ROM into your favorite microprocessor card load the integrated programmer debugger onto your PC connect a serial cable and begin taking the credit for a job well done RS 232 485 or PC I O cards Get started for e RS 485 multidrop distributed system Easy
135. es the problem at hand and that I ll still use when finally do buy a modern computer That s what happened with the Frugal Networker a crosspoint switchboard for the RS 232 I m still using a 1980 vintage TRS 80 Model and am not ashamed to admit it also have a serial terminal modem and a few other serial devices all of which need to be cross con nected in different ways at different times At first used a bunch of toggle switches to change connections and who hasn t played the game of swap ping cables all over the place As added new devices had to rearrange my switch setup There had to bea better way recently bought a microcontrol ler board from New Micros Inc built around the F68HC11 Forth chip which is a Motorola 68HC 11 with a complete Forth language in the chip s ROM The 68HC11 is an interesting and powerful chip that has been well described in several recent Circuit Cellar INK articles Forth is a minority language Some people love it to the point of fanaticism or at least that s what the people who hate it say Most don t The Computer Applications ournal know much about it and feel the latter group is missing out on a useful tool In fact the main reason still use my TRS 80 is because it has a good Forth system But back to my problem The controller board also has an RS 232 port on it started to add some more toggle switches to my original network to handle t
136. escribed above except they transmit their ID code 0 through 5 11 periodi cally Passive badges transmit their ID only when they hear that ID from another source Active badges are quite simple because they do not need any receiver hardware However because each badge transmits without regard for the others a room full of badges might produce no recognizable messages due to all the collisions You must pick the repeat rate to minimize the number of collisions while not introducing too much delay in determining when a new badge enters or leaves the room Passive badges on the other hand must include a receiver that is active continuously so they will dram their batteries faster In addition IRGATE must know which badge IDs to send because a passive badge responds only to its own ID code While there are no collisions IRGATE must poll all possible badge IDs to find out which ones are within range l Il just point out that designing the badge hardware is not easy and leave it at that The receiver and transmitter hardware used by IRGATB need the changes Steve describes in his article to ensure it can cover an entire room If your system uses active badges IRGATB needs no changes because it cannot tell the difference between a remote control unit and a badge After all there are only 5 12 possible codes and the bits mean whatever you want them to Your controller must poll W ant low power Is 10 microwatts low
137. essed off codes for the strobes The strobes went on again four minutes later Hey Ken Issue 26 April May 1992 The Computer Applications J ournal A sleepy and somewhat bemused Ken look my call and listened to my plight In between yawns he asked if Ihad disabled automatic refresh Disable automatic refresh I didn t even remember enabling it OK no sleep tonight until this gets fixed Down in the Circuit Cellar fired up the PC and booted HOST to talk to the HCS How do isay Cease and desist The X 10 status table on the screen showed a bunch of modules on that shouldn t be on fired up another PC laptop and a stand alone PL link to monitor the power line Once in logging mode it started vigorously listing X 10 transmissions that were occurring about every 5 seconds Say what After looking at my XPRESS listing had indeed not specified anything about refresh rate so added REFRESH 0 no refresh to my program quickly recompiled and reloaded the HCS went out to the control board to detach the laptop when noticed that X 10 commands were still being sent once every 8 10 seconds or so Come on Ken I don t need bugs like this at 3 a m Considering that this was starting to look like a runaway controller cutting off the output seemed like a logical alternative In exasperation reached up to the PL Link and unplugged the TW523 X 10 transceiver Disconnecting the HCS from the power line would stop the tr
138. et implement long integer 32 bit variables some of the computations are more laborious than you might expect As an exercise compute the frequency near 12400 Hz from the average frame time near 1290 us without either overflowing 16 bits or discarding most of the significant bits RELEASE NOTES The BBS files this time indude RGAT E HEX whichis the EPROM data for the full function IR gateway firmware The source code for RGAT E HEX is available for licensing from Circuit Cellar Inc Also included are the Micro C source files needed to create RMON HEX which is a receiveonly nonnetworked version of IRGATE It will report all the MC145030 codes it sees and includes the calibration function needed to adjust the remote unit s oscillator to 12 4 kHz You can use this code as the basis for receiving and decoding other remote control codes if you are inclined to use a different chip Next time a networked Home Control System LCD panel and keypad so the HCS II Supervisory Controller can show you what it s up to and you can give it suggestions E The only 8051 52 BASIC compiler that is 100 BASIC 52 option Compatible and compatibile has full floating point integer byte amp bit VEUC CES E m Memory mapped variables a n line assembly language Compile time switch to select 805 1 803 1 or 8052 8032 CPUs m Compatible with any RAM or ROM memory mapping a Runs up
139. etector Finally you sample the current signal at these zero crossings It is a basic principle of it although an original signal phasing needs to be provided but would need too much space and some graphics capabilities for all of that The popularity of halogen lamps is increasing every day Their benefits over ordinary incandescent bulbs including higher effi ciency whiter light and smaller size add to the attraction But how do they work and what are some practical issues to keep in mind when using them Msg 51464 From ANDREAS MEYER To ALL USERS Here s a question for you home control wizards I m using a commercially available photoswitch to 100 Isgue 26 April May 1992 The Computer Applications Joumal control an incandescent lamp in my living room so when it gets dark outside the lamp or whatever is plugged into the switch is turned on The lamp I m using is the type that takes a 3 way bulb which may or may not be relevant but it seems that at a fairly regular interval one of the bulb s stages has burned out and need to replace the bulb This interval seems markedly shorter than the average life of the same sort of bulb so suspect there s something about the way the photoswitch works that is shortening the life of the bulb Can someone explain why this is happen ing and what can do to prevent it Also I m thinking of replacing the entire incandescent lamp with a halogen torchiere
140. ever if you happen to take a trip to the bathroom during the night you d like the hall light to come on and dim down to a tolerable level Listing 3 shows how such a setup might be done It also points out a number of programming gotchas that will likely bite novice HCS II programmers The first global if is only executed between the time it gets dark out and when you go to bed The statements are very similar to those in the other examples with lights going on in response to motion and off in response to a timeout In the second global if take a look at the condition The HCS II time of day is based on a midnight to mid night cycle so the condition responds as if it were written IF Time gt 0 00 DY AND Time lt Morning THEN When counting from 0 to 23 it s not necessary to test if the value is greater Photo 1 A typical status screen displayed by HOST shows two X 10 housecodes 16 inputs and 8 outputs on the SC network activity and current time and date The size of the windows and the amount of information displayed change dynamically depending on the equipment you have in your system than or equal to 0 it always will be The same applies here Obviously the hall lights won t come on between bedtime and midnight but how often do you get up within the first hour after you ve gone to bed If it s a problem for you just add a bit more intelligence to the program to fill the gap Next notice the extra co
141. ever actually climbed the fence or entered the backyard Steve also tells us he s already taken midnight motion by house occupants into account in his system Editor Readability Counts Too This is a letter that may interest many when it comes to producing readable code in any programming language The first tip describes a method of formatting equations in programming languages that do not reformat what you type Once an equation is written it usually becomes impossible to visualize it would like to suggest a method that have used to ease the burden of visually interpreting and getting the parentheses right when initially programmed an equation The algebraic form of the equation to find the roots of the familiar quadratic equation ax bx c Ois b Vb 4ac 2a X The usual programming style for one root is X1 1 b S QR B 2 4 a c 2 a My programming style is X1 b SQR B 2 4 a e C2 a 4 Issue 26 April May 1992 The Computer Applications J ournal Agreed it uses a lot of white space but it doesn t require a magnifying glass to decipher and mentally visualize the equation Note the ease in which parentheses can be matched Another tip is in the use of mnemonic variable names Many programmers do not describe what their short and usually cryptic variable names were derived from and what their type is When you are reading someone else s program or your own ye
142. f low level devices in an industrial setting IN CONCLUSION International standards for embedded controller networking have been slow to develop and some will eventually have a large impact But as have demonstrated the large number of hardware and software components available make the construction of practical embedded controller net works possible today U Jim Butler is a software engineer at Cimetrics Technology He received B S and M S degrees in engineering from M I T 401 Very Useful 402 Moderately Useful 403 Not Useful The BITBUS Interconnect Serial Control Bus Specification ntel Corporation 1988 Ken Davidson Echelon s Local O perat ing Network Circuit Cellar INK issue 21 Connecting with Neurons Embedded Systems Programming Sept 1991 Choosing a network for local industrial control EDN Nov 24 1988 ARCnet Chip Tackles Real Time Embedded Control Electronic Design Nov 8 1990 The deterministic character of ARCnet proves ideal for the factory floor EDN Sep 15 1988 ARCnet Token Bus Network Technical Overview ARCnet Trade Association Arlington H eights IL The Return of ARCnet BYTE Feb 1991 Ethernet Ten Years After BYTE Jan 1991 David Flint The Data Ring Main an Introduction to Local Area Networks Wiley Heyden pub 1983 Good Ethernet information also a good general reference on networks Jim Butler
143. fice and only use it for IR remote control seemed especially strange Not that have any great ambi tions to deal with a computer as if it were another person but home control system software can be greatly personalized if the system has a special program that runs when it knows you are there For example the HCS H s normal control program might be simply to turn a table lamp on in the solarium when someone enters the room sensed by a motion detector However if after 5 r m it identifies that am the person entering the room rather than just turning on the one lamp it could make my hard day at the office a faded memory as it turns on the table lamp dims it to half and then switches on and dims the lights over the bar as it queues the stereo and CD player All need now is the automatic martini maker a serious consideration tx 75176 TH 4 L ests ve iene soe TO 1N4148 3 24 F DOWN TERMINATION 61 9k Encode Decode Out u 1 2 15k 1g MC145030 Decode In Sk Encode EnblL 6 18 nme 212345678 0022F Adjust for Mylar 12 4 kHz CD43 Receive pulse to interrupt input pA SHARP IS1U69 Figure 3 A basic receiver uses a Sharp IS1U6QJR receiver to condition the incoming signal and the MC145030 to decode it When the code matching the one set on the switches is received the MC145030 generates a pulse This scenario can be extrapolated even furth
144. grams but rapidly become unwieldy for age ones Each bubble represents a discrete state while the lines and arrows show transitions between states based on input conditions The Computer Applications Joumal Input Condition Current State b a ee eeeiedalcaae d fw ae an oe Figure 2 In p ace of the bubble diagram a state amp b e is sometimes used The mws represent the current state of the machine while the columns represent the input conditions For a large number of states and input conditions he state table also becomes unwieldy the green red transition turn on red light turn off green light THE STATE TABLE Bubble diagrams like Figure 1 are useful for small state diagrams but rapidly get unwieldy for large ones The number of possible transitions grows as an exponential function of the number of states so a state diagram quickly outgrows small sheets of paper A better approach is to use a state table an array that usually has the rows representing the current stnte of the machine and the columns repre senting the input conditions Thus each entry in the state table represents one possible combination of a current state and an input condition This organization is one of the advantages of the state table it forces the consid eration of all possible states and all possible inputs The state machine represented by the bubble diagram in Figure 1 is shown as a state table in Figure 2 Again w
145. gulator isn t always obvious so thought I d go over how came up with the component values used The output voltage is set by the resistor divider formed by R7 R8 and VR1 The output voltage is determined by Vou RZ R8 VRI 1000 VR1 provides a limited adjustment of the voltage allowing Vpp to be set to 14 75 volts for the MC68HC705C8 or 19 volts for the MC68HC805C4 If only one type of part is to be pro grammed the value of R8 and VR1 may be changed to 13k and 2k respectively for the HC705C8 or to 16k and 5k for the HC805C4 The current limiting in the supply is provided by R6 and serves to limit the Issue 26 April May 1992 63 inductor current as well as the output current Determine the peak inductor Mode Pin 31 Pin 32 Pin 33 Pin 34 Operating Mode current using o GND GND GND GND Program and Verify from an external EPROM Ipk 210max V2 Vi 2x10mAx1sV 9V 33 mA In the equation above I is the maximum output current and is set to 10 mA I is the peak inductor current and V and V are the output and input voltage respectively The value of I will be used to determine the current limiting resistor Substi tuting 33 mA for J in the equation that determines the value of R6 yields R6 9 5V 2 05V 2150 Ip 0033 A The calculated value of R6 is 15 Q 1 then decreased the value of R6 to 10 Q for a little more margin The inductor used in the supply is al00 pH part from Toko
146. he new serial device but the number was getting to be a bit much My new board had just presented me with my next project THE GREAT CHIP SWITCH Chips designed for one purpose often find homes in other kinds of applications chose the Mitel Semi conductor MT8809 for my project It s an 8 x 8 analog crosspoint switch designed for use in telephone switch ing equipment I ll describe using it with my F68HC11 but there should be little trouble adapting it to any system The switch contains an array of 64 CMOS transmission gates arranged as a matrix of eight columns by eight rows The columns are called Y I Os and the rows are called X I Os see Figure 1 A corresponding set of 64 latches acts as a control memory for this array These latches in turn are controlled by a 6 to 64 line decoder When interfacing it to a controller all you need to do is treat it much like a 64 byte by l bit memory device Data on the DATA input is asynchronously written to the latch selected by the address on AXO AY2 whenever CS and STROBE are hdd low and it s latched on the rising edge of STROBE A 1 written to an address turns on the corresponding switch and a 0 turns it off Only the crosspoint switch being addressed at the time is changed by a given write and any combination of X and Y I Os can be interconnected by giving the right sequence of write commands Bringing the RESET pin low resets all latches to 0 and
147. he self modifying code method for vectoring to an action routine is shown below Here assume the addresses of the action routines are stored in a table as in Listing 5a DW is the assembler operative for define word In the code fragment in Listing 5b locations 40 41 and 42 are used to store the synthetic jump instruction ACTION_ROUTINE_1 ACTION_ROUTINE_2 igs bCs cs ACTION_ROUTINE_n action s at location 40 in and and Address of Address of routine 1 routine 2 Address of routine n opcode Store the op code for JMP RAM Get the action opcode Double it Get high byte of action routine store it in RAM Get action routine RAM low byte of store it in Do a JSR through instruction to constructed action J MP routine COMPARING VECTORING METHODS have examined three different methods of vectoring to action routines based on an action opcode Which is best for your particular application The advantages of the jump table method are that it is entirdy con tained in ROM does not require RAM registers and can be done without PUSH and POP instructions The disadvantage is it requires a jump table containing 3 bytes for every action routine The PUSH and RTS method has the advantage of using a shorter action code routines table and 2 bytes per action routine However the action code table does require that the assembler be able to extract the low and high bytes of a
148. he terms and rules used in decision making have to be loaded into on chip registers The DI DO SK and CS implement a clocked serial interface compatible with commodity serial EEPROMs At RST the NLX230 will automatically access the external EEPROM load the initialization info and start process ing assuming the M S pin is high selecting master mode If M S is low selecting slave mode after RST the NLX230 will wait for another device to clock the initialization data in using the afore mentioned signals In slave mode a R W input is also available allowing two way communication with the host Moving on chip Figure 5 shows the guts of the NLX230 Let me trace its operation starting with an input and tracking it through to the output Each of the 16 fuzzifiers can be assigned to an input either one of the eight input channels or a loopback from the output The purpose of a fuzzifier Figure 6 is to classify the degree to which an input is a member of a fuzzy set To this end each fuzzifier has specified its center location and width The center location 8 bits corresponds to the input value which is fully a member The width value 5 bits determines the range outside of which an input is no longer considered a member of the fuzzy set So the input and center location are passed through a sub tracter that determines the distance between them i e ABS CENTER INPUT The Alpha Cut Calculator
149. head can be significant depending on the protocol you use and the amount of network traffic Asynchronous serial communication Most microcontrollers with built in serial communication capability have UARTs that can be used for networking Two techniques have been used to reduce asynchronous serial communi cation processing overhead and most microcontrollers can make use of at least one of them Intel s 9 bit multi processor mode reduces communica tion processing by using the ninth bit of each 9 bit character to indicate the beginning of a message the first character of which is the node address Motorola s technique uses an idle line to delimit messages Of the two techniques Intel s is found in more microcontrollers including Motorola s more recent parts see sidebar If you are interested in the description of a network protocol that makes use of 9 bit multiprocessor modes refer to my article A Simple RS 485 Network in Circuit Cellar INK issue 21 Network nodes OSI layers specified Electrical specification W 485 cable twisted pair length speed Protocol Transmission asynchronous serial Hierarchy master slave Media access Error detection features Application layer features up to 250 32 per cable segment physical RS 485 recommended data link application up to 1200 meters per cable segment depends on microcontroller 62 5 kbps typical NSP an adaptation of IEEE 1118
150. hem all off before each new setup I ll define a Forth word to do Supply Voltage Analog Input Voltage Package Power Dissipation CHARACTERISTICS SY Quiescent Supply Current CHARACTERISTICS Voo 12V Voo 10V Vop 5V On state Resistance Difference in on state resistance between two switches CHARACTERISTICS 3 Frequency Response 30B Channel ON 20LOG VouT Vxi 3dB Total Harmonic Distortion THD Feedthrough DT Channel OFF Feed 20LOG Vout xi Crosstalk between any two tall channels for switches Xi Yi and Xj Yj Xtalk 20LOG Vyj Vxi VSS OV Voc Vop 2 IVxi Vyjil 0 4V Vop 12V Vss 0 Voc Voo 2 IVxi Vyjl 0 4V 45 MHZ Switch is ON Vina 2Vpp sinewave RL 1kQ 0 01 Switch is ON ViNA 2Vpp sine wave f 1 kKHz RL 1kKQ All Switches OFF Wna 32 dB 2Vpp sine wave f 1 kHz Rr 1kQ 45 dB VINA 2Vpp sine wave f 10MHz Ri 75 90 dB VINA 2Vpp sine wave f 10kHz Ri 600Q 65 dB VINA 2Vpp sine wave f 10kHz RL 1KQ 60 dB VINA 2Vpp sine wave f 10kHz RL 10k Q Figure 2 Specificatons for he M78809 show that while the chip was designed for voice switching it a so works well for switching serial lines The Computer Applications Journal this action but first l Il define a constant named XSWITCH Thus B5BF CONSTANT XSWITCH Recall from the above discussion that B5BF is 1 byte
151. hn Wharton Microprocessor Report Notable quotes of the year were remembered fondly We do lots of things with Apple We spend billions of dollars on lawsuits for example Bill Gates speaking at Bay Area Mac Users Group BMUG Their last original idea was to copy Intel Andy Grove speaking about the lawsuit between Intel and AMD in the 80s IBM progressed from the A prompt to the C prompt Jim Canavino at the Agenda 92 conference paraphrased Next the terrified audience all fearful they might be singled out for an award was treated with announce ments of Worst kept Development Secret Chips amp Tech 386 Time From First Rumor To Delivery NexGen Best Self induced Setback Software Patents Hey come on Nick it s not too late for law school Finally he closed with the perennial favorite Figure 2 Nick Tredennick postulates that a scientific approach should be used to rank the contenders for inventor Of The Microprocessor Annual Update Y rdav T Unix PCs GaAs Optical Storage VHDL CDROM Neural Nets e Fuzzy Logic Annual ward Po Y esterday Today and Tomor row s Technology of Tomorrow Figure 3 Thanks a lot Nick Now I ve got all my topics for 92 and don t have to write about 4 bit processors I m glad there is a Nick Tredennick because he has single handedly established a gigantic irreve
152. hould arrive The first sync bit produces an interrupt in the middle of the bit frame that defines when all of the other bits should occur The INTO intdrrupt handler sets the hardware timer to interrupt one quarter of a bit frame later in the middle of the last half of the first bit frame and sets a variable to indicate that reception is in progress The timer interrupt handler then begins sampling the input and verify ing that the data matches the MC145030 data format Each sample must be followed by its complement 01 or 10 to form a valid bit frame and the silent periods 00 must occur at the right times During the two groups of frames holding data bits the interrupt handler shifts the second sample of each frame into a pair of 16 bit variables After the final silent period the firmware compares the two variables to ensure that both data values are equal If so and if all the silent periods were truly silent the firmware adds the data value to the receiver s ring buffer for later analysis by the higher level C code The INTO input continues to generate interrupts whenever the IR signal goes on so the firmware puts that information to good use The timer should be midway in its count to the next sample at each negative transition so the INTO handler reloads it with exactly one quarter of the bit frame time think about it which allows the firmware to track remote units with slightly off frequency oscillator
153. hows in the number of decision and jump state ments Unlike the load and store instructions branches tend to be a source of error For example condi tional branch instructions are usually associated with loops making it easy to introduce errors such as executing a loop too many or too few times or inadvertently branching past code Thus the number of branch state ments can be taken as a very rough indicator of code complexity In this example the control logic of the compare and branch method contained 140 branch statements but the control logic of the state machine method contained 18 branch state Distributed Control and Data Acquisition PC Master slave controller 3 Z180 Connectivity is implemented at low cost with a network designed by CIMETRICS TECHNOLOGY Our hardware software solution includes Microcontroller code PC XT AT interface card NSP protocol and application development software toolkit CIMETRICS tecunoLocy the network solution for embedded controliers 120 West State Street Ithaca New York 14850 Phone 607 273 5715 FAX 607 273 5712 60 Issue 26 April May 1992 The Computer Applications ournal ments three in the state machine logic and sixteen in the action routines there are an additional 21 J MP instructions in the state machine jump table Clearly the control logic of the state machine is much less complex and therefore simpler to debug Furthermore and thi
154. iability of X 10 transmissions do you really want to trust them At the high end of the scale are the units that start in the 3000 range and can only be obtained through authorized dealers who must do all the installation and programming What good are these devices to experimenters who know what they want to do and just need some specialized hardware to do it The Computer Applications ournal There are a few low cost systems available that allow the experimenter to add hardware piecemeal and do the programming but they are based on the premise that you don t mind leaving your 200 W IBM PC running all the time to do the controlling wouldn t want to see that electric bill And what happens when your kids want to play Tetris HCS Il REVISITED In the last issue of Circuit Cellar INK Steve introduced the new Circuit Cellar Home Control System II and discussed the brains of the operation the supervisory controller The HCS II is based on a number of separate building blocks that may be connected using a network made up of a single twisted pair wire and is designed for people who know what they want to do and how to do it but need some low cost hardware and software to use as tools The Supervisory Controller SC is responsible for determining how the system operates and when things happen It has 24 bits of TTL I O optionally up to 48 bits of buffered I O in addition and eight channels of 8 bit analog t
155. im CA 92805 714 385 1707 Fax 714 385 1708 54 Issue 26 April May 1992 The Computer Applications J our nal 129 challenges The Motorola 68000 hasa Listing 2 continued number of instructions that support this kind of program but single chip next_state yellow a yel low micros like the 6805 do not and you next_state yellow b yel low are forced to use some ingenious next_state yellow c red next_state yellow d red hacks Define the output action codes IMPLEMENTING THE NEXT no_output 0 STATE print_illegal 1 print_emerg 2 To recap wish to store next state addresses in a two dimensional array Define the output action array and access the next state address by output_action red a no_action two indices output_action red b print_illegal output_action red c print_illegal Let me discuss how the next state output_action red d print_emerg section of the program would appear in the 6805 refer to Listing 3a To begin will consider how the machinery works to determine the next state In output_action green a print_illegal output_action green b no_action output action green c print_illegal output_action green d print_emerg fact actually do the output action i f before changing the state but the output_action yellow a print_illegal latter is easier to understand so I ll do output_action yellow b print_illegal rape output_action yellow c
156. in the design stages of a project All too often designers discover the weaknesses in their systems late in the design cycle when there is no recourse other than applying patches to correct the deficiencies This solution is usually difficult because at times problems lay deep within the bowels of our code RAM integrity is compromised in different ways An operation may not run to completion perhaps only partially updating some vital control block The system can suffer a static hit or power surge possibly modifying some RAM bits A hit of sufficient magnitude may even disrupt the normal sequential operation of the processor itself resulting in its attempt to execute data or to resume at some arbitrary point of the program Should this irregularity happen to be in the RAM_C LEAR routine all bets are off Obviously the most desirable response to such system anomalies is for some recovery mechanism to put things straight and for normal opera tion to resume At the very least you want the system to detect the error and either continue to run in a degraded mode or to remove itself from operation and possibly issue a distress call to the host computer THE WARM AND COLD OF IT The first thing you want to determine early in the power up sequence is whether the system is performing a cold or a warm start On Power up Initialization Hardware Initialization Restore Test Byte Clear Under Test Flag Cold Start Initializ
157. infor mation Many of the components used in this article may be purchased from Pure Unobtainium 89 Burbank Rd Tolland CT 06084 2416 Voice fax 203 870 9304 CONTACT Mitel Semiconductor 4320 Stevens Creek Blvd Suite 225 San Jose CA 95129 408 249 2111 Fax 408 249 1635 407 Very Useful 408 Moderately Useful 409 Not Useful FEATURE ARTICLE Ken Davidson Programming the Home Control System II In the last issue of Circuit Cellar INK members of the engineering staff introduced the Circuit Cellar HCS Il Find out now how to program the system to run your home 42 Issue 26 April May 1992 ave you taken a good look at what is on the market these days for home automation systems At the low end is the X 10 CP290 controller You plug this box into a PC set on and off times for a bunch of X 10 modules and disconnect the PC While inexpensive it is nothing more than an easy to program timer Next is the Enerlogic ES 1400 It uses a language similar to what I m about to describe but again it can only talk to X IO modules Its advan tage over the CP290 is its capability to receive from the power line and base decisions on what it hears but it has no direct inputs or outputs How do you connect a motion detector light level sensor or temperature sensor to it There are X 10 units that send commands onto the power line based on motion and light leva but given the rel
158. ing capability to an embedded controller design using a variety of methods Virtually all require additional hardware and many also require some software These additions implement a network protocol The OSI seven layer network model is often used in the description of network protocols Most network protocols do not specify all seven OSI layers for example Ethernet specifies only the bottom two layers Thus some network protocols are composed of two or more protocols that specify different OSI layers Simple networks may require the specification of only three layers which are 1 The physical layer defines the physical medium and how message bits are encoded It is implemented in hardware 2 The data link layer defines message construction medium access control and low level error checking among other things It may be implemented in hardware firmware software or some combination of these three 3 The application layer specifies high level network commands as well as the interface between the network software and application programs It is usually implemented in software or firmware Methods for adding networking capability to an embedded controller can be categorized as follows 1 Use a microcontroller with built in networking hardware and firmware and add physical medium interface circuitry 2 Interface a LAN controller chip set to the embedded controller and add software for the application layer
159. is needed to put the address and value in the proper order for finicky C I am now able to type in things like 1 2 ON and make new words by SETUP ALL OFF 1 8 ON 8 1 ON POB 8987 121 The Computer Applications Journal SETUP2 ALL OFF 1 5 ON 5 1 ON 170N 710N Tm sure you get the idea I ll also make two other words CONNECT 2DUP ON SWAP ON DISCONNECT 2DUP OFF SWAP OFF 1 2 CONNECT is thesameas 1 2 ON 2 1 ON andsimilarlyfor DISCON NECT At this point I can add a few other features to this little application For example I ll declare the jacks that my various devices are plugged into as constants Thus 5 CONSTANT modem 6 CONSTANT PC 7 CONSTANT terminal 8 CONSTANT 100s That lastone by the way is the New Micros 100 Squared board The controller s RS 232 port can be plugged into one of the jacks so it can switch itself around the network Even though these are called constants their values can be changed later with the help of the word or TICK EMBEDDED CONTROLLER for Quick Development The EC 32 is a versatile 80C32 microcontroller board It is ideal for quickly developing products prototypes or test fixtures e 80C32 microcontroller 805 1 compatible e BASIC 52 or MONITOR 52 available e Program in C BASIC or assembly language 8 to 92K RAM EPROM or EEPROM e Breadboard area and expansion bus e RS 232 port and 12 digital I O lines e 100 for 11 MHz 145 for 20 MHz
160. itasking package is available for the NEC V and Intel 80x86 Series micropro cessors for 595 The complete source code is available for an addi tional 295 125 The Computer Applications Joumal Issue 26 April May 1992 47 until it is closed Also note that if motion is detected again before the timer times out the timer is restarted from zero The result is the lights stay on for five minutes from the last detected motion and not the first Since we re dealing with the IR Link elsewhere in the issue how about an example of performing one set of tasks based on the presence of a particular person and another if that person is absent Listing 2 shows such code When Steve walks into the living room wearing his IR badge the system will be nice and turn on the lights and stereo If Ed happens to walk into the same room but Steve isn t there we ll razz him with an air horn and turn the lights off If Steve is with him though we ll be nice again because we don t want to subject Steve to all that noise For something more practical suppose you have a motion detector in the bedroom and you want the lights to come on after dark You really don t want the lights coming on during the night every time you turn over in bed and you also don t want them to come on when it s light out Similarly you have a motion detector in the hall just outside the bedroom and you want the hall light to come on when it s dark How
161. ith a large number of states and inputs the state table eventually becomes unwieldy and you must eventually resort to a different approach One possibility is to break the single large table into several smaller tables The state table technique is an example of a table driven program its behavior is defined by a data structure rather than by a block of procedural code Once the procedure that inter prets the table is fully debugged the system will operate according to the contents of the state table This aspect makes it very easy to debug and to modify Each entry of the table has two parts e the next state of the machine the output action to occur with this transition If there is no transition for a given state then the next state is simply the current state If a particular input does not occur during a particular state then you can choose to have the state machine ignore the input or generate an error message The error message can be quite informative because a particular input has occurred in a particular state eg Can t push that button while the light is red The interpretation of the state machine ignoring outputs for a moment can be reduced to a fiveline program similar to what I ve shown in Listing la This code says the next state of the machine is determined by the current state and the input_ condi ti on The program reads the state_tab1ematrix to determine the next state and then sets
162. itter Receiver PC board and all components exduding TW523 including 803 1 processor RAM IC sockets PL Link firmware in EPROM and user s manual Complete kit order PLINK 1K Assembled and tested order PLINK IA TW523 X 10 power line adapter not sold separately 99 00 159 00 30 00 Item 3 IR Link Smart Infrared Transmitter Receiver PC board and all components including 8031 processor RAM IC sockets infrared LED 38 kHz infrared receiver module IR Link firmware in EPROM and user s manual Complete kit Assembled and tested order IRLINK 1 K order IRLINK 1A 119 00 169 00 Issue 26 April May 1992 The Computer Applications Joumal Item 5 LCD Link Smart 4 x 20 LCD Display Network Interface PC board and all components including 8031 processor RAM IC sockets LCD Link firmware in EPROM and user s manual order LCDLINK 1 K order LCD25 4 Complete kit 4 line x 20 character LCD 99 00 59 00 Item 6 ADIO Link Smart Analog Digital 1 O Network Interface All components including 8031 processor 8 bit ADC RAM 24 bits I O IC sockets ADIO Link firmware in EPROM and user s manual Complete kit Assembled and tested 4 channel b bit DAC upgrade order ADIOLNK 1K 199 00 order ADIOLNK 1A 299 00 35 00 Miscallaneous Link Pwr 4 00 PS 11 19 00 12 V modular power supply for link units 5 V 0 9 A modular power supply for HCS II All items are shipped FOB Vernon Connecticut and ship
163. ject off the boards fi Steve Ciarcia is an electronics engi neer and computer consultant with experience in process control digital design and product development SOURCES See the box at the left for the availability of HCS II modules Many of the components used in this article may be purchased from Pure Unobtainium 89 Burbank Rd Tolland CT 06084 2416 Voice fax 203 870 9304 404 Very Useful 405 Moderately Useful 406 Not Useful REALIZE THE POWER OF PARADIGM The Model for Programming Productivity 3301 Country Club Road Suite 2214 Endwell NY 13760 607 748 5966 FAX 607 748 5968 The Computer Applications Joumal Issue 26 April May 1992 31 The Frugal Networker A Crosspoint Switchboard for RS 232 34 How many times have you wanted to be able to easily switch two or three computers between Say a printer two modems and a microcontroller Find out how to do it easily using a telephone chip Issue 26 April May 1992 FEATURE ARTICLE Frank Cox id you ever have one of those prob lems that could be easily solved by buying say 1000 worth of new computer hardware and software Well it hap pens to me more often than to most But instead of getting out my credit card usually react to these situations by heating up my soldering iron not that always save money Sometimes come up with something really useful that more than solv
164. l Il want to connect the attached devices together in different ways to do different jobs don t want to turn on and off different configurations of switches Being able to type something 36 Issue 26 April May 1992 such as PC modem CONNECT and terminal PC DISCONNECT would be nice as would being able to group commands For example WELL could mean connect the terminal to the modem and also let the computer listen then dial the WELL and ignore all traffic on this line until tell you to turn everything off again Doing this sort of thing is easy in Forth and having an on line language system means you can build commands like this example as you need them first need to build a few primi tives though I m not sure this description is the best one for a Forth word To turn a switch on and off need to write a 1 or a 0 to the respective corresponding address So in Forth could type PARAMETER HEX BS5CO C lt ENTER gt H EX will turn on hexadecimal mode and C pronounced C Store will write an amp bit value of 1 to hex address B5C0 and connect the input of jack J1 to its output making a loop back for anything plugged in there Now that the hex arithmetic is set I can type 0 B5CO C to turn it off again I ve already mentioned the write only nature of the MT8809 One way around the problem of being unable to read the state of the switches is to just turn t
165. l LEDs LED7 On LED6 On LED5 Off LED4 Off LED3 Off End of RAM data transfer halted Cannot record card is write protected Low battery system halted Data corrupt system halted Rear Panel Switches Push Button1 Switch1 Switch2 Transfer enable Record Playback mode Serial Parallel mode Figure 2 M Bucket LED indicators and configuration switches connection to suck the bits back out one at a time Just about any micro can be used in this project chose to base it on an 803 1 because of its built in UART and the availability of a 44 pin PLCC package If you really need to combine functions for an even smaller design there is an 875 1 PLCC version The latches can be replaced with a couple of 8255s PLCCs available here too but think you ll find the latches 1 No memory card installed system halted Toggles with each data byte transferred R 249 TERMINAL Featuring e Standard RS 232 Serial Asynchronous ASCII Communications 48 Character LCD Display 2 Lines of 24 each 24 Key Membrane Keyboard with embossed graphics Ten key numeric array plus 8 programmable function keys Four wire multidrop protocol mode Keyboard selectable SET UP features baud rates parity etc Size 5 625 W x 6 9 Dx 1 75 H Weight 1 25 Ibs 5 x7 Dot Matrix font with underline cursor Displays 96 Character ASCII Set upper and lower case Options backlighting for display RS 4221 0 20 Ma current loop W O COMP
166. l observation tool in application areas presently requiring use of bench top spectrum analyzers and other instruments Moreover because the Probe is so small you can actually probe and explore circuits where you might not do so with a full fledged instrument In use a wide variety of observations can be made For example quickly check amplifier stages for bandwidth spot undesired resonances adjust oscillators for fundamental or overtone operation probe shielded enclosures or connector back shells for leakage and test rotating machinery for internal arching The Model 107 features a 60 dB display range and a low input capacity rather than low Z 50 ohm input A 10 pF capacitor couples signals to its input minimizing loading of circuits under test Maximum input rating is 1000 VDC decreasing to 1 volt at 100 MHz A 50 ohm coaxial input adapter is provided A BNC connector connects the probe to a scope s vertical input Other specifications include a vertical logarithmic linearity within 3dB a tangential sensitivity of 60 pV 3dB at 50 MHz with flatness within 2 dB from 5 to 100 MHz and low frequency degradation of about 8 dB at 1 MHz Spurious responses are about 40 dB with an IF bandwidth of 180 kHz at 3 dB Horizontal linearity is specified to be within 7 The Model 107 Spectrum Probe is priced at 249 Smith Design 1324 Harris Rd Dresher PA 19025 215 643 6340 Fax 215 643 6340 The Computer Ap
167. lag can also be interpreted as indicating a busy condition by the data collection code which would inhibit taking more measurements until the condition clears Now the ring buffer manage ment code can be centralized in the mainline loop or perhaps run as a task that polls the write pending flag and if set attempts the write opera tion After completing a successful write the flag is cleared and normal operation resumes The simplicity of this approach handles all write operations in a clean and consistent manner No decision making is required as to whether am recovering from a power interruption in a buffer full condition or just doing normal a write operation Actually a small PROGRAMMABLE CONTROLLER BOARDS 803 1 Common features e 8031AH CPU 11 0592 MHz clock speed User interface is via a terminal emulator program running on a host computer and linked through the RS232 Serial Port on the controller board e 32 K FLASH MEMORY Eliminates the need for Programmer and UV Eraser 16KEPROMand8KRAM 32 Buffered I O lines Assembled and Tested board 155 gt DG32F Board 4 80 x6 00 e 16 K EPROM and 8 K RAM e 32 Buffered I O lines Assembled and Tested board 129 gt DG31 e On board 8 or 16 K EPROM 8 or 32 K RAM capacity e Ports 1 and 3 processor lines on 20 pin headers I O expansion lines on 20 p header Assembled and Tested board 80 gt EMC32 Board 3 00 x4
168. last bulb a 40 W bug lite So it works both ways Msg 51495 From ED NISLEY To ANDREAS MEYER The high filament has a shorter life expectancy than the low filament on the assumption that you only turn up the steam when you need more light That assumption SOE TIME is completely wrong for those of us with lights on timers as we never touch the lamp switch finally gave up on one of my lights and installed a standard bulb of the right wattage works like a champ gives off more light and lasts longer too If you ve got a real problem try a rough duty bulb that will cost more than the photoswitch but will continue to work while you pound it on the floor Msg 51567 From KEN DAVIDSON To ANDREAS MEYER Something to be careful of is whether you use a 120 V or a 12 V halogen lamp If the photoswitch uses a triac to do the switching chances are the waveform getting to the lamp is somewhat chopped That is fine for a 120 V lamp but the low voltage lamps use a transformer that could be damaged by the chopped power We ve been shopping for halogen lights for our new house and want to control them with X 10 lamp modules Just the other day it dawned on me that we can t consider the low voltage variety if want to use the X 10 module The Ciarcia Design Works Does your big company marketing department come up with more ideas than the engineering department can cope with Are you a small company
169. later in the list so a certain precedence can be achieved by where in the list a particu lar equation falls Input levels and edges stay static throughout a pass through the list changing only after a pass is complete An input edge is always cleared at the end of a pass but may be tested multiple times in a single pass One concept I m sure is going to bite some people is once an equation evaluates true and its companion action has been carried out that action won t be executed again until the equation evaluates false at least once then true again For example suppose have the statement IF Input 3 ON THEN Module J2 ON END If I were to send out an on com mand to module J2 every time the condition Input 3 ON evaluated true d have a very busy power line until input 3 went off Executing the on command just once then skipping it until input 3 goes off then on again is one way to get around the problem Another way get around the above problem is to be a little smart about X 10 commands Transmitting an on command to a module if the module is already on is kind of silly Therefore check the status table first and if the module is on don t send another command This check doesn t work for bright or dim com mands because the light will likely be already on when you want to dim or brighten it to a new level so you have to make your program a bit smarter A Speed Development wh
170. lied to the other chips 3 V is still The Computer Applications Journal a valid TTL switching level Asa result of the regulator the frequency should stay the same during calibra tion or use The final IR Link design did away with the hardware encoder decoder chip and synthesizes the Manchester codes in software Ed describes the command set in his article so won t duplicate the explanation here other than to reiterate our design approach Like the other HCS II COMM Links the IR Link is intelligent and designed for both independent or network operation As an independent periph eral connected via RS 232 the IR Link adds IR codeactivated control and recognition to any PC BADGE READERS AND PEOPLE TRACKING The idea behind the IR Link is to use a trainable hand held IR remote controller like the one you might already be using with your TV and have it contain 10 or 20 of these control codes Simply aim the remote at the IR Link and the code will be received by the HCS II s Supervisory Controller SC Within the SC s event repertoire you might have IF IRcode 20 1 THEN Exhaust _Fan ON END or Photo 2 the infrared ID badge the key fo the people tracking system is no larger than a small pager hear the transmission regardless of their orientation IF IRcode 32 1 THEN Al arm_ Bell ON AllLightsOn C END Given 512 codes and the intelligent programming of the SC your hand Photo 3 The
171. ly respected for his blunt as you ll see assessments of the local high tech thrills and spills If you ever deal with Nick you ll find he is quite an interesting fellow First check out his business card Figure 1 Also as his signature he signs the mirror image of his name All in all a real California kind of guy Why is Nick this way don t know and actually I m afraid to ask Anyway the first part of Nick s presentation postulates that a scien tific approach much like the NFL quarterback rating system should be used to rank the contenders for Inventor Of The Microprocessor The foil in Figure 2 pretty much summarizes his scheme Figure 1 Nick Tredennick is more than your average computer industry consultant The Computer Applications ournal Going further naturally Nick highlighted some of the year s best headlines U S SEEKS WorKSTATION Limit San Jose Mercury Pentagon officials afraid the computers will be used to design weapons Because the United States is the leading exporter of weapons either this situation is a case of the government s right hand not knowing what its left hand is doing or a stealth like version of industrial policy Go figure Pian FoR MIPS CONFUSES Experts New York Times Is ACE a Joker guess it means things will work out for MIPS as long as they don t confuse beginners or themselves Winpows 3 Users 0 Jo
172. m on your forehead as you search your mind for an explanation NONVOLATILE RAM Used to be that embedded systems were simple minded ma chines They powered up and per formed their tasks until power was removed Then reminiscent of some government officials they didn t remember We quickly found that for many applications maintaining the contents of RAM memory in the absence of power could add features and open up new applications Using the various backup power supply options available many people cobbled up backup protection schemes that worked reasonably well More re cently commercial products have been released that specifically address the issues of RAM nonvolatility Close The Computer Applications J ournal examination of these RAM non volatizing capabilities indicates many offer features beyond what can be attained reasonably using a discreet approach Reasonably that is in regard to component count board space and the need for manual tweaking The arrival of these reliable integrated RAM protection circuits may lull many people into the belief that the valuable contents of their RAMs are secure Well folks hate to rain on the parade but it ain t necessarily so Unfortunately a whole new set of software considerations exists in a system that relies on nonvolatile RAM for its continued successful operation Knowledge of the varying levels of security attainable and their pitfalls are important
173. mage Capture Utility Tiff Utilities Image Drive Ram Disk Emulation STARTER PAK Cortex Pak NEC TI2Z3EX Camera With Lens 9 Video Monitor Frame Grabber Software amp Cables OEM PRICING AVAILABLE MA ENATION CORP P O Box 84568 Vancouver WA 98684 PH FX 206 944 9 13 1 147 Listing 2 Measuring the remote MC145030 s oscillator frequency requires determining the bit frame time based on the received data This firmware routine analyzes an array holding the time of each negative transition in the IR signal The first element of the array is the length of the pulse formed by the first two sync bit frames All the debugging output statements controlled by ShowDetail are removed to save space in this listing IRCal Remote ShowDetail int ShowDetail BYTE FrameNum FrameCount Index unsigned int FrameTime FrameTimel FrameTime2 AvgFrl ime do memset IRTimes 0 sizeof IRTimes SerWaitOutDone IRSample get the IR transition times get differential time between each sample Kl OJis start bit frame time estimates true frame time is time since the start so it is already a delta time for FrameNum MAXIRFRAMES 1 FrameNum gt 1 FrameNum IRTimes FrameNum IRTimes FrameNum IRTimes FrameNum 1 convert times fromtimer ticks to microseconds magic number is 1 085 microsecs per timer tick but we must do it in two tiny
174. mbine with the tungsten atoms deposited on the envelope walls it helps keep the tungsten redeposition process going at a good rate The may have seen lamps with dimmers that seem to require a higher setting of the variable intensity control to turn ON than to turn OFF a sort of hysteresis This too is explainable in terms of changes of filament resistance with temperature It takes more current to make a cold filament start producing light than to keep it producing light once it reaches operating temperature Msg 51691 From KEN DAVIDSON To STEVE LANGER That is why always thought halogen lamps shouldn t be dimmed We learned in physics that in order for the processes in the halogen lamp to work properly the lamp must get very hot Dimming the lamp it would seem to me would not allow the lamp to achieve the proper temperature and would greatly shorten its life Msg 51996 From STEVE LANGER To KEN DAVIDSON Yes but if the lamp is dimmed only for short periods and is allowed to operate at its normal high temperature most of the time it should be all right don t you think just saw some desk type lamps with a halogen bulb in them and they also had what looked like an SCR dimmer Of the three samples on display at the store two had nonfunctional dimmers they would function like a ON OFF switches but wouldn t do any dimming the third one was working as intended wonder why SOMO TIME Msg 52042 From KEN D
175. me as for the counter example Now you can incorporate some error traps whereby problem status can be communicated to the calling routines by adding more return codes to the basic buffer functions DATA PREPPING AND ROUTING At this point you have reduced the likelihood of undetected errors and provided some redundancy for fault tolerance in the basic structure of the ring buffer Now will show you how to structure the code that will actually deposit and extract the data records Consider for my example a hypotheti cal system that performs some measurements writes the measure ment data to the ring buffer and transmits data from the ring buffer to the host computer on a continual basis The question now is when the data record actually becomes nonvola tile Consider that the controller has performed its measurement and now has critical data it wishes to dispatch to the ring buffer At this time the data is in a work area and if power to the system is interrupted the data will be lost Worse the possibility of insufficient space remaining in the ring buffer to accept this data record exists and am left with the dilemma of how to proceed One way to handle this situation is to store the data record in an intermediate nonvolatile buffer as soon as it becomes available A pending buffer write is then signalled by the setting of a flag write pending which also resides in a nonvolatile area in RAM The write pending f
176. mers This addition keeps the timers reasonably accurate even if the firmware sends many IR messages Because the interrupt handler knows nothing about the message format the higher level code can send any bits it wants In this application used the MC145030 data format but similar code could mimic nearly any other chip Such mimicking is espe cially valuable when the chip may change at any time or when the requirement becomes either of these two remote control chips after the first one becomes obsolete Sending a message is as simple as issuing the S command to IRGATE over the serial link The number after the S must be in the range 0 to 511 The firmware holds outgoing messages in a ring buffer so it can accommodate bursts of commands from the SC or your program BITS FROM THE ETHER Receiving bits from a remote MC145030 transmitter is somewhat more difficult A Sharp IS1U60 IR receiver translates the IR signal into a ITL voltage for the 803 I s INTO input 72 Issue 26 April May 1992 Listing 1 These three functions translate an integer between 0 and 511 into the format required by the MC 145030 chip Each entry in the output array represents the state of the out put The entries are transferred to the output by an interrupt handler routine driven by the on ps bit frame chip timer pin for halfofa 1290 Convert argument into Manchester data frame two outputs per call
177. missing part was the magnetic path a wire alone will not do And definitely it cannot be wound around the motor lead What goes around the motor lead is the magnetic core Mostly often a toroidal doughnut shape but any closed path is OK Then you have a winding of several turns around that core In fact the motor lead can pass the hole in the core several times as well What you get is a trans former The ratio depends on the turns just like in any transformer but normally you consider the voltages and then the ratio is direct In CTs the ratio is inverse Let s say your primary current is 10 amperes max Make 10 turns through the core and you have 100 ampere turns Now make 1000 turns as the secondary The ampere turns must match so you get 0 1 amperes times 1000 turns to produce the 100 ampereturns Simple After the current transformer YOU MUST HAVE a load resistor Consider the primary being 230 V Your turns ratio if there is no load will produce 23 000 V Hardly something you want to happen For a 0 1 A current and normal electronic signal levels of 5 to 10 VAC you need a 50 to 100 ohm power resistor preferably two in parallel secured directly to the secondary winding ends not into some terminal strip far away You don t want the load to ever be opened accidentally As to the phase angle detection you need another transformer that takes your voltage down to the same 5 or 10 V level Then you make a zero voltage d
178. n address for each entry The self modifying code method has the advantageous PUSH and RTS method but it does not require that the microprocessor have a PUSH instruction However it does require 3 precious bytes of RAM and induces a slightly queasy feding in those who adhere to the tenets of structured programming The Computer Applications Journal EPROM EMULATORE An EPROM emulator appears as an EPROM to a target system Instead 0 programming EPROMs you simply download your code to the emulator In seconds you see results 27256 EPROM EMULATOR Emulates 2764 27128 amp 27256 EPROMs Plugs into target EPROM socket and connects to PC parallel port viatelephone cable Loads Intel Motorola hex and binary files Reset outputs restarttargetafterdownl oadi ng 199 Downloads 32K in 2 sec 12 MHz PC AT 27010 EPROM EMULATOR Up to 4 units can be daisy chained to emulate consecutive EPROMs and to support 16 and 32 bit systems Emulates 2764 27128 27256 27512 and 27010 EPROMs Plugs intotargetEPROM socket and connects to PC parallel portviatelephone cable 349 em PAAL AX 7 916 721 8217 Fax 916 726 1905 Parallax Inc 6200 Desimone Lane 69A Citrus Heights CA 95621 Reset outputs restart target sytem Dealer OEM Pricing Available without notice ropriate sales tax 00 for UPS 2nd day next day Prices subject to Califorr ide Add 4 00 for UPS 15 00 for U
179. n fact it could be off by as much as 1 5 When you look at the specifica tion of the IS1U60 this frequency shift does not appear to degrade perfor mance but given some of the physical tests performed think some of their specifications are optimistic The 1S1U60 is an extremely good IR receiver but is also a narrow band re ceiver AS soon as you move off fre quency the sensitivity rapidly drops THE IR LINK HARDWARE To complicate matters transmis sion frequency is only part of the equation A trainable remote also uses a processor and internal timebase to sample and reconstruct IR waveforms It is also susceptible to the same timebase errors described above If we synthesize a signal with a certain error and then sample and regenerate it with more error we could poten tially move out of the bandwidth of the IR receiver again To eliminate error sources from our end put a hardware 38 kHz oscillator on the IR Link board The Issue 26 April May 1992 23 Encode Decode Out Out MC 145030 9022uUF Adjust for Mylar 12 4 kHz cO4 11 IRFOS1290 HEXDIP Decode In Encode Enb CD4011 Figure 2 A basic transmitter circuit uses the MC145030 to encode the data and to gale a 38 kHz oscillator in response toa button press The code sent is set witha bank of switches software still encodes and creates the serialized Manchester data but from there it is ANDed with the 38 kHz signal to produce the
180. n names the output eg Vac u urn specifies an initial value e g 50 and specifies either Accumulate or Mmediate output mode for the action value Notice how terms and outputs can freely allocate fuzzifiers and rules within the total limits of the chip sixteen terms sixty four rules The allocation corresponds to the resolu tion of the input output In this example Pressure and Dirt inputs are classified with twice the resolution of texture six vs three fuzzifiers On the output side beater height can be set to chip for actual execution or both As for I O 8 channel 8 bit analog to digital and digital to analog conver sion in addition to digital I O are eight levels while the bag full light is only on or off eight vs two rules The NLX230 kit allows you to simulate operation download to the provided Z80 Z180 HD64180 HD647180 In Circuit Emulators Affordable state of the art in circuit emulation for Z80 family processors Increase your productivity with features like e Symbolic and C Source Level Debugging e Pull Down Menus and Command Line Interface e Complete Context Sensitive Help e Real Time Emulation up to 12 MHz e Serial Interface works on any PC even on laptops Photo 1 NeuraLogix makes a complete PC based development system for the NLX230 280 2180 284C13 284015 HD64180 HD647180 TMP84C015 Satisfaction guaranteed with a risk free 15 day trial Rentals also
181. ndeterminate For obvious reasons you will want to exclude this block from the area subject to the RAM test The RAM recovery code should be exercised early in the power up sequence by interrogating the under Figure 3 Using checksums and redundancy is one way to protect valuable da amp against corruption Calculate Checksum over Block A Calculate Checksum over Block B Copy Block A to Block B Make Local Copy for Buffer Routine Copy Biock B to Block A Make Local Copy for Buffer Routine Complete 94 Issue x26 April May 1992 Normai Completion test flag Should this flag be set pick up the pointer get the data and put it back You want to do this reset right after the obligatory hardware initial ization before the cold or warm determination After all you may have whacked your warm RAM indicator If the start happens to be a cold one after all this extra step obviously causes no problems THE DIVISIBLE DATA STRUCTURE Another problem could occur when updating fundamental data structures Should the processor die in Get Control Info Calculate Checksum over Static Control Block Block B Processing Unrecoverable Error The Computer Applications Journal the midst of updating a double preci sion count or say a 16 bit pointer the result could be meaningless The problem is most aggravated when using B bit processors because many of the elements such as counters and pointer
182. ndition in the first F statement and the extra I F statement following it Remember said that if an X 10 module is already on don t send another on command That is why the previous statements can be written without checks to see if the light is on it s done automatically If motion is detected after the light is turned on and before the timer times out the timer will be cleared but the on command is skipped When you re dealing with dim and bright com mands though you have to be smarter You may want to intention ally dim a light that is already on so can t block the dim command like can the on command You have to add an extra condition to check for whether the light is off and send the dim command only if it is That way the command is only executed once and you don t end up with a light dimmed all the way to black The second F statement is necessary to retrigger the timer should more The Computer Applications Journal motion be detected before the timer times out When the conditions in neither GI F are met which is true any time it s light out then nothing happens in response to any of the motion detec tors which is just what we want CONTROLLING THE FUTURE That about does it for version 1 0 of the HCS II As we get more feedback from those of you living with the system we ll be refining it to more closely meet your needs Let us know what you think LJ Ken Davidson is the managing
183. ndler Az 85244 1329 Phone 602 9260797 FAX 602 926 1198 TELEX 49980SOMILNK 117 The Computer Applications Journal e ga 0S rae Qe vRe YA OTe 50 N 8122 Engineer Road San Di ego 619 5654500 CA 92111 FAX 619 565 1511 oe Your Window To Emulation Productivity Flexible user interface you ran completely contig urethe windows for size content location and color iceMASTER is convenient t connects easily to your PC requires no disassembly nor does it take up any expansion slots It works on ony PC DOS or 0S 2 Micro Channel or EISA Even laptops Supports source level debug Cand PL M and source level trace 4K trace buffer with advanced searching and filtering capabilities New Products 68H 1 A D E F 8XC552 8X 528 8XC515A and 8XC517A 7 f 7 Meta luit Ey o Y 3 3 3 Issue 26 April May 1992 37 EXPANSION JACK Setup Suitches GNO Sul Sw2 Port A ae 74HCE8S New Micros 100 Squared F68HC11 BOARD UL PAHCLO 6 U3 MT8809 DATA AXO AXL Aax2 AYO AYi AY2 Je RS 232 In7Out Figure 3 The Frugal Networker uses an off the shelf micro telephone cross point switch and some level converters to make a smart
184. nments Tom gets fuzzy again as we try to decide what he s talking about And filling in in Practical Algorithms J ohn Dybowski provides some hints for making programs that deal with nonvolatile memory more bulletproof The next issue should be dynamite as we look at Real Time Program ming in the feature section and Embedded Sensors and Storage in the Special section 2 Issue 26 April May 1992 The Computer Applications J ournal CIRCUIT CELLAR 6 THE COMPUTER APPLICATIONS JOURNAL FOUNDER EDITORIAL DIRECTOR Steve Ciarcia MANAGING EDITOR Ken Davidson ASEH TANT Weeetate EDITOR TE Lisa Nadile ENGINEERING STAFF J eff Bachiochi amp Ed Nisley CONTRIBUTING EDITORS Tom Cantrell 8 Chris Ciarcia NEW PRODUCTS EDITOR Hat v Weiner ART DIRECTOR Lisa Ferry STAFF RESEARCHERS Northeast John Dybowski Midwest Jon Elson amp Tim McDonough West Coast Frank Kuechmann Cover Illustration by Robert Tinney PUBLISHER Daniel Rodrigues PUBLISHER S ASSISTANT Susan McGill CIRCULATION COORDINATOR Rose Mansella CIRCULATION ASSISTANT Barbara Maleski CIRCULATION CONSULTANT Gregory Spitzfaden BUSINESS MANAGER Jeannette Walters ADVERTISING COORDINATOR Dan Gorsky CIRCUIT CELLAR INK ISSN 0896 8985 is published bimonthly by Circuit Cellar Incorporated 4 Park Street Suite 20 Vernon CT 06066 203 875 2751 Second class postage paid al Vernon CT and additional offices One year 6 issues sub
185. no_action it first roa output_action yellow d print_emerg assume the location in put_ condi t ion is properly set by external Aa MONS MALS SEN e prog a m ME events To retrieve the next state from current_state red start in state 0 the next state table need some kind continued of indexed LDA instruction In 6805 assembler it is of the form DOS Where You Want It Runs on Disk ROM FLASH Develop your programs on a standard PC and run them in ROM with ROM DOS the flexible affordable operating system that was designed for embedded applications Compat i ible with MS DOS 3 3 1 ROM DOS boots and runs from ROM disk or FLASH memory Features include small size i low as 36K runs executable files from ROM FLASH disk support remote disk and multimedia support and a powerful utility suite Confirmed compatible by VeriTest an independ ent evaluator ROM DOS is already in widespread use on multiple system types Developers Kit which contains all the tools and utilities needed to configure ROM DOS to your i system and includes license for 20 copies costs only 495 Already in widespread use on a variety of platforms ROM DOS royalty fees depend on quantity purchased and ROM DOS has proven its dependability range from 3 to 25 per copy Free Demo Disk Call Today Toll Free 1 800 221 6630 m
186. nterface design State machines are also very effective at decoding messages This attribute makes them useful in communication systems like network protocols and in parsing the text of a command language or a computer program THE BUBBLE DIAGRAM If each one of the machine states is represented by a bubble Figure 1 then the transition from one state to another is represented by an arrow Associated with the arrow is input condition a b c or d which allows the transition to occur For example a might represent the transition condi tion stop timer timeout and cause a transition from the red state to the green state Generally most assume that the default condition is for the state machine to stay in a particular state However showing a transition with a condition looping back into the current state is sometimes useful This representation indicates that the condition causes the machine to stay in that particular state The outputs from the state machine are not shown on Figure 1 but of course they must occur for the machine to be useful Outputs are produced from a state machine during either a particular state or the transi tion between states For example consider the transition from red to green may indicate that the red state actuates the red light an output conditional on a particular state Alternatively could indicate next to Figure 1 Bubbie diagrams are traditionally used for small stale dia
187. nterpreting received messages These days the most active marketer of silicon implementing ARCnet appears to be Standard Microsystems Corporation Hauppauge NY The Standard Microsystems COM20020 16 23 each in 1000 quantity is a 24 pin ARCnet controller chip designed to interface with the Motorola 68xx and Intel 80xx families of processors Figure 4 shows an example The COM90C66 and the COM90C165 are good for Intel 80x86 based designs ARCnet interface cards are available for the PC allowing you to put PCs and embedded controllers on the same ARCnet network Vendors of ARCnet board level products include Standard Microsystems and Ziatech San Luis Obispo CA Datapoint is working on ARCnet Plus which promises higher speed 20 18 Issue 26 April May 1992 Mbps longer messages up to 4096 bytes and more nodes up to 2047 as wal as downward compatibility with ARCnet Ethernet Ethernet is perhaps the most widely used network solution at the data link and physical layers for PCs and minicomputers see Figure 5 Ethernet has also been promoted for factory automation by companies like DEC The original Ethernet specifica tion developed by Xerox Intel and DEC was used as the basis for IEEE standard 802 3 which has a slightly different message format Ethernet has the highest data rate of any of the solutions describe 10 Mbps but it may also be the most expensive solution for you Ethernet performs bes
188. o digital conversion The PL Link module handles all X 10 power line communication including both transmitting and receiving The IR Link which Steve and Ed discuss in this issue allows you to issue com mands with a hand held infrared controller The LCD Link contains an LCD display that responds to a subset of standard ANSI terminal control sequences and also has four bits of I O The DIO Link adds eight bits of TTL I O and its cousin the ADIO Link includes 24 bits of I O aght channels of 8 bit analog to digital conversion and four channel s of amp bit digital to analog conversion Up to 32 of these modules may be connected to a single network although cost will probably limit system size to fewer than that A complete HCS II system can be as simple as a lone SC or as compli cated as you want to make it COMMUNICATE THIS While the HCS II is made up of several autonomous building blocks you need some way of interacting with the system as a whole in order to program it In any properly configured home control system you should be able to set it and forget it so we use an IBM PC compatible for doing the setting then disconnect it when finished to do the forgetting The program used to communi cate with the SC is called HOST When run HOST displays a number of windows containing such information as current time and date current state of X 10 modules you decide which housecodes current state of
189. of any memory segment that is a mul tiple of 256 This block of memory starts at hex address B5CO and ends at B5FF the last byte before the F68HC 11 s EEPROM The remaining two gates in U1 combine the F68HC1 I s R W and E signals to create a data STROBE for U3 AO Yi VO i 0 7 Figure 1 The Mitel MT8809 has eight inputs and eight outputs that may be cross connected in any combination good place in the memory map for the MT8809 s 64 bytes The New Micros board hasa MEMDIS pin on the expansion jack that makes this search easier Pulling MEMDIS low disables RAM allowing a section of memory to be notched out by an external device A neat feature The New Micros chip moves the F68HC1 I s 64 configuration registers to B000 and its 5 12 bytes of EEPROM to B600 The 1536 byte island between them seemed like a good place to put my switcher used a 74HC688 plus a 3 input NAND gate from a 74HC10 to build my address decoder which gives a lot of flexibility to move the address around later if want to With a decoder giving a CS and MEMDIS signal each time my device is addressed all needed was the proper STROBE whenever a write took place Using the remaining two gates from the 74HC10 to combine the 68HC1I s R W and E signals took care of this requirement Figure 3 shows the schematic of the circuit U2 and one gate from U1 form the address decoder that responds to a 64 byte block of memory to
190. of codes but never having been left in the dark before forgot the obvious need for a flashlight to find a plug Going for a wall switch was even more trying When you don t need wall switches and outlets they are quite easy to misplace know an outlet was somewhere along this wall six years ago What Who put this bookcase and file cabinet in front of it can t even reach it anymore Argh Eventually found an outlet inserted the manual controller and pressed All Lights On for the three house codes J use The whole house was lit up like a Christmas tree At least wasn t in the dark anymore After a few hours of this charade remembered why hated manual X 10 stuff and built an automated controller in the first place Guinea pig or not was committed to installing HCS II posthaste Given the ease of writing the control sequences in XPRESS had the entire lighting system running in an evening After all how difficult is it to write a control equation that actually makes sense as opposed to some languages It would be more than an oversight for me to say that first night of testing went completely trouble free Al about 2 a m the driveway chime sounded indicating that someone had just driven in About 20 seconds later it sounded again Another car Next the high power blue strobe lights in the driveway started flashing and the chime sounded again What a motorcycle convention grabbed an X 10 controller and pr
191. of the beginning and end of messages address recognition O bit insertion and CRC computation are common features You will have to implement upper protocol layers in software and depending on the microprocessor you choose you may also have to imple ment some of the data link layer Microcontoller peripheral networks Another common serial communi cation feature on microcontrollers is a clocked synchronous serial communi cation subsystem for communication between microcontrollers and periph eral chips over a small area typically within a controller or appliance This feature can allow chips to communi cate using just two or three connecting wires One of the most popular serial bus specifications is the Philips Signetics PC bus a two wire multimaster serial bus capable of up to 100 kbps In addition to PC peripherals and microcontrollers Philips Signetics offers PC chips that allow some non PC components to communicate on an PC bus SERIAL COMMUNICATION ICs A few microcontrollers and most microprocessors lack built in serial communication capability If you intend to use such a processor you may be able to add a serial communi cation chip to your design at a cost significantly lower than adding an ARCnet or Ethernet chip set described previously What will you do with this board UGG DX weireK vas K git WA BBE DaS f O wl Quru Epe Bics rs No Risk Satisfaction gu
192. ompleted within one character reception time or about 1 ms at 9600 bps or data will be lost Also the host must be able to digest the data being played back at this rate Parallel data transfers have two advantages The first is the number of data paths used While serial has a single path or bit stream parallel has eight paths or a byte stream This difference can mean higher through put The second advantage is hand shaking The STroBe and Acknowledge play a please and thank you game to ensure good data transfers using two additional control lines Supporting SRAM modules up to 64K is a simple and direct task Going beyond the 64K limit of an amp bit micro s address range requires bank switching In most bank switched applications only part of the total 64K data space is switched An unswitched portion of RAM is used for variable storage while the remaining part is switched a nice boundary of say 32K might be used Because this microcontroller has nothing to do but store and retrieve data and the variables and stack all fit within the 803 1 can bank switch the total 64K of data space In fact an 8751 could be used which would eliminate the need for an external EPROM The total code is a few hundred bytes or Ser ry P 7 Foo F Ri tour jo 5 IC REx Ci C2 Ci C2 Cu cu pe moa 13 Jes touf S 5 RX SER XPAR ASES g TRANSFER 6 LE REC PLAY 1 5 STA
193. or close apply more or less power to the head positioner The J term deals with the accu mulated error i e area under the error curve over time Imagine your Brand X drive has some contaminants fouling the positioner When it gets stuck along the way from track A to B the J term will continually increase the power until something gives The D term accommodates differing rate of change in the error If the head is flying towards track 0 perhaps the result of getting unstuck thanks to the I term the D term will attempt to put on the brakes before terminal overshoot i e hard drive seppuku occurs PID algorithms are commonly implemented on micros Indeed the core of a PID loop usually looks something like Output P x Error 1 x Error Integral D x Error Derivative where P I and D are the gain factors applied to the relevant Error measure Though straightforward the software PID approach does have drawbacks First the calculation can be slow to execute especially if floating point is called for Fortunately integer approximation tricks can often be used but even then a typical micro may be limited to a few hundred loops per second Second determining the optimal gain factors is often nontrivial Ideally the controlled process is completely modeled to calculate the required gains however this operation is only feasible for those of you who 86 Issue 26 April May 1992 NLX2
194. order and operates in a similar fashion but has a higher radio transmission rate And we just think they re a nuisance As a final note it is interesting that not all orders of generating polynomials allow for easy bit fiddling as indicated above You ll need to be a math major as am told to really understand why though And since I ve been cited before for not providing references you ll find a good description of the XOR shift register solution to the CRC 16 problem in the Sept 86 BYTE article on the subject You might also check the Sept 90 C Users Journal We invite you call the Circuit Cellar BBS and exchange messages and files with other Circuit Cellar readers It is available 24 hours a day and may be reached at 203 871 1988 Set your modem for 8 data bits 1 stop bit no parity and 300 1200 or 2400 bps a o OS Software for the articles in this and past issues of The Computer Applications Journal may be downloaded from the Circuit Calar BBS free of charge For those unable to download files the software is also available on one 360K IBM PC format disk for only 12 To order Software on Disk send check or money order to The Computer Applications Journal Software On Disk P O Box 772 Vernon CT 06066 or use your VISA or Mastercard and call 203 87 52199 Be sure to specify the issue number of each disk you order Please add 3 for shipping outside the U S kN 431 Very Useful 432 Mo
195. ou re dead in the water and your options are limited Figure 1 summarizes what s involved in a typical power up sequence Make sure you don t overlook the recovery time parameter when working with the integrated nonvola tile controllers The recovery time implemented in most controller circuits is the dead time during which the controller inhibits RAM access following power up This pause allows the system to come under control before access to the RAM chip is permitted For example the DS1210 s average recovery time is specified as 80 ms and can span from a minimum of 2 ms to a maximum of 125 ms which is quite a range and believe me you don t want to be marginal on this one THE NONDESTRUCTIVE NONDESTRUCTIVE RAM TEST In many cases once a system is put into service and initialized it may run warm for the remainder of its operating life Periodically performing system diagnostics is still highly desirable but under such circum stances it may not be possible to bring the system down to do so Therefore diagnostic routines must be devised to operate unobtrusively and nondes tructivey The nondestructive RAM test having the right to affect every The Computer Applications J oural byte in RAM is especially critical The general premise behind this test is to read the contents of a RAM location save the contents in a register perform some write and read verifications on the RAM location and restore th
196. ounter as primary For good measure copy the new count and checksum into what is now the secondary counter in order to havea valid backup copy SEC URE RING BUFFERS Ring buffers are frequently employed in embedded designs Often these are quite large and may hold collected data that is uploaded to the host computer either on line or on demand As such errant operation may not be restricted to the faulty system itself and ultimately may adversely affect the network commu nications and host computer In a multidropped environment the problem could affect all the attached controllers as well by disrupting normal communications At this point will describe the potential problem areas and how to safeguard them A ring buffer is implemented by allocating a linear region of RAM asa storage area The bounds of the storage area are defined by the start and end pointers Each time a write or read pointer is incremented it is checked against the end pointer If it has just incremented past the end pointer it is set equal to the start pointer The buffer functions in a ring or circular fashion using these means The ring buffer is considered empty when both the read and write pointers are equal For all intents and purposes the buffer is full when the area between the write pointer and the read pointer is insufficient to hold the data you wish to store The success or failure of the requested operation is communicated back to
197. pace when surface mounted on a board The PGMHCOS is completely self contained and powered by a VDC wall transformer An RS 232 connec tion to the host PC is the only other requirement Vpp is generated on the board and is automatically switched on by the programmer after the 5 volt supply is stable The RS 232 interface is provided by a MAX232 transceiver which generates the necessary voltages for communication with the PC Motorola has made two software packages available on their freeware bulletin board system that were designed for their programmer One is used to send files to the programmer and other for programming the parts Rather than reinvent the wheel simply made the PGMHCOS compat ible with both programs You ll also find the programs on the Circuit Cellar BBS l Il discuss the software more in a bit but first I ll cover the hardware THE HARDWARE Many of Motorola s microcontrol lers feature a data loader and program ming logic built into ROM on the chip Therefore the brain of the PGMHCOS is the MC68HC705 itself The rest of the board is broken up into five major sections the MC68HC705 support circuitry reset circuit RS 232 interface Vpp supply and 5 volt supply Figure 1 shows a complete schematic for the programmer board The MC68HC705 support cir cuitry consists of the clock oscillator and miscellaneous configuration resistors The microcontroller has an internal oscillator tha
198. physical data link 92 ohm coax twisted pair optical fiber 2 5 Mbps up to 20 000 ft separation between farthest nodes using standard timings Protocol Transmission Hierarchy Media access Error detection features serial ARCnet open standard none peer to peer token passing message acknowledgement 16 bit CRC Figure 3 ARCnet was originally introduced in 1977 by Datapoint Corp and has since become a de facto standard factories and buildings For a more complete description of Echelon s LON refer to Ken Davidson s article in Circuit Cellar INK The microcontroller embodiment of the LON nodes are the Echelon designed Neuron chips manufactured by Toshiba and Motorola which integrate a microcontroller and data communication hardware implement ing a proprietary seven layer network protocol LonTalk Transceivers handle the interface between Neurons and the communication media Neurons are programmed using Echelon s Neuron C Echelon claims the features of Neuron C including network variables and other Lon Builder development tools make the development of distributed applica tions simpler faster and cheaper Development tools are available from Echelon but the price may be a barrier to some the LonBuilder starter kit costs 17 995 lease options are available Neuron chips cost about 10 each in large quantity but the chip makers project the price will fall to about 5 in
199. ping is extra All assembled and tested units come with l year limited warranty A repair service is available to kit builders at an hourly charge HCS II Link designs and software are available for commercial license was an industrial control system disguised and downsized as a con sumer leva home controller albeit a consumer with an engineering degree Because of my susceptibility to lightning and general interest in expanding beyond the basic limits I ve described to you implemented my HCS II in its industrial guise so could utilize industry standard isolated 1 O The large green cards in the center of the wall contain optoisolators and relays They connect by ribbon cable to a card cage on the right which contains the SC and battery backup electronics l Il keep you posted on future developments I ve already started looking at a speech I O capability for the HCS II I ve selected a fine audio digitizer that can sound as good as anything annunciated by the Enter prise s computer but I m having trouble finding a recognition unit find it hard to believe that no one has introduced a cost effective voice recognition unit beyond the designs did using the SP1000 chip almost eight years ago suppose if have to could resurrect an old Lis ner 1000 and nail an Apple II to the wall If you manu facture a voice recognition board or know of a workable system tell me about it so can get this pro
200. plications Joumal Issue 26 April May 1992 9 INT AIA 2X0 Doren NEWS ECONOMICAL 8051 SINGLE BOARD COMPUTER A low cost 805 1 based single board computer designed for experimental use has been introduced by Suncoast Technologies Completely assembled and tested the 70691C computer board contains the popular 805 1 micro controller chip with its standard 128 byte internal memory Also included is the circuitry for RS 232 serial communication between the 8051 and its host computer The 70691 C easily connects to the host computer s serial interface using a standard four conductor modular type telephone line cord The board measures 3 875 x 4 5 and features a socket for a 2764 8K outboard EPROM Four teen programmable I O ports sixteen if RS 232 communication is not required offer the you a low cost computer engine The breadboard area allows customizing J issue 26 April May 1992 Y 3888 LLLTTTE the board for specific applications Operating from a standard 5 VDC source the 70691C draws only 100 mA allowing the use of the available prototyping area for the construction of a small power supply An assembled and tested power supply is available The 70691C single board computer is priced at 38 The unit is available without the RS 232 inter face circuitry for 34 Options include an interface cable 4 95 and a 5 VDC power supply 5 95 without 6 12 V transformer
201. r s power the two LEDs may flash momentarily Type BURNO5S filename ext on the PC where f i 1 ename ext is the name of the S record file to be programmed into the part The PC should display public domain cross assembler for the PC and BURNO5 copy charge for 5 Add 5 00 for shipping and handling on Kit or Asy Connecticut residents add sales tax Motorola Freeware BBS 512 891 3733 BURNO5 and PROG7 software Digi Key Corporation 701 Brooks Ave South P O Box 677 Thief River Falls MN 56701 0677 800 344 4539 Fax 218 681 3380 20 Key Keypad Motorola 6805 WDC 65C02 NSC 600 e1 Year warranty Monday Friday 8 am 5 pm PST Stand Alone Gang Programmer 8 ZIF Sockets for Fast Gang Programming and Easy Internal Programmer for PC New IntelligentAveragingAlgorithm Programs 64Ain 10 sec 256 in 1 min 1 Meg 27010 011 in 2 min 45 sec 2 Meg 27C 2001 in 5 min Internal card with external 40 pinZIF e Reads Verifies and programs 2716 32 32A 64 64A 128 128A 256 512 513 010 011 301 2702001 MCM 68764 2532 4 Megabits e Automatically sets programming voltage we e Load and save buffer to disk Binary Intel Hex and Motorola S formats Nopersonality modules rewired e 10 days money back guarantee j s Adapters available for 8748 49 51 751 52 iig NEEDHAM S ELECTRONICS 4539 Orange Grave Ave Sacramento CA 95841 the
202. r supply included Single evaluation units S 1799 ea Competitive quantity pricing Business Instruments Computer Innovations Since 7978 Order 1 800 UP I JUMP MC VISA Company Check Tech 214 980 9990 FAX 2 14 980 7030 13410 Preston Rd Dallas TX 75240 1111 tioned below may have significant impact on embedded controller networking Industry specific stan dards are also being developed CEBus is an emerging home automation standard that has been under development for the last several years Interested readers can refer to three previous Circuit Cellar INK articles for details see references CEBus hardware is beginning to appear Intellon Corporation Ocala FL recently introduced a power line modem IC capable of communication at 10 000 bps IEEE 1118 is a recently approved standard for a serial control bus based on the BITBUS protocol However am not aware of any products other than BITBUS products that are IEEE 1118 compliant at this time General Motors adopted MAP Manufacturing Automation Protocol in order to allow the networking of GM s numerous PLCs and robots Subsequently MAP was adopted by several other large corporations At the lower protocol layers MAP was based on IEEE 802 4 token bus and 802 2 MAP has the reputation of being very expensive to implement which has certainly slowed its acceptance FieldBus is an emerging ISA and IEC serial communication standard for the networking o
203. r under a coffee cup You only need it when you rock the boat In computerese this translates to mean having the decoder chip is redundant Given the low data rate involved the decoding function can be completely simulated in software All we need is to connect the IS1U60 IR receiver directly to the processor and add a little fancy Nisley stuff The added advantage of receiving it totally in software is that the 9 bits transmitted can now be com pletely used as data Rather than designate a single address confir mation as the hardware unit does the 9 bits can be used to designate 5 12 codes for ID badges optical keys hand held remote corn mands and so forth Any way you can transmit the Manchester code the IR Link could now receive and process it Back at the transmitting end we now had a different problem wanted everyone to utilize the new IR Link for remote control but had a lot of trouble justify ing the fact that we d have to supply a costly hardware trans mitter to use it While was mulling over this obvious production problem testing of the basic elements continued To eliminate changing jumpers every time wanted a different code bought a trainable IR controller at Radio Shack and trained it with a dozen or so codes Rather than change jumpers or add a keypad encoder to the prototype now just used the trained remote Wel it took four nanoseconds for lightning to strike this time
204. rallel ports are not 8 bit bidirec tional Some discrete ports can be altered to tristate the output latch with an unused chip select See Circuit Cellar INK issue 2 March April 1988 for the printer port modification used in the all too famous Circuit Cellar Neighborhood Strategic Defense Initiative This cut and jumper fix has been used in a number of projects discussed here in The Computer Applications Journal Tf you have a bidirectional parallel port you can handshake data both into and out of the bit bucket If you have a unidirectional port parallel data can be saved but you ll have to use a serial LED2 simple multitasking executive O task manager O intertask comm O preemptive manuals OsmxProbe task debugger o1 O 150 usec typical task switch O 8 to 25 KB code size MICRO pd picitaL Cl 6402 Tulagi St Cypress CA 90630 5630 80 Issue 26 April May 1992 FULL FEATURED KERNEL O memory manager O error manager O i o events amp timing O resource manager O ROM able EASY TO USE O libraries for Microsoft C Borland C C Zortech C C and assembler O Quick Start Users Guide and Reference QO standalone PC and DOS platforms O 6 months free support and updates FAST amp SMALL 5 usec max interrupt latency Ask about our 95 evaluation kit for information 1 800 366 2491 FAX 714 891 2363 The Computer Applications J ournal Front Pane
205. rcise the batteries treat them as you would your car battery If you anticipate periods of inactivity pop a tape in and let the camcorder run a tape in the play mode Recharge the battery immediately after each use 4 Never discharge the battery to zero Most camcorders will shut off at about 10 8 to 11 O volts This is as low as you want to go NiCd batteries should never go below 1 volt per cell going lower will risk cell reversal and ultimately render the battery useless Your camcorder is the best battery recycler you have there s no need to spend extra money on add on accessories Bob Kozlarek Secaucus NJ How Did She Do It have one question after reading the story of Mr Ciarcia s problem with locking himself out of the house The Computer Applications fournal issue 25 How did Mrs Picker get over the fence also thought that for systems to be successful t hey had to be user friendly can assume that Mr Ciarcia would have the system activated while he slept Did he consider awakening and an emergency run to the bathroom That could be more traumatic than forgetting a key But then again every design has to be tested in the field J oe Privitier Burbank CA We re talking about a man who cooks souffle in dark hooded clothing We don t want to speculate on what his nighttime habits are or for that matter those of his neighbors By the way if you look more closely at the story Mrs Picker n
206. rd called for a maximum data length of 4096 bytes for use with MORE UH PROJECTS GET KOUR 7 TODAY ie The Circuit Cellar Project File Volume 1 has over 200 pages of new and expanded hands on projects and tutorials The Computer Applications J oumal s editors have chosen a dozen of the top projects from the Circuit Cellar Design Contest inde pendent submissions and topresponse articles to make a book with something for every interest only 24 95 includes domestic delivery Order your copy today 24 95 Visa Mastercard Check ar Money Order US Funds Only Add 2 00 for delivery to Canada ar Mexico 4 00 for delivery to other nan U S addresses Te Chui Celar Fret File Yue 4 Park Steet Vemon CT 06066 Tel 203 875 2199 Fax 203 872 2204 The Computer Applications Joumal Issue 26 April May 1992 103 SOAS TIME a 16 bit CRC sum TANSTAAEL There ain t no such thing as a free lunch Msg 52904 From ED NISLEY To KENNETH SCHARF Uh subject to one of the mathematical heavyweights giving you the true poop l Il venture an opinion The CRC can be implemented by a tapped shift register into which you feed the data as a serial bit stream and out of which you get the final CRC value effectively in parallel at the end of the calculation If you started with the final CRC value in the shift register and shifted it backwards you d also have to stuff the original
207. rence umbrella under which minor league blasphemers can take shelter from risk averse editors can safely push the envelope knowing that Nick has already shredded it burned it and spit out the fire I M O K YOU RE FUZZY Fuzzy logic certainly exhibits some symptoms of a permanent Technology Of Tomorrow Two years ago wrote about a fuzzy chip Circuit Cellar INK issue 15 Since then little has happened except that the company wrote about apparently couldn t wait for the Revenues Of Tomorrow Nevertheless in the Phoenix like way of many high tech outfits a new company N euralogix has_ risen from the ashes of the old data sheets Is this persistence just another case of as Nick might say you can t keep a The Computer Applications Joumal Micropr _ amp Tomorrow Technoloav Of Tomorrow r Inventor Ratina System e Patents amp Patent Priority Commercial Products Publications amp Publication Citations Relevant Experience Professional Acceptance Self Promotion e Size of Public Relations Staff Spouse s Assertiveness 4 Figun 3 The Technology of Tomorrow is a moving amp get not often hit with much accuracy bad idea down or is there really something more to this fuzzy stuff after all Let me take a few paragraphs to explain fuzzy before delve into NeuraLogix s latest offering otherwise you could possibly dismiss it as just another
208. res a fair amount of overhead The disk reliability problem is widespread There an Alternative Dust moisture and vibration kill rotating disks every day Instant Access No Motion solid state memories offer extremely high reliability light speed access and hermetically sealed data integrity Instant Access is available in FLASH EEPROM and NVRAM and is programmable in DOS or WINDOWS Rely on Instant Access the demonstrably superior No Motion Memory APELA TIONS Mission Critical Mobile High Security Diskless PC Banking Hazardous Military Environments Communications PRODUCTIVITY ENHANCEMENT PRODUCTS INC 26072 Merit Circle Ste 110 Laguna Hills CA 92653 1 800 451 DISK FAX 714 348 1310 COMDEX 15 82 Issue 26 April May 1992 The Computer Applications Journal The Heart of the Matter RTXC Real Time Multitasking Executive HITACHI 6303 INTEL 80x88 x86 80x96 80x51 MOTOROLA 680x0 683xx 68HC11 68HC16 e INMOS T400 T800 ZILOG Z80 Z180 Written in C e Source Code Included No Royalties Technical Support e Broad C Compiler Support e Sensible License Agreement e Most Popular C Compilers Supported Preemtive Scheduling Fixed or Dynamic Priorities Timeout on some services Configurable and ROMable e Intertask Communications Messages Queues Semaphores Memory Management e Resource Manager e Over 50 Executive Services Available Sys
209. ric Liquid Crystal Display 480 Dot x 128 Dot 80x 16 line _ 152 each or 2 for 20 9 Driver board available 60 00 CONTROLLER CARD BLOWOUT XT hard drive controller Contos 2hard dives u AY MEM contoler1 2 cad 8 bi es 44 00 AT Hard Drive controller 16 bi Port AND TOS WAH unsupto 12 Mrz ony 924 00 16 BIT SCSI CONTROLLER BOARD with flappy controller built ON COMES N kit fo with cables amp software Mig Sumo rm These are 16DX Mhz co processors Fully tested and Quasarteed to work atthe desired speeds below 16Mhs 105 20Mhz 15 e 54h 125 256K x 9 SIMM modules 120ns 7 50 150ns 6 50 Novell Netware up to 60 off list Call with version and number of 85Key XT AT Switchable Keybd 24 00 users you are looking for Wseatwnd Bar Code Reader 99 Model HBCR 8300 3Com 3C603 175 00 101 Key XT Keyboard S24 W 5 00 We accept cashiers cheks MC or VISA No personal checks or COD CA resents add 8 25 sales tax We an NA responsible for typgraphical errors Ni marchands subject to prior sale Phone orders weicame forvign orders requie Special handing Prices subjad to fl Order desk only USA 800 872 8878 ca 800 223 9977 Technical hto 310 217 8912 OEM INQUIRIES WELCOME ax 310 532 6304 20 Restocking fee for remed orders 102 The Computer Applications Journal issue 26 April May 1992 5
210. s Timing the interrupts this way ensures the data samples occur in the middle of each half of the bit frame where they are least likely to be corrupted by noise or timing errors Because the receiver and transmit ter use the same hardware timer in different ways IRGATE cannot receive while it is transmitting so unlike Smart X10 IRGATB cannot monitor its own output The INTO handler checks the timer handler s state variable before clobbering the timer the valid state transitions are IdleReceive and Idle Transmit but not Receive gt Transmit or vice versa IRGATE records all received codes in a table that it displays when you issue the Q query command over the serial link There are several different formats so you can get the values you need in the fewest charac ters After sending the table s contents IRGATB clears it so each Q reports only new codes BADGE TRACKING Although IRGATE s main purpose is receiving inputs from push button remotes to control Steve s new HCS included all the functions you need to build a system that can track people wearing IR badges Ken s SC has code built into it to support active badges more in a moment and allows you to initiate actions based on what room a particular badge is in so the ground work is done As far as IRGATE is concerned there are two types of badges active and passive Active badges are essen tially identical to the remote units d
211. s require multiple instruction steps in their manipulation Admit tedly the window for such an error is small This possibility becomes a real concern over a large installed base especially in the hostile environment embedded systems seem to find themselves in and particularly when doing a lot of data manipulations A problem call from the field indicating a controller once again exhib ited some strange phenom enon has an unsettling effect on the current hot project Of course they never mention the guy doing the installation lashed the thing to a 440 volt compressor Say you have to keep a multiprecision running tally that is critical in nature One way to deal with this issue is implementing dual counters that are updated in tandem You can provide an effective way of trapping an errant count by maintaining check sums for each counter The addition of a flag to indicate the current primary counter completes the scheme see Figure 3 This arrangement uses the following process to update a count Calculate the checksum over the counter denoted as primary in accordance with the current counter flag If the checksum verifies the count is OK so read the counter If the checksum verification fails you can fall back to the secondary counter and try the same procedure Do as you will to the count and calculate a fresh checksum Then store the count and checksum to the secondary counter and mark the secondary c
212. s true If you know the original seed for the polynomial accumulator and the length of the byte string and the length is less than 4K can you reconstruct the string from the CRC result i e work the polynomial equation back wards What a hell of a data compression scheme Can someone tell me why this won t work Msg 52890 From ERIC BOHLMAN To KENNETH SCHARF The contention that a 4 byte CRC will be unique for all possible 4096 byte data streams can t be true There are 232 possible 4 byte CRCs but 232768 possible 4K data streams By Dirichlet s pigeonhole principle that means at least one CRC will be associated with more than one data stream though it does NOT mean that each CRC will be assod ated with EXACTLY 1024 data streams The real contention probably was there would be an almost negligible probability that two 4K data streams that were almost identical most transmission errors affect a few bits leading to a received data stream that s almost identi cal to rather than totally different from the transmitted one would share the same CRC However by the pigeon hole principle above different data streams will map into identical CRCs the error detecting power comes from the fact that it takes major rather than minor transformations to change one data stream into another one that shares the same CRC Msg 52892 From KENNETH SCHARF To ERIC BOHLMAN Well knew was missing something The standa
213. s looks complicated to do in software and wouldn t want to code it without a serious math library but it turns out to be a very simple thing to do in hardware by bit fiddling with a couple shift registers and XOR gates Like everything else it always helps if you know the answer ahead of time so knowing the hardware solution would greatly accelerate the programming approach time 104 Issue 26 April May 1992 The Computer Applications J ournal Anyway the idea here is that the reverse bit fiddling is not an option Therefore the receiver processing overhead would likely be overwhelming In the time it might take the receiver to reconstruct the message assuming you could make an accumulator wide enough you could probably have just sent the entire message conventionally Probably more than once But your idea does have some practical uses There are some other schemes whereby the receiver actually does do a little math to wal not quite reconstruct a message but correct a few bits of the transmission A good example would be the Motorola Bravo radio pager This device uses a coding scheme called 23 12 Golay which is a Signaling format designed to correct a few bits in the pager address field and a couple bits in the data message field This is all done without sending the message a second time Pretty slick This format uses a 23rd ordered polyno mial as the generating polynomial POCSAG another paging format uses the same
214. s point is very important the state machine ap proach assumes no defaults Every input condition for every possible state has an entry in the state and action tables and has therefore been ac counted for On the other hand the compare and branch logic assumes the default occurs if none of the compari son branches occur Overlooking an erroneous state and input combination would be very easy Finally for applications where speed is critical the state machine approach is attractive because it minimizes the number of tests and branches required to make a decision and to produce output L Peter Hiscocks teaches electronics at Ryerson Polytechnical Institute in Toronto and free lances in electronic design construction REFERENCES Jack V Landau State Description Techniques Applied to Industrial Machine Control IEEE Computer February 1979 32 40 G A Van den Bout Designing A Command Language BYTE Magazine June 1979 176 1 87 David E Cortesi Using Finite State Machines BYTE Magazine October 1979 70 72 William E Hamilton State Machine Models Simplify Software Development EDN 4 August 1982 129 134 413 Very Useful 414 Moderately Useful 415 Not Useful SPECIAL SECTION Edward Oscarson Programming the Motorola MC68HC705C8 he latest entry in Motorola s stable of 05 series 8 bit microcontrollers is the MC68HC705C8 The part is becoming Most low
215. s programming status information via the PC display THE SOFTWARE B U R NO 5is abasic no frills program that will only do device programming using a PC as the host It accepts a standard S record file as its input and bums the program into the microcontroller s on board EPROM Typical programming time is about 30 seconds with larger files taking proportionally longer BURN 0 5 ex ecutes from the DOS command line and requires no switch manipulation once the board is turned on and Vpp is applied to the chip which is done automatically by the PGMHC05 When the programming is complete Figure 3 As with power up the power supplies must be sequenced during power down The top trace shorn Vpp and the bottom shows Vec The scales are 5 volts per division vertically and 50 ms per division horizontally the verification status is displayed on the PC A typical BURNO5 command would be BURNO5 TEST 19 where TEST S19istheS record file PRO G7 is a fancier menu driven program used to program load and execute programs under control of a host PC The program is cumbersome to use when programming parts and programming times are significantly longer than when using BURNO5 but PROG7 has some extra features not MultiTask Execs and GOFAST Math Speed Time to Market J your application with peak performance using tested code and expert support Control real time scheduling with MultiTask source code executives or RO
216. scriptionrate U S A and possessions 17 95 CanadaMexico 21 95 all othercountries U2 95 Al subscription orders payable in U S funds only viainternational postal money order o check drawn onU S bank Direct subscription orders toCircuit Callar INK Subscriptions P O Box 3050 C South eastern PA 19398 a cdl 215 630 1914 POSTMASTER Please send addresschanges to CircuitCella INK CirculationDept P O Box 30506 Southeastern PA 19396 HAJAR ASSOCIATES NATIONAL ADVERTISING REPRESENTATIVES NORTHEAST Debra Andersen 617 769 8950 Fax 617 769 8982 MID ATLANTIC Barbara Best 908 741 7744 Fax 908 741 6823 SOUTHEAST Christa Collins 305 966 3939 Fax 305 985 8457 MIDWEST Nanette Traetow 708 7893080 Fax 708 7893082 WEST COAST Barbara J ones amp Shelley Rainey 714 540 3554 ax 714 540 7103 Circuit Collar BBS 24 Hrs 300 1200 2400 bps 8 bits no parity 1 stop bit 203 871 1988 9600 bos Courier HST 203 871 0549 Al programs and schematics in Circuit Cellar INK have been caretully reviewed to ensure their performance isin accordancewith the specifications described and programs are posted on the CircuitCellar BBS for electronic transter by subscribers Circuit Cellar INK makes no warranties and assumes no responsibility or liability of any kind for errors in these programs or schematics or for the consequences of any such errors Furthermore because of possible variation in
217. sine wave The sensitivity to high frequency noise on the hot line is 2 V peak to peak from 10 kHz to 10 MHZ The Probe 100 is priced at 149 95 Eastern Time Designs Inc 2626 Brown Ave Manchester NH 03103 LEDs periodically The manual gives a complete explanation of the distur bances it can detect 603 645 6578 Fax 603 623 8930 506 DC CAD introducing THE TERMINATOR Super High Density Router Complete with Schematic amp PCB EDITOR Features the following powerful algorithm amp capability Rip up and Ret Pre routing of SMT components a Real Time via minimization a Real Tie clean up passes User defined strategies Window 10 capability as DOS Task a mil Autoplacer and Autoparming Two way Gerber and D Automatic Ground Plane w Cross Hatching Complete w Schematic amp Dolly Libraries protected mode for 386 users Optional simulation capability PCB LAYOUT SERVICE AT LOW COST LEASE PROGRAM amp SITE LICENSE AVAILABLE MW Design Computation 1771 State Highway 34 Farmingdale NJ 07727 908 681 7700 908 681 8733 FAX DC CAD The focal point of future CAD market IMAGE PROCESSING Victor Library for C programmers Image Processing bright contrast sharpen outline resize overlay matrix conv etc TIFF PCX GIF bin use exten d expan d conv mem images up to 4048 x 32768 grayscale color EGA VGA Up to 1024x768x256 Las
218. sure Operating current is less than 200 mA while waiting for a character In the parallel record mode a character is ready when the external parallel port activates a strobe The strobe is tied to the INTO line on the microcontroller which triggers an external interrupt The interrupt occurs on the falling edge and a loop is entered that waits for the rising edge an indication of data ready If an end of RAM check says that s it then exit without saving the data otherwise get and save the data to the memory card and set up the next memory address The INTI line is connected to the ACK pin on the external paralla port An acknowledgement signal of at least 5 ms is used to indicate to the PC that the data has been read prior to RET P_P LAY Parallel Play Mode P_P LAY istheonly routine that does not use interrupts This routine simply checks for the end of RAM and exits if done Otherwise data is read from the memory card written to the paralla output port and the INTI line ACKj is used as the strobe to signal the external parallel port that data is available This time the external paralla port s STB line is the one that acknowledges the data Once the INTO line is seen strobing low the INTI line is set removing the data available signal The next address is set up and the P_PLAY routine begins again FILLING AND EMPTYING THE BUCKET Transferring serial data at 9600 bps requi
219. t is designed to operate correctly with either a ceramic resonator or a crystal Again to keep costs down use a 2 MHz ceramic resonator that is about half the cost of a crystal and two capacitors The 2 a RS 232 GND RS 232 OUT 68HC70S PO7 PC7 PD5755 PCS PO4 SCK PCS 32P03 MOSI PC4 i Po2 MISO PC3 21 POLsTDO pc2jes PO RDI PC1 pool 7 ERIF RESONATOR 9 x GREEN Oscl pas Ls PBS PB4 PB3 PB2 PB1 PBO PA PAG PAS PA4 j i PaA3 MAX698 GGE py US PAL PAO TCMP TCAP MAX232 2 0 RS 232 IN RI 4702 RESET L1 1 uH 1N4001 POWER GROUND TABLE ncsenczesce u s CMPINH_FREO SUB_CATH 1 l2 13 3 e F MAXE9S uS 1 2 3 4 8 u3 s he l lio CLS BASE BASE COL ANODE TL497 BOSES SN Gno amp 14 ucc cg ence ee an F S6uF edu Pe Rio 1NS227B 2702 Figure The brain of the PGMHCOS is the MC68HC705 being programmed A TL497 switching regulator is used to generate Vpp while a MAX232 is used to generate proper RS 232 levels accuracy of the resonator is more than adequate for generating the program ming timing pulse and the clock for the 9600 bps serial interface The configuration resistors are used to select one of the MC68HC 705 s many programming modes see Table 1 permanently configure the programmer for to mode 2 using the resistor networks connected to pins 3134 Mode 2 allows the PC to load a program into RAM
220. t when transmitting long messages under light to moderate traffic loads Unlike token passing protocols such as ARCnet and IEEE 802 4 an Ethernet node can get immediate access to the network if there are no messages currently being transmitted However Ethernet is not deterministic there is no upper bound on how long it may take for a network node to gain access to the network Ethernet chip sets are usually designed to interface with micropro cessors rather than microcontrollers Adding Ethernet capability to an embedded controller design typically requires two or three packs plus microprocessor bus interface circuitry The Ethernet controller will handle the transmission and reception of messages but as with ARCnet the software running on the microproces sor will be responsible for formatting messages to send and interpreting The Computer Applications Journal received messages Ethernet chip sets are manufactured by several compa nies including Intel National Semi conductor AMD Philips Signetics and Standard Microsystems Ethernet interface cards are available for the PC allowing you to put PCs and embedded controllers on the same Ethernet network MICROCONTROLLERS WITH BUILT IN SERIAL COMMUNICATION MODES For applications in which hard ware cost must be minimized you should consider designing a network that makes use of serial communica tions capability which is built into virtually all common 8 and 16
221. tem Level Debugging Utility System Generation Utility 450 Page User Manual Ask about ASSIST Our new PC Development Package Combination One Time License Fee From 995 Discounts for Multiple Licenses Ports The only real time kernel you ll ever need A T BARRETT amp ASSOCIATES INC 11501 Chimney Rock Houston TX 77035 FAX 713 728 1049 Phone 800 525 4302 or 713 728 9688 156 Two additional bits are sent in addition to the 8 bits of data a start bit and a stop bit Forgetting that this transmission is in reality 10 bits for each 8 bits of data is easy to do At 9600 bps that s 960 characters of data per second or 57 600 characters per minute The bit bucket meets these ideal transfer rates by taking about 68 seconds to transfer a 64K file using a variety of methods The simplest is using a DOS copy command COP Y BI TBUCK TXT B COQM1 A to send serial data to the bit bucket Procomm or any similar communication pack age can capture the bit bucket s serial output to a file A parallel data transfer will be much faster because data is moving 8 bits at a time Although handshaking is employed and timing depends on the length of the strobes used a transfer rate of 4800 characters per second can be achieved with the standard DOS copy command This time the file is sent via PRN instead of COM1 Transferring the data from the bit bucket to the parallel ports requires two things First a bidirectional port
222. ter Applications Journal Microcomputer Megatel Wildcards provide PC functionality in a flexible small format Vid Mem e 640Kb User memory e Video Colour LCD controls CGA Hercules IBM Mono runs LCD Panels For information on our representatives please contact our head office at the number below 416 245 3324 megatel Issue 26 April May 1992 87 Figure 6 The purpose of a fuzzifier is to classify the degree fo which an input isa member of a fuzzy set Center Location Width Values Next comes the minimum comparator that combines the mem bership info from the fuzzifiers with the rules stored in on chip rule memory the NLX230 can hold up to 64 rules Fuzzifiers are assigned to inputs in the same way as rules are assigned to outputs i e each output has between 1 and 64 rules associated with it exclusively One rule can t apply to more than one output at a time A rule consists of 24 bits Sixteen bits specify which of the fuzzifiers are applied to the rule each bit specifies a fuzzifier The remaining 8 bits comprise the action value the value that is output from the chip Actually besides direct output an accumulator mode allows the output to be the sum of the action value and the previous output So each output s rules are applied against the the rule specified fuzzifiers and their associated inputs Finally the minimum and maximum comparators serv
223. tes you can t go wrong and BP Microsystems offers o thirty day money back guarantee to ensure product satis faction Remember BP Microsystems is The Engineer s Programmer B mick systems 10681 Haddington 713 461 9430 e e Houston TX 77043 3239 FAX 713 461 7413 1991 BP Microsystems Inc 122 40 Issue 26 April May 1992 need one more word before can define the word WELL which men tioned previously STAND BY essen tially says do nothing until tell you STAND BY BEGIN TERMINAL IF KEY 18 ELSE 0 THEN UNTIL This word loops or stands by until it sees an 18 hex or CONTROL X So if want a command that dials the WELL and sets me up for an on line session could use well 100s modem ON ATDT 415 332 7398 CR CR 100s modem OFF terminal modem CONNECT pc modem CONNECT STAND BY for CTRL X terminal modem DISCONNECT pc modem DISCONNECT terminal 100s CONNECT You probably recognize that ATDT asa command to the modem to dial a number Notice these few lines of code that I ve shown have already built up a useful program You can embellish it to best fit your application One improvement would be a STAND BY word that does more than just waste time looping Max Forth allows multi tasking as one fancy way of improving it Another alternative is to use some other interrupt driven scheme l Il leave that as an exercise for you Finally I d like to cover some
224. tested for either on or off using the MODULE keyword There iS no easy way to keep track of a lamp module s dimmed intensity so we don t even try A dimmed lamp simply shows up as being on The current time of day may be tested in a number of ways using the TIM E keyword The typical gt gt lt and lt operators may be used to compare the time with a constant made up of hour minute and day of week There isn t any way to make comparisons with month or day of month but we found little use for such comparisons and left them out There are many situations where elapsed time must be measured A common example is turning a light on for a certain number of minutes when motion is detected then turning it off Sixty four timers are defined for the HCS II 32 that time in seconds and 32 that time in minutes Each timer may be tested for whether it is on or off and may be checked for whether it is less than equal to or greater than a constant value using the TI MER keyword Before you think I m crazy for providing 64 timers keep in mind who the primary user of this new system is Steve and what his control requirements must be For those cases where a counter must be maintained or simple true and false states must be stored there are 16 Sbit variables available When multiple IR Links are connected to the system knowing which IR Link received a particular 44 Issue 26 April May 1992 code or command from the
225. th other types of computers However they differ in their application Embedded controller networks are generally used for distributed control or data acquisition whereas office LANs are used for such things as file sharing and electronic mail In a typical distributed control application each embedded controller controls a piece of equipment The network carries messages containing controller status information and high level control commands Frequently the source of the control commands will be some central control station that constantly queries the status of the embedded controllers This central controller may also allow a human operator to monitor and control the entire system Network nodes OSI layers specified Media access Error detection features Application layer features up to 250 32 per cable segment physical data link application up to 1200 meters per cable segment 62 5 kbps 375 kbps up to 300 meters 500 kbps to 2 4 Mbps up to 30 meters BITBUS based on IBM s SDLC protocol open standard Electrical specification RS 485 cable twisted pair length speed Protocol Transmission synchronous serial Hierarchy master slave controlled by master node message acknowledgement 16 bit CRC sequence count data transfer task control Figure 1 BITBUS is a serial control bus specification first developed by Intel in 1984 METHODS OF NETWORKING EMBEDDED CONTROLLERS You can add network
226. the 8031 32 microcontroller or with Intel s 8052 Basic microcontroller The R 31 becomes a complete development system when used with R ware R ware consists of an on board monitor pro gram and integrated menu driven PC based host software for edit assembly PC to board communications and debug functions Board includes power supply and regulator up to 64K of memory using static RAM with batter back up or EPROM an EPROM burner used with the 8052 basic microcontroller serial port up to 12 digital input output ports an 8 channe 8 bit analogue to digital converter a battery backed clock calendar 3 RS 485 422 line driver receivers and a comprehensive manual with circuit diagrams and example software The R 31 is available with various options with or without R ware unpopulated as a kit oi assembled and tested Kit prices start at 195 Rigel Corporation P O Box 90040 Gainesville 157 The Computer Applications Journal FL 32607 904 373 4629 Reader Service 187 Issue 26 April May 1992 83 Twenty Years of Micros Now What The computer industry has come a long way in the last twenty years One of the more esoteric technologies to be developed is fuzzy logic Tom takes another look at this somewhat ticklish subject 84 Issue 26 April May 1992 SILICON UPDATE Tom Cantrell t was twenty years ago today the gurus taught the chips to play to para phr
227. the Editor rk Street on CT 06066 Liquid Crystal Displays 16 Characters x 1 fine 3 for ee 4 Characters x 21i ne 2 for 25 40 Characters x 4line 25 8 16x2 128 2x4 20x2 12 BV power required e Built 1N C MOS LCD driver amp controller e Basy Microprocessor interface 98 ASCT character ganerator Certain models are bacidt cal for more hfo ADAPTEC 4070A muy 40004 wean SCSI Controller your choice 602 Flip up LOD display 9 16 VDC Can communicate with any computer having i RS 232 port Can communicate with another Microterminal Use by itself as electronic notebook Onboard microprocessor data RAM 32K Sg and Video RAM 64K Complex built in diagnostics and set up capabilities IF ICU UTILE BOARD rc 79 256K RAM included expandable to 768K on board 256x9 SIMMS Floppy Controller 360K 720K 1 2Mb 1 44Mb 2 serial ports and 1 parallel port LA ER DIODE Keyboard input amp Speaker Output Has Sh f LTOMC FH aone oaei pae arp part optional pal amp contro er Boar is Sil Min eater IO the size of a 5 25 floppy drive Single board 286 12 and 16 computer 99 eee TA BOARD ape ee MAGNETIC CARD READER 95 Magnavox at Color Monitor ncludes e 20 character dot mati display with ful alpha numeric Copablity pane with ful alpho _ meric entry e separate 7 5 VDC O 5 Amp power iupplys standard telephone interface extension zord ihium battery and fiot cone speaker
228. the quality and condition of materials and workmanship of reader assembled projects Circuit Cellar INK disclaims any responsiblity for the sale and proper function of reader assembied projects based upon or from plans descriptions or information published in Circuit Cellar INK Entire contents copyright 1992 by Circuit Cellar Incorporated All rights reserved Reproduction of this publication in whole or in part without written consent from Circuit Cellar Inc is prohibited Bs INSIDE ISSUE 26 1 4 Embedded Controller Networking Alternatives by James Butler 22 Infrared Tracking and Remote Control Meet the New HCS II IR Link by Steve Ciarcia 34 The Frugal Networker A Crosspoint Switchboard for RS 232 by Frank Cox 4 Programming the Home Control System Il by Ken Davidson Ng OU FOP UO Embedded Programming State Machines in Software A Design Technique for Single Chip Microprocessors by Peter Hiscocks Programming the Motorola MC68HC705C8 by Edward Oscarson Editor s INK Ken Davidson ms ilicon Update Tom Cantrell Divide and Conquer Twenty Years of Micros Now What Reader s INK Letters to the Editor Ym Practical Algorithms ohn Dybowski Writing Code to Support Nonvolatile Memory New Product News edited by Harv Weiner PPE ConnecTime Excerpts from the Circuit Cellar BBS conducted by Ken Davidson Firmware Furnace Ed Nisley infrared Home Control Gateway shy Steve s Own INK Steve Ciarcia A Night in The Life
229. the upper nybble holds control information This way each byte would pass commands and data at the same time Commands might indicate that the data in the lower nybble is part of a data byte or is part of an address to read or write The path you decide to take will depend on your specific application Keep in mind you will end up witha less universal device if you design a more complex control format Univer sal is the key word here no special transmission codes to interpret no special file formats to handle just dump your data out and let the bit bucket do the rest Once recorded the memory card can be write protected and stored or transported easily from site to site I m betting on the PCMCIA standard As for its future wall it s in the cards Jeff Bachiochi pronounced BAH key AH key is an electrical engineer on the Computer Applications Journal s engineering staff His background includes product design and manufac turing SOFTWARE Software for this article is avail able from the Circuit Cellar BBS and on Software On Disk for this issue Please see the end of ConnecTime in this issue for downloading and ordering infor mation 422 Very Useful 423 Moderately Useful 424 Not Useful 8031 Embedded Controller Development System etreeseresrer Seed eeeseeen A Multipurpose Board for Embedded Systems or Software Development The R 31 board may be used with
230. tion state character get action code call action_subroutine action do output action new_state next_state current_state character next state current state new state loop These are the action routines move to new state end of main loop 7 procedure action_subroutine action if action 0 endif no output if action 1 print Illegal input endif if action 2 return LDA WORD X where WORD issome2 byte quantity and X is the content of the X index register The effective address is the sum of WORD and the contents of the X index register For example LDX 5 LDA 200 X would have the effect of loading the accumulator with the contents of location 205 So recognizing that have four input conditions in my table the offset into the table of a next state will be given by current state x 4 input condition For example if the current state is GREEN i e 1 and the input condi tion is C i e 2 then the table offset of the desired next state entry is 6 Using assembly language would retrieve the next state as shown in Listing 3b All well and good But notice avoid having to use a multiply by selecting a number of input conditions that is a power of two The multiply is accomplished by using left shifts 131 56 Issue 126 April May 1992 The Computer Applications J our nal D key input print Emergency Red endif W illegal input
231. to it a NO ACTION EOU 0 PRT_ILLEGAL EQU 1 PRT_EMERG EOU 2 Output action table OUTPUT_ACTION EOU ACTION RED DB ILLEGAL ILLEGAL EMERG ACTION GREEN ILLEGAL ILLEGAL EMERG ACTION_YEL D ILLEGAL ILLEGAL NO_ACTION EMERG DB DB DB AR_NO_ACTION NOP AR ILLEGAL print AR_EMERG print JMP_TABLE EOU JMP AR_NO_ACTION JMP AR ILLEGAL JMP AR_EMERG We assume the offset of the action code is LDA OUTPUT_ACTION X STA TEMP ASL ADC TEMP print NO_ACTION NO ACTION Input no action action no action illegal print emergency Name start of table Input Input Input Input oov Input Input Input o0uw gt r Input Input Input Input oOWwD action routine illegal emergency routines jump table action code 0 action code 1 action code 2 in the X register retrieve action code from table multiply it by 3 first multiply by 2 and then add it in again to get the jump table offset TAX JSR J MP TABLE X action somewhere in ROM Each table entry assuming a 16 bit address bus will consist of a low and high address byte 2 Index into this table and retrieve the 2 byte address of the action routine using the action code 3 Push the 2 bytes of the action routine onto the stack in the same The Computer Applications Journal set up for indexed jsr to the vector in the table routin
232. tput port connects to a relay card or terminal block A variety of relay cards and relays are stocked Call for more info RS 422 available distances to 4 000 feet PS 8 port selector may be used to control satellite AR 16 interfaces up to 16 384 relays RD 8 REED RELAY CARD 8 relays RH 8 RELAY CARD IO amp SPDT 277 VAC 69 a EX 16 RELAY EXPAN CARD 16 channel 59 9 ANALOG To aP IGITAL 10 BIT 12 BIT CONNECTS TO RS 232 ADC 16 16 channel 8 bit Input temperature voltage amperage pressure energy usage energy demand light levels joystick movement and a wide variety of other types of analo signals Inputs may be expanded to 32 analog or 12 status Inputs using the AD 16 or ST 32 expansion cards 112 relays may be controlled using EX 16 expansion cards Analog inputs may be configured for temperature input using the TE 8 temperature input conversion RS 422 available PS 8 port selector may be used to connect satellite ADC 16 interfaces up to 4 096 analog inputs 16 384 status inputs and 14 336 relays Call for info on 10 amp 12 bit converters terminal block and cable sold separately ST 32 STATUS EXPAN CARD 32 channel 79 95 Input on off status of relays switches HVAC 2quipment thermostats security devices smoke detectors and thousands of other devices iepte isolators sold separately 8 TEMPERATURE INPUT CONV 49 95 Includes 8 linear IC temperature sensors Temperature range is minus 78
233. tributed design after having spent an issue talking about its control capabilities THE ISSUE AT HAND There are many off the shelf solutions to distributed control applica tions and J im Butler gives us a sampling of some of them J im has previously written for Circuit Cellar INK about using the nine bit multipro cessor Serial format supported by so many of today s microcontroller chips In a similar vein when you have numerous devices that support point to point serial communications usually using RS 232 you often end up with a jumble of cables and switch boxes that all must be rerouted manually Frank Cox shows us how to build an automated switch box using a conventional chip in a somewhat unconventional way Going back to the HCS il Steve adds another link to the chain with his article about the IR Link and its optional people tracking capability Ed covers the firmware aspects of the module finish up my part of the project by describing the actual language used to program the system In our special section this issue we talk about the somewhat ambiguous subject of Embedded Programming Is that physically program ming memory devices for embedded applications or is it writing code for embedded applications We couldn t decide so picked articles that cover both areas J eff finishes up his description of the emerging memory card standards by designing a simple interface that can be used for storing collected data in harsh enviro
234. tunately the Mitel devices only handle a maximum of 12 volts peak to peak and an RS 232 can be as much as 30 volts Also wanted to plug my circuit into the expansion jack of a microcontroller board with only 5 volts available decided to use a pair of MAX238s so could run the transmission gates at 5 volt logic level These are quad 5 volt only RS 232 line drivers and receivers from the wizards at Maxim This choice gave me eight receivers that can withstand a full 30 volts peak to peak and eight line drivers that can put out a legal RS 232 signal using on chip charge pump DC DC converters A MAX238 needs four external capacitors for its power supply so used a total of eight in my prototype but two chips can share larger V and V caps as shown in the sche matic according to a Maxim applica tion note Maxim has since come out with the MAX235 which has these capacitors inside the package They had to use a 0 6 inch wide package though so it wouldn t save any board space but it would simplify board layout and should also increase reliability suggest you try them if you want to reproduce this design The 68HC11 doesn t separate memory and 1 O spaces like on Z80s and Intel chips so needed to find a CS STROBE DATA RESET _ generate CS for U3 and MEMDIS for the controller Changing the jumpers on the B inputs of U2 will move this block to the upper or lower 64 bytes
235. y expansion beyond the internal RAM of the 80C32 Also the system can be battery powered by a single 9 volt battery Software is provided on disk for interfacing with the keypad LCD and RS 232 communica tions A demonstration program showing the capability of the board is included in an EPROM Uses for the RS 232 SBC include front ends for existing control systems prototyping data collection testing or educational purposes The RS 232 SBC is priced at 109 95 Applied Logic Engineering 13008 93rd Place North Maple Grove MN 55369 612 494 3704 Fax 612 494 3704 501 8 Issue 26 April May 1992 The Computer Applications J ournal WAAD NEWS RS232 DATA COLLECTION DIRECTLY INTO PROGRAM A program that collects data directly from any RS 232 serial line modifies it and sends it to the keyboard buffer without affecting normal keyboard functions is available from Labtronics Inc EasyData is a TSR that tricks the foreground application program into think ing the data was manually entered from the keyboard This process takes place transparently in the background without interfering with the foreground program Any RS 232 device with a regular data format can be used EasyData is especially useful for edectronic measur ing devices bar code readers scales data loggers and portable data storage terminals Automatically insert keyboard characters and ASCII codes macros before and

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