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1. mode and switch to transpar ent operation X Switch to transparent opera tion L lt text gt Line check retransmit lt text gt to the remote computer A Abort hang up line Power On Reset 1807 JeWegANoeu The local command set consists of the following H Display a list of these com mands on the local console dis play M Display computer mode AT or PC XT Ma Select AT mode Mx Select PC XT mode B Display boot delay time Bnn Set boot delay time 0 to 99 seconds The boot delay time is the amount of time ONDI waits after executing the S command in remote mode This is to pre ventaccidentally injecting simu lated keyboard data before the keyboard s power on transac tions have been completed C Display selected COM port Cl Sedect COM port 1 C2 Select COM port 2 This is the COM port used when the Ccom mand is processed in remote mode Local Command Line K lt text gt Send lt text gt as keyboard data P Display password Pc text gt Set password P Deletes the password The password is case sensitive L lt text gt Line check retransmit text to the local computer X Switch to transparent operation SOFTWARE STRUC TURE The code structure is segmented in a modular fashion such that use ful pieces can be extracted or modified for your own use It should be evident from the preceding discussions that the main application runs in
2. For Info amp Customer Service 1 619 484 0933 UNIVERSAL PROGRAMMER wm 30 Day Money Back Year Warranty 5 S opion 4 Gang Adapter j ammer i iversal device progr peng OP CIXTIATIS86 or compatibles N rallel interface card to FPL Sio EEL EPLD EEPLD 3 Sarat BIPOLAR PROM p Software C interfaces High spee grams GAL E E PRO Microcontroller e an fast pr r Ape with Normal intelligent Relia i i ise algorithms MEn Se NTEL Extended H Bi ts EX Binary forma i be 16 and 32 bit word on iinet See most compilers in JED u xELTEK ie CA 94086 o Aye Sunnyvale s 4 sa Sa 745 7974 Fax 408 745 140 fel M up to AMBits Ram EX Motorola S COD VISA MC AMEX Reader Service 200 December 90 January 97 85 CONNEC TIME Conducted by Ken Davidson The Circuit Cellar 300 1200 2400 bps 24 hours 7 days a week 203 871 1988 Excerpts from the Circuit Cellar Four Incoming Lines Vemon Connecticut These are busy times on the Circuit Cellar BBS In this issue welll be covering discussions about state machines modem usage in other countries and a nifty TV antenna now on the market Let s start off with a subject near and dear to those just starting ouf in engineering school Msg 31195 From ROBERTO PUON To ALL EEs I ve had electronics as a hobby for around four years Most of what I know I have learned either by trial and error or from The Circuit Ce
3. ing Intel THE COMPUTER Tie Theory APPLICATIONS of Control JOURNAL Designing with Motorola s 68HC11 N I ve Seen the Future recently led a panel discussion at the Embedded Systems Programming Conference I met interesting people arranged for a few articles and ran into lots of folks who were carrying crystal balls in their fanny packs I thought you might like to know what they say you re going to be doing in the next few years OPERATING SYSTEMS You re going to be using an operating system I m not talking about the operating system on your desktop computer but the complete multitasking operating system that you ll be building into each and every control project Depending on who you talk to you ll be using an MS DOS variant a UNIX variant or a specialized embedded OS for your development All of these will make your life easier your software more powerful and your breath fresher They may be right but I m not fully convinced First an operating system assumes that you can accept a hefty chunk of overhead in your software Anyone who s still forcing their code into 8K EPROMs will be in special trouble but there will be more about that a little farther down the page Most folks at the show weren t worried about memory constraint and they weren t terribly worried about the cost the OS adds to the project I ve seen prices ranging from 99 for Coherent a UNIX like OS
4. OEM Dealer Dist inquiries invited IMAGENATION CORPORATION Specializing in Computer Vision PO Box 84568 Vancouver WA 98684 0568 Telephone FAX 206 944 9131 Reader Service 141 92 CIRCUIT CELLAR INK The Circuit Cellar BBS runs on a 10 MHz M icromint OEM 286 IBM PC AT compatible computer using the multiline version of The Bread Board System TBBS 2 1M and currently has four modems connected We invite you to call and enge ideas with other Circuit Cellar readers It is available 24 hours a day and can be reached at 203 871 1988 Set your modem for 8 data bits 1stop bit and ether 300 1200 or 2400 bps SOFTWARE and BBS AVAILABLE on DISK Software on Disk Software for the articles in this issue of Circuit Cellar INK may be downloaded free of charge from the Circuit Cellar BBS For those unable to download files they are also available on one 360K 5 25 IBM PC format disk for only 12 Circuit Cellar BBS on Disk Every month hundreds of information filled messages are posted on the Circuit Cellar BBS by people from all walks of life For those who can t log on as often as they d like the text of the public message areas is available on disk in two month installments Each installment comes on three 360K 5 25 IBM P C format disks and costs just 15 The installment for this issue of INK December 90 January 91 includes all public messages posted during September and October 1990 To order either Soft
5. 415 659 8800 Fax 415 659 8444 Reader Service 507 DrnalCantral E FE WwW EE GE tE Modular data acquisition and control for your IBM PC Our hardware and software are designed to work together so ProControl makes process control MORE simple and LESS expensive IBM PC Host Adapter 129 95 Interfaces IBM PC s to PreCentre bus O modules AND provides 24 digital O lines TMR 36 Timer Module 3 expandable to six programmable counter channels Includes C and BASIC examples and driver software AlfV 124 A D Module Four expandable fo eight 2 bit digital to analog channel Graphical Instument Library G L CGA Version FREE with any PreCentre module VGA EGA CGA Hercules version may be purchased with or without source Cal or see our catalog for pricing i Advanced Design Et Solutions 1920 Moores Mill Road Atlanta GA 30318 69 95 129 95 More I O modules are available Call for our FREE catalogue today 404 352 4788 sader Service 102 STOMP OUT EPROM MADNESS The PROM KING emulates EPROMS saving both time and money during your development cycle Programmable in seconds via your PC printer port or any computer RS232 port it can emulate most 27xxx devices e 8K 8M bit devices e 8 256 bit downloads e High speed download Easily expandable Universal RS232 4 EPROMS per unit PC printer port 8 units e Menu driven software e Battery backup Also programs like a r
6. ADVANCED COMMUNICATIONS PRODUCTS SEALEVEL SYSTEMS PROVIDES THE EXACT COMMUNICATION CARDS YOU NEED PRODUCTS 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 I O BOARDS e DISKLESS EPROM BOARD WITH PROMKIT SOFTWARE BY ANNABOOKS e NEW LAP TOP ADD ONS MADE IN USA e DELIVERY FROM STOCK SATISFACTION GUARANTEED e EXCELLENT TECHNICAL SUPPORT A SEALEVEL SEALEVEL SYSTEMS INC PO BOX 1808 Sa Ra EA EASLEY SC 29641 MUNIEA TIONG 361 0 803 855 1581 Reader Service 184 December 90 January 91 43 BASIC 11 BASIC 11 KS EEPROM_ A BASIC 11 RTC series Expansion boards 8000 A000 0700 BASIC 11 Program in EPROM 18K max Non volatile ESAM Area 13K max BASIC 11 EE Start User RAM BASIC 11 User RAM BASIC 11 User RAM 13K max RAM Start 103F RAM Start S9 N Internal to 68HC11 MCU N Available address space for this mode 7 Y Not available used by BASIC 11 A extra 1K of user RAM can be utilized in modes 1 and 2 if the on board clock calendar is disabled Figure 5 The flexibility ofthe MC68HC TT s memory mapping leads to a number of possible configurations when running BASC 17 Bese Internal to68HC11A1 MCU originally designed to run on Motor ola s MC68HC11EVB but it s a real performer on the RTC HC11 Ch
7. AO 15 CSL Chip Select Low CSM Chip Select High 74x273 CONTROL SIGNALS RESET Figure 5 Moving some buffering onto a separare memory card reduces Ine amount necessary interface hardware eeerare a 3aRPaNze PARRIN a RESETe Figure 6 DIP switches are used to set the board s address in the PC s O space tion of eight parallel device chip en ables The conventional separate chip enable decoding method has lower power consumption Using this method Figure 3 upper page sig nals l 6 and P7 decode which SIM M is selected Page selection becomes more complicated when accounting for density upgrades To understand this there are two things to keep in mind each SIMM socket handles a maxi mum of 64 pages i e 4 megabyte SIMMs and Al 7 is used on a 2 mega bitdevicebutisa N oC onnect onthe I megabit part A No Connect pin implies that page selection will not be contiguous with SIMMs less than four megabytes in size Accommodating noncontiguous pages increases soft ware complexity Regardless of the page decoding method a jumper scheme rearranges the page signals and accommodatesdensity upgrades Introducing VICTOR the video capture and image processing library Victor is a library of functions for C program mers that simplifies development of scientific imaging quality control security and image database software Victor gives you device control i
8. Cat 50 100 00 95mW Kit with 110VAC input power supply Cat HNKA 95 130 00 eo VISIBLE DIODE MODULE 0 8 mW typical io output power 670nm red Factory made module that includes the diode collomator and power supply all in a 1 6 x 63 diameter housing Operates on 3 9 to 5 VDC 80mA Cat LDM 001 4 5mW 633nm Red output with 12VDC input power supply Draws 1 5 amps Cat HNKD 50 200 00 es 2 3 mW POLARIZED HEAD Operates on 1800VDC 6 5mA Dimensions 10 8 x 1 75 diameter Cat 230HP 90 00 4 5mW Kit with 110VAC input power supply Cat HHNKA 50 220 00 st 6 5mW 633 Red output with 12VDC input HELIUM NEON POWER SUPPLIES New factory made switchers 10 14VDC input micro P S for 06 tube Only 2 1 x 88 dia Cat 12 B 75 00 amp power supply Draws 1 5 amps Cat HNKD 100 230 00 6 5mW Kit with 110VAC input power supply Cat HNKA 100 250 00 150 00 50mW 543 Green output with 110VAC ADJUSTABLE SUPPLIES From 1 2 to 2 6KV 4 6 5mA For 5 to 7mW HeNe Lasers 12VDC input supply Cat 12 C 75 00 110VAC input supply Cat 110ADJ 95 00 ew input power supply l Cat 6HNKA 10 la orodith Instruments 6403 N 59th Avenue Glendale Arizona 85301 Reader Service 158 465 00 Call or write today to receive a FREE CATALOG which includes Optics Holography Kits Scanners Books and more
9. SECOND EDITION Gerald Farin 1990 444 pp 39 95 ISBN O 12 249051 7 The Desktop Fractal Design System Michael F Bamsley Includes The Desktop Fractal Design Handbook and one floppy disk Ste ee dre gee af IBM Version The system requires an IBM or compatible PC with a graphics board EGA or VGA and 640K memory 1989 39 95 ISBN 0 12 079063 7 Macintosh version The system runs on Macintosh Plus the Macintosh SE series and the Macintosh II family of computers with a megabyte of memory Color graphics is not required No math coprocessor is necessary The software will work with version 6 0 or higher of the Macintosh operating system August 1990 39 95 ISBN O 12 0790645 LAN GNTROORETION rot RAY MVNA Ieg Fractals Everywhere Michael F Bamsley 1988 394 pp 39 95 ISBN O 12 079062 9 An Introduction to Ray Tracing edited by Andrew S Glassner 1989 327 pp 49 95 ISBN O 12 286160 4 Write for a FREE brochure Order from your local bookseller or directly from ACADEMI PRESS CALL TOLL FREE 1 800 321 5068 Harcourt Brace Jovanovich Publishers Quote this reference number for Book Marketing Department 10120 free postage and handling on 1250 Sixth Avenue San Diego CA 92101 your prepaid order gt 10120 Prices subject to change without notice 1990 by Academic Press Inc All Rights Reserved TC SS 10120 Reader Service 101 December PO January 9 75 M
10. 5 Enable local operation 6 Disable local operation 7 CD went on amp CD went off 9 DSR went on 1O DSR went off 11 Enable auto answer 12 Disable auto answer THE KEYBOARD ACCORDINGTO IBM The keyboard as implemented by IBM for its PC XT and AT computers performs physical key scanning using an on board processor that detects when a key is pressed or released and signals the computer by sending a make or break scan code Keyboard scan codes are assigned by number ing the physical keys on the original PC keyboard from left to right top to bottom The computer s BIOS converts the unique key codes to ASCII repre sentation where possible for use by the computer Keys that have no cor responding ASCII symbol areassigned a value of ASCII null which indicates that the next byte should be inter preted as a scan code and not an ASCII code The keyboard communicates to the computer over an interface that consistsof a data and dock linedriven by open collector devices that are pulled up with resistors at each end The PC XT keyboard computer interface is implemented in hardware using a shift register where the data bits are sequentially shifted in on the falling edge of each clock transition When an entire character has been assembled the receive logic issues an interrupt and simultaneously pulls the clock line low until the received char acter has been processed This is an indication to the keyboard that it now
11. 602 934 9387 THE SOURCE FOR LASER SURPLUS P 0 Box 1724 Glendale Arizona 85311 December 90 January 91 P Kp lt 1 P Kp 1 P Kp gt 1 1 LM1458 x SUE LM1458 V Kf Vat Vo where Kin Figure 3 An integral mode output changes faster for larger rates of eror input and drives the output at a slower rate asthe eror input approaches zero Reader Service 187 74 CIRCUIT CELLAR INK where P output Kp gain constant Te rate of change of error Po output with no error rate ADDING THE PROPER INGREDIENTS Most industrial applications which use closed loop control make use of a combination of controller modes Thisisaccomplished by combining the proportional mode with either the integral or the derivative or both The PI proportional integral mode eliminates the offset error normally associated with the proportional mode The I D proportional derivative mode is used to handle fast process load changes While the PID mode can handle virtually all process conditions it is the most complex Process control does not necessarily mean computer control This is obvious in the simplicity of our home heating systems Once other parameters enter into the picture however things change Nightly temperature setbacks different temperatures in each room interfacing for external control eg hand held infrared make control impossible for a simple mechanical thermostat Microcon trollers give
12. DspH q and other related topics BittWare Research Systems 400 East Pratt St 8th Hoor Baltimore MD 21202 800 848 0436 Fax 301 879 4465 Reader Service 505 multiplexers eight op amps eight voltage regulators 16 latched digital output lines and 16 latchable input lines For custom circuit applica tions a breadboard area is provided around the DUT that can accommodate up to 3516 pin DIP components The FB 1000 uses a 24 bit control bus made up of three 8 bit ports Several manufac turers make 24 bit I O cards for the IBM PC and com patibles and sample IBM BASICA subroutine drivers to control the FB 1000 from two of these products are provided Any 24 bit digital 1 O controller that is TTL compatible can be used The FB 1000 package includes a parts list sche matic board layout instruc tion manual software drivers sample programs for the IBM PC and compatible computers and the FB 1000 printed circuit board The package in quantities of one to three sells for 250 dropping to 150 for quanti ties of 10 and above Latel Engineering P O Box 391 Topsfield MA 01983 508 887 9506 Reader Service 506 NEWPRODUCTNEWSNEWPRODUCTNEWS ADVANCED STEPPER MOTOR COUNTER CONTROLLER A new advanced counter controller has all the necessary commands and fea tures to do complete motion and I O control in one small package The I O Master RC 207 from Semix has a high speed counter I O
13. English commands for position speed units limits etc 299 Telephone Control Card On off hook generate and decode touch tones call progress detection 159 X 10 Controller Control and sense standard wall outlet power modules 149 Voice Synthesizer Unlimited vocabulary text to speech software built in 159 D A Four 8 Bit Outputs Adjustable full scale 149 24 line TTL I O Connect 24 signal TTL O 5V levels of switches 8255A 72 A Bus Adapters and Software Adapters connect A Bus cards to your particular computer Plug in adapters for IBM PC XT AT 388 and compatibles 89 Micro Channel 93 Apple Il Commodore TRS 80 Serial adapters for Mac PC etc Odin PC compatible software Control relays from analog inputs or time schedules Logging Runs in background 129 December 90 January 91 31 FEATURE ARTICLE An Interface for Portable Battery Backed RAM Using the Mitsubishi BEE Card for Nonvolatile Data Storage Tim McDonough amp Bruce Webb ou can t take it with you Not so long ago the adage about wealth and death held with equal validity for portable or remote data gatheringapplications Portableunits lacked the power to support floppy disk drives and networks are simply not feasible in every situation Fortu nately engineers have provided sev eral possible solutions to the data portability problem in recent months One solution gaining acceptan
14. GR 614 486 2495 FAX 614 486 2788 j D Main Street P O Box 67 Meriden NH 03770 800 888 2495 Reader Service 118 Reader Service 115 UNLOAD ON US Call or write to tell us about your shipping or carrying problems WE HAVE SOLUTIONS December 90 January 91 69 Magnetic Levitation An Example in Closed Loop Contol How to Defy Gravity Without theUseof Black Magic l J ve always had an urge to be a magician While other kids were watching Mighty Mouse on Saturday mornings I d be tuned into Mark Wilson performing impossible feats of prestidigita tion One of the more common il lusions is the levitation of ob jects The magician or illusionist will cause an object to literally rise or float without any visual means of support Solid hoops or rings are passed around the ob ject to confirm the reality of the situation Even though we know there is logically some unseen means of support we allow our selves to be hoodwinked simply for entertainment purposes Suc cessful magicians are most profi cient at disguising their secrets NO VISIBLE MEANS OF SUPPORT If you ve been in any gift novelty store recently you may haveseen one of the floating orb novelties This is asimple freestanding framein which an object usually a sphere is held visually unsupported in midair Quite a stunning illusion Upon closer examination you ll discover that mag netism is the key to
15. In your published reply Circurr CeLtar INK 11 you could not offer a renedy but asked that we write back if we found a solution Well it does seem that we have solved the problem since nearly a year has passed and we have not had a recurrence The solution found was neither the use of desiccators nor of fungicides but the use of a cupboard kept a few degrees above room temperature This remedy was suggested by a friend who said it was used by photographers to store stocks of film and keep them free of mildew It seems to work for diskettes as well with no bad sideeffects Thecupboard is warmed by a bulb of about 10 W I use either a 60 W 240 V bulb at 120 V or two 25 W bulbs in series as could not get a 10 W bulb suspect that others living in humid climates may have this problembut without recognizing it If you exam ine the surface of your disks especially back up copies in reflected light mildew appears as light blotches it is difficult to see otherwise Frequent use keeps it at bay for some time but may eventually lead to disk errors Con tinuous air conditioning no doubt also prevents mildew Andrew Mancey Guyana South America a BACK TO THE COMEFROM The article by J Conrad Hubert entitled Implenent ing a ComeFrom Statement Circuit CELLAR INK 15 brought back memories of a project led in 1980 to devdop a microcomputerized controller for the paging system at Lambert St Louis International Airport We wanted
16. RESET output be comes the 74x138 decoder s active high enable This controls the chip or write enables for the flash memory devices Figure 8 A FEW ADDITIONAL POINTERS Ground MEMCSI16 so the PC AT recognizes your board with a 16 bit bus width The original design operated in both 8 and 16 bit sys tems This flexibility is accomplished with additional decoding that multi plexesthehighdatabusonto thelower data bus Again the IC memory card automatically conforms to either bus width because the extra decoding is handled internally As with any drcuit design it is important to follow good design prin ciples For example decouple power supplies with 0 1 uF capacitors be tween Vand V of every device and shortboardtraceshelpminimizenoise SOFTWARE Hardwarewithoutsoftwareislike a computer without a processor There fore understanding program and erase algorithms is the first step to wards functional flash memory Re call from our earlier discussion that operations on flash memory are soft ware controlled using the internal command register architecture have included the complete algorithms Figures 9 and 10 Editor s Note Softwarefor this articleis availableon the Circuit Cellar BBS and Software On Disk 18 Seepage92 for downloadingand or dering information 1 After working the Intel flash memory hotline would like to discuss the common mistakes The best piece of advice that can give is pleas
17. and an increased command set that facilitates its use for distrib uted stepper motor control via a computer or as a stand alone system The 110 kHz counter and 1100 points of memory allow the RC 207 to do complex multiple axis control Up to twenty I O Masters can be daisy chained with just a three line cable to a host com puter located up to 2500 feet away Each I O Master can control two stepper motor drivers alternately and 20 inputs l6 outputs thus centralized control and monitoring of as many as forty motors can be done from one computer Program ming can be done in a simple language such as BASIC or C The RC 207 can be configured for stand alone control as well By writing the program into each I O Master s EEPROM the units can be used without a host computer except at initial programmmg The RC 207 features 8K bytes of EEPROM and 8K bytes of SRAM as well as many commands to allow the process to be easily manipu lated and changed Some of these include selectable baud rate echo back capability jump routines flag settings 4 counters a timer and stall detection The unit s compact 2 2 x 4 1 x 1 1 size and rugged casing which is noise and EM1 shielded allows it to be placed in small places near mechanical components reducing complex wiring and the usual noise generation Price was not available at press time Semix Inc 4160 Technology Dr Fremont CA 94538
18. communicate with the keyboard This arrangement incorporates a commu nication protocol that provides for errordetection timeoutabort retrans mission and recovery from line con tention A command set is also sup ported both to and from the keyboard Fortunately experience shows that for the most part these elements can be ignored and reliable communica tions can be attained by simply clock ing the key codes into the computer The basic procedure for translat ing ASCII data to key codes is the same regardless of which style key board we use The method basically consists of performing a table lookup using the ASCII character as an index The table returns either the translated scan code a flag that indicates that a secondary lookup must be performed using the shift table or a flag that indicates that the control table must be consulted Once the final scan code is determined the sequence is as sembled and transmitted to the com puter For unshifted characters only one scan code is transmitted but in the case of shifted or control charac ters the scan code must be framed with a shift or control make code and a shift or control break code as appro priate Note the performance degra dation when transmitting strings of shifted characters particularly in the AT emulation routines since for ev ery shifted character three extra bytes must be transmitted It will be left as an exercise to the reader to consider how
19. communications devices help you connect devices that have computer interfaces already built in C Net provides the option of connecting many different RS 232 devices to a single serial port on your computer We also carry converters to other standards including M 422 RS 485 and IEEE 488 C Net Adapter Connects the master control computer to C Net 74 Quad C Net Module Connect 4 RS 232 serial devices to C Net Each device is configurable baud rate parity etc and has 4 8K byte input and output buffers 9895 C Net Device Module Connect any RS 232 Device to C Net for data collection or communication with handshaking 195 Alpha Boxes and A Bus cards both provide ways to interface other types of devices to your computer Aloha Boxes sense measure switch and govern They feature Each box is an attractively packaged self contained module that connects directly to the computer and includes power supply The input boxes offer the option of logging data off line and downloading it rapidly to the computer Built in intelligence provides a simple and consistent interface to your software A Sampling of Alpha Box Products Digital input 84 TTLYCMOS 0 5V input channels 495 Digital Output 84 TTL CMOS 0 5V level outputs 9495 120VAC control available Digital I O 32 TTL Level 0 5V Inputs and 32 outputs 8495 Analog Input 18 channels 0 5 1V 20mV steps 8 bit 2000 readings sec 9495 Exp
20. industry definitions The catalog is menu driven and has illustrations of home automation and security equipment An IBM PC or compatible computer with graphics is required The unique diskette format allows for dynamic changes so that each catalog distributed may have the most current information prices and new products Additionally far more information can be distrib uted on diskette that can cost effectively be distributed via paper mail The catalog is available from Home Control Concepts for 1 00 refundable with any product order or free from several computer bulletin boards including GEnie Home Contol Concepts 9052 Westvale Rd San Diego CA 92129 619 484 0933 Reader Service 500 FRACTAL GRAPHICS SOFTWARE A drawing program that uses fractal geometry to create complex images is available from Cedar Software The program Fractal G rafics can be used for graphic design scientific visualization and educational illustration as well as desktop publishing and presentations Fractal Grafics takes a simple template drawn by the user and automatically contin ues the pattern For example the user draws the trunk and first few branches of a tree and the program will draw the rest A mouse or keyboard can be used to rearrange parts of any shape without losing texture or detail The changes can then be reflected through all levels The program features an on line interactive tutorial point amp click m
21. nous serial interface is available for communications with external I O devices such as EEPROMs ADCs PLLs or other RTC HC11 processor boards This interface can transfer serial data at up to 1 MHz clock phase and polarity are software program mable Because its operation is rela tively complicated you ll excuse me for glossing over its relevance and suggesting that you seek out a Motor ola 68HC11 Programmer s Reference Manual for more details YOU WANT IT WHEN Data collection and control appli cations are usually time dependent The addition of a hardware clock calendar relieves the microcontroller from timekeeping overhead The Oki M6242B CMOS dlock calendar U10 has both a clock calendar and se lectable interrupt outputs Thirteen registers hold time and date informa tion and three registers are used for control purposes These registers are addressed by the latched addresses BAO BA3 To enable the chip I O se lect jumper JP2 pins 7 and 8 must be connected This decodes a 1K I O block for access to the clock chip be ginning at address 7C00 Table 2 is the complete clock calendar register address function table Each register is a nibble 4 bits wide with the lower 4 bits of the data values significant Each value is between 0 and 15 most are from 0 to 9 a decimal digit The STD P output from the M6242B can be used as an interrupt source The upper part of JP25 allows selection of either HNTO or
22. the designer to concentrate on Application Specific Circuitry only because the 8052 RAM EPROM and I O sections are built in and fully functional The prototyping bread board is integrated into the system Save days of development time 220 Call us for your custom product needs Other products available MyGAL GAL Programmer 199 FORTH Card FORTH development card for STD Bus 279 OEM 1 99 HiTech Equipment Corp Activity Road San Diego CA 92126 FAX 619 530 1458 619 566 1 892 Reader Service 138 December 90 January 91 57 base address for the eight I O ports Using the proper offset read the I O port that enables the base memory address transceiver For SIMMs cal culate the memory capacity by first reading the Presence Detect pins fol lowed by reading the individual flash memory device identifiers Alterna tively read the Card Information Structure in the PCMCIA standard memory card for the capacity The preceding steps will confirm the basic functionality of your hard ware Practice programming the flash devices with data from a RAM based array For example Software to read in ASCII test 7 pattern to program into flash DATA ARRAY SEGMENT STORE _IN FLASH DB ASCII test pattern to DB be stored in flash DATA ARRAY ENDS CODE SEGMENT mov ax DATA_ARRAY mov ds ax mov si 0 mov cx size STORE_IN_ FLASH more input mov al si call FLASH PROGRAM inc si loop mor
23. 2N3773 1 49 2N3055 0 89 2N6056 1 49 1 95 2N5038 1 95 2N3772 1 95 2N6308 2 49 Figure 4c shows how the dividend is aligned to the high end of a four byte unsigned long int and the divisor shifted into the middle of another This produces the result directly in the lower two bytes of the quotient An unshifted divisor would put the result CRYSTALS 4 000 14 318 4 915 20 000 5 068 ALL IN MHZ 1 25 ARRAY PLASTIC TRANSISTORS 6 FOR 1 2N3904 PN2222 2N4124 2N3415 PN2907 2N5401 2N3417 2N3565 2N5172 2N5089 2N5086 2N6517 2N3392 2N5551 VOLT REG ICs 7808 0 49 7812 0 49 ar set Tabs on top 7815 0 49 78H12 4 95 CMOS EPROMS 7824 0 49 78H05 3 95 7905 0 49 723 EEE 0 49 7912 0 49 7915 0 49 7924 0 49 MJ2955 2N6547 2N6254 2N5881 2N5879 re 2 95 LM317T 0 69 LM337T 0 69 TL497 1 49 h 5A 400V 0 49 0 99 coated F 5 7 10in F L 5 35 0 99 fixed aperture of 1 75 in in the middle of the quotient thus needing a shift after the division In both routines I calculate the signs separately and perform the long arithmetic on unsigned quantities to avoid obscure problems with C s sign extension and bit shifting logic m pretty sure the code can be tuned up Whatever you do test your code at the ugly boundary
24. BASIC together with its source code listing on a utility disk The PIO INT sells for 399 Keithley MetraByte 440 Myles Standish Bivd Taunton MA 02780 508 880 3000 Fax 508 880 0179 Reader Service 503 EXPRESS CIRCUITS MANUFACTURERS OF PROTOTYPE PRINTED CIRCUITS FROM YOUR CAD DESIGNS TURN AROUND TIMES AVAILABLE FROM 24 HRS 2 WEEKS Special Support For TANGO PCB TANGO SERIES II TANGO PLUS PROTEL AUTOTRAX PROTEL EASYTRAX smARTWORK HiWIRE Plus EE DESIGNER EE DESIGNER Il PADS PCB Reader Service 134 e OTHER PACKAGES ARE NOW BEING ADDED e FULL TIME MODEM e GERBER PHOTO PLOTTING Express O Circuits 314 Cothren St PO Box 58 Wilkesboro NC 28697 Quotes 1 800 426 5396 Phone 919 667 2100 Fax 919 667 0487 December 90 January 9 9 NEWPRODUCTNEWSNEWPRODUCTNEWS DIGITAL TROUBLESHOOTING KITS Three digital logic test kits which are TTL and CMOS compatible have been announced by Global Specialties The LTC 6 LTC 7 and LTC each feature a logic probe LM 2A 16 channel logic monitor DP 1 logic pulser and SQ 1 tone ohmmeter packaged in a rugged plastic carrying case An accessory kit consisting of interchangeable probe tips ground clips tip adapters and quick hook cables is also supplied The tone ohmmeter locates bad ICs and circuit shorts without unsoldering parts The DP 1 digital pulser is a pocket sized pulse generator used to stimulate
25. Control ap CORPORATION 3555 Aero Court San Diego CA 92123 FAX 619 565 1 186 619 565 1 500 Reader Service 175 40 CIRCUIT CELLAR INK SERIAL OPTIONS A standard asynchronous serial port with selectable baud rate parity character length and stop bits is pro vided as an on chip peripheral sub system This subsystem is externally interfaced through both a MAX232 RS 232 driver U5 with true positive and negative voltage leves and an SN 75176 RS 485 driver U6 capable of driving up to 6000 meters of 24 AWG 2 conductor cable Both inter face chips are always enabled with Port D bit 2 controlling the direction of data flow on the RS485 interface A logic one 1 on Port D bit 2 places the RS485 interface driver into transmit mode Another jumper terminates the RS 485 transceiver with a 100 ohm resistor Access to the serial port through BASIC I Lis accomplished simply by using BASIC sPRINTand ineur state ments since this is the default console port for the BASIC interpreter A four wire In Out Clock Se lect full duplex high speed synchro MC68HC11Al1 SIGNAL DESCRIPTION RESET This active low bidirectional control pin is used as an input to initialize the MCU to a known startup state and as an open drain output to indicate that an internal failure has been detected in either the clock monitor or the computer operating properly circuit XTAL EXTAL Provide the interface for either a crystal or a CM
26. East Lake Street Regular price 795 00 For first 25 customers only Bloomingdale IL 60108 995 52 PLCC to 48 DIP adapter 55 Call 708 894 1440 WICE Z8 emulator complete system 86C08 09 18 pin adapter w analog comparators 55 U K dist Merwood Engineering Tel 0253 827787 Distributors for the Far East wanted Reader Service 199 LCDitself consumes about 1 W 5 V 60mA 25 V 30mA max the backlight requires 17 W 12 V 1 4 A to operate 36 W 12V 3A during start up Unfortunately for our wallets the TM26D01VC s 211 mmx 158 mm die is easily one hundred times the size of even the latest and greatest wunderchip The term WSI Wafer Scale Integration has been used to refer to forthcoming silicon wafer size 6 8 diameter chips Since the TFT uses a similar sized pane of glass WSI could also mean Window Scale Integration Either way WSP means big bucks and for now tight availability According to Hitachi most OEMs can get a panel or two to play with at about 3500 a shot Though the price is lower say 2000 for manufacturing quantities it s kind of moot since production is just getting up to speed imagine it will be two years before panas are widely available SAFETY First predict that another factor will emerge in the LCD s favor Safety In my opinion it is only a matter of time before CRTs are plastered with warning labels alerting the u
27. L skipbit MOV A DPL 7 pnt to next table entry INK engineering staff aie saa ma z ADD A ENTRYSIZE gizmos do strange and won rous t ings e woy r re is by turns a beekeeper bicyclist Registered DINZ nextbit 7 pose convert packed BCD to characters at pointer Professional Engineer gunsmith and ama MOV R4 2 7 Move BCD to input loc teur raconteur MOV R5 3 CALL _ConCvtHInt pretend it s hex IRS MEAO RET _ _PxpCvtPract ENDPROC 415 Very Useful men 416 Moderately Useful Listing 2 continued 417 Not Useful The ideal solution for embedded control applications and stand alone development Cg A rugged CABBAGE CASE lined with plenty of foam for your equipment can TAKE A LOAD OFF YOUR MIND when you ve got to travel TAKE A LOAD OFF YOUR BACK with our exclusive tilt wheels and extension handle option o Intel 8052AH BASIC CPU e Serial printer output and 5 8 bit VO ports e 5 in prototyping area e Memory 8K RAM expandable to 128K e Power requirements 5V DC 300 ma only e PROM progammer ZIF socket for 2764 or 27128 EPROM o Interrupt handling capability e Built to exacting standards and warranteed o Still only 228 00 including documentation quantity 1 Inquire about our PDK51 8051 8052 product development kit for the IBM PC XT AT 595 Our BXC51 8051 8052 BASIC compiler 295 Call now 603 469 3232 CABBAGE Besccec cae T apace COLUMBUS OHIO 43212 1356 q Binary Technology Inc
28. O channel bus The subsystems within this de sign Figure 1 are the memory decode circuitry I O and its associated de code logic and a 12V generator for Mion The Intel flash memory resides in four SIMMs The board handles an upgrade path to 16M bytes based on 4M byte SIMMs ADDRESS DECODING Flash memory addresses can be decoded in one of two ways row column and conventional decoding using separate chip enables The row column approach of Figure 2is appro priate if you are motivated to reduce board traces In row column decod ing rows are Output Enables OE Write Lows WRL and Write Highs WRH and columns are Chip En ables CE Although the SM28F001AX uses only four chip enables eight are provided since four megabyte SIMMs could consist of six teen 2 megabit flash memory devices Page selection discussed in more detail later is accomplished by writing the page number through an B bit I O port to a latch This will allow access to 256 64K byte pages Page signals PO P2 are directly con nected to A15 A17 on each SIMM They decode pages on the device level The row column signals are de rived by decoding page signals P3 P7 They enable components on the SIMMs The row column approach how ever suffers from simultaneous selec December PO January 97 51 TO SIMMs 74x138 3TOB DECODER NIKO CROSS DEVELOPMENT SYSTEMS SAVE Development and Debugging lime _ of Embedded Microp
29. RAM start of 1100 xkxeke print S records for BASIC interpreter PRINT S9030000FC REM print termination record END REM KKKKK EXIT weeex REM CK 0 REM S record checksum REM IF PEEK 1040 55 THEN 32140 ELSE 32160 REM debug flag PRINT PRINT Memory read from hex SA to hex HA PRINT S Record starting address shex SA OF PRINT LL 16 REM of data bytes in Sree excl address amp cksum TB HA SA 1 REM calculate total bytes continued Listing 2 S record dump program 46 CIRCUIT CELLAR INK can then be captured by a PC based communications program like Pro comm or Kermit This Srecord file will contain your BASIC application code from RAM a copy of the inter preter itself from ROM and a few bytesof information that BASIC needs to auto start the ROM based applica tion This file can then be sent directly to an EPROM programmer to pro duce a 32K device 27256 which when inserted into socket U8 will automati cally run your BASIC 11 application on reset or power up The last configuration Mode 3 allows a portion of battery backed static RAM to be used for seniperma nent program storage Here s how it s done BASIC I 1 has an zsave Keyword which is intended to move a program from BASIC s program RAM to some category of nonvolatile external to BASIC RAM storage ssave uses the value contained in an internal vari able to determine where in memory to place the saved p
30. ROBOTS ALARMS RECORDERS DOS THREE EASY STEPS 1 Develop on PC 2 Download to SBC 3 Burn into EPROM LCD INTERFACE KEYBOARD INPUT 2 PARALLEL 3 SEATAL PC TYPE BUS RAEAL TIME CLK BIOS OPTION BATTEAY OR SV FREE SHIPPING IN U S 5 YEAR LIMITED WARRANTY Box 994 Merrimack NH 508 792 9507 Reader Service 159 DOSIN ROM PROGRAMMER PLUGS INTO PRINTER PORT 00 ROMS FOR SBC OA MVDISK PROGRAM 2764 27010 EPROMS 8088 SINGLE BOARD of time to complete the quantization and coding steps This active time depends on several things such as the overall resolution theconversion tech nique and the component processing speed This aperture time refers to the time uncertainty or the time win dow during which a measurement is made And as such it results in an amplitude uncertainty if the signal changes during this interval To understand this better con sider the diagram shown in Figure 3 Here the input to the A D converter changes by AV the maximum error due to the signal change during the conversion time window t The error in this measurement canbe estimated in two ways as an amplitude error or as a time error which are related to each other by dv t dt where do t dt is the rate of change with time of the input signal If a sinu soidal input signal is enployed the maximum rate of change occurs at the AV Ta EPROM about other ENVIRONMENT 96 Developme
31. Since it relied on ambient light the LCD watches still needed a high power lighting system and the dam button for use in the dark In practice there was usually enough daylight or even moonlight so that button fumbling was kept to a minimum From humble wrist watch beginnings the LCD has slowly but surely improved and flourished Now LCD technology has reached the point that big changes in displays and associated products are on the horizon In fact it can be argued that the historical mainstay display the CRT is threatened by the energing LCD tech nology Sure it won t happen overnight but read on and judge for yourself to what degree the LCD puts the CRT at risk of extinction tive LCD Figure 1 The organization of a simple TN reflec SILICON UPDATE Tom Cantrell THE GOOD BAD AND UGLY As mentioned the original and still claim to fame for the LCD is low power consumption A brief explanation of LCD basics will show why The liquid crystal phenomenon actually was discov ered over 100 years ago but the concept laid dormant until the 60s when revitalized research finally gave us our 70s LCD watches and calculators Figure 1 shows the organization of a simple TN Twisted Nematic reflective LCD Naturally the key for LCDs is the liquid crystal ma terial a proteingoo Likeacrystal the material has the property of turning light in a certain direc tion Like a liquid the orientat
32. The character is the BASIC I 1 prompt Type rrez and press the Return key BASIC 11 should re spond with a decimal number MORE TO COME This article reads a little like an equipment manual but there aren t too many other ways to describe a hardware and software microcon troller design I d much rather be de tailing the trials and tribulations of remotecamera positioning is an unil luminated environment or experi menting with substrateleve particle acceleration caused by collapsing elec tromagnetic fields initiated through errant program execution In all seriousness have a few projects in mind where the RTC HC11 is perfectly suited and I ll bring then to you as soon as they are working Since this is my first 68xx project in a long time my original Home Control System HCS used a 6802 there s a big hole to be filled Special thanks to Gordon Doughman for his contributions to this project Thanks also go to all those at M otorola who went out of their way to provide us with assistance Steve Ciarcia pronounced seeA R seeAH is an electronics engineer and computer con sultant with experience in process control digital design and product devdopment Burt Brown received a BS in Computer Sci encefrom California State U niversity and has been working with computers and electronics for over ten years In his free time he enjoys bicycling running and Italian food nN 5 Th
33. a complete stand alone system or as a compre hensive embedded controller ON BOARD EPROM PROGRAMMER HIGH SPEED CMOS PROCESSOR 96K BYTES OF APPLICATION 48 DIGITAL I O LINES MEMORY SPACE 1 TWO AS 232 SERIAL PORTS FOUR EXTERNAL INTERRUPTS MULTITASKING BASIC LANGUAGE PARALLEL PRINTER PORT COMPILER IN ROM SINGLE BOARD FORM FACTOR XPANSION MODULES Space allocated on board Keypad Module LCD Display 4x 4 keypad module s ASSEMBLED AND with tactile ml oo TESTED 495 00 feedback PO Box 130 Frenchtown NJ 08825 ARIES ELECTRONICS INC NJ 908 996 6841 FAX 908 996 3891 84 CIRCUIT CHLAR INK Key Pad eal Time Header CD Headers Pulse Event Counter Parallel Printer Port Pulse Event t A D Converter Frequency Counter Realtime calendar clock Reader Service 10 lt Front Polarizer lt Glass w Color Filter lt Liquid Crystal lt Glass w TFTs lt 4 Rear Polarizer lt _ FL Backlight Figure 5 The TFT LCD isa cross between a regular LCD and a DRAM area per transistor will cost much more than ten dies with one times the area per transistor Remember little stands in the way of making silicon dies smaller indeed the problem these days is coming up with packag ing wiring schemes to handle ever more connections with an ever ti nier die Of course the cost reduc ing die shrink concept can t be applied to displays
34. a standby current draw of around 2 S pA must be used to prevent excessive current drain from the on board battery Higher current RAM chips will still work but you will be replacing batteries far more often RTC HC11 SOFTWARE DEVELOPMENT The MC68HC11 series is one of Motorola s most popular 8 bit micro controller families and there areabun dant software development tools One teleohone call to Motorola s Freeware bulletin board system provided us with an IBM PC based cross assem bler aROM monitor 68HC11 simula tor avery fast integer BASIC and aC compiler Editor s N ote The M otorola Freeware BBS can be accessed at 512 891 3733 parameters N81 In addition software for this article is available from the Circuit Cdlar BBS or on Software On Disk 18 See page 92 for downloading and ordering information The BASIC 11 interpreter required a few changes to its console I O routines since it was 42 CIRCUIT CELLAR INK Ois the receive data input and bit 1 is the transmit data output for the SCI Bits 2 through 5 are used by the SPI subsystem PORT E Used for general purpose static inputs and or analog to digital channel inputs in all operating modes RESETS The MCU can be reset four ways an active low input to the RESET pin a power on reset function a computer operating properly COP watchdog timer timeout and a clock monitor failure The RESET input consists mainly of a Schmitt trigger that senses the RESET
35. amp logical addresses e Outputs binary Intel Hex and Extended Intel Hex files Compatible with M80 SLR 2500AD and Avocet Assemblers Built in MAKE facility supports depen dency file checks FREE demo disk available Compatible C Compilers available soon If you re ready for a fast full featured affordable product give us a call You ll be pleasantly surprised EE EER EQTOOIS we L Foroa N Ellicott City MD 21043 ZN 301 750 3733 CIRCUIT CELLA RINK 301 750 2008 Fax BBS Reader Service 186 80 H lt 4 Liquid Crystal 1 1 amp Glass Figure 2 The double super twisted nematic display adds another ayer of liquid crystal backlight technologiesareavailable which offer various tradeoffs for light level and color size durabil ity and power consumption The major contenders are EL eectrolu minescent and FL fluorescent lighting schemes EL is best for low end applications due to reduced thickness weight and power con sumption while at the cost of wors ening these three factors FL gener ates a brighter full spectrum light Another pair of related prob lems is limited contrast and view ing angle both are byproducts of losses and variabilities in the light s twists and turns Basic TN LCDs may have contrast ratios as low as 4 1 read light black characters on a dark gray background in other words don t lose your eye doctor s phone number Further
36. automatically A single write instruction selects one of four conversion sequences resulting in a conversion complete flag after the first four conversions Simply convert one channd four times and stop sequential results are placed in the result registers AUTOST CALL PORTD IF THEN ELSE ADC TIME CLEAR LIST PRINT DIM ABS RTIME CONT LUST FOR NEXT PEEK FDIV PACC DATA NEW WHILE ENDWH POKE RND EEP NOAUTO RETURN REM SGN ELOAD ONIRQ RETI TRON CHR ESAVE ONTIME STOP TROFF HEX FREE PORTA SLEEP ONPACG HEX2 INBYTE PORTB GOTO ON GOTO TABO INPUT PORTC GOSUB ON GOSUB Table J BASIC 77 keyword summary ERAC CO SINCE 1974 Toshiba CD ROM Drive Model TXM 3201A1 660MB 400 mS access Kit includes int ext drive SCSI controler and aabie audio Interface setup software drivers and Microsoft Extension Meets Yellowbook standard 60day warr 265 Microsoft Bookshelf 10 Volume CD ROM Reference Library The American Heritage Dictionary Quotes Chicago Manual of styie Thesaurus Spelling 109 checker Forms letters amp more 48Meg Hard Drive Kit KPTIKit includes 3 1 2 RLL 35mS drive W DRA2 Contr cabies and 5 1 4 maune hardware 1 year warrantee DX5000 386 motherboard 80386 25 33 64K to 256K Cache user upgrade Weitek 80386 16Meg on board OK Dallas non volatile ciockjset up AMI BIOS is OS 2 XENIX Windows 3 Compat ible FuATForm 6layers NortonS 31 6 25 40 5 33 Pwr Meter MIPS 5 93 25 9 3
37. buggers and in oe you can Sa support for source leve el debugg of compiler circuit emulators Paradigm LOCA compilers from Micr We got with com compilers oni ula 2 orts popular C Pascal BASIC amp Mod sa Borland and others a math coprocessor anu ual emulation suppor m compiler stat tup code amp a sites ull al OMF output problem with our Turbo bug your target examples K w free technical support Not a Lack of an emulator got gen wie Debugger interface option hardware from the comfort a P E digm LOCAT E Debugger Interface tion Guaranteed 4 Satistac err ee aa 70 748 5966 195 00 Orders 8 Technical SU Sup BIX join sarang re Freanastercard C O system jub Road Suite 2244 aoo 43760 gistered taden mark of Bor nal orland Internatio Reader Service Y171 eachpixellocationincontrast toolder LCD s remotely driven scheme The basic merit of the TFT ap proachis thankstoreductionincross talk precise threshold control and Contrast Ratio Response Time Power Consumption with backlight use of less twisted i e faster liq Viewing Angle uid crystal the pixel canbe switched Thickness very quickly by the local transistor wane Plus exploiting FL backlight con Resolution trast ratio is dramatically improved Color compared to the older LCDs e g Cost 40 1 vs 18 1 Figure4 compares some general specs for the older LCD
38. designed to be appended to the end of your debugged application and then entered via a Goro to line 31000 The program will dump a Motorola S rec ord format file to the serial port which PROM m PUT DOS AND APPLICATION IN EPROM DISKLESS OPERATION UP TO 1 MBYTE ROM DRIVE WITH 16K FOOTPRINT PROMKIT SOFTWARE BY ANNA FLASH EPROM SUPPORTED BATTERY RAM MODULES SUPPORTED DELIVERY FROM STOCK SEALEVEL COMMUNICATIONS 6 1 0 SEALEVEL SYSTEMS INC PO BOX 1808 EASLEY SC 29641 803 555 1581 December W January 97 45 490 500 510 520 1530 540 550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 700 710 720 730 32000 32110 32120 32130 32140 32150 32160 32165 Ww I oO REM This program will dump a combined user program and REM BASIC11 interpreter image at a start address of 8000 REM AUTOST will be set store 55 to 1040 for debug mode REM gather info from page zero memory REM SH PEEK 0004 256 SL PEEK 0005 BB SH SL IF PEEK 1040 55 THEN 31090 ELSE 31100 PRINT BASIC start address is HEX BB SH PEEK 0006 256 SL PEEK 0007 BE SH SL IF PEEK 1040 55 THEN 31140 ELSE 31150 PRINT BASIC end address is HEX BE SH PEEK 0008 256 SL PEEK 0009 VB SH SL IF PEEK 1040 55 THEN 31190 ELSE 31200 PRINT VAR start address is HEX VB SH PEEK 000A 256 SL PEEK 000B VE SH SL IF PEEK 1040 55 THEN 31240 E
39. error O amp l sample time additional gain dependent on E E o 0 noP Since the A D and D A converters both have 8 bit resolution data in both directions will be in an unsigned character format of ranging O 255 If we use an integer in the range of O 10 to replace the normal gain value and remove the factor of 10 later all the math can be done in integer format which speeds up overall program execu tion The program shown in Listing 1 executes at 40 milli seconds per sample when run under interpreted BASIC 52 At a40 ms sample rate the ball drops quickly to the floor Fortunately by compiling this BASIC 52 routine with BC151 Integer BASIC Compiler also sold under the Q1 TIL413 D1 Infrared LED be Air space i A D SU IN I Microcontroller RTCS2 amp RTCIO D A 5U OUT S 4 4 ULN37SIZ D2 L1 U ce 1N4Q01 Guardian 120 Figure 6 The interface for the floating orb project shows the R transmitter and receiver sections and the magnet contol 10 TCON TCON AND OF7H REM CLEAR INT 20 TCON TCON OR 04H REM INTI EDGE TRIGGERED 30 KP 9 REM 90 PROPORTIONAL 40 EP 0 REM INITIALIZE TO ZERO 50 EO 0 REM INITIALIZE TO ZERO 60 KD 10 KP REM 10 DERIVATIVE 70 V KP EP KD EP EO 100 10 REM CALC s0IF V lt 0 THEN V O REM LIMITS MIN TO ZERO LIMITS MAX TO 255 REM OUTPUTS VALUE TO DAC 110 XBY OE010H 0 REM SELECTS CHAN 0 AND STARTS A D CONV IF TCON AND 08H 00H THE WAIT
40. into a lal gt grade audio visual brainwave synthesizer The Synergizer uses predsedly controlled light and sounc pattems to safely induce electrical adtivity in the brain providing easy access to Alpha and Theta states Features of the Synergizer include independent light and sound co ntrol multiple time ramps and sound light levels over 32 000 on board stereo sound generation with waveform filter and other soiund parameter controls and an optional Software Toolkit The latte prisvides the source and object code necessary to custom program the unit The Synergizer provides more capability than any other similar device at a remarkably low price Requires DOS 3 0 or above 512 K RAM and hard drive MINDSEYE SYN ERGIZER 305 Boar are lights manual ERNAL UNIT 95 EXTERNAL CONTROL UNI STUDIO TYPE HEA DPH ONES 35 Standard MiniStereo plug 50 _ SOFTWARE TOOLKIT SYN ETC SYSTE The leader in ae ane Tech ORDER PHONE 800 388 6345 Credit Cards Accepted Information 206 632 722 PO Box 95530 Seattle Washington 98145 104 Reader Service 189 December 90 January 91 27 gure 11 Most A D and D A converters troduce some degree ofoffset gain and of nonlinearity enor Here each input code word produces a single discrete analog output value generally as a voltage There are 2 dif ferent values produced including zero with that output having a one to one cor
41. line logic levd RESET PIN To request an external reset the RESET pin must be held low for eight Ecyc two Ecyc if no distinction is needed between internal and external resets To prevent the EEPROM contents from being corrupted during power transitions the reset line should be held low while VDD is below its minimum operating level POWER ON RESET POR Occurs when a positive transition is detected on VDD The processor remains in the reset condition until RESET goes high COMPUTER OPERATING PROPERLY COP RESET The MCU contains a watchdog timer that automatically times out if not reset within a specific time by a program reset sequence If the COP watchdog timer is allowed to timeout a reset is generated which drives the RESET pin low to reset the MCU and the external system The COP reset function can be enabled or disabled by setting the control bit in an EEPROM cell of the system configuration register Once programmed this control bit remains set or cleared even when no power is applied and the COP function is enabled or disabled independent of resident software CLOCK MONITOR RESET The MCU contains a clock monitor circuit which measures the E dock input frequency If the E dock signal is lost or its frequency falls beaow 10 kHz then an MCU reset is generated and the RESET pin is driven low to reset the external system INTERRUPTS There are seventeen hardware interrupts and one software interrupt ex duding reset type i
42. must not transmit An idle keyboard releases the clock line allowing the pull up resistors to hold it at a positive state and asserts the data line to a logic low therefore the interface is capable of unidirectional traffic only The PC XT keyboard is capable of encoding 128 unique key codes A byte with a value of 0 to 127 is considered a make code Break codes are formed by adding hex 80 to the make codes For example key 1 produces scan code Olh on make and 8th on break The bit format for data transmission consists of a T start bit and eight data bits The AT keyboard uses a bidirec tional serial interface to carry signals between the keyboard and the com puter As in the PC XT keyboard all keys are classified as make break however in order to increase the total number of keys that can be encoded the method of indicating break codes is different When a key is released the break code consists of hex FO fol lowed by its make code Since the interface is used for bidirectional communication the data and clock lines are both released and passively pulled up when the keyboard is idle This permits either the keyboard or the computer to take control of the interface Data transmission to and from the keyboard consists of 11 bit data streams composed of a 0 start bit aght data bits odd parity and a 1 stop bit Unlike the simple hard ware interface of the PC XT the AT uses a dedicated microcontroller to
43. one address an I O port to transfer data This method requires the least amount of system memory space but also yields the lowest per formance A page mapped memory system is a hybrid of these two approaches It allowsaverylargememoryarray with a minimal system interface A page is a moveable window into the total memory array It selectively opens Address VO Control System Vpp Enable different portionsof the array by writ ing a page number to the decoding circuitry This page ranges in size from 8K to64K bytes Analogous to a cache a larger page size requires less fre quent switching Although switching pages represents a performance deg radation this can provide the optimal balance between performance and memory space availability within the system Our design is based on this page mapped technique A 64K byte page size reduces the decoding circuitry The PC AT has been chosen as the execution platform but with minor modifications to the control signals any microprocessor environment can be used Before beginning this design it would be helpful to reacquaint Presence Detect Intel Flash Bus VPP Generator and Memory Array Xceivers Page Select Chip Enable CE Read RD WEL WEH Transceiver Select Figure 1 The subsystems in a flash memory board design include memory decode I O and a 72V generator yourself with the basics of the AT I
44. pensive in terms of both code size and execution speed Microcontrollers don t have numeric coprocessors by definition think so all calculations must be done in software or if you please firmware The canonical Hello world occupies 5903 bytes using the Avocet fixed point library the floating point version requires 16008 bytes and doesn t include any floating point operations To put this in perspective the Firmware Furnace routines don t use printf orthefloating pointlibrar ies AS aresult the keypad LCD clock NVRAM and C utility routines pre sented so far weigh in at about 8K bytes There are some good reasons why I m not enthusiastic about float ing point arithmetic iiiiiiii ffffffff eight fraction bits eight integer bits Numbers are represented in two s complement form 0 0 00 00 1 0 01 00 1 0 FF 00 0 5 00 80 0 5 FF 80 0 0039 00 0 0039 FF 127 9961 7F 128 0 80 Figure 3 The fixed point numeric format used in the Firmware Fumace project al lows for numbers between 128 and 128 with a resolution of 0 39 Each number occupies two bytes FAST COMPLETE ACCURATE DRAM TEST DIPs SIMMs SIPs TAR ins RESOLUTION ACCESS SPEED VERIFICATION 80 ns thru 180 ns Std 249 00 45 ns thru 110 ns Fast 349 0 4MEG Option Add 89 0 AUTO LOOP Continuous Test 6 25 MBits sec ADAPTERS SIMM SIP ADAPTER 189 010 Tests 6
45. physical connection If am right the British system is something else than modular jack based In Ireland under stand the modular jack has been introduced by Northern Tele corn but that is a different story So have some good alligator clips included in the tool kit MS DOS EPROM PROGRAMMING SYSTEM NEEDS NO INTERNAL CARD EEPROMS 2804 2816A 2864A 28256 EPROMS B ae 3 supply 27C16 2516 Socket Adapter Required Diagrams Included CONNECTS T0 VOUA SYSTEWS PARALLEL PRINTER INTERFACE A FULL FEATURED EASY TO USE SYSTEM WORKS WITH ANY DESKTOP OR LAPTOP MACHINE ADAPTIVE HIGH SPEED ALGORITHM MINIMIZES PROGRAMMING TIME AND INSURES VALID DATA SYSTEM PROGRAMS ALL STANDARD DEVICES OR EQUIVALENTS FROM ANY MANUFACTURER ALL SYSTEM COMPONENTS FIT NEATLY INTO CASE FOR TRAVEL OR STORAGE SYSTEM SOFTWARE COMMANDS PROGRAM EPROM S SAVE EPROMI S OR COPY EPROM S FROM DISK FILE BUFFER TO DIS VERIFY EPRO READ DISK FILE INTO PROGRAM EPROM S ERASED BUFFER FROM BUFFER BUFFER EDITOR READ EPROM S INTO COMPARE EPROM S SELECT DEVICE TYPE BUFFER WITH BUFFER DEVICE CHECKSUM BUFFER EDITOR HAS 18 BYTE LEVELCOMMANDS FOR DETAILED OPERATIONS SYSTEM INCLUDES PROGRAMMING UNIT POWER PACK CONNECTING CABLE OPERATION MANUAL amp SOFTWARE SOFTWARE AVAILABLE ON 3 1 2 OR 5 1 4 DISK 239 TO ORDER SEND CHECK MONEY ORDER WRITE OR Cait ANDRATECH MASTER VISA MILFORD OHIO 45150 C
46. put into your own software programs Software provides sampling rate variations graphics based editing and data compression utilities Create software sound files voice memos more Send voice mail through LANs or modem A superior speech sound development tool INTERACTIVE SPEECH INPUT OUT PUT Tag your own digitized speech files to voice recognition macros Provides speech response to your spoken commands all from within your application software Ideal for business presentation education or entertainment programs you currently use Augment the system for wireless uses in robotics factory process controls home automation new products etc Voice Master Key System does it all EVERYTHING INCLUDED Voice Master Key System consists of a plug in card durable lightweight microphone headset software and manual Card fits any available slot External ports consist of mic Inputs and volume controlled output sockets High quality throughout easy and fun to use ONLY 149 95 COMPLETE ORDER HOTLINE 503 342 1271 Monday Friday 8 AM to 5 PM Pacific Time VISA MasterCard phone or FAX orders accepted No CODs Personal checks subject to 3 week shipping delay Specify computer type and disk format 3 1 2 or 5 1 4 when ordering Add 5 shipping charge for delivery in USA and Canada Foreign inquiries contact Covox for C amp F quotes 30 DAY MONEY BACK GUARANTEE IF NOT COMPLETELY SATISFIED CALL OR WRITE FOR FREE PRODUCT CATALOG COVOX I
47. see Figure 5c The ampli tude of the original signal is preserved in the modulation of the pulse enve lope with the amplitude of each pulse sample being stored between samples within the sample and hold From this a reasonable reconstruc tion of the original signal can be achieved see Figure 5d Now the important question must be answered How much sampling must do what resolution to retain most of my input information Obviously if sample at a rate where little or no change takes place between samples won t lose much Equally obvious is the fact that infor mation is being lost if there is a large amount of change in signal amplitude between samples So to get an answer let s consider the Sampling Theorem which states If a continuous bandwidth lim ited signal contains no frequency com ponents higher than f then the origi nal signal can be recovered without distortion if it is sampled at a rate of at least 2f samples per second The best way to understand this is to consider the diagrams in Figure 6 Here Figure 6a shows the frequency spectrumof a continuous band width limited analog signal with frequency components out to f When the signal is sampled at a rate off the modula Samplin Pulses 8 Frequency Figure 7 An inadequate sampling rate causes an alias frequency tion process shifts the original spec If the sampling frequency f is not trum out to f 2f 3f and so on
48. shrinking a mainframe to fit on the head of a pin makes sense but people like their screens a little larger Fabricating the TFT LCD pang is only part though the most ex pensive part of the story The TM26D01VC also includes a number of control and driver ICs that together offer a digital video CRT type interface quite similar to that of typical PC The electrical interface between the glass panel and silicon chip portions of the panel is interesting A conductive organic adhesive is used bringing new meaning to the term glue logic The backlight also plays a big role since stringent brightness and spectral characteristics are required for best results Hitachi offers a unit theTB2602 consisting of six fluorescent lamps and a diffuser Note that while the New Features 64 K hardware breakpoints Breaks on Ad dress address range and Data RD WR 7 PC based real time ICE Easy to use low cost amp high perfor mance Complete development support for single chip amp ex panded modes Complex real time hardware breakpoints Sym bolic debugger Windowed user interface Data watch windows for memory registers amp stack On line assembler disassembler single step and trace commands 595 Logic analyzer trigger output Introductory price 115 2K bps RS 232C link 30 day money back guarantee WICE 68HC11 emulator Suite 140 185C
49. sign is KA7PHM subscribed to Circurr Cerar INK because hoped to find a place that would give some tutorials on computer circuit design such as how to go about putting together a computer from scratch you know what chips are needed what ones go together what the significance of microprocessor timing diagrams is how to interface to memory and get the RAS and CAS signals timed right and so forth In short need help to get me going with some assurance in hardware What have in mind is to learn enough to try to design a microcomputer have wanted to build for several years now so can try my hand at writing the system software for it and the stuff dreams are made of you know REMOTE CONTROL MODULE TX 88 9 95 Tiny size only 1 X 1 5 powered by 12VDC 4096 possible codes 100 200 line of sight distance RE 01 19 95 Small size 1 25 X 2 75 powered by SVDC Single channel RF receiver RE 99 19 95 Same as RE 01 except it s a multi channel RF receiver 8 bit address codes 4 bit data codes UPS Red RC 99 Combination of TX 88 amp RE 99 29 95 Above items are board level ELECTRONICS 1 2 SS A DIVISION OF MING E amp P ING 1 Exclusive items at good prices 2 Unique items at better prices 3 Popular items at the best prices 1 800 669 4406 ORDER DESK ONLY 1 Prices are subject to change without notice 2 VISA MASTER CARD and
50. so forth Gen erally a range of a few hundred units and resolution of about 1 is entirely adequate although your application may need more bits on one end or the other Figure 3 shows a fixed point numeric format suited to the Furnace Firmware project Values range from 127 996 1 to 128 0000 with a resolu tion of 0 39 or 1 part in 256 Each number requires two bytes with an implied binary point dividing the number into eight integer bits and eight fraction bits Re member that the point doesn t occupy any storage Although there is a bi nary point in the middle the numbers add and subtract just like ordinary integers Figure 4a shows how they combine if this looks like third grade all over again that s how simple it really is Notice thatresultsbeyond the valid 128 range cause over flow because there are not enough bits to encode the full integer value this is a drawback of fixed point numbers in general and not the fault of this par ticular representation Multiplying two fixed point numbers is a little bit trickier because the product contains twice as many bits Figure 4b shows that ordinary multiplication produces the correct result but the binary point is located in the middle of the four byte result used unsigned long int variables which are 32 bits in the Avocet C SUPERVISION 8 VIDEO IMAGE GRABBER ITO POWER CSI 100 RS232 Serial Powerline interface Circuit board accepts RS232 seria
51. the brute forceadditionofanotherlayer of liquid crystal Contrast and view inganglearedramaticallyimproved and a true black is possible The downside is besides adding weight and thickness DSTN needs brighter backlighting to overcome losses throughtheextracrystal glasslayer The latest version Film STN Figure 3 reverts to the STN single layer format but adds a thin polymer film to fill the role of DSTN s second LCD Though contrast ratio for Film STN about the same as regular STN i e 10 12 1 isn t as good as DSTN s 18 1 the viewing angle is a much more usable 60 degrees or so Users of modern portable PCs which wouldn t even exist without the LCD can testify that the display quality is quite good a far cry from the first generation of squintable laptops Nevertheless relative to the CRT these LCDs suffer from three major weaknesses 68HCT1 PC based emulator for 68HC11 SEE EEM 90 91 W PC plug in or FE 232 box Pages 01320 1323 Pull down menus with full window support combined with command driven User Interface E Up to 16 MHz real time emulation No Intrusions to the 68HC11 s resources 48 bit wide 16K deep trace All functions usable without disturbing emulation Time stamping Two level trigger Symbolic and C Source Level Debugging including in line assembler and disassembler Supports A E D and F parts Prices 64K Emulator and pod 2590 4K Trace 1995 us only CALL OR W
52. this example of parlor trickery A magnetic field is generated by an electromagnet hidden in the top of the frame and attracts the sohere upward An infrared transmitter receiver pair is mounted across the frame about one inch below the top As the orb is gently lifted into the IR beam s path the signal strength is re duced at the IR receiver When the linear output of the IR receiver drops to about 2 5 volts an electromagnet is switched on As the IR reception is further reduced by the sphere rising toward the electromagnet the voltage to the coil is also reduced This reduces the magnetic field and gravity begins to win When the sphere drops the received IR increases which strengthens the magnetic field An FROM THE BENCH Jeff Bachiochi equilibrium is reached where magnetic attraction exactly counters gravity somewhere within the IR beam s path OPEN VERSUS CLOSED LOOP Any control process can operate in an open or closed loop fashion However the term open loop is an oxymo ron As the word loop suggests it is made up of a continuous path whereas open suggests a noncontinu ous path Open loop control is simply an action without any knowledge of the result like turning on the porch light without looking out the window to see if it actually went on On the other hand closed loop control adds some kind of verification that the control has had some effect on the task One peek out the window confi
53. time depends on how long it takes the output to settle info the limits of the enor band nal signal spectrum As a result the folded part of the spectrum causes distortion in the recovered signal Otherwise if the sampling rate is in creased to f f gt f then the two spec tra are separated and the original sig nal can be recovered without distor tion Therefore frequency folding can be eliminated by either using a suffi ciently fast sampling rate or by filter ing the signal before sampling to limit its bandwidth to f 2 Figure 7 demonstrates the effect of an inadequate sampling rate on the sinusoid in Figure 5 If a sampling rate less than twice per cycle is employed an alias frequency in the recovered signal willresult However if according to the Sampling Theorem we usearategreaterthantw ice a cycle the original fre quency will be preserved nalog Output AMPLIFIERS AND FALTERS I m not going to say too much about amplifiers and filters within this article since most of you have been repeatedly exposed to those devices Suffice it to say that the front end of our DAAC system shown in Figure 1 extracts a signal from a 24 CIRCUIT CELLAR INK device that measures a physical pa rameter our pressure transducer or thermocouple and thenamplifiesand filters it Both are critical to the sys tem s overall performance The am plifier may act to boost the signal amplitude buffer the signal co
54. to keep track of the shift mode so we won t have to frameeachand every shifted character with the shift se quence Note that the only break codes that are transmitted are for the shift and control keys Our keyboard emu lation routines have the capability to transmit the source string from pro gram memory or internal data mem ory Finally bear in mind that we re working under the assumption that the keyboard isinactiveand that we re operating from a known state other wise we would have to constantly monitor the keyboard traffic for codes such as ALT make shift make control make and the toggling of caps lock SERIAL COMMUNICATIONS Communications for the systen are fixed at 1200 bps no parity and one stop bit Due to the nature of the discrete memory areas in the DS2250 the transmitter can be set up to trans mit from program memory external data memory or internal data mem ory Although the transmitter is fully interrupt driven it is used in a polled mode in this application The receive interrupt handler implements the buffered command line where the backspace character allows editing of ASCTT Pick up ASCII code commands Received character echo ing is handled from the receive inter rupt and may be enabled or disabled Receive timeout and escape sequence detectionarehandled withalittle help from the timer interrupt routine The escape sequence is def
55. transistors about the same as a megabit DRAM Indeed the transistor setup is quite like a DRAM with TFTs on glass substituting for the DRAM s MOSFETsonsilicon Unfortunately while can toddle down to local hacker emporium and pick up I megabit DRAMsfor little more than 5 the TM26D01VC is a much more serious proposition Hmm should get a color TFT LCD based PC or a new car You see the cost has little to do with the number of transistors after all the fundamental force driving the IC revolution is more transistors for less money Instead it s the die size that kills yield That s because the statistical chance of encountering a process material defect grows much faster than the area itself A die with ten times the INCREDIBLE MICROCONTROLLER aoa MULTI TRAX 8 Channel Va A D Converter 4 External interrupts Multitasking Programmable Controller Features a 100 Compiled wwo Basic Interpreter The MultiTRAX Microcontroller is a high capability cost effective single board control and data sensor acquisition system With its multitasking BASIC compiler the MultiTRAX Controller provides real time response anb extra ordinarily fast program execution in a quick and effective program ming environment complete with on board EPROM programmer With its expandable single board form factor and extensive I O capability the MultiTRAX Controller adapts to a wide variety of applications as
56. types TN STN DSTN Film STN and the TFT LCD The TFT LCD has a couple of fundamental advantages over our beloved tubes The latter rely on phosphors to emit light while the LCD uses the combinationof backlight and passive dyes Thus the LCD can achieve wider color range since the variety of dyes is much greater than that of usable phosphors and remember TFT LCD black is really black Also since the CRT s phosphors emit light from the surface of the screen dispersion in all directions introduces a bleeding effect By contrast in direct line of sight the LCD shows absolutely no overlap between adja cent pixels The bottom line is TFT LCDs work real well now and they will only get better In fact the major barrier to wide spread use isn t performance imagine 90 of PC users Desktop 9 Track Tape Subsystem Now 9 tirack tape lets your micro exchange data with minis and mainframes 9 TRACK is the first choice for file interchange among data processing professionals Now Quaistar s low cost 1 2 inch 9 track Streaming tape systems bring full ANSI data inter change to IBMPCsor Macintosh giving your micro the freedom to exchange data files with nearly any mainframe or minicomputer in the world Available in both 7 and 10 1 2 versions compact Qualstar tape drives can sit OR your desktop usingless space than gn ordinary sheet of paper Systems include DOS or XENIX compatible software coupler ca
57. various loops corre sponding to the various statesand modes Also it should be noted that for the most part the required lower level support functions remain consistent as we traverse the vari as process loops With the above in mind the structure adopted for the main line processing is composed of two parts the main MAIN application driver which handles the specifics of the moment and the low level resource handler IDLE that s responsible for perform ing the grunt work mie IS a callable routine that is the interface between the application and the hardware and background interrupt functions The functions of mie include monitoring and de bouncing the toggle switch and mo dem CD and DSR signals returning only when a change in state occurs and relaying the SlO related informa tion such as receive complete receive timeout receive error and escape detect These events are indicated by returning result codes to the calling routine in the accumulator The bene fit of this approach is that the applica tion software becomes much simpler to code and comprehend since the details of handling the data input are centrally processed in a routine that Local Transparent December 90 January 91 13 RELAY INTERFACE PROVIDES SOFTWARE CONTROL OF RELAYS CONNECTSTO w 232 AR 16 RELAY INTERFACE Two 8 channel relay et ports are provided for control of up lo 16 relays expandable lo 126 relays 4sing EX
58. 1 6 expansion cards Each relay output port sonnects lo a relay card or relai al block A variety of elays cards and relays are stocked call for more info 38 422 available distances lo 4 000 feel PS 6 port selector may be used10 control satellite AR 16 ntertaces up lo 16 364 relays 3D 8 REED RELAY CARD 8 relays 4 RH 8 RELAY rae ae amp SPDT 7 AC s 63 95 EX 16 EXPANSION CARD 16 channel 59 95 ANALOG TO DIGITAL CONNECTS TO RS 232 DC 16 16 channel 99 95 nput temperature voltage amperage pressure synergy usage energy demand light levels joystick novement and a wide variety of other types of analog signals Inputs may be expanded to 32 analog or 128 tatus inputs using the AD 16 or ST 32 expansion ards 112 relays may be controlled using EX 16 xpansion cards Analog inputs may be configured for emperature input using the TE 8 temperature input tard RS 422 available PS 8 port selector may be used 3 connect satellite ADC 16 interfaces up to 4 096 inalog inputs 16 384 status inputs 14 336 relays use 38 232 for satellites up to 50 feet or RS 422 for iatellites up to 4 000 feet terminal block and cable sold separately 3T 32 STATUS EXPANSION CARD nput on off status of relays switches HVAC quipment thermostats security devices smoke letectors and other devices The ST 32 provides 32 talus inputs opto isolators sold separately E 8 TEMPERATURE INPUT CARD 49 95 ncludes 6 solid slate te
59. 11 board There are two sockets U8 and U9 which can each accept an 8K or 32K static RAM or EPROM A Dallas Semicon ductor DS1210 power fail battery backup chip converts one of the exter nal memory sockets into nonvolatile memory for data logging or program development purposes In a typical RTC HC11 system shown schemati cally in Figure 3 U8 will contain EPROM and U9 will contain RAM The 68HC11 MCU contains 256 bytes of internal RAM located at ad dresses 0000 through 0100 This memory region is also referred to as page zero RAM Typically a pro gram will place data which needs to be frequently accessed in this area There are also several machine lan guage instructions which operate exclusively on data in this area The Al version MCU also contains 512 bytes of nonvolatile EEPROM mem ory Each byte may be individually accessed and the entire memory array can easily be bulk erased By default the EEPROM is located at addresses B600 through B7FF This can be changed by reprogramming a con figuration register An 8K or 32K static memory chip may be inserted into U9 to provide December 90 January 97 37 JP Woe u7 HC11PAL 8000 AOJO Cog OKI 8 170 Select JP A U3 74HCT373 AD 18 19 Ba u4 24HCT245 as sept aD ADE 17 re CPU 1 Mode fon c2 f ih 22PF 22PF 7aHE BAG la B2 ADS ADS
60. 14 15 BAS las ge S AOS A D and 12 BA4 14 AD4 TTL 170 BA3 AS BSI as gal 2502 16 AD2 BAL A 3 el 17 ADI 9 6 BAZ 3q A 2 10 BAG B2 o z njw fa janjo fujo jo D N 18 ADO Y 8 000 D Fa aL A B EN ER DATA BUS PEE PE4 PEO PBO PBI 68HC11 PB4 PBS PBS PB PAG Nore paj pBz 42 PB3 H3 ADDRESS BUS CONTROL BUS Closed BUFFALO Installed A i Timer and TTL Iv0 D 3 n Figjure 3a The first half of the RTC HC 1 schematic shows the processor bus buffers VO programs with additional memory The U9 socket is decoded in the range of 0000 to 7FFF Reads or writes to this area are disabled by the MCU during any access to an on chip stor age location Access is also disabled for addresses 7C00 to 7FFF by the U7 PAL see Figure 4 if the 1 O select jumper for theon board real timeclock is installed The ROM monitor BUF FALO 3 4 does not require the use of external RAM Several jumpers must be set to indicate the size of the installed chip and to enable the battery backupand write protect circuitry The U8 socket is de coded at addresses 8000 to FFFF During normal RTC HC11 operat
61. 2 V Reducing the output capacitance value and limiting the number of flash memory compo nents accessed simultaneously de creases the ramp time The diode MUR120 prevents inductor current absorption from the charged output capacitor During system power up spurious noise may generate writes which are actually the sequence of flash memory commands that initiate erasure or programming Disabling V pp until voltages stabilize provides power up protection The Motorola MC34064P is an undervoltage sens ing circuit that begins functioning when V is above 1 volt Between 1 and 4 6 volts the MC34064P s RESET output or AT system RESET dears the 74x74 While the 74x74 remains cleared or Q 1 the 2N3904 is on the VC input of the LT1072 is 0 volts and the VOLTAGE SWITCH VSW output is off Writing a one to the Vap enable latch forces Q low turning off the transistor This puts the VC input at 5 V and VSW output generates 12 V You do not need the circuitry just described if your system s 12 V sup ply meets the V specifications How ever because software may acciden tally or coincidentally generate a valid flash memory command to a flash memory address install a switch toturnoffV when notin use A low resistance amp T Motorola MTD4P05 performs this duty The possibility of sourious writes to the flash memory devices during power up still exists Again the same undervoltage sensor MC34064 solves this problem The
62. 2V 2A 12V 4A 5VI20A 12V 4A 12V 1 5A 5Vi1 5A 5VI30A 100A 200A 291991159 AT Full Size 270 W 69 MISCELLANEOUS Serial Mouse 100 microsoft comp 250DPI Twobutton db9 db25conv With Dr Halo 38 42 Speedlink2400i Modem 300 1200 2400 baud 2 yrs warr Hayes comp 1 4 card volume con trol TiChip set tel cable internal 65 AT 1 0 2 Serial COM 1 4 patr port Ipt 1 2 game port manual 2 ser port ext cabies 20 DC Fans 12v Brushless 3W 5 biade 1 deep 3 1 4 mounting holes 5 Battery Holder holds 4 AA ceils Velcro backing and 4 pin connector use for AT XT etc 150 Computer Power cords 2 15 for 20 Key Switches with spade lugs and keys 2 OC Test Probe wire Rubber Red or Biack 4FT 1 00 IC Sockets Soider tail 14 16 18 pin 10 1 00 Car Lighter Adapter 15 Cable pig tas 1 00 KAYPRO PARTS AND SERVICE CALL Reader Service 133 68HC11 BASED SINGLE BOARD COMPUTER ELD The CP 11 is a single board computer targeted for 68H Cll based embedded control applications Board resources include 32K EPROM 28K RAM 512 bytes of EEPROM 24 available parallel port lines 3 serial ports 2 of which are RS 232C buffered 8 channel 8 bit A D converter 5 only power supply require ment and processor supervisory circuit Quantity one pricing bareboard with docs 75 00 assembled and tested 250 00 ALLEN SYSTEMS 2346 Brandon Road Columbus Ohio 43221 614 488 7122 Reader Service 104
63. 3 tyear Warrantee 873 1 106 Msoft MS DOS 3 3 GW BASIC Users guide and users reference 12 8 P O BOX 1108 POWAY CA 92074 1108 619 679 8360 VISA or Master Card add 3 3 Check or Money order no CODs Calif orders add 7 25 AT BUS DESIGN The first book to fully document the PC XT AT ISA bus Covers detailed signal definishions timing diagrams and compatability issues Also Included are the 8 16 bit part of the EISA buss The author Ed Sotariis a member of the P996 working group that developed the AT bus stand ard for IEEE Over 200 pages Including 100 timing diagrams and tables 7 x9 69 95 Baby 80286 Motherboard 6slot 12 MHz G2 chipset 9 X 9 AMIbios 4 Meg Ram sipps or dips OK 4 Layer 1 CPU CARDS amp BACKPLANES 80286 8 CPU Card Kaypro Phoenix 80287sct uses ext mem board 65 Turbo 80286 10 8 CPU Card I BUS Chips amp Technchip set AMI bios 80287 socket Owait 1 Meg 0K Dip nicad ext batt 24 pg manual 109 80286 12 CPU Card Action Instruments G2 TAG chip set Award 1 2size 80287 socket 4M simms OK Par and 2 comm ports con figarable Dallas clk instr Manual 2 AT Backplane 12 slot 3 4 spac ng blank 15 AT Backplane 8slot withkeyb amp pwr conn fits standard case 6 AT amp 2 PC slots 39 AT Backplane 12slot amp up diff styles 54 amp up SWITCHERS 5VIT5A 12V 6A 12V 3A SV 5A 5V 9 5A 12V 3 8A 12V 8A 5VIBA 12V 2A 12V 1A SVIGA 24V 125A 12V 6A 12V 6A 5VJ3A 1
64. 4 P7 respectivedy The Presence Detect PD pins from all four SIMMs are wire ORed together into the 74x244 This eliminates hav ing to read each SIMM s I D pins sepa rately but SIMMs must be installed with equivalent density and speed The page number is written and read through the same I O port Minimal circuitry ensures that the system powers up at page zero The page memory board s RESET signal connected to the CLR input of the 74x273 latch accomplishes this task V p GENERATION Why is Vie generation necessary on this flash memory board when the AT I O channad already has a 12 V supply True IBM compatible PCs specify the necessary 5 12 V sup ply tolerance However some systems have wider 12 V supply tolerances Local 12V generation via the circuitry described below ensures fast reliable flash memory operation Linear Technology s LT1072 switching regulator a 5 V to 12 V feedback regulated boost convertor is the heart of the V p generator Fig ure 7 A 100 uF capacitor at the out put handles up to 200 mA necessary for software that programs or erases 8037 Single Board Computers Experience the power of low cost embedded control in your next project The Control R pronounced Controller series of 8031 Single Board Computers are designed and imanufactured to provide the features you need at a price that won t blow your budget We are commited to providing cost effective pro
65. 4 41 83 51 Fax 94 4194 72 A ALPHA Products 242 C West Ave Darien CT 06820 USA 203 656 1 806 Fax 203 656 0756 Reader Service 105 Low cost Data Acquisition and Control A Bus Sensing amp Measuring Read switch status Detect or measure voltage Read pressure temperature weight and other sensors For example High Speed 1 2 bit A D converter 8 10s analog inputs 1mV resolution 179 8 Bit A D 8 inputs 0 5 1V in 20mV steps 7500 conversions sec 142 12 Bii A D 4V in 1 mV steps 130mS conversion time 1 input expandable 153 Temperature Sensor 0 200 F 1 Accuracy 1OmVPF 12 Digital Input 8 opto isolated Read voltage presence switch closure 85 Latched Input Each individually latched to catch switch closures or alarm loops 885 Touch Tone Decoder 87 Counter Timer 3 16 bit counters Generate or count pulses Time events 132 Clock with Alarm real time clock with calendar and battery backup 998 A Bus Switching amp Governing Switch any type of electrical device Adjust level or position A sampling Relay Card 8 individually controlled industrial relays 3A at 12OVAC SPST 142 Digital Output Driver 8 outputs 250mA at 12V For relays solenoids 78 Reed Relay Card 8 individually controlled relays 2QMA 60VDC SPST 109 Multiplexer Switch up to 32 channels to a single common 83 Smart Stepper Motor Control Micropro cessor controls 4 motors
66. 4K 256K 1 M amp 4M Devices 8 or 9 Bit versions NTX ADAPTER Tests 64 Pin Dual Edge Lasetwriter Type SIMM s 149 00 4 X ADAPTER 89 0 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 MAADE IN U S A xder Service 123 December W January 9 18 10 A 63 The Firmware Furnace code must display some frac tional values temperatures at least with the 10 bit ADC flow rates time inter vals and so forth I ve put together a simple fixed point math package that illustrates how to design a special pur pose numeric format FLEXING THE AX Photo 1 A small 4x 20 LCD display works nicely to display all the In CIRCUIT Cenar INK 9 necessary information described the fixed point numeric format used in the Mandelbrot En gine which was an array processor dedicated to evaluating the Mandel brot set formula Because the calcula tions required high precision the num bers only ranged from 8 0 to 8 0 but with a resolution of about 10778 More mundane applications usu ally require a wider dynamic range and fewer decimal places For ex ample domestic temperatures are under 100 degrees furnace circulator pumps run at a few gallons per min ute edapsed times are a few hours minutes orseconds and
67. 9 00 202 G Street BCC521 Fulindustiai wmperatre range 294 00 220 00 Antioch CA 94509 BCC52CX CMOS Expanded BCC52 w 32K RAM 259 00 159 00 415 754 3879 FAX 415 754 5506 MICROMINT INC 4 Park Street Vernon CT 06066 Reader Service 135 Reader Service 164 68 CIRCUIT CELLAR INK LCD and keypad routines were slightly modified to support the ANSI driver oe SEG Utilcode _ PxpCvtFract PROC i PUBLIC FxpCvtFract gene convert fraction to packed BCD ae UP NEXT MOV DPH HIGH FixTable point to table MOV DPL LOW FixTable MOV R2 0 7 clear BCD total Most benchmark programs meas MOV R3 0 MOV Ri ANUMENTRIES J number of loops ure execution time by repeating the L nextbit MOV A BITLOC pick a bit same subroutine over and over again ANL AKo TEIR That s OK if you only care about the r JZ L skipbit average elapsed time but what if you MOV A BCDLOC fetch BCD equivalent MOVE A ASDPTR 2 high byte need to know how long a particular MOV BA instruction takes Get out your scope oe ra teepeen 2 EOW yee and find out of course I ve wanted to is F f ADD A R3 combine with total measure 80x86 instruction timings for DA A adjust total Mov R3 A quite a while and I think now s the MOV A B time to start gt ADDC A R2 DA A z adjust total Ed Nisley is a member of the Circuit Cellar MOV R2 A Eaa ave mak
68. ARD 513 831 9708 P O BOX 222 CALL or were FOR MORE wero ADD 5 00 FOR snierina 4 00 con Reacelsdiruice 106 90 CIRCUIT CELLAR INK There are also the regulatory issues In most of Europe the teleohone system is a monopoly and like monopolies they try to promote their own business In this case it may mean that a renting of the modem from the tdephone company is required at least officially Let s just hope that M argaret Thatcher has ob soleted those kinds of requirements since my last visit to that country Msg 32142 From BOB JENNER To BOB PADDOCK don t have personal experience but I ve come close enough to ask the question The answers received suggested that the things to watch for are different modem signal protocols the noisy and long turnaround phone lines and the rather different political setup using someone s phone line for an unauthorized purpose like data communications can jeopardize their ability to have that phone line At least one person suggested using a service that goes overseas rather than making the long haul directly Good luck and good traveling I m Sure you ve seen the print ads for those silly TV top satellite dish antennas Here s one caller who wanted t o check their validity the original poster s name has been changed to spare him any embarrassment BTK52 BASIC 52 TOOLKIT The BTK52 is an intelligent front end for program development on the MCS BAS
69. COD add 3 accepted 3 Freight charge adds 5 UPS Ground 8 UPS Blue 15 977 S Meridian Ave Alhambra CA 91803 TEL 818 281 4065 FAX 818 576 8748 RC 01 Combination of TX 88 amp RE 01 29 95 fROM SRAM DISK CARD RDC 512 0 KB 179 95 RDC 1024 0 KB 199 95 It would be nice to get some help Of course for you to run tutorials might alienate some of your other subscrib ers for the same reason have gotten tired of some of the other computer magazines that seemed to run yet another Getting started in BASIC or assembler or C or article every 18 24 months wonder if the information am looking for can be found in the books of Ciarcia s Circuit Cellar articles or whether should get some other more theoretical books and try a few projects like Don Lancaster s Cookbooks perhaps Any adviceand direction you can provide would be appreciated Richard P Winslow Riverton NY When Circurr Crrrar INK was started we discussed the idea of presenting articles for computer novices We decided that there was no way to do that without watering down the content for our core of readers experienced engineers and pro grammers Wedo print tutorials but they re amp signed to teach old dogs new tricks and not to give folks an elementary education There are many books that contain the sort of information you re looking Ciarcia s Circuit Cellar Volumes 1 7 Don Lancaster s Coo
70. Continue execution lt addr gt lt addr gt T lt host dwnld command gt lt addr1 gt lt addr2 gt lt addr gt or lt addr gt lt 1 gt lt s2 gt lt d gt lt arg gt Memory dump Memory modify Block move Offset for download Register modify Trace until addr lt n gt Trace n instructions Table 4 BUFFALO 3 4 ROM monitor command summary disk before powering down the RTC HC11 Some people like to keep their program and data on instant call Stor ing the codein ROM or battery backed RAM is the alternative This is where Mode 2 the EPROM mode and Mode 3 the battery backed RAM mode come into play Referring to the memory map in Figure5 note that BASIC 11 itself uses ALLOWS BOOKS vader Service 185 Execute code at addr Modify EEPROM range Load S record from terminal Load or verify S records up about 9K of the avail able ROM space leaving 23K in which to storea ROM based BASIC pro gram Since the RTC HC11 has only two memory sockets careful attention must be given to the values used to configure BASIC I l s RAMStartandEEstart to help eliminate the pos sibility of being able to create a program which is too large to store in either EPROM or bat tery backed RAM Sec ond some way to transfer the pro gram out of the RTC HC11 s RAM and into an external EPROM is re quired One solution is to use the pro gram shown in Listing 2 This code is
71. ELLEVIEW ST LOUIS MO 63119 314 962 7833 Reader Service 120 December 90 January 91 53 According to Figure 2 the jumper settings are as follows l M Byte SIM M J7 J2 J9 J4 2 M Byte SIMM 16 x 28 F010 J7 J1 B J5 2 M Byte SIMM 8 x 28 F020 J7 J1 J9 J3 4 M Byte SIMM 16 x 28 F020 J8 J1 J6 J3 Figure 4 shows the buffering re quired for system bus interfacing The PC I O channa bus is limited to two TTL loads on any one line The A transceivers are connected directly to the I O channe bus Additionally each SIMM has its own pair of B transceivers to reduce capacitive load ing that results from tying more than eight flash memory devices together SIMPUIRED DECODING HARDWARE You are not limited to using SIMMs in your design The same basic techniques will work for discretecom ponents or other module types such asmemory cards TheIC memory card provides the simplest solution with its integrated decoding Writing the GBH TF Additional features include z Asynchronous serial port with full duplex 232 and halt duolex RS 485 drivers e MHz synchronous serial port e CPU watchdog security e Low power sleep mode ad operation e RTC stacking bus FE MICROMINT INC 54 CIRCUIT CELLAR INK VPPEN IOR Read to determine Vpp status lt 74x125 O DATA LINE 0 D owe VPPEN RESET 120k we OFF ON POWERUP Figure 7 A regulated boost conve
72. Each jack has an IW inside wire feeding it The IW is either a 2 or 3 pair cable The phones only require a single pair red green leaving the yellow black pair available for a low cost 2 wire LAN Most homes do not have the second telephone line in stalled so all that is required is that the yellow black pair be disconnected from the jack used by a telephone This is required since many phones use the yellow black pair for switch hook signaling A and Al leads have used this second pair for quite some time with no major problems The average home hasbeen prewired with five jacks so the odds are pretty good that there is one near the PC or desired location at this time have a suggestion to make so that the LAN can be used by more than one device Transmit the data on a single wire yellow using the last wire black as a circuit busy wire This way when you have multiple devices connected they will not access the data line at the same time Don Houdek Spring Grove IL DG31 8071 BASED CONTROLLER BOARD fe ppd d 8031 microcontroller running at 11 0592 MHz 16 EPROM and 8K SRAM JEDEC sockets 8255 parallel I O MAX232 for RS232C serial I O port ULN2803A output drivers 7 16 lines 30 V input buffers 20 lines Screw terminals on 32 1 0 lines Full schematic diagram operating manual on disk DG31 controller board assembled without EPROM 129 00 Controller KIT DG31 K PC board and all components except s
73. FOR EOC TCON TCON AND OF7H RE 140 EO EP REM SAVE PRESENT SAMPLE AS LAST EP XBY 0E010H REM GET A NEW SAMPLE GOTO 70 REM GO CALCULATE AGAIN END 90 IF V gt 255 THEN V 255 RE 100 XBY 0E020H V 120 GOTO 120 REM RESET INT FLAG listing 1 Software to control the orb consists of only a few lines of BASIC 52 code name IBASIC 52 from Micromint this routine runs at 1 4 ms per sample on an RTC52 This is a smidge over what I d hoped for but still gives 10 samples during the 14 ms it takes the ball to fall 1 mm This proved to be adequate Correction In the RTC V25 project presented in the last issue of Circurr CELLAR INK themaster crystal should be labeled 16 MHz A revised RTC V25 schematic is available which contains this correction plus some design revisions To obtain a copy send a SASE to Circuit Cellar INK 4 Park St Vernon CT 06066 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 8051 compatible e 35mA operating current 100 uA standby e Program in C BASIC or assembly language e 8 92K RAM EPROM EEPROM e Breadboard area and expansion bus e RS 232 port and 12 digital I O lines e 100 lota Systems Inc POB 8987 Incline Village Nevada 89450 702 831 6302 Reader Service 147 AND THERE YOU HAVE IT Photo 1 shows a slow sin
74. Figure 5 Likea regular LCD the TFT LCD relies on a sandwich of from front to back polarizer glass liquid crystal glass polar izer and backlight The only difference is that additional layers are placed on either side of the liquid crystal in front a color filter panel and behind a thin film of transistors aS eee Ten EASY TO USE CAD TOOLS Easy to Use PC Software ICON Based Ultra Fast Performance Mouse Driven Complete With Advanced Editing Tools Output to Printers Plotters amp Lasers IN Full range of products available from entry level through to auto routing A family of products that feature modern graghical user interface amp an intelligent diagram editor Products as low as 149 us R4 SYSTEMS Inc P O Box 451 ee Evaluation Package West Hill Ontario Canada MI E 4Y9 _Write or Call Today 416 439 9302 Download DEMO from BBS at 416 289 4554 2400 8 N l Reader Service 180 December PO January 97 83 Conceptually the TFT LCD is simple Each transistor is respon sible for energizing the liquid crys tal associated with the individual color components of a pixel The Hitachi unit uses a vertical stripe arrangement in which each pixel corresponds to three R G B verti cally aligned dots the total pixel size 0 33 mm is about the same as a CRT Thus the 640 x 480 pixel panel is really composed of 640 x 480 x 3 or 921 600
75. IC 52 CPU It reduces 8052 program development time substantially and can be used with any MCS BASIC 52 based target system The BTK52 runs on any IBM PC XT or compatible Program download from PC host to target Program upload from target to rc host BASIC program renumber utility with from through wart and increment Full screen program editing Single line editing with automatic enor line number detection Full on line he p facility Transparent adaptive line compression for fu input line buffer utilization All functions accessiblewihonly one keystroke from the terminal emulator 125 BXC51 805118052 BASIC COMPILER Fully compatible with code written for MCS BASIC 52 interpreter Now with integer byte and bit extensions for code that runs more than 50 times faster than the MSC BASIC 52 interpreter FUN floating point support In line assembly language option e Compile time switch to select 805 1 8031 or 8052 8032 CPUs e Includes Binary Technology s SXA 51 cross assembler and Hex file manipulation utility Compatible with any RAM or ROM memory mapping Runs on IBM PC XT or compatible 295 603 469 3232 FAX 603 469 3530 Binary Technology Inc P Main Street P 0 Box 67 Meriden NH 03770 Reader Service 116 Msg 31442 From GEORGE MASON To ALL USERS Does anyone know of a source that I can look up info on TV antennas A friend of m
76. ICES START AT 249 00 QTY 1 eMac Inc EQUIPMENT MONITOR AND CONTROL 618 529 4525 P O BOX 2042 CARBONDALE IL 62902 Reader Service 131 December 90 January 91 77 Goodbye CRIT Hello LCD can t remember for sure but think my first experi ence with an LCD Liquid Crystal Display was during the digital watch craze of the mid 70s Everybody tried to get in the business the boom attracted unlikely entrants including Intel where worked the idea was to sell chips with wrist bands Needless to say that episode isn t dis cussed in mixed company Anyway my first digital watch had a seven segment type LED display The only problem was that due to high powerconsumption the_EDdisplaycouldn tbeleftonall the time nstead the watch had a tiny button to turn on the display only when necessary Of course the concept was an ergonomic nightmare For instance working the watch while talking on the phone meant either switching the phone into the shoulder ear jam position or executing a maneu ver something akin to punching yourself in the nose Checking the time while driving a car was also an exciting proposition leading to the insight that it s better to be late for an appointment rather than never arriving at least in one piece at all Enter the LCD a technology which thanks to reflecting rather than emitting light consumed so little power that the display could remain enabled at all times
77. INT1 for the interrupt Two modes of interrupt can be selected through the control registers D F of the M6242B The IRT interrupt mode gives a one time interrupt pulse while the ST stan dard mode creates a recurring inter rupt pulse DON T FORGET The RTC HCI 1 hasbeen designed sothataDallasSemiconductorDS1210 Power Monitor IC can be installed in socket U13 This chip monitors the 5 volt power supply and automatically December 90 January 91 4l Reg Name Function Addr 1 Seconds 7C00 S10 Tens of seconds 7C01 MI1 Minutes 7C02 MI10 Tens of minutes 7C03 H1 Hours 7004 H10 Tens of hours 7C05 D1 Days 7C06 D10 Tens of days 7C07 MO1 Months 7C08 9 MO10 Tens of months 7C09 10 Y1 Years 7COA 11 Y10 Tens of years 7COB 12 w Day of the week 7C0C 13 CD control register D 7COD 14 CE control register E 7COE 15 CF control register F 7COF 0 1 2 3 4 5 6 7 8 able 2 The functions and register ad dresses for the OK M6242B CMOS clock calendar Chip switches either U8 or U9 to battery power if the supply voltage falls be low 4 75 volts In addition the R W line is held high to prevent data cor ruption when the changeover to bat tery power takes place Jumpers JP8 through JP10 are used to configure either U8 or U9 for battery backup Note You cannot back up both U8 and U9 at the same time Also if you elect to install thisoption a low power static RAM with
78. LOC EQU offset of BCD RELEASE NOTES NEGLOC EQU ENTRYSIZE EQU size of each entry NUMENTRIES num of bits to process The demo routines for this col umn exercise the ANSI driver and Convert a fixed point fraction into ASCII fixed point math packages The other char FxpCvtFract FIXPTNUM FPVal char String i a f P Target string pointer is on stack files include the additional functions Integer part is in R4 which we ignore needed for the fixed point math code Fraction part is in R5 Can t have overflow from fraction to integer most notable are cgets in CONSOLEA A51 to handle input ed Listing 2 Converting a fraction to ASCII is ordinarily a tedious operation but using tables iting and strcat in CLIBA A51 to provides a shortcut combine two strings The console I O PROFESSIONAL CIRCUIT DESIGN QiCAD Save time and money BCC72 BASIC 72 Computer Controller The BCC52 Computer Controller is Micromint s hottest selling stand alone single board microcom puter its cost effective architecture needs only a power supply and terminal to become a complete de amp velopment or end use system programmable in BASIC or machine language The BCC52 uses Micromint s 80C52 BASIC CMOS microprocessor which contains a ROM resident 8K byte floating point BASIC 52 interpreter The BCC52 contains sockets for up to 48K bytes of RAM EPROM an intelligent 2764 128 EPROM programmer three paral
79. LSE 31250 PRINT VAR end address is HEX VE SH PEEK 000C 256 SL PEEK 000D HL SH SL IF PEEK 1040 55 THEN 31290 ELSE 31330 PRINT Highest line is HL HEX HL REM REM print first line of combined EPROM S Record REM VC VE CK 0 PA 8000 REM start address of combined EPROM IF PEEK 1040 55 THEN 31370 ELSE 31390 PRINT Combined EPROM start HEX PA PRINT RS PEEK SFFCO 256 PEEK FFC1 PRINT S1 sPRINT OE CK CK S 0E 80 REM update checksum BB BB RS REM subtract RAMstart from BASBEG CK CK BB AND S FPO0 256 AND SFPF BB AND SFF REM chksum PRINT HEX BB REM print new BASBEG for EPROM BE BE RS CK CK BE AND SFF00 256 AND SFF BE AND SFF PRINT HEX BE REM print new BASEND VB VB RS CK CK VB AND S PFO00 256 AND FF VB AND FF PRINT HEX VB REM print new VARBEGIN VE VE RS CK CK VE AND FF00 256 AND FF VE AND SFF PRINT HEX VE REM print new VAREND CK CK HL AND SFF00 256 AND SFF HL AND SFF 55 PRINT HEX HL 55 REM print new HILINE and AUTOST flag CK CK EOR SFFFF PRINT HEX2 CK AND FF REM REM REM SA BB RS HA VE RS OF 6F0B GOSUB 32000 REM REM REM SA D000 HA SFFFF OF 0 GOSUB 32000 REM get RAMstart constanl sPRINT HEX PA REM start S rec print REM print checksum x x x print S records for user program REM set to 6F0B for a user
80. NC 675 CONGER ST EUGENE OR 97402 TEL 503 342 1271 FAX 503 342 i 283 eader Service 127 December PO January 9 35 FEA TURE ARTICLE Steve Ciarcia amp Burt Brown come from the school that says all computers are equal some just run a little faster than others Provided that the price is not the overriding issue such as 8088 chips suddenly being regularly priced at 39 each generally choose a processor for my projects based on ease of use and ease of explanation In point of fact how ever most of my projects treat the mi crocontroller as a ge neric device may state the processor type but I use high level lan guages so that the code is transportable and not oie processor specific RAM For me develop ment tools and low cost high level language support take prece dence over issues like brand loyalty As most of you already know don t like to program any more than have to usually use a control ler board with an 80C52 BASIC processor that can be directly pro grammed in BASIC Many of my applica tions oriented projects have been greatly expedited by incorporating off theshelf BCC52 and RTC52 control lers rather than reinventing the wheal each time While I ll be the first to say that a computer is a computer temper that assertion with a little reality When it comes down to fitting a variety of specific control functions
81. NS Figure 2 Jhe block diagram for the MC68HC 1MCU shows a host of on board devices address space and while the MCU is in any of four different operating modes See the sidebar and Figure 2 on MCU operating modes for a more detailed discussion Included on the processor itself are a 16 bit timer sub system with programmable prescaler and S bit pulse accumulator a stan dard NRZ asynchronous serial inter face a high speed synchronous serial interface an eight channe 8 bit A D converter 512 bytes of EEPROM 256 bytes of static RAM and Computer Operating Properly COP and clock monitor watchdog timers In addition there are seventeen hardware interrupts and one software interrupt with all on chip interrupt sources being maskable Two external inpu ts IRQ INT1 and XIRQ NTO are provided for interfacing to other devices with the IRQ input being pro grammable for either edge or level sensitive operation Software features include low power STOP and WAIT modes which can be exited by internal or external interrupts and a spedal wake up feature for using the asynchronous serial interface in networked systems Double accumulators and index reg isters along with a full complement of bit manipulation and branch instruc tions are provided Six different ad dressing modes allow for code opti mization in all situations INTERNAL AND EXTERNAL MEMORY Up to 64K of external memory can be used onthe RTC HC
82. OS compatible clock to control the internal clock generator circuitry The frequency applied is four times higher than the desired E clock rate E Provides an output for the internally generated E clock which can be used for timing reference The frequency of the E output is one fourth that of the input frequency at the XTAL and EXTAL pins IRQ The asynchronous interrupt input to the MCU Either negative edge sensitive or level sensitive triggering is program selectable This pin is configured to be level sensitive during reset An external resistor connected to VDD is required on IRQ XIRQ Provides the capability for asynchronously applying nonmaskable interrupts to the MCU after a power on reset POR During reset the X bit in the condition code register is set and any interrupt is masked until enabled by software This input is level sensitive and requires an external pull up resistor to VDD MODA LIR AND MODB VSTBY During reset these pins are used to control the two basic operating modes and the two special operating modes The LIR output can be used as an aid in debugging once reset is completed The open drain LIR pin goes to an active low state during the first E clock cycle of each instruction and remains low for the duration of that cycle VRL and VRH Provide the reference voltage for the A D converter R W SIRB Provides two different functions depending on the operating mode In single chip mode the pm provides STRB outp
83. RITE FOR FREE DEMO DISK noHa 51 E Campbell Avenue Campbell A 95008 CORPORATION 408 866 1820 FAX 408 378 7869 Reader Service 170 82 CIRCUIT CELLAR INK Figure 3 The Film STN display adds a thin poly mer film to fill the role of DSIN s second LCD lt Glass Most obvious is the lack of color Generally all the previously described LCDs are monochrome Second even the best LCDs don t achieve the contrast ratio of a CRT one reason color isn t a good match Finally a flaw you can t see in a brochure s static screen shot is that the LCD display update rate is relatively slow Any user of con ventional LCDs knows that when the beautiful screen starts scroll ing it quickly turns into an unrec ognizable blur Unfortunately these limita tions are in fundamental conflict with the emerging computer stan dards notably the shift to Macin tosh Windows like color bit mapped mainting device oriented visual interfaces Even if monochrome is deaned acceptable the slow update problem is a real show stop per lt Front Polarizer Polymer Film a Liquid Crystal t Glass Rear Polarizer EL Backlight Now a new LCD technology is energing TFT Thin Film Transistor also called Active Matrix As the names imply the concept relies on placing a transistor at you 68HC11 sz Mars I a ple e embedded system pause for popular f C t 0 with your ch oice cati a et cit a
84. SBPECIALS LAMP MODULES AE go APPLIANCE MODULES EA r LIMITS KENI z LIST 14 99 Mini Controllers WALL SWITCH MODULES ONLY 9 LIST 12 99 Stanley Wireless Motion Detector LIMIT 4 X 10 Compatible Indoor ce Homeminder ONLY 109 rate Surrey outdoor operation Works with X 10 s RC5000 Base Transcelver Schedule your home usinggraphiclcons ory your TV Remote phone Interface memo ONLY 3 With Base 49 50 pad security mode message system LIST 84 99 LIST 39 99 LIMIT 24 LIMIT 8 password protection more With 2 mod fi Leviton Wall Switch ules Infrared remote Cable Use to controlfiuorescent lighting Enerlogic ES 1400 celling fans motors etc X 10 tc compatible White ivory or Brown ONLY 369 prices Model 6291 List 72 50 HCC 48 intelligent X10 scheduler with 2 way inter face Monitors powerline amp allows IF THEN Sundowner Controller One ForAl Remote zman ane Replaces 13 remotest ory 0 N LY 16 X 10 Compatible when used ahd LIST 10 05 LIMIT 4 with Infrared command Center ies LIST 129 Photocell tums up to 4 lights on atdusk amp off 0 N LY 87 LIMIT 3 atdawn Also functionsasa mini Controller infrared Command Center 320 05 ORDER REQUIREMENTS 100 minimum per order No minimum quantities We accept Mastercard Visa Olscover Check or money order Limited time specials HOME CONTROL CONCEPTS A TOLL FREE ORDER HOTLINE ba 1 800 828 8537 ec
85. Service 172 December 90 January 9 15 i a a a a a a e a L e U a a a S timer a general purpose timer is supported for counting delay times from one second to five minutes A sync flag is also set every time the timer interrupt is invoked PUSHING THE CODE AROUND Although we could use any stan dard communications program with file manipulation capabilities to trans fer our hex file to ON DI this would require a multistep process to config ure the DS2250 load the program and verify the program A better solution iS My xoaper utility Not only does it build a D 2250 configuration file for setting up the chip but the program will accept a command file either on the command line or interactively that will not only direct toanzr to execute the required programming steps but willalsoconfigure LOADER S opera tional communication parameters The process of downloading to ONDI simply consists of setting the load switch to the load position and invoking toaper Once done we set the load switch to the run position and ONDI immediately begins executing the program Editor s Note Soffware for this article is availablefrom the Circuit Cellar BBSand on Software On Disk 18 For downloading and ordering informa tion see page 92 1 THE EXPANDED CONTROL DEVICE After test driving the prototype code it is apparent the device can in fact operate a computer remotely Still this rudimentary implementation requires
86. T butisn t quite as convenient implementation to hold the interme diate results and product Extracting the result isa simple matter of shifting the product eight bits to the right and returning the low order two bytes Division being the inverse of multiplication requires more setup 7x5 LED Matrix For Moving Message Signs Etc By IEE 2057 c c rows Your Choice 2058 c a rows 95 With Hook Up SIZE 2 X 1 5 in 2 ea 8 For 17 95 RARE SURPLUS FIND NEW 12 VDC POWER SIEMEN RELAYS S SMART LED 1 by OMRON DPDT 10 A cont 150 ohm coil 1x1 5x 75 inch 2 95 ea DLO 7135 2 by P amp B SPST N O 30 A cont 160 ohm coil 1 5x1x 75 inch 1 99 ea CAPS FOR HAMS High Voltage Very Dangerous 110 MFD 450VAXIAL iiia 1 99 800 MFD 450V CAN 4 95 5100 MFD 350V CAN 6 95 ALL NEW NAME BRANDS HARD TO FIND CAPS FOR POWER SUPPLIES 8200 MFD S50V RADIAL 0 99 12 000 MFD 75V CAN 3 95 21 500 MFD 40V CAN 2 95 41 000 MFD 35V CAN 3 95 47 000 MFD 25V CAN 2 95 Displays entire 128 ch 2N3771 5x7 Red Built in logic Requires only a chip select and an ASCII input Operates on 5 VDC 1 inch tall With Data New Units 3 95 each or 8 for 24 95 6 V 4 A H BATTERY Gell Cell style Brand New fresh units 4x3x2 inch 27C32HQ house 1 49 TO 3 POWER TRANSISTORS 2N4398 1 49
87. Useful 40 1 Moderately Useful 402 Not Useful with MI FORTH For Programming Professionals an expanding family of compatible high performance compilers for microcomputers For Development interactive Forth 83 Interpreter Compilers for MS DOS OS 2 and the 80386 e 16 bit and 32 bit implementations e Full screen editor and assembler e Uses standard operating system files 500 page manual written in plain English e Support for graphics floating point native code generation For Applications Forth 83 Metacompiler e Unique table driven multi pass Forth compiler Compiles compact ROMable or disk based applications e Excellent error handling e Produces headerless code compiles from intermediate states and performs conditional compilation e Cross compiles to 8080 Z 80 8086 68000 6502 8051 8096 1802 6303 6809 68HC11 34010 V25 RTX 2000 e No license fee or royalty for compiled applications Laboratory Microsystems Incorporated 4 Post Office Box 10430 Marina de Rey CA 90295 Phone Credit Card Orders to 213 306 7412 FAX 213 301 0761 Reader Service 1 16 CIRCUIT CELLAR INK PROGRAMMER The EP 751 procrams 87C751 27C752 and 2716 through 27512 Software included Quick pulse algorithm Simple installation Combine with PA51 FC to rogram 87C51 87C51 FA FE_ FC 652 854 528 Combine with PA51 FC amp PLCC adapters to program 87C51 FA FB FC 87C552 87C451 PA28 32 re
88. VE 75492 DIP BRIDGES DIP ULN2003 DIP 0 69 LM3900 DIP LM2900 DIP XR2240 DIP DIP TTL OSC We carry most common frequencies all 2 49 e INER ELECTRONIC 214 242 8702 FAX 214 709 504 1 TERMS Send check or use Visa MC NO COD USA Canada Only Add 3 85 1301 W Beltline Rd 105 Carrollton Tx 75006 _ Store prices vary Reader Service 190 min for UPS Texas add sales tax 90 Day limited warranty on all items 15 min December 90 January 97 65 m oi fernace leqger cdemef ix ci ines99 Csl 7 Photo 3 The output of the CDEMOFIX program shows the results of all four basic arithmetic operaffons on two userentered numbers for all the one bits The final result is a fourdigit packed BCD value repre senting all eight fraction bits Display is then just a matter of calling a routine that converts a two byte binary value into an ASCII hex string Think about it there is no way to tell whether 1234 is hex or packed BCD Slick eh Besides I ve always wanted to use the Decimal Adjust instruction The cpemorrxx program runs through several test sequences then prompts you for a pair of fixed point numbers and displays the results of 5 0 1 0 12739961 F160 127 9961 1 0 10 1 0 all four arithmetic operations Photo 3 shows the results on a PC monitor sorry they don t fit on the LCD panel The source code includes sev eral h
89. a card is inserted power is applied to the computer and the system is reset In most cases customers have devel oped their final applications to begin running immediately after reset re quiring no further operator interven tion A 32K BEE card holds a lot of data if you choose your storage algorithm correctly In a typical temperature loggingapplication a thermistor type R 535 Prototyping Board with R Ware AComplete System for Developing Embedded Control Applications Board includes power supply 80535 processor enhanced 8052 with 3 timers plus watchdog timer and 12 interrupt sources at 4 programmable priority levels up to 128 k on board memory Eprom burner RS 232 serial port at 9600 Baud 28 digital I O lines 8 analog input lines 2 1 8 by 6 1 2 breadboard with 8 pushbuttons 8 toggle switches 16 LEDs 2 numeric displays R Ware includes ROM resident monitor program and PC based menudriven assembly PC to board communication integrated software for edit download and debug Plus users manual and control experiments with example software Prices start at 395 RIGEL CORPORATION P O Box 90040 Gainesville FL 32607 904 373 4629 34 CIRCUIT CELLA RINK Reader Service 1 probe might be sampled four times per hour and its amp bit value stored along with the time and date to the BEE card Even without doing any clever programming to compress the informatio
90. amp H60 amp Hxx where xx is represents the lights in binary bit 0 for Scroll Lock bit 1 for Num Lock and bit 2 for Caps Lock For example amp H5 turns on Scroll Lock and Caps Lock and turns off Num Lock Keep in mind that changing the lights in this manner does not change the actual shift states which are controlled by bits 4 5 and 6 at address 0040 0017 BIOS KB_FLAG Msg 31055 From ED NISLEY To FRANCIS DUNLOP Dale s got the direct keyboard interface knocked but you can also diddle the shift flags and call the keyboard BIOS INT 16h AH 01h to have it do the updating I don t know if your application can stand to have the BIOS in there but that s surely the easiest way to do it A little experimentation should tell you if the BIOS goes off into the bushes for longer than you can stand IRS 424 Very Useful 425 Moderately Useful 426 Not Useful iei 195 erformance 172 the Cost VIDEO FRAME GRABBER e Real Time e Hi Res CORTEX I v Dual Resolution Modes Single Frame 512 X 484 Quad 4 Frames 256 X 242 v 256 Grey Levels 8 Bits v Pixel J itter lt 1 10 pixel 512 v Input LUT Programmable v Software includes Utility C Library Configurable as RAM Disk DOS Prompt Commands TIFF Conversion Utility v Composite Video BAW NTSC RS 170A RCA Phono 9 Pin D Sub y External Trigger TTL with Prog Delay v Half Slot IBM PC XT AT 386 Compatible v90 Day Warranty Parts and Labor v VISAIMC Accepted
91. andy routines induding input and display functions for both integer and fixed point numbers If your controller application re quires transcendental functions or other exotica you ll be well advised to use the standard floating point li braries and functions instead of writ ing your own code However if your calculations are more along the line of 0200 00co 0200 0600 80FF 7F01 127 0039 127 0039 00010000 00028000 FFEEQ000 00060000 00800000 01000000 00020000 00000080 02000000 00010000 00000200 EEQ00000 00020000 FFFFEE80 EE000000 FFEC0000 00000080 Figure 4 a Because the numbers use two s complement notation fixed point addition and subtraction work just like Integer arithmetic Notice that overflow occurs for results exceeding the valid 128 range b Multiplying two fixed point numbers produces a result with fwice as many bits The product tem is containedin the middle two bytes of the four byte result c Dividing two fixed point numbers requires two alignments The Fumace Firmware code moves the divisor to the middle two bytes of a four byte variable and puts the dividendin the high bytes ofanother four byte variable The result appears in the lower two bytes of the quotient 66 CIRCUIT CEL LA RINK scaling offsetting and displaying reasonable numbers using a fixed point math package will give you a substantial performance boost and a significant size reduction benefits not to be s
92. anges were also made to allow BASIC 1 to take advantage of the RTC HC11 s n board battery backed RAM and real time clock calendar chip The following sections contain a brief summary of each of the BASIC and assembly language development options and a few examples of how an embedded application can be config ured for the RTC HC11 BASIC I 1 For many of us the quickest way to develop embedded software will be to use BASIC 11 a fast integer BASIC interpreter with built in sup port for most of the 68HCIl s on chip peripherals This BASIC can execute a thirty thousand iteration FOR NEXT loop in less than four seconds an IBM PC takes 38 seconds by comparison and has built in keywords for access to the 1 O ports interrupt request lines timer pulse accumulator A D converter and EEPROM Using bat tery backed RAM a BASIC 1 appli 44 CIRCUIT CELLAR INK cation can be directly saved and auto matically executed on reset or power up eliminating theneed to repeatedly program and erase EPROMs A BA SIC 1 1 keyword summary appears in Table 3 Listing Lisasimple BASIC 11 example which uses the RTC HC1 I s ADC EEPROM and timer subsys tems Line 40 sets up an interrupt service routine and uses the 68HC1 l s timer subsystem to generate an inter rupt every hour When the service routine at line 500 is called the ADC is sampled and the readings are printed to the console serial port and also saved i
93. ansion Option 18 more channels 100 12 Bit Analog Input 18 channels programmable gain 10000 inputs sec max 8995 Option 18 more inputs 200 Analog Output 4 channel 12 bii D A 5 1V outputs 9495 Expander Option 12 more outputs 200 Counter 18 inputs 24 bit 595 We can make your PC do things you l wouldn t believe C From Your PC Command Control Communications Bring new dimensions to your computer with A Bus C Net and Alpha Boxes No longer is your computer limited to number crunching or word processing Now you can connect it to all kinds of equipment sensors or machines This offers unprecedented power from production lines to experiments to home control Each product is designed to fit your needs They re affordable Compare our prices the cost of a solution is surprisingly low They re simple and easy to connect to your computer and your application and carefully designed to adapt to your software easily They re versatile An infinite number of combinations is possible one of them is right for you Easily expanded or changed for future projects They re proven We have customers around the world including Fortune 100 companies most major universities governments and individuals Overseas distributors UK Pinna Electronics Scotland Tel 9294 805298 Fax 9294 88288 Asia Batam DA Singapore Tel 473 4518 Fax 479 8498 Scandinavia A S Con Trade Norway Tel 9
94. apaci tances Then as the amplifier ap proaches its peak value it may over shoot and then reverse and under shoot the full scale value before fi nally entering and remain ing within the specified error band As seen within Figure 8 this settling time is measured from the start time to the final entry into the specified error band typically 0 01 to 0 1 of the full scale transition ANALOG MULTIPLEXERS An analog multiplexer is the device which time shares an A D converter between a number of ana log input channds It is composed of an array of parallel switches con nected to acommon input line with only a single feedthrough active at one Analog Time gt Register ee ear D A Converter a 4 C Deglitchsd WA Converter FS 314 output Output Glitches or Spikes Actuator Sample Hold Figure 10 Output spikes glitches and a deglltched DAC actuator system time and a decoder driver circuit which decodes a binary input word that specifies the appropriate switch setting The decoder driver interfaces with standard TTL logic Primary characteristics of the multiplexer which you should keep track of are transfer error this is defined as the input to output error of the multi plexer with the source and load con nected expressed as a percent of in put voltage break before make switch a small time delay between the connection to the next channel and disconnecti
95. ared to understand why things work the way they do and how to do things the right way There is absolutely no way you ll be able to come straight out of school and design a circuit that works is cost effective and is easy to manufacture unless you ve had hobby or summer experience but even then you ll probably need some help Hell we weren t even taught how to solder while in school Just keep plowing through it and telling yourself you ll be a better person for doing it Msg 31280 From STEVE CIARCIA To ROBERTO PUON I are an engineer too How much math you use is really dependent upon the job If you are assigned to design radar antennas and don t know math you are in big trouble and soon out of that job Just using off the shelf ICs in noncritical control designs with the manufacturer s specs under one elbow is not particularly math intensive In my opinion you cannot be a good engineer without knowing a good deal of math This math could be broad ranging including physics and chemistry and not necessarily just narrow hard headed stuff for designing your own ICs A good engineer EE will know what Fourier transforms are but 20 years after study ing then he might not know how to solve then by hand A good EE will instead know immediately where to find a book on the subject a math egg head to do it for him or a computer program that will do it If all else fails he can hope that he s been on the
96. arious parameters QUANTIZATION AND SAMPLING THEORY Many of the commer dally available A D and or D A boards may combine 20 CIRCUIT CELLAR INK several of these individual functions But understanding the basic concepts behind each of the above described components is of extreme importance when designing and configuring your DAAC system or for when you use an integrated data acquisition board Your original analog data is manipu lated and altered by these devices So how you quantize sample and code your measured data will in fact deter mine the quality of your measure ment results Here quantization re fers to the process of transforming a continuous analog signal into a set of discrete output states which are then coded into a discrete digital word which represents each output state during a specified sampling time inter val THE QUANTIZER TRANSFER FUNCTION Quantizing an input analog sig nal divides the signal into discrete levels or states whose size or range determine the overall resolution of Switch Driver Sample Control Figure 4 h order to keep the input signal steady during the conver gon a sample and hold circuit is typically used the A D process Typically this con version is characterized by a nonlin ear transfer function like that shown in Figure 2 This figure represents the quantizer for an ideal 3 bit system with eight output states like that used in a 3 bit A D converte
97. ata are sent again to the unverified byte Mask the command sent to the device that verified to maintain word wise programming A mask is the substitution of a reset command for the program and verify commands That way the programmed bytes do not get further programmed on sub sequent pulses The page memory board will perform these software techniques However first write the software that determines the location and capacity of the board First scan the I O space for the board s identifier The location of the first identifier byte is also the 031 In Circuit Emulation Our emulator provides most features of an 8031 in Circuit Emulator at a significantly lower price It assists in integration debug and test phases of development Commands include disassembly trace breakpoint alter register memory and load Intel Hex file 199 8051 Simulation The 8051 SIM 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 8031 51 Single Beard Computer fast and inexpensive way to implement an embedded controller 8031 32 processor 8 parallel I O up to 2 RS232 serial ports 5 volt operation The development board option allows simple debugging of 8031 51 family programs 99ea Prototyping System The IPC 52 development system allows you
98. ators To see how the above components can be combined to create a workable computerized feedback control sys tem consider the diagram shown in Figure 1 Here measurements of some heating process within a pres surized vessel are used to monitor and generate feedback control se quences which will optimize the de sired process The primary inputs to this DAAC system are the measure ments of analog physical parame ters such as temperature pressure velocity acceleration or displacement To gain an elementary under standing into the design configura tion of the needed elements within the DAAC system shown let s trace the Output Output Code States Word 8 111 110 3 75 1 25 25 5 0 6 25 7 5 InputVoltage Q 2 0 Q Q 2 Quantizer Error Figure 2 Due to the stairstep nature of the digitization process there is always a small amount of quantization enor associated with the digitized signal pressure measurement from the con tainment vessel s pressure transducer through the interface to the computer Then we ll follow the computer s re sponse back through the control inter face to the actuator located at the pressure vent control valve where modifications in the processes status will be made Let s assume that the pressure or force per unit area within the con tainment vessel is measured using a standard pressure transducer Here an elastically deformable sensing de ment r
99. ccess to ports 1 and 3 of the 8031 as well as providing access to the 5 volt DC power bus and ground con nections Additional connections are provided for an RS 232 compatible serial communications port and an external reset switch for the 8031 Aside from the use of the BEE card the system is a fairly conven tional 8031 based single board com puter that should be quite familiar to Circurr CELLAR INK readers A 7415138 address decoder provides selection of 8K memory devices at OOOOH 2000H 4000H and 6000H Jumper blocks on the CE line of each 28 pin socket let theuserselectthebaseaddressofeach package depending on individual needs Two gates of a 74LSO00 NAND package are used in conjunction with the 8031 s PSEN and RD signals to derive a three wire bus that can be used to configure on board memory in one of three ways The jumpers allow each 8K device to be designated as RAM or EPROM like you might ex pect A third position BOTH causes the 8031 s Program and Data memory spaces to be overlapped within a given 8K block This option is provided to allow compatibility with certain ver sions of Forth and other high level languages that require a single com bined memory space for proper op eration A jumper is also provided on pin 31 of the CPU to enable or disable the internal ROM found in some 8051 family microcontrollers This makes i t possible to use mask programmed 8031 microcontroller derivatives such as th
100. ce is the data card a credit card sized device containing battery backed RAM Credit card styleRAM cards have recently appeared in such consumer products as video games and even personal computers such as the Atari Portfolio pocket computer These applications typically use a mask pro grammed ROM card or a similar one time programmable ROM card but the RAM cards are also available in EEPROM and battery backed SRAM versions that make them ideal for storing and transporting infor maua Currently available RAM card storage capacities range from 8K bytes to 1 megabyte of stor age Recently we designed a basic general purpose single board computer the Datalog R pronounced data logger one see Photo 1 that could be used for simple process control functions and would also provide nonvolatile renovable storage We chose to incorporate a 32K byte BEE card from Mitsubishi Plastics in our design 32 CIRCUIT CELLAR INK The SRAM version of the BEE card we used has 32K of 250 ns CMOS static RAM Mitsubishi part no 0256SRMSP25 Power consumption is 200 milliwatts maximum at 5 volts and the package has a rated operating temperature of 0 60 C Each card measures 54 mm wide by 86 mm long and is approximately 2 3 mm thick The card includes a holder for a thin circular lithium battery type CR 2016 that provides power to retain the cards data any time external power is not supplied Mitsubishi rates batter
101. conditions I thought I had this stuff working quite a few times before it reached this condition Displaying a fixed point number involves two steps because the inte ger and fraction parts must be con verted separately The former is easy enough see ConShowInt in consorte C5 1 for details Convert ing the fraction to ASCII is ordinarily a tedious operation involving long division and considerable hocus po cus Listing2 showsa shortcut entries in a table relate fraction bit locations and the corresponding packed BCD equivalent accurate to four decimal places The code in Listing 2 tests each bit position and accumulates a BCD total STEPPER MOTOR 3 95 TRIAC BT139 500 12 AMI IBM Surplus 8 wire 4 windings 7V 350 mA 1 8 200 steps per rev DC res 20 ohm ea 25 oz in torque Works great on 5vdc W Data FOR ROBOTICS CMOS 8032 MICROPROCESSOR 80C32 By Matra 40 pin DIP 12 MHZ Very lowpower 3 95 500 PRV TO 220 0 99 TRIAC DRIVERS MOC3010 MOC3040 MOC3011 MOC3041 0 99 LINEARS OPO7 DIP 1 49 TLO62 house 0 49 TLO72 DIP LM324 DIP LM358 DIP LM348 DIP i MC4741 DIP 0 59 LM318 DIP 2 LF356 can STATIC RAMS ER BR a MC3403 DIP 0 49 SS TEE TLORE DE iinei s09 rasees 1251 RC4BSA DP 0 49 T eso ALG De esier 2 69 ve 991 LM339 DIP 0 49 LM350K 3 95 75491 DIP esses secure 0 FULL WA
102. configuration B600 B7FF for EEPROM and 7C00 7FFF for the Oki clock calendar chip To make things even simpler the I O and EEPROM blocks can be moved to the start of any 4K page and the Oki dock and EEPROM blocks can be disabled altogether Refer to the Motorola 68HC11 Reference Manual ISBNO 13 566720 8 Prentice Hall for thenec essary HC11 instruction set and regis ter details Listing 3 is the equivalent of Hello world for RTC HC11 devedopment it simply blinks the RTC HC1 l s LED to indicate that at least the MCU itself isalive The programcan beassembled with the AS11 assembler and then downloaded to the board using either the ROM monitor s soap T com mand or puoap exe aquickand dirty download program for the IBM PC Another development option is to use one of the BUFFALO series of ROM monitors to download and test your code directly on the HC11 This monitor contains a built in line as sembler disassembler so short test routines can be entered directly into RAM Standard memory move change fill and EEPROM support is also included The monitor itself re sides in a single 8K EPROM and is installed in socket U8 on the RTC HC11 Don t forget to install JP12 so the instruction trace and breakpoint commands will work RTC HC11 INMAL SETUP Setting up the RTC HC11 is very simple Any standard RS 232 serial terminal can be used as a console device for the RTC HC11 Alterna 32170 WHILE TB l
103. controller Many examples and sample programs are included to help you master the unique instruction set of the 8051 Also included is a disk which contains an assembler and simulator that runs on IBM PCs and compatibles This disk assembles and allows you to t purchase any additional 8051 har est your programs without having to dware The disk was developed by David Akey of PseudoCorp You can purchase the text with disk in cluded for only 49 00 local tax Shipping and handling T To order call or write West Publishing Company Attn COP Department e P O 64833 3773 Hwy 149 1 800 328 9352 Visa Reader Service 197 Eagan MN 55123 and Mastercard accepted December 90 January 91 47 EQU EQU EQU ORG Internal RAM 1000 04 SPCR f 0 DDRD Y ld Idaa staa lds ldaa staa base of on chip I O regs z set port D pin mode z set top of stack set data direction register ldb bset 05 PORTD Y 20 timing loop turn led ON Jer dly50 decb bne ipod ldb 505 belr PORTD Y 20 delay for half a second turn led OFF jsr dly50 decb bne lp1 jmp top repeat forever a 50 ms delay subroutine pshx ldx 41le dex bne pulx rts d501p Listing 3 LED blink test program 48 INSIDE THE MC68HC11A1 SINGLE CHIP MODE The MCU functions as a self contained microcontroller and has no external address or data bus This m
104. crew terminals RAM and EPROM 70 00 EPROM 27C128 CMOS programmed with TILE firmware Programmable controller with Real Time Clock 20 00 EPROM 27C64 CMOS programmed with DG31M and disk IBM format with monitor program modules source code listings and manual 30 00 HOME AUTOMATION and SIMPLIFIED SECURITY SYSTEM complete project using TILE controller and low cost electronic modules shipping included 10 00 L S ELECTRONIC SYSTEMS DESIGN 280 Camilla Rd Mississauga Ont LFA 258 Canada TERMS Shipping US Canada 6 Check on money order please Reader Service 156 6 CIRCUIT CELLAR INK ONE FOR MODULA 2 This letter is about the choice of language for Scott Ladd s column on Practical Algorithms and responds to Mr Don Lasley s letter to the editor in Cicurr Cettar INK 17 Please enter my vote for Modula 2 as the choice for algorithm exposition C is not more powerful than Modula 2 anything including bit twiddling that can be done in C can be done in Modula 2 Of course you have to know Modula 2 as well as you know C in order to be able to do the same things equally easily Mr Lasley can t complain that the language he hasn t bothered to learn is clumsier or harder to use than the language he s used extensively Asaprindpal engineer performing quality control for a major consulting engineering company review work by a large number of engineers and analysts Based on this exposure my conclusion is that t
105. d consists of three byte wide ports provided directly from a standard 8255 PPI On board circuitry monitors two of the three ports and is capable of generating interrupts on either the change of any bit in the port s or when a specific bit combination or pattern ap pears With a bit interrupt a change of any unmasked bit from either Oto lor 1to Owill generate an interrupt Changes can be read from the Status Register and only those bits that are activated by the interrupt Mask Registers will generate an interrupt With a pattern interrupt an interrupt is generated on a given pattern of bits in any port Only unmasked bits can participate in a pattern match interrupt and they are com pared with a stored pattern of bits in the PIO INT s Pattern Match Registers The third port while not monitored and without inter rupt generation capability can be used as an auxiliary I O port and can be divided into two nybble wide ports Each port can be individually configured as an input or output port To prevent spurious interrupts generation of an interrupt is delayed by a two stage digital filter The filter is clocked by a programmable discrete decade frequency ranging from 1 Hz to 10 MHz The effect of the filter is to allow actuation ddays from 100 200 ns to 1 2 seconds before interrupt generation Beni Filter delays are selectable independently for the two ports The PIO INT is provided with a sample assembly driver callable from
106. d driver software has made the desktop PC a necessary part of the well equipped lab or shop floor Chris Ciarcia has a Ph D in experimental nuclear physics and is currently working as a staffphysicist at a national lab He has exten sive experience in computer modeling of ex perimental systems image processing and artificial intelligence Chris is also a principal in Tardis Systems IRS 403 Very Useful 404 Moderately Useful 405 Not Useful PC Based Logic Analyzers i EESE Sophisticated Logic Analysis a Unsophisticated Prices 1D160 50 MHz for 695 1D161 100 MHz for 895 50 MHz or 100 MHz Sampling 8K Trace Buffer e 32 channel E CIRCUIT CELLAR INK Main Street eP O Box 67 e Meriden NH 03770 30 Reader Service 114 Operation Multi Level Triggering e Event Timer Counter e Performance Histograms e Hardcopy Output Disassembles popular E bit micros and much more 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 State Pass Counting Reader Service 145 New Products Alpha Products proudly announces two new product lines C Net serial communications devices and Alpha Box interfaces These new products are not merely A Bus accessories but complete sets of products for all of your interfacing needs All the products are used to connect different types of devices to your computer Our
107. diameter IBM P N 1501906 COM SCOPE CAT RG 11 1 100 foot roll 15 00 1 l 2 200 foot roll 527 50 for the 48 continental U S A 3 50 per order All others including AK Hi PRor Canada must pay full shipping All orders delivered in CALIFORNIA must include state sales tax 6 1 4 6 3 4 7 1 4 Quantities Limited NO C O D Prices ubject to change without notice Call Toll Ree or clip this coupon FREE 60 Page Catalog Containing over 4 000 ITEMS ALL ELECTRONICS CORP P O Box 567 Van Nuys CA 91408 Reader Service 103 22 CIRCUIT CELLAR INK Figure 5 The digitization process involves sampling the original signal at fixed inter vals The samples are then used to recon struct the original It is derived from the device that samples the input signal voltage and stores it on a capacitor for the time required by the A D quantizer to do its thing This means that the aperture N Frequency Folding time of the A D converter is often reduced by the typically shorter time of the sampleand hold circuit which is a function of its bandwidth and switching time A sample and hold is simply a voltage memory device in which an input voltage is stored on a high qual ity capacitor A popular version of this circuit is shown in Figure 4 Here A is a high impedance input buffer amplifier such as an analog multi plexer A is the output amplifier which buffers the voltage on the hold capaci
108. ducts to sspeed construction of your prototype systems and make one of a kind products trully affordable All SBCs operate from 5 volts DC and come iassembled and tested with complete documentation and sample 2rogramming information Control R I 11 0592MHz 8031 SBC with 8K EPROM socket optiona RS232 serial port and header connection to ports 1 amp 3 of the 8031 16 I O lines make it perfect for small control and data aquisition applications 39 91 Control R II 11 0592MHz 803 SBC has all the features of the Control R I plus an 8K SRAM socket and expansion bus with address data and RST INT1 WR RD PSEN ALE T1 and power 64 9 MAX232 RS232 option for either computer 6 9 SRAM 8Kx8 SRAM type 6264 for Control R II 10 00 PseudoSam51 MSDOS cross assembler for the 8031 50 00 3 00 Shipping UPS Ground for all US orders Illinois residents must add 6 25 sales tax PHONE 217 529 7679 Visa MasterCard COD Cottage Resources Corp Suite 3 672 1405 Stevenson Drive Springfield Illinois 62703 Reader Service 126 December PO January 97 55 ees ADOR GOH PLSCNT 0 Figure 9 The flash erase algorithm eight flash devices simultaneously Turning V__ off when not in use con serves power but this capacitance value requires approximately 100 ms 56 CIRCUIT CELLAR INK to fully charge to 1
109. e calcu lates enor and generates a series of contol se quences which are fed back to the process for contol manipulation 18 CIRCUIT CELLAR INK Analog Pressure Vent Q Multiplexer Control Valve Containment Vessel Pressure Transducer gt Thermocouple Analog Channels PC Control Controller Sequencer Bidirectional Computer Data Bus We can all appreciate that the world around us very rarely lends itself to simple understanding evalu ation or control especially if we at tempt our control using a computer system Most real world physical para meters are analog and require some form of interface to the world of artifi dal computation and control DATA ACQUISTION AND CONTROL The basic interfacing modules which are employed in most real world interactive systems are the analog to digital A D and digital to analog D A data converters The A D converter is a circuit which con verts an analog continuous voltage or current into an output digital code And conversely the D A converter converts a digital code word into an output analog voltage or current Of course that s not all there is to a real world interface In reality DAAC sys tems are created using one or more of the following components A D and D A converters e transducers sensors amplifiers filters analog multiplexers sample holds edigital control sequencers PC computer controller and I O bus actu
110. e Micromint 80C52 BASIC CPU or the Intel 8052AH BASIC CPU A third gate in the 74LSO0 pack age is used to generate a BCS BEE Card Select signal from address line 15 of the CPU Sincethe BEE card serves as a mass storage device in this system the RAM ROM BOTH op tions are not jumper selectable Other connections to the BEE card are similar to any other memory de vice WR RD high order address lines and demultiplexed data and low order address lines are all run to the special 32 contact socket where the BEE card itself is inserted The printed circuit board for the Datalog R includes space for a 5 volt DC regulator to make it simple to run the data logging system from an exter nal 12 volt power source Twelve volts DC is readily available in vehicles and is easily obtained in out of the way locations where instrumentation and sensing equipment are often powered by photovoltaic arrays that charge secondary storage batteries MOVING THE DATA Although perhaps not typical of a logging device we chose to equip our design with an RS 232 compatible XUR PSEN 1 Z44500 Figure 1a The Datalog R consists of a basic 803 circuit with a simple expansion header ROM RA BOTH ___ RD CRAM 741520 K BCS 8Q0 QH FFFFH 7415138 PiL p12 _ 6009 December 90 January 91 33 communications port The port is implemented using the 8031 s built in UARTa
111. e RTC HC1 1 is available from Micromint For pricing and data sheets call 800 635 3355 or fax 203 872 2204 IRS 409 Very Useful 4 10 Moderately Useful 411 Not Useful Markus A levy with Hash Memory ls There a New Altemative to EPROM and SRAM Faa memory in general is capturing market share from other memory tech nologies It is replacing EPROMs that were traditionally used for code storage because along with equivalent nonvolatility it also allows in system updates Bat tery backed SRAMs that once were used for data acquisition parameter storage and even solid state disks are now targets for the inherently nonvolatile and lower cost flash memory devices Many notebook computer OEMs conclude that low power light weight and reliability are most easily obtained with a completely solid state machine Flash memory has achieved a densty ramp from 256K bits to 2 megabits in two years Combined with a special flash file system from Microsoft flash memory can even replace the mechanical disk drive With the design described in this article you have a platform demon strating flash memory s functionality and flexibility Applications range from data acquisition through an I O port to a DOS compatible solid state disk But first a few essentials EPROM AND BEYOND Derived from an EPROM process base Intel s ETOX II flash memory technology has similar nonvolatility reliability and array densities I
112. e follow the algorithms Many people unsuccessfully try their own custom versions There are no cutting comers Starting with the ba sics letmeel aborateafew pointsabout the algorithms 1 Flash is programmed to a bi nary zero by adding charge to the transistor s floating gate Contrarily charge removal erases the cell to a binary one During the erase opera tion the device is flashed as charge is simultaneously and equally pulled off the floating gate of every memory cell The device must be prepro grammed to all zeros before erasure so an already erased cell is not further depleted of charge 2 Prior to writing any command switch on Voi and allow ample ramp time for proper operation Dropping Vir below 7 5 volts from within any operation places thedevice in the read mode Similarly abort an operation by issuing two consecutive reset commands FFH followed by the read command 00H 3 Closely observe delay times to achieve the highest performance and Figure 10 The flash programming algo rithm reliability Use the srz instruction in the software drivers to avoid systen interrupts during these delays Execute ctr once the corresponding verify command is issued 4 The verify operation internally creates marginal conditions to ensure accurate and reliable results The 6 us slew time delay following the verify comma
113. e input SOURCE Intel Literature 800 5484725 Data sheets SM28F001AX 1 M byte SIMM IMCOO1FL 1M byte IC memory card 4MC001FL 4 M byte IC memory card 28F020 2 M bit device Application notes AP325 Guide to Flash Memory Reprogramming AP343 High Density Applications Using Intel Flash M emory NEW 68000 COP800 PIC16Cxx versions UASM TM TEXT EDITOR CROSS ASSEMBLER AND COMMUNICATIONS FACILITY IN A COMPLETE TER OG DEVELOPMENT ENVIRONMENT us 149 95 MA CONDITIONAL ASSY LOCAL AUTO LABELS SYMBOL TABLE CROSS REF SOR HEX FILE OUTPUT DOWNLOADS Cross Assemblers for the Macintosh PLUS S H 290244 290399 290388 290245 292059 292079 simple Now the fun begins Once you ve put your Flash Paged Memory Board together and tried it out imagine con verting it into a solid state disk It s beendoneusingsoftwaredriversfrom Microsoft In an upcoming article we will discuss the structure of the Micro soft Flash File System and show you how to interface it to your board Finally would strongly suggest thatbeforeattemptingthisdesign you obtain the appropriate flash memory literature from Intel see the source box gt Markus Levy is an application engineer at Intel Corporation in Folsom California and holds a B S E E from California State U niver sity Hisspecialties includesoftwareand hard ware implenentations Of solid state disks in portable computers His favori
114. e mode Remote state CTTY mode Like the transparent mode except that ONDI issues the DOS MODE and CTTY commands to the local com puter via simulated keyboard input prior to entry On exit ONDI CTTYs back to the console via the COM port Local state command line mode The local computer is in direct corn munication with ONDI and has access to the local command set Local state transparent mode The computer s COM 5 port is connected to the mo dem ONDI monitors the computer transmit line If the escape sequence is de tected control returns to the local state com mand line mode This is the point of entry when the mode switch is set to local operation go Ss yy NOW THE COMMAND SETS Where possible to reduce the amount of unique com mand mnemonics the practice of us ing the command without an argu ment is used to return the function s status In entering the commands upper or lower case is OK The remote command set is as follows H Display a list of these com mands on the remote console display S Power status returns ON OFF indicating the computer power status S Turn computer power on Report if computer logic power is not detected within five sec onds delay for boot up as pro grammed via the local command line mode S Turn computer power off K lt text gt Send lt text gt as simulated keyboard data C CTTY to COM port as selected via the local command line
115. e s no one to buy your product There simply isn t a more important engineering function than building respect and care for your customer into the product
116. e to fumble with wrapping paper or fight the holiday crowds just give usa call We ll make sure your lucky recipient has a full one or two year subscription to Circuit Cellar INK along with a gift card announcing the givers name and starting issue To make sure your gift card amves before the holidays call 203 875 2199 before December 15 1990 CIRCUIT CELLAR INK THE GIFT OF TECHNOLOGY Msg 31530 From ED NISLEY To STEVE SAMPSON My buddy Dave Long who had 37 antique TVs at the height of his craziness and you should hear _that_ story built a 5 foot parabolic mesh dish and mounted it on one of his antenna masts He s in Poughkeepsie and gets tolerable reception from Philadelphia 150 miles away as the crow flies On the other hand he picked his house by reading the Dutchess County topo maps finding the highest points then checking for a house with a basement big enough for a rifle range Found one too He also built of mesh and fiberglass resin a 6 meter power steerable satellite dish back in the days when this was the cutting edge and LNAs were so expensive your eyes fell out He mounted that one on footings that look like a civil engineering final exam pity the next owner who really wants a lawn at that spot Msg 30905 From FRANCIS DUNLOP To ALL USERS I have written a keyboard interrupt handler that intercepts scan codes reassigns some of them and so on It works fine except I don t know
117. e wave fed into the A D converter and the resultant processed D A output You can clearly see the samples leading the input Adding the extra input and output circuitry to the microcontroller was the easy part The software was twiddled slightly decreas ing theeffect in the derivative path and the success proved exciting Now if only could make the ball disappear One last note If you value any of your software experiment with magnets at a considerable distance from your computer and media storage Unless of course you wish to bulk erase everything in sight f BIBLIO G RAPHY Process Control Instrumentation Technology by Curtis D Johnson John Wiley amp Sons Jeff Backiocki pronounced BAH key AH key is a member of the Circuit Cellar INKengineering staff His background includes work in both tke electronic engineering and manufacturing fields In his spare time Jeff enjoys his family windsurfing and pizza IRS 418 Very Useful 4 19 Moderately Useful 420 Not Useful THE TOTAL SOLUTION FOR EMBEDDED DATA AQUISITION AND CONTROL APPLICATIONS EMAC OFFERS A COMPLETE LINE OF INDUSTRIAL STRENGTH SINGLE BOARD COMPUTERS ANDSUPPORTPERIPHERALS WITH ALLTHE FEATURES NECESSARY TO PROVIDEYOU WITH ATOTAL SYSTEM SOLUTION FEATURES INCLUDE DIGITAL AND ANALOG 1 0 TIMER COUNTERS AS232 422 SERIAL PORTS DISPLAY BOARDS TERMINAL BOARDS SIGNAL CONDITIONING CARDS EMBEDDED FORTH amp BASIC LANGUAGES PR
118. eal EPROM 599 for 150nS units with 256K bits Ask for pricing of other options Made in USA by TRRAXEL LABS INC BOX 239 RONKONKOMA NY 11779 516 737 5147 FAX 51 6 737 0349 ader Service 194 December 90 January 9 11 ONDI The ON line Device Interface Software for Remote PC Control Havns developed the hardware fora flexible remote computer control system we will now investigate how the IBM keyboards work and take a look at the prototype software fora simple remote control application Our system configuration will consist of a computer ONDI and a Hayescompatible mo dem ONDI and the modem will remain powered up at all times THE FUNCTIONS OF A REMOTE CONTROL DEVICE We won t get too fancy but we ll try to touch on some of the more important elements To get started we must have the capability to control and monitor the computer power Keyboard emulation for both PC XT and AT style keyboards will be needed The modem will typically be required to auto answer an incoming call which we will want to enable or disable under software control This will be accomplished serially via the Hayes AT command set by either set ting the modem to answer on the first ring or by issuing the reset command which will return the modem to its switch selected settings To ensure that the modem is al ways configured to the desired state we will also monitor DSR and trans mit the appropriate sequence on a t
119. ect Continues by Ed Nisley The fine points of getting the right results and showing them to the user are the heart of this installment From the Bench Magnetic Levitation An Example in Closed Loop Contol How to Defy Gravity Without the Use of Black Magic by J ett Bachiochi Closing the loop with a floating ball can teach you a lot about how a control system works Silicon Update Goodbye CRIT Hello LCD by Tom Cantrell New LCD devices and controllers make LCD a more viable choice than ever before for demanding display applications ConnecTime Excerpts from the Circuit Cellar BBS Conducted by Ken Davidson Steve s Own INK The Whole Job by Steve Ciarcia Engineering doesn t end when the solder cools Steve talks about the rest of the job Advertisers Index 300 1200 2400 bps 8 bits no parity 1 stop bit 203 871 1988 The schematics provided in Circuit Cellar INK are drawn using Schema from Omation Inc All programs and schematics in Circuit Cellar INK have been care fully reviewed to ensure that their performance is in ac cordance with the specifi cations described and pro gramsarepostedon theCir cuit Cellar BBS for electronic transfer 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 emors Furthermore be cause of the possible vari ation in the qua
120. enus and full color control A 120 page guidebook and over 150 hands on examples explain and illustrate fractal art science philosophy mathe matics history and literature Example templates which can be modified as required are included Chaos theory and the formulas used to create fractals are explained and a program to draw the famous Mandelbrot and Julia sets is included Fractal Grafics works on IBM PC compatibles with 384K RAM and CGA EGA or VGA displays A mouse and math coprocessor are optional PCX file compatibility allows the exchange of images with all major graphics programs The program sells for 79 00 and includes one free program update Cedar Software R1 Box 5140 Morrisville VT 05661 802 888 5275 Reader Service 501 8 CIRCUIT CELLAR INK VARE WRAP PROTOTYPE CARD FOR PC AT A manually wrappable prototype card for Geoa0 IBM PC AT and f compatible com D126 A DRG puters has been an oa announced by 06 races CANA Group ONE fig RO The Protosystem AT has been designed to A 3 simplify prototype ahs design and save j 4 debugging time aou RO The board Bioes Hos features wire Meo wrap pins mea RO soldered in place 8 o ora on every signal Ale RG line tantalum eee ax se bypass capacitors a DROZ ts on every power s line and holds o more that 10016 pin IC sockets The board is designed for ease of use and minimization of assembly errors The signal pins are never closer to
121. er to the LCD panel so you can see what went wrong This simplifies debug ging and also permits programs to display bare escape characters which show up as a left arrow Not all ANSI drivers support this func tion so you can t depend on it The cDEMoaNS programexercises the ANSI driver by sending a series of test patterns to both the console and LCD The two displays should match save that your color monitor will have colored characters for some sequences Editor s N ote Software for this article is available on the Circuit Cellar BBS and Software On Disk 18 See page 92 for downloading and ordering information 1 Photos 1 and 2 show how a faked status display looks on both displays while the PC console is more attrac tive the LCD panel gets the job done If you look closely at those pho tos though you ll see something suspicious where did those decimal points come from FRACTIONAL VALUES Integer arithmetic is good enough for nearly all microcontroller applica tions but sometimes you really need fractions For example a stepper motor might move 7 5 degrees per step and drive a slider 0 05 inches each time You could pick tenth degree units in one case and 10 mil steps in the other but Wouldn t It Be Nice If you didn t have to write special arithmetic and display routines for each situation The obvious solution is to use floating point numbers The catch is that floating point arithmetic is ex
122. er with dedicated keywords for 1 O port A D converter timer interrupt and EEPROM support In addition a flex ible EEPROM based configuration system allows a BASIC program to be saved in the on board battery backed static RAM and then automatically executed on power up Micromint also offers several hardware and software options for the RTC HC11 including the full line of RTC series expansion boards as well as an assembler ROM monitor and C language cross compiler RTC HC11 2 Board W 8 bil ADC EEPROM 8K RAM and ROM monitor RTC HCT 3 Board as above w battery backed RAM clock calendar and BASIC 1 tinROM To Order Call 1 800 63 97 3377 4 Park Street Vernon CT 06066 203 871 6170 Fax 203 872 2204 239 00 269 00 Reader Service 163 rr RESET C34064P UNDERVDLTAGE SENSING CIRCUIT 74x138 3 TO 8 DECODER MEMDECODE Chip Enables will not be active until Vcc 4 6 volts At this point signals are stable and involuntary writes will not occur gure 8 An MC34064P undervoltage sensor is used to disable all writes to memory when the power starts to fail or ITT Cannon to use with the mem ory card laying out your board so that the memory card can be retrieved out the back of your PC Pushing the but ton on the connector ejects the mem ory card for data security or transport I O PORTS ON THE PAGE MEMORY BOARD The page selecting I O port mentioned is one of eight por
123. ere until the next character comes in The state machine driver code is too bulky to fit here but there is one interesting aspect that bears mention ing Most state machines you ll see are based on a table of current state versus input character that deter mines which routine gets control Because the ANSI sequences have a fairly restricted syntax figured out how to trigger the code based on ei thera specific character the equal sign or a general class of character any digit Take a look at ANSI a5 1 for this column to get the details it may simplify some of your own code The driver stores all characters in a buffer so the action routines trig gered by the final letter can validate their parameters Because the Set Cur sor Position and Display Attribute sequences have several numeric para meters separated by semicolons included a semicolon detector ac tion to extract each preceding number Do action based on final letter Figure 2 This tate machine decodes the ANSI control sequences shown in Figure 1 The final letter in each sequence deter mines the function from the buffer into a numeric array When the terminating letter arrives the decoder action routine can access the saved parameters from the array A side benefit of buffering all the characters comes when the ANSI driver receives a defective sequence Rather than just ditching the charac ters the driver dumps the buff
124. erial port ring buffer L fetch lt lt lt serial port code omitted gt gt gt gees polish the character L polish CJUNE MOV A CR L 1 A LF L 1 SIF 0 A amp S7F R3 A R2 0 ENDPROC use LF instead of CR 3 strip high bit 7 high byte always zero ising 1 Combining keypad input with the serial port requires only a few lines of code if the keypad routine hasa character ready it will take precedence over one from the serial port ring buffers December 90 January 91 61 Screen coordinates start with Row 1 and Column 1 in the upper left column The effect of coordinates outside valid screen boundaries is undefined Cursor Control ESC ESC Move cursor ditto this r cH lt ef ESC nA ESC nB ESC nC ESC nD Move Move Move Move cursor cursor cursor cursor ESC ESC Save cursor location ESC ESC Display Attribute Control to specified row and column is a synonym up n rows stop at top row down n rows stop at bottom row right n columns stop at right column left n columns stop at left column Restore cursor location Erase display and move cursor to upper left Erase line from cursor to right edge Once set an attribute applies until it is changed Some codes set multiple display attributes ESC xm ESC x ym The most useful x parameters are Cancel all attributes Bold or bright Dim or normal Blink Reverse video 30 37 40 47 S
125. esponds to an omnidirectional fluid gas pressure The deformation within this element usually the com pression of some sort of bellows or convoluted diaphragm is then meas ured and an electrical signal is gener ated which varies as a function of that deformation displacenent This ana log signal is then fed through an amplifiertoboost theamplitudeofthe transducer output signal to a reason able level for down line processing The typical transducer output usually rangesover the microvolt to millivolt level and may be a high impedance signal a differential signal with com mon mode noise a current output a signal superimposed on a high volt age or a combination of these It is usually amplified to a range of 1 10 volts Theamplifier output is channeled through a low pass filter which re duces the undesirable high frequency components noise within the signal Sometimes the signal is then passed through a nonlinear analog function circuit which may modify the signal by squaring multiplying dividing doing RMS or log conversion or lin earizing it The processed signal is introduced to an analog multiplexer which se quentially switches between a num ber of different analog input channels Each input is connected to the output of the multiplexer for a set time inter val during which the sample and hold module receives the signal voltage for sampling while the A D converter converts that value into a digital form Th
126. et foreground color Set background color Color codes are 30 40 black 31 41 red 32 42 33 43 34 44 35 45 36 46 37 47 green yellow Set display attribute to x You can set several attributes at once return to white on black only on displays that support blinking black chars on white background blue magenta cyan white Figure 1 These ANSI control sequences allow a remote device to control the cursor location and display colors on a local terminal emulator The ESC symbol designates the Escape character ASCH code 27 decimal or 1B hex There are no spacesin the sequences and the last letter must be capitalized as shown rewrite the whole smash from the top every single time Something Must Be Done ANSI ESCAPEES Fortunately the American Na tional Standards Institute ANSI has defined a set of cursor color and screen control codes that are loosely implemented in the PC world Figure 1 shows the most useful codes while the LCD can t display colors it should at least gracefully ignore those codes Most PC terminal emulators have an ANSI BBS mode in their bag of tricks 62 CIRCUIT CELIARINK so you can probably use these codes with no trouble Notice that these control se quences start withan escape character 1B hex 27 decimal yclept ASCII 27 hence their common name of ANSI Escape Sequences A left hand square bracket follows the ESC which identi fies th
127. gether than 0 200 double thenormal distance The signal lines are grouped into address data and control buses and each signal pin has a large functional name label The labels are on both sides of the board for ease of troubleshooting The board deals with a number of bugs that plague high speed circuits by eliminating the conditions that cause them The hand wiring can be used to reduce the chance of cross talk by using several levels of loose wiring rather than a neat bundle The power and ground planes are low inductance paths to the power pins around the edge of the board that reduce losses The large number of locations for power pins eliminate the need for daisychaining and long power leads thereby reducing voltage drop and noise propagation A manual entitled The Principles of Wire Wrapping is included with the board This brochure describes techniques in color coding of wires socket ID labels and test points to make a circuit much easier to test and debug The Protosystem AT is available from stock and costs 149 95 CANA Group 100 Walnut St Suite 402 Peoria IL 6 1602 800 747 2262 Reader Service 502 NEWPRODUCTNEWSNEWPRODUCTNEWS PATTERN RECOGNITION BOARD A pattern recognition board featuring 24 TTL DTL digital I O lines is available from Keithley MetraByte The PIO INT is an IBM PC XT AT compatible board that has been designed for use in data acquisition and control applica tions an
128. h whenever the external device is being accessed Up to 21 bits of TTL logic level I O can be utilized on the RTC HC11 processor however several of these lines are input only output only or shared with another subsystem Table lisa brief description of each1 O port or signal which can accept a TTL level input or output as well as the connector s on which the signal ap pears The on chip A D converter can be used to measure analog inputs in the range of O 5 VDC All channels are single ended referenced to ground with an adjustable precision reference driver This chip must be installed for the ADC to operate to its maximum range Each of the eight input channels can be read and the resulting voltage calculated as follows Input voltage V_ 256 x Port input value For example if V_ 5 00 volts and channa 0 of the A D converter is read and its value is 200 decimal then the input voltage to channel 0 is 5 00 256 x 200 3 91 volts Listing 1 illustrates the use of the analog to digital converter while in a BASIC 11 program PC Bus Data Acquisition and Control Quality U S manufactured cards and software for single user OEM or embedded applications nEw PRODUCTS NEW CATALOG NEW PRICES ADA2100 395 4 Diff 8 S E channels 12 bit resolution 20ps A D 12ys or 8ys optional Programmable gains of 1 2 4 8 amp 16 Three 8 MHz timer counters Two 12 bit D A output
129. he register the sample and hold is switched into the hold mode After the DAC has changed to its new value with all spikes settled out the sample and hold is then switched back into a tracking mode As a result of this process the output changes smoothly from its previous value to the new value ERROR FUNCTIONS IN A D AND D A CONVERTERS Of course actual A D and D A converters don t have the wonderful ideal transfer functions I ve described above In reality they contain three different types of operational errors called offset gain and nonlinearity errors They are all functions of time and temperature and they all appear simultaneously Examples of these error functions are shown in Figure 11 They are de fined as offset error results from transfer function failure to pass through zero gain error is the difference in slope between the actual transfer function anditsidealone tisusuall yexpressed as a percent of analog magnitude nonlinearity error is defined as the maximum deviation of the actual transferfunctionfromani deal straight line at any point along the function It is expressed as a percent of the full scale or in least significant bit size It assumes that the offset and gainerrors have been adjusted to zero Today most A D and D A con verters enable external trimming of offset and gain errors at least at ambi ent tenperature Nonlinearity error however cannot be adjusted out and remains an i
130. here is no doubt that while C is great for quick and dirty hacks nobody includ ing the programmer should expect to go back later and understand what was done Programs written in Pascal and especially Modula 2 on the other hand tend to be clearer and better organized making them easier and faster to review and verify They are also more likely to produce reusable code Stephen R Troy Severna Park MD P C B ARTWORK MADE EASY Create Printed Circuit Attworkon your IBM or Compatible MENU DRIVEN HELP SCREENS ADVANCED FEATURES EXTREMELY USER FRIENDLY AUTO GROUND PLANES 1X and 2X PRINTER ARTWORK 1X HP LaserJet ARTWORK HP and HI PLOTTER DRIVER optional 49 00 REQUIREMENTS IBM PC or Compatible 384K RAM DOS 3 0or later IBM compatible printers PCBoards layout program 99 00 PCRoute auto router 99 00 SuperCAD schematic pgm 99 00 DEMO PKG 10 00 Call or write for more information PCBoards 2110 14th Ave South Birmingham AL 35205 205 933 1 122 Reader Service 1 73 NEWPRODUCTNEWSNEWPRODUCTNEWS HOME AUTOMATION CATALOG ON FLOPPY DISK Home Control Concepts has released its newest catalog on diskette The 1990 Home Automation Catalog on Floppy Disk includes home automation and security equipment specifica tions pricing explanations and uses The catalog also includes information on home automation the CEBus Consumer Electronics Bus home automation standard SMART HOUSE and
131. how to turn on off the keyboard lights Num Lock Caps Lock Scroll Lock Is there some command that you send to the keyboard to do this I have noticed that if you toggle bits at memory address 40 17 or thereabouts and then let DOS have control of the keyboard the lights go on and off However for my CROSS 32 V2 0 META ASSEMBLER m Table based absolute macro crossassembler using the manufacturer s assembly mnemonics a Includes manual and MS DOS assembler disk with tables for ALL of the following processors 1802 6801 6805 6809 6811 68000 8048 805 1 8085 8086 8096 64180 37700 6502 50140 6 5816 7500 COP400 SUPER8 COP800 TMS320 Z8 TMS340 Z80 TMS370 Z180 TMS7000 2280 TMS9900 MORE m Users can create tables for other processors or ask us we have many more m Generates listing symbol table and binary Intel and Motorola hexcode mw Free worldwide airmail shipping amp handling US 199 00 CDN 239 00 UNIVERSAL CROSS ASSEMBL MS P O Box 6156 9 Saint John N B E2L 4R6 Canada Voice Fax 506 847 0681 rol Reader Service 195 December 90 January 9 J 91 real time application I can t let DOS have control Any help would be appreciated Thanks Msg 30920 From DALE NASSAR To FRANCIS DUNLOP I don t know if it will do exactly what you need but you can control the three keyboard lights AT only by issuing the follow ing instruction OUT amp H60 amp HED followed by OUT
132. human intervention from the remote computer and is quite limited Our DS2250 with its inherent intelli gence however can be programmed to function independently First we might implement the capability of re cording key code sequences directly from the keyboard so that we could later play them back to the computer Next wecould provide for stand alone initiation of sequences where ONDI would operate the computer using predefined sequences in response to external events With the addition of a communication protocol we could relegate remote communications to Total control run between unattended computers Consider a secure modem appli cation The remote calls in and leaves a password ONDI hangs up powers up the computer and starts a pro gram inputting the password on the command line Now the computer takes over and searches its database logs the transaction and if the pass word has a corresponding teleohone number it dials it directly This turns out to be an almost trivial exercise mainly because the computer is used to compute and the controller to con trol Just a simple matter of software Stay tuned My appreciation goes out to Dan Burke for his participation in this project John D ybowskihas been involved in thedesign and manufacture of hardwareand software for industrialdatacollectionand communications equipment His crowning achievenents are his daughter Ondi and his son John IRS 400 Very
133. ice 202 STEVE S OWN INK Steve Ciarcia finally did it After several happy years using an 80286 based Cone computer joined the 1990s and in stalled an 80386 fire breather on my desk suppose that should be feeling pretty excited about the whole affair but the transition focused my attention on a subject that shouldn t come up any more As went through software installation on all of the various programs I ve come to depend on it became painfully obvious that some pro grams were guided by the hand of a marketing staff and some by the hand of an engineer have a definite prefer ence for one type and think you ll be surprised to hear which one l Il start by describing two installation procedures It doesn t really matter which program I m talking about because there are scores of packages that use each method What does matter a great deal is the attitude each method exhibits toward the user In the first installation turn to the manual section titled Getting Started Following the directions and il lustrations insert Disk 1in driveA type Install Menus windows animated palm trees and pop up in structions guide me through all 27 screens and 7 disks worth of installation When I m through a new subdirec tory tree has been created and can use the manual as a guide to check on the contents of my AUTOEXEC sar and CONFIG SYS files In the second installation turn to the ma
134. ice if your ap plication does not require nonvolatile program storage or automatic load ing on power up Volatile program storage is not a problem if you use a terminal emulator that supports ASCII transfers on a PC for communications Simply list the program and save it to ASM BF BR BULK BULKALL CALL GO PROCEED EEMOD LOAD VERIFY MD MM MOVE 799 p LA12100 i 2 Price is complete Pods and Software E ncluded OI aa 100MHz sampling rate 12 channel a 24 Bit trigger word e TTL threshold level e Internal and External Clocks Menu driven software FREE software updates on BBS 20 and 24 pin PALs EPLDs 46V8 20V8 22V10GALs 2716 27020 EPROMs 87xxx MICROS EEPROMS incl 6 pin serial POWERFUL AFFORDABLE INSTRUMENTS Ah Reader Service 154 100 MHz Logic Analyzer 24 Channels 50 MHz Timing and state 2K sampies channel 12 Channel mode e More sophisticated units also avallable almost UNIVERSAL PROGRAMMER OD oto 16 amp 32 bit INTEL HEX Motorola S files balls NVS RAM pro gramming PC XT AT COMPATIBLE FREE software updates on BBS Call 201 994 6669 Link Computer Graphics Inc 4 Sparrow Dr Livingston NJ 07039 FAX 994 0730 lt addr gt Line asm disasm lt addr1 gt lt addr2 gt lt data gt Block fill memory lt addr gt Set up bkpt table Erase EEPROM Erase EEPROM and CONFIG lt addr gt lt addr gt Call subroutine
135. icrocontroller through an analog to digital converter providing an error signal The output control uses a digi tal to analog converter to vary the voltage of the electro magnet The hardware selected for this project includes the RTC52 and RTCIO Editor s Note See From the Bench in the April M ay 89 issue of Circurr Cerrar INK 8 for a description of the RTC52 and RTCIO boards 1 Both an A D and a D A converter are included on the RTCIO board Figure 5 shows the test setup which is fairly simple to construct A hefty electromagnet s field is directed by a steel bar added to the top pole This bar is bent down at each end creating flux lines which tend to pass through the sphere being levitated An IR transmitter and receiver are placed below the electromagnet within the magnetic s limit of attraction The analog circuitry to interface the IR input and solenoid driver is wired on a prototyping board The hardware stays the same no matter what algo rithm software we use Because the process load will be changing rapidly I ve chosen the combination propor Graphics Gems edited by Andrew S Glassner This handbook provides practi cal solutions to graphics problems and every graphics programmer will find it an essential tool in saving time and energy in their daily programming activities August 1990 833 pp 49 95 ISBN O 12 286165 5 Curves and Surfaces for Computer Aided Geometric Design A Practical Guide
136. in high enough then the part of the addition to the one at the origin a spectrum centered around f will fold piece of this spectrum is in Figure 6b over frequency folding into the origi Cross Assemblers romsso Simulators from 100 00 Cross DisassemblersS roms Developer Packages from 200 00 a 50 00 Savings Make Programming Easy Our Macro Cross assemblers are esy 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 re create the original assembly language source Thousands Of Satisfied Customers Worldwide PseudoCorp has been providing quality solutions for microprocessor problems since 1985 Processors Intel 8048 RCA 1802 05 Intel 8051 Intel 8096 196kc Motorola 6800 Motorola 6801 Motorola 68HC11 Motorola 6805 Motorola 6809 MOS Tech 6502 WDC 65C02 Rockwell 65C02 Intel 8080 85 Zilog 280 NSC 800 Hitachi HD64180 Mot 68k 8 10 New Zilog Z8 Zilog Super 8 All products require an IBM PC or compatible For Information Or To Order Call PseudoCorp 716 Thimble Shoals Blvd Suite E Newport News VA 23606 804 873 1947 FAX 804 873 2154 Redaef service 177 December PO January 97 23 Overshoot Full Scale Full Scale Input Step Settling Time error band Figure 8 The length of an amplifiers settling
137. ine is living in an area where there are no cable TV lines run Recent small talk has brought up a rumor that a company has developed an antenna which sets inside your window and is sort of like a mini satellite dish Ever heard of this This dish sounds more appealing than a huge roof top antenna Any help would be appreciated Msg 31450 From STEVE SAMPSON To RICHARD MITCHELL I ve seen the ads If it s the same one I saw I never had such a good laugh in my life The thing you need to know is that VHF and UHF dish antennas are not as effective as beams The little dish that you set in the window is for decoration only It works no better than a set of rabbit ears If rabbit ears will suffice and you want to look like a yuppie with a mini dish then by all means Otherwise you can go two routes buy a beam antenna cut to the exact frequency wanted or buy some wide band beams such as those sold by Radio Shack Depending on the distance and terrain nothing may help I wouldn t plan on reception over a hundred miles Where do you get these things In big cities There s usually an antenna specialist company I don t have a good answer there UHF dish antennas are becoming popular but these area couple of feet wide and the programming is not worth the reception GIVE THE GIFT OF TECHNOLOGY Circuit Cellar INK gift subscriptions are avail able for the technologically inquisitive people on your gift list You don t hav
138. ined as at least one second of silence followed by three minus characters The re ceive abort timer is implemented as a softwareretriggerableone shotthatis rearmed every time a character is re ceived The receiver signals the fore ground when a return is received or on buffer overflow indicating either normal completion or an error SYSTEM TIMEBASE All system timing is referenced to the timer interrupt routine that exe cutes every 25 milliseconds In addi tion to handling the escape sequence guard time timer and receive abort 129 0 without memory 149 169 32K x8 SRAM 32K x 8 NV SRAM Avoid the hassles of programming EPROMs A ROM Emulator can greatly reduce the time spent writing and debugging ROM code ck 0 tk E ial o gt Uui g0 aiid M S z gt lt S A Emulates 2764 27128 amp 27256 Plugs into target ROM socket and connects to PC parallel port via modulartelephone cable Accepts 32K x 8 SRAM or NV SRAM Loads Intel Hex Motorola S hex and binary files High and low RESET outputs for automatic startup after downloading Includes all necessary software and cables works right away PPALLAX 7 916 721 8217 AX 916 726 1905 Parallax Inc 5200 Desimone Lane 69A itrus Heights CA 95621 MasterCard AMERICAN alifornia residents add sales tax Bhipping 4 00 for UPS ground 69 00 for UPS 2nd day 18 00 for UPS next day Reader
139. ined by t P t K Ep t dt P 0 0 where P t output at timet Ki scaling constant t Ep t dt change of input at time t from time 0 Jo P 0 controller output at time zero A derivative output is directly related to the rate of change of the error That is the output is driven not by the amount of error but by how fast the error input is chang ing Therefore there is no output from either constant or no error and maximum output from instant error This mode is used in combination with the other modes due to its ineffectiveness when the input error is constant The derivative equation is defined as P K P dt si VISIBLE LASER DIODES Toshiba TOLD 9200 O 3 mw 670 nm Red output C Cat LDV 9200 75 00 O POWER SUPPLY for Toshiba 9200 series diodes 4 5V input 75 x 6 dia Cat LDD 92 35 00 os COLLIMATING LENS for visible diodes Just press over diode s2 Cat L DC 6 20 00 4 LASERS HELIUM NEON LASER KITS Kits consist of matching laser head and power supply along with a user s manual All kits are FDA approved HELIUM NEON LASER TUBES amp HEADS i m New hard sealed units 5 1 0 mW TUBE Operates on 1300VDC 4 0mA Dimensions 5 8 x 1 0 diameter Cat 06 35 00 95mW 633nm Red output with 12VDC input power supply Draws 85 amps Cat HNKD 95 110 00 5 7mW TUBE Operates on 2200VDC 6 5mA Dimensions 13 8 x 1 45 diameter
140. ing modes the chip inserted into this socket will con OKI CSRAM X8000 XA000 XC000 the board 38 CIRCUIT CELLAR INK Al5 tain executable code and the MCU will fetch its reset vector from loca tions FFFE and FFFF In some situ ations it may be desirable to install a low power static RAM in U8 and configure the battery backup jumpers to continuously maintain its contents GETING IN AND OUT Since the 68HC11 processor con tains several on chip peripheral sub A15 Al4 A15 OKI Al5 A14 AI5 A14 Al4 A13 Al2 All A13 Al3 A13 A12 A12 A12 XC000 SEL8 E SELA E SELC E Figure 4 Use of a PAL greatly reduces the number of discrete gates on Ald BDIO decoding and seral interfaces systems most of the external I O lines are shared with at least one other subsystem For example any or all of the eight A D converter inputs can also be used as TTL inputs Thus an application which required only four channels of A D could use the re maining four channels as TTL input This flexibility allows for allocation of on chip resources with a minimum amount of waste As a result configu ration of each on chip subsystem be comes somewhat compli cated with the 68HC11 having over sixty con figuration registers the details of which are be yond the scope of this article Tofullyutilizeall the features of the 68HC11 rec
141. ion of the crystal is fluid in particular the orientation can be changed by theapplicationofanelectronicfield To make a display the liquid crystal is sandwiched between a grid of electrodesand sheetsof glass The other key are two polarizers front and back which are oriented 90 degrees out of phase Polarizers have the property of only passing light which is aligned with the polarizer Perhaps you once tried this experiment during the heyday of polarized sunglasses Take two lenses and put them on top of each other N ow look through the pair as you twist them relative to each other Sure enough more or less light passes as the alignment between the two lenses is changed Finally behind it all is a reflector pane Remember the simplest LCDs rely on ambient light So light enters the first polarizer and is aligned in one direction Next the aligned light enters the liquid crystal and is eather twisted or not depending on whether the crystal is energized or not Light that is twisted by the crys tal can successfully pass through the second polarizer which is twisted relative to the first polarizer to thereflec tor and ultimately back to your eager eyes On the other hand light which doesn t get twisted by the crystal is lt Front Polarizer lt Glass H lt t _ Liquid Crystal fy 4 Glass lt 4 Rear Polarizer lt 4 Reflector December WJanuary 97 79 blocked by the
142. is group of commands Some commands have one or more numeric parameters and all end with an upper or lower case letter and the case is significant For example the sequence to set the cursor to row 2 column 3 looks like ESC 2 3H The sequence ESC 1 33 4 Im changes the color of allsubsequent characters to bright yellow on ared background at least on a color display Remeber that ESc represents the escape character The numbers are simple ASCII not binary codes the color change sequence is ten characters long not eight An ANSI driver intercepts all characters going to the display It passes through all normal charac ters unchanged but interprets the ANSI control sequences and takes whatever action is appropriate the control sequences are not displayed on the screen Under DOS the ANSI console driver is a separate chunk of software installed as a device driver while under OS 2 you get ANSI con trols free with every session Although you could write spa ghetti to decipher the sequences Fig ure 2 shows a state diagram that may make more sense and certainly re sults in better code When each char acter arrives the action you take depends on which state you re in If the character doesn t match any of the actions for the current state you reset everything and send the character to the LCD display Renember that the states themselves don t do anything they justremember whereyou w
143. is resultant digital word is then December 90 January 91 19 Ta aperture time AU amplitude uncertainty gure 3 Any analog to digitalconversion takes a finite amount of time during which the inout signal may change dumped onto the DAAC system s bidirectional data bus for access by the PC controller This of course is not the only approach to data acquisition In an often used alternative the measured signal is amplified and converted into digital form at the transducer The output is then transmitted to the PC through a serial port However im plementation of this technique re quires that the data be converted to parallel form and then multiplexed onto the data bus In the feedback control portion of the DAAC interface for all intentsand purposes we do the inverse of the input data acquisition process The computer based on analysis of its input determines the necessary out put control functions required to dict a specified response within the de fined process according to its opera tional guidelines These control out puts are digital in form and must be converted to analog form to drive the process This conversion is accom plished by employing a D A con verter usually coupled to a storage buffer which stores the digital word until the next update These buffers are under the control of the sequencer The output of the D A converter is used to drive actuators which directly control the v
144. ise and if you drop a note on the BBS after you ve studied the problem for a while we ll even help you out I m not entirely satisfied with C for microcontrollers The amount of code per line seems excessive the C language library routines are entirely too bulky and there are regrettably some vicious bugs Is it better than s gt conversion table entries contain BASIC Yes indeed Is it better than 7 0 binary fraction bit location gt s gt 1 2 packed BCD equivalant of that binary bit assembler Yes mostly Isitoptimum go 324 packed BCD 9 s complement of that bit Umm certainly not 7 must be ordered from highest to lowest bit for string conv i C can perform reasonably well if PRENET Y eo vbr apn you are willing to devote an inordi DW d nate amount of time to creating your a T own library routinesin assembler and keep an eagle eye on your code space SEG Constants usage If your project permits that ORG CONSTBASE FXP_CONST i level of attention C is probably the FixTable FixEntry 80 5000 5000 righ o vou can write more FixEntry 40 2500 7500 amp t way tog M A FixEntry 20 1250 8750 complex logic with less effort than in FixEntry 10 0625 9375 mbler for sure The catch is that FixEntry 08 0313 9687 asse 7 FixEntry 04 0156 9844 you may run out of either space or FixEntry 02 0078 9922 time sooner than you expect FixEntry 01 0039 9961 y pS BITLOC EQU offset of bit ID BCD
145. ize problems and find quicker solutions 88 CIRCUIT CELLAR INK Msg 31279 From KEN DAVIDSON To ROBERTO PUON That sums it up pretty well When I was going through school I kept saying But that s not the way it works in the real world Strictly speaking with digital electronics you rarely worry about poles and zeros and Norton equivalents but it s absolutely necessary in my opinion to have a solid background in that stuff just so you know why things work the way they do Much of the theory and math doesn t directly apply to real world engineer ing but you often have to keep it mind when deciding on design tolerances and what you can and can t get away with I have a friend that I graduated with who is working on cordless phones at AT amp T His digital experience is pretty weak but he s an ace analog designer He uses a lot of the math and theory every day that I ve been exposed to in the past but was happy to put behind me I was just talking with him this weekend and he was saying something I agree with you don t go to engineering school to learn about what chips are out there or the best way to lay out a PC board You go to school to learn the basics of the design process and to learn how to learn The best thing that can happen to you when you graduate is to be paired with a 20 year veteran He ll be able to teach you things you never dreamed of in school but with the proper background you ll be prep
146. job long enough to have enough seniority to reassign the task to the new kid on the block and go back to his tough management job managing the coffee and doughnut fund Engineering is 90 intelligent gut reaction and 10 mathemati cal analysis The only problem you ve got as a young engineer is that the majority of old geezers on the project will be winging it by then on politics and reputation and the new guy with have to do the work In that case you better know some math Don t get me started on this If you are in school then learn some thing If you really shouldn t be an engineer don t find it out on the job Msg 31295 From ED NISLEY To ROBERTO PUON The single most fundamental mathematical operation you ll ever learn is long division and was taught this long after gradu ated so you can savesome time What you do when you re starting work on a problem is take two critical parameters and divide one into the other If the ratio doesn t make sense the project is usually in serious trouble When you do this sort of thing in your head you develop a reputation for Great Wizardry Unfortunately in order to know which two numbers to divide and when the result makes sense requires a solid background in the math you ll get in college For example you need to know how fast is do able how strong is something about that thick and how heavy is something about that big which you get from knowing physica
147. kbooks and any number of titles from Tab Books can get youstarted down the road tomicrocomputerand control ler design Good Luck DIGITAL VOICE RECORDER 3 DVR 120M 149 95 4 Mb DRAM up to 2 minutes recording time 16 variable length messages each w direct trigger terminal Very low standby current only 8 mA VOX on off switch REPEAT mode available Built in back up system to prevent memory loss ENDLESS feature for continuous recording Completed product w dynamic MIC amp AC adapter TALKING ALARM TIMED MESSAGE DEVIC VERBAL NOTEPAD GUIDANCE SYSTEM HAM OPERATION TALKING COMPASS TELEPHONE MUSIC ON HOLD TALKING BIRD TRAINER VOICE WARNING SYSTEM NEW UPDATED VERSION INSTANT EPROM ERASER Erase EPROM in only 5 seconds IEE 9088 149 95 SALE wes 249 99 Reader Service 166 Now boot from SRAM RDCS12 only The best way to prevent Computer Virus Put DOS amp app files in EPROM or SRAM Vibration dust and humidity proof REMOTE CONTROL SYSTEM ZEMCO SA 432 Only 49 95 BEST C SELLING December 90 January 91 5 PHONE WIRE IAN was reading through CIRCUIT Centar INK 17 when ran across Low Cost LAN using X 10 Technology in the ConnecTime section There is an excellent base for a low cost home LAN using the existing teleohone wire
148. l CONTROL BUS o Emulates up to 8 1 Megabit EPROMS with one control card e Downloads Megabit programs in less than 10 seconds AIOWS examination and modification of in dividual bytes or blocks Nd p 1 jojo js fon fon ps wo py iS IN Ww LiL 6 J4 JS 16 7 819 BEECARD EPROM EMULATION SYSTEM Accepts Intel Hex Motorola S Record and Binary files e Software available for IBM PC and Macintosh systems Call or fax today for more information Base 27256 EPROM System 395 00 Other configurations available Incredible Technologies Inc 709 West Algonquin Road Arlington_Her hts Illinois 60005 708 437 243 Fax 708 437 2473 Visa Mastercard and American Express accepted Reader Service 142 TALK TO YOUR COMPUTER WITH VOICE MASTER KEY FOR PCs COMPATIBLES VOICE RECOGMTION WITH SPEECH RESPONSE GIVE A NEW DIMENSION TO PERSONAL COMPUTING The amazing Voice Master Key System adds voice recognition to Just about any program or application Voice command up to 256 keyboard macros from within CAD DTP word processing spread sheet or game programs Fully TSR and occupies less than 64K Instant response time and high recognition accuracy A real productivity enhancer SPEECH RECORDING SOFTWARE Digitally record your own speech sound or music to
149. l ASCII commands Irom any PC serial pu modem or dumb terminal CEBus language or X 10 commands may e directly entered through serial port for output on the AC powerline The battery backed clock and 256 event table conto CBM 100 or X 10 modules 350 by time of day independent of the PC CSI 100 MS Menu Software NO CHARGE CBM 100 Powerline 1 0 Module Features six digital VO lines which are brovugit out to 1 header for easy anachment to accessory 1O boards One VO line also drives an on board opto coupledtriac capable of controlling a 1201240 VAC 4 amp load via screw terminal barrier strip Board 95 is compatible with CEBus commands CBM 1 00 02 CBM 100 03 CBM 100 01 Opto lsolated Input Relay Driver Terminal Board 45 32 30 COMING SOON Analog Powerline Modules 269 95Std Res 256 x 244 369 95 High Res 512 x 488 Supervision 8 is an adapter with software the latest ineconomically capturing high quality real world images with your computer e HalfSize Cards e 256 Grey Levels 8 Bit e Capture Time 1 60 second e TIFF and PCX Format PC XT AT Commatible e Binary Image File BIF MC Visa AM Express RS 170 Video Source IDEC INC 1195 Doylestown Pike TEL 215 538 2600 Quakertown PA 18951 FAX 215 538 2665 Reader Service 143 Reader Service 10 64 CIRCUIT CELLAR INK A BRPS Files ra fornace Logger cdenn Photo 2 The same display as in Photo looksmuch nicer on a ful color CR
150. l and electrical properties took the dreaded Fields amp Waves courses in the Physics rather than the EE department because really gummed up my sched ule took a semester off killing calves at a medical research center but that s another story The EEs learned about transmission lines klystrons and stuff like that In the physics classes we did the really grim math I knew was in good company when the Physics major in the back row asked What s a tensor after the first lecture the hard way But while can t do any of that stuff any more have a reasonable appreciation for why you build high frequency stuff the way you do No you ll not need much of what you learn but everybody uses a different portion The value of your education is what you know when you ve forgotten everything you learned in class think about it All too often we get stuck in the mindset that for a digital circuit to doany useful work a processor must be included M any times though a simple state machine may do the trick using less board space and at a much lower cost in terms of both actual hardware and design time Msg 31396 From DAVID M WILLIAMS SR To ALL USERS Does anyone have or know where can obtain plans for a digital cypherlock have a twdvekey keypad and need something for the kids to use to activate the garage door opener had a unit made by 3M but a lightning strike took it out and it s to hard to get pa
151. lel ports a serial terminal port with auto baud rate selection a serial primer port and is bus compatible with the full line of BCC bus expansion boards BASIC 52 s full floating point BASIC is fast and efficient enough for the most complicated tasks while its cost effective design allows it to be considered for many new areas of implementation It can be used both for development and end use applications QiCAD is a full featured printed circuit layout package that gives you everything you need to design circuit boards quickly e ON LINE HELP e AUTOROUTER Processor Input Output 80C52 BASIC 8 bit CMOS microcomputer sconsole VO RS 232 serial port s Paii ii ies sjum oe conversion to ae printet RS 232 de pat on 1 32 functionali three programmable TTL compatible e HPGL 8K bytes ROM full BASIC interpreter parallel 1 0 ports using a 8255 PPI e GERBER 256 bytes RAM alternate console RS 422 RS 485 sthree 16 bit counterAimers e POSTSCRIPT TT iat S em dock To Order Call e EXCELLON DRILL 6 interrupis 1 800 67 5 3355 EGA VGA compatibile Menon bee iole a h TEGA P sxpandale 1062K bylos Fax 203 872 2204 sup to four 6264 8Kx8 static RAM TELEX 643331 either an 8K 2764 or 16K 27128 EPROM ag 1 95 00 complete price Ca GOLLE Single Ory 100 Ory BCC52 BASIC 52 Controller Board with 8K RAM 189 00 149 00 BCC52C coner power all CMOS version of the BCCS2 199 00 15
152. lity and con ditionof materials and work manship of reader as sembled projects Circuit Cellar INK disclaims any re sponsiblity for the safe and proper function of reader assembled projects based upon or from plans descrip tions or information pub lished in Circuit Cellar INK CIRC UITC ELLAR INK ISSN 08968985 is published bi monthly by Circuit Cellar In corporated 4 Park Street Suite 20 Vemon CT 06066 203 875 2751 Second class postage paid at Ver non CTand additional of fices One year 6 issues subscription rate U S A and possessions 14 95 Canada Mexico 17 95 all other countries 26 95 surface 38 95 air All subscription orders payable in U S funds only via intemational postal money order or check drawn on U S bank Direct subscription orders to Circuit CellarINK Subscriptions P O Box 3050 C Southeastem PA 19398 or call 215 630 1914 POSTMASTER Please sendaddresschangestoCir cuit Cellar INK Circulation Dept P O Box 3050 C Southea stem PA 19398 Entire contents copyright 1990 by Circuit Cellar In comporated All rights re served Repfoductionofthis publication in whole or in partwithoutwnittenc onsent from Circuit Cellar Inc is prohibited December 90 January 91 3 MILDEW REDUX wrote to you last year concerning the problem of mildew attacking diskettes which have been stored for six months or more in a tropical climate without air condi tioning
153. llar Right now I am a junior in college and I am an EE major I ve not taken but one digital electronics course I really enjoy electronics and if my job is going to be as fun as my hobby has been work is going to be a party I have one question for all of you Electrical Engineers which you might have asked yourselves when you were in college How much of the math that you studied in college do really use in the field Msg 31211 From JAMES D STEWART To ROBERTO PUON As a non degreed engineer who worked his way up from fixing missiles in the Army in 1970 to project leader presently I would guess very little Ohm s law and basic math skills are all I ve ever used You could probably argue that they are all that I have The one place that I have been stuck in the past is trying to understand algorithms used with digital signal processors It hasn t been a serious problem yet and my contingency plan is to hire a tutor as needed when I start to work with them seriously The University of California at Berkeley is next door and there are lots of math giants willing to work cheap I think the amount of math that you need is greatly dependent upon the type of engineering that you are doing Most engineers doing microprocessor development do very little math If you work in communications process control or signal processing you will need more higher math I feel that if I had had more math perhaps I would be better able to visual
154. logic circuits with either a single pulse or continuous pulse train The LM 2A simultaneously displays the static and dynamic states of 16 logic inputs Each kit contains a logic probe to find pulses even too fast for an oscilloscope The LTC 6 kit contains the LP 1 10 MHz probe the LTC 7 kit contains the LP 3 35 MHz probe and the LTC 8 kit contains the LP 5 100 MHz probe The price of the test kits range from 299 to 379 Global Specialties 70 Fulton Term New Haven CT06512 203 624 3103 Fax 203 468 0060 DSP OPERATING ENVIRONMENT An IBM PC based operating environment designed to develop or study Digital Signal Processing DSP algorithms is available from BittWare Research Systems D SP H eadquarters DspHq allows an algorithm designer to write functions to operate on a block of data and it will supply the test data handle file and memory management and generate graphics DspH q was designed to be an open architecture to allow users to integrate included functions popular function libraries and their own routines written in C or Pascal Algorithms pass and share common data structures and can be calculated by PC or downloaded to a signal processor DspH q includes a 10 CIRCUIT CELLAR INK Reader Service 504 menu interface command interpreter batch command processor file and memory management and screen graphics with hardcopy support for dot matrix laser PostScript and HPGL de
155. ltiple channels on the same card Theresultis thatthisunitcanbetreated as a standard I O peripheral using canned software drivers Examples of different peripheral configurations that you can find on the market are e Analog in A D only with 8 to 256 channel input capability e Expanders forapplications need ing extra analog channels Microcontroller Board PC 8031 Multi Application areas e real time control e Data Acquisition e software development evaluation Production Software e Powerful Monitor Debugger PROM included e BASIC Forth Assembler Monitor optional FM 603 469 3530 ram etc 4952 603 469 3232 Binary Technology Inc 8xc552 CPU e wire wrap area with uncommitted DIN 41612 connector e RS232 interface 9 way AT or 25 way XT connector e Single 5 volt supply e Power fail detect e Processor contains 8 channel 10 bit ADC 2 channel PWM 16 extra I O lines over function timer counter with capture and compare e Standard 8031 peripherals I O serial port timers Analog out D A only with 4 to 64 channe output capability Analog out expander boards for multichannel analog out capability CombinationA D Aunitswith 8 to 64 analog I O channels To be honest there are other con figurations but you get the point There is a whole realm of real PC oriented application DAAC systen components available The availabil ity of hardware and associate
156. mage processing display and TIFF PCX file handling routines Your software can have features such as live video on VGA resize and zoom display multiple images with text and graphics Image processing functions include brightness con trast matrixconvolution filters sharpen out line etc linearization equalization math and logic overlay resize flip invert mirror Size number of images limited only by memory Display on EGA VGA up to 800x600x256 And to get you up and running quickly we ve Included our popular Zip Image Processing software for rapid testing and prototyping of image processing and display functions Victor supports Microsoft C QuickC and Turbo C all for only 195 Victor and Zip support ImageWise and sther popular video digitizers NEW ZIP Colorkit the software that allows any pray scale digitizer to create photographic quality color images it s easy to produce stunning color images with the ZIP Colorkit capture threeimageswith a tray scalevideo digitizer using red green and slue filters and save the images Colorkit loads he image files and uses a unique optimizing tlgorithm to calculate the optimum color mage Supports PIW PIF PCX TIFF GIF ind TGA file formats ZIP COLORKIT 75 VICTOR LIBRARY includes FREE ZIP Image Processing VICTOR LIBRARY with video frame grabber ZIP Colorkit oo 75 Call 314 962 7833 to order VISA MC COD CATENARY SYSTEMS 470 B
157. module are paired up as high and low bytes They are selected using the SIM M s write enable high and low WEH and WEL signals Intel s IC memory card adheres to the Personal Computer Memory Card International Association PCMCIA standard This standard specifies physical electrical information struc ture and data format characteristics of the card Most impressive is the size measuring 85 6 mm x 54 0 mm x 3 3 mm Its 68 pin interface includes 26 address lines used to directly ad dress 64 megabytes All buffering and chip leveal decoding is contained within the card greatly simplifying the board level design Intel s flash memory card is available with one and four megabytes These cards will continue to grow in density becom ing more and more competitive as disk drive replacements MEMORY METHODS Three fundamental addressing methods can be implemented when interfacing a flash memory array to a system bus linear I O and paged Eachmethod hasits benefits and draw backs A linearly addressed memory array is mapped directly into the sys INTEL PAGED FLASH MEMORY EL URLURTIUN BOARD tern s memory space and allows the highest performance However the memory array would be insufficien tly small in systems having limited memory space as with the 8086 But this method is practical in an 80386 or other 32 bit processor family system with a large memory space available An I O mapped memory array uses
158. more the useful view ing angle may be as little as 30 35 degrees If you ve ever tried to share an LCD display with another person show ing them something on the screen for example you know it only works if both of you are real good friends Unless you butt heads one of you will see mush The solutions that have emerged for contrast viewing angle problems are variations of the Super Twist theme lt Front Polarizer lt Glass lt 4 Liquid Crystal 2 lt Glass lt Rear Polarizer lt A Backlight HAJAR ASSOCIATES NATIONAL ADVERTISING SALES REPRESENTATIVES NORTHEAST MIDWEST Lisa D Ambrosia Nanette Traetow 49 Walpole Street 242 East Ogden Avenue Norwood MA 02062 Suite A 617 769 8950 Hinsdale IL 60521 Fax 617 769 8982 708 789 3080 Fax 708 789 3082 MID ATLANTIC Barbara Best ESE ROASE 569 River Road Barbara Jones Fair Haven NJ 07704 amp Shelley Rainey 201 741 7744 3303 Harbor Blvd Fax 201 741 6823 Suite G I 1 Costa Mesa CA 92626 SOUTHEAST 714 540 3554 Christa Collins Fax 714 540 7103 7640 Farragut Street Hollywood FL 33024 305 966 3939 Fax 305 985 8457 The simplest is called STN Super Twisted Nematic The only differ ence from TN is that STN twists the light more which resultsin a 20 50 improvement in contrast and view ing angle The next iteration DSTN Double Super Twisted Nematic Figure 2 is nothing more than
159. mperature sensors emperature range is minus 76 lo 145 degrees F 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 IC s 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 lo 19 200 baud Use our 600 number lo order free information packet Technical Information 614 464 4470 24 HOUR ORDER LINE 800 842 7714 Visa Mastercard American Express COD ELECTRONIC ENERGY CONTROL INC 360 South Fifth Street Suite 604 Columbus Ohio 43215 Reader Service 130 14 CIRCUIT CELLAR INK once we have working we will not be apt to disturb Typically the applica tion calls mz whenever it has com pleted its specific function such as interpreting a command or transmit ting a string of data On return the application has the option of either processing or ignoring the return code as appropriate A quick look at this arrangement confirms the premise that a typical program executes five per cent of its code 95 percent of the time m s return codes are Received text available 2 Receive error command line overflow 3 Escape sequence received Q Receive timeout
160. n data stored in a format such as YYMMDDHHMM lt data byte gt would allow for an entire month s 31 days worth of data to be collected before the BEE card needed to be changed Throw out the year and the month or write them only once as header information whenever the system is powered up and the storage time can easily be stretched to fourty eight days Our approach with this design was to build a system that was appro priate for smaller simple applications It has helped us solve some unique problems and we ve gained valuable experience regarding the use of RAM card technology along the way We would like to thank Claire Bienen at Mit subishi International for helping out with tech nical information support and of course the BEE cards used in our original prototype M any thanksalsogo to Carl Baxter of Business and Technical Consultants for his real world testing of several early prototypes Tim McDonough and Bruce W ebb are princi pals in Cottage Resources Corporation Sources Mitsubishi International Inc 520 Madison Avenue New York NY 10022 An assembled and tested Datalog R less the 32K BEE card is available for 179 95 plus 3 00 S amp H per order 32K BEE cards are available for 57 95 each when purchased with the Datalog R I Cottage Resources Corporation 1405 Stevenson Dr Ste 3 672 Springfield IL 62703 217 529 7679 IRS 406 Very Useful 407 Moderately Useful 408 Not Usefu
161. n EEPROM Line 500 resets the ONTIME setup so that BASIC s rme variable continues to increment prop erly Once a program has been de bugged several options are available for permanently saving the tokenized code depending on how the inter 10 REM Storesalleight A D converter channel readings to the 20 REM first eight EEPROM locations once each hour 30 TIME 0 40 ONTIME 3600 500 50 GOSUB 700 60 GOTO 50 500 ONTIME TIME 3600 500 51 520 PRINT 530 FOR 0 TO 7 A ADC T PRINT A EEP I A NEXT I PRINT RETI PRINT n REM read the A D converter REM send the reading to the console REM save reading in nonvolatile EEPROM REM This subroutine is called whenever the timer interrupt REM is NOT being serviced REM hour timer RETURN i e most of the time for a one Listing 1 Using BASIC I s ADC and EEP functions allows BASIC to directly exercise the A D and EEPROM a ee a I TT IT preter s configuration bytes have been set Ul timately my intention is to have configuration bytes that are located in the on chip EEPROM which determine how RAM and EPROM memory will be shared by the BASIC 11 inter preter initial software releases will involve separate EPROMs for each operating mode In the simplest configu ration Mode 1 BASIC is given access to all available RAM from 1040 to 7FFF This allows you to develop the largest possible RAM based program about 28K and is the best cho
162. n fact the flash memory cell is identical to the EPROM structure except for the thinner gate tunnel oxide This is where the similarities end The thin ner gate oxide enables flash memory to be erased and reprogrammed in circuit typically 100 000 times The name flash is derived from its one second chip level erase and microsec ond level byte write times versus the slower millisecond leve byte write times for conventional EEPROMs Flash memory devices have a command register architecture that providesamicroprocessor compatible 50 CIRCUIT CELLAR INK write interface Erase program veri fications and other operations are initiated by issuing the proper com mand to the flash memory device Twelve volts must be applied on V for the command register to respond to writes and execute the operation The 12V requirement doubles as an added security feature for data integ rity If you are familiar with other memory subsystems designing with flash memory is as simple as any other technology In addition to discrete compo nents Intel offers flash memory in SIMM and IC memory card formats This design will use these modules so I ve induded some pertinent infor mation The512K bytex 16 Intel Flash SIMM SM28F001AX is based on an 80 pin JEDEC standard that accom modates density upgrades and pres ence detect a hard wired ID that indi cates SIMM density and speed The eight megabit flash memory devices on this
163. nal decoders determine which input transition edge is sensed The output compare pins provide an output whenever a match is made between the value in the free running counter in the timer system and a value loaded into the par ticular 16 bit output compare register When port A bit 7 is configured as a PAI the external input pulses are applied to the pulse accumulator system The remaining Port A lines may be used as general purpose input or output lines PORT B In the single chip mode all port B pins are general purpose output pins Port B may also be used in a simple strobed output mode where the STRB pulses each time port B is written In the expanded multiplexed mode all of the port B pins act as high order bits 8 15 address output pins PORT C In the single chip mode port C pins are general purpose input output pins Port C inputs can be latched by the STRA or may be used in full handshake modes of parallel I O where the STRA input and STRB output acts as handshake control lines In the expanded multiplexed mode Port C pins are configured as multiplexed address data pins During the address cycle bits 0 through 7 of the address are output on PCO PC7 during the data cycle bits 0 through 7 PCO PC7 are bidirectional data pins controlled by the R W signal PORT D In all modes port D bits O 5 may be used for general purpose I O or with the serial communications interface SCI and serial peripheral interface SPI subsystems Bit
164. nd a Maxim MAX232 to main tain single voltage power supply operation An 11 0592 MHz crystal allows no hassle programming of standard data rates from 1200 through 9600 bps A serial port makes sense in this application for a couple of reasons First and most important it allows a Datalog R board with appropriate firmware to be used as an inexpensive BEE card reader back at the lab so the user can move the collected data to another computer for analysis and further processing Second we recog nized that there is a lot of scientific instrumentation equipped with com munications ports that the original manufacturer assumed would be connected directly to a host computer By using a Datalog R as a sort of mini host that polls the equipment for information and stores it in the BEE card it is possible to use the equip ment in a remote location without having to dedicate a PC or an expen sive laptop computer to data collec tion when the total volume of data is small IN THE RELD Using the Datalog R is quite simple Although we have inserted and removed the RAM card from an operating system many times it is advisable to have the power off when ever swapping cards This avoids the possibility of inserting or renoving the card while it is being accessed by the 8031 and perhaps corrupting the data or damaging the card The BEE card is inserted in the Datalog R with the legends and the electrical contacts facing up Once
165. nd allows the margin voltages to settle In the verify mode pro grammed data is guaranteed to be permanent whenitmatches thedata being programmed USING YOUR PAGE MEMORY BOARD AS A DATA RECORDER There is a nearly endless list of data recording applications includ ing digital imaging digital photogra phy point of sale terminals patient monitors and flight recorders The page memory board is appropriate for many data recording applications whereanl Oportof the PC AT accu mulates data The programming algorithm demonstrates the byte programming capability of flash memory In other words once the device is erased bytes reprogram randomly In some record ing applications data is received in packets A pointer determines where to begin programming the next free location within the flash memory Interleaving increases write per formance by using the idle time dur ing the 10 us program delay Ad dresses are offset such that each suc cessive data byte gets written in dif ferent devices looping back in time to issue the verify command Reading the data back would be doneina similar fashion Word wise or parallel program ming of two devices provides an additional means of increasing write performance Note that flash memory devicesmayprogramatdifferentrates Therefore the original algorithm must be modified during the verify opera tion If only one byte of the word has verified the program command and d
166. nds when the testing is finished I m convinced though that working hardware or software is only part of the job Getting to working hardware or software may in fact be the easier part of the total The rest of the job is making that product easy for a customer to use Documentation help files user interface with or without graphical in front and packaging are all crucial parts of a good professional product All too often they re parts that are left to under trained people struggling to make a deadline that the technical professional ignored It s a shame that the as pects of a product that play the majority role in forming a customer s impression of the package receive the least attention from the engineers Writing isn t easy Programming pop up windows takes time that could be devoted to optimizing thelast 10 of the program Indexing a manual isn t nearly as much fun as designing a fast frame grabber board In spite of all these facts the human interface is an important part of the job too important to be left to people who didn t have a hand in the development of the hardware and software l vealwaysbelieved that theengineer should write the manual but the struggles with upgrading my computer made me go back and look at the manuals we ve written In many cases there is definite room for improvement I m an engineer not a marketing guru but can learn a lesson Engineering s just a hobby if ther
167. nherent characteristic of the converter But renember be careful when you operate a converter over a signifi cant temperature range Theeffect due to this change must be carefully deter mined Of key importance is whether the device remains monotonic that is whether it has missing codes This can be determined by computing the dif ferential nonlinearity tenpco speci fied for the converter If you assume that the converter has at least half the least significant bit of differential non linearity error then the change in temperature resulting in an increase to 1can be written as n 6 yee RID 2DLT where n is the converter resolution in bits and DLT is the specified differen tial nonlinearity tempco in parts per million ppm of full scale range per degree Casius Here is the maxi mum change in temperature that the convertercanhandlebeforeitbecomes non monotonic This suggests that an organized approach be undertaken when you design your DAAC system The A D and D A converters are the primary components so you should draw up a checklist of required characteristics which at minimum should include the following key items 1 converter type 2 resolution 3 speed 4 temperature coefficient After your choice has been nar rowed down by these considerations you should then determine how your system fits the following 1 analog signal range 2 type of coding 3 input impedance 4 power su
168. niffed at You will probably find that the dynamic range of 128 available with a single integer byte is not enough The next logical step is two integer bytes and one fraction byte giving you 32K with 0 39 resolution If you can afford four bytes add eight more fraction bits and extend the reso lution to 15 parts per million The algorithms I ve used scale nicely to more bits and digits although you will have to modify the register usage because avoided buffering interme diate results in RAM SUMMING UP At this point you have nearly everything you need to build an 8031 system that 11 blow their socks off interrupt driven ring buffered serial I O console support for both LCD and keypad hardware fixed point math nonvolatile RAM analog in puts timekeeping and a great glob of glue code All you need is the pro gram that connects the pieces But do you need C No it turns out that most of the code doesn t de pend on C at all True the calling conventions are peculiar to Avocet C but those can be readily adapted to other compilers or to your own as sembly language standards as you see fit Of late I ve ignored the BASIC 52 interpreter because shoehoming the codeinto that straitjacket requires too much fiddling around for my pur poses here However did write the LCD and keypad code with BASIC 52 in mind so it would not be too diffi cult to support BASIC console I O l II leave this as an exerc
169. nse la by Tim McDonough amp Bruce Webb CIRCULATION Credit card memory offers non CONSULTANT volatile storage in a portable package Gregory Spitzfaden Interfacing to Mitsubishi s version ART amp PRODUCTION couldn t be simpler DIRECTOR Tricia Dziedzinski pianists Using the Motorola MC68HC11 A Venerable History and a ARTIST ILLUSTRATOR Lisa Feny Certain Future es by Steve Ciarcia amp Burt Brown BUSINESS Motorola s 68HC11is a powerful 8 bit MANAGER processor It s a perfect choice fora Jeannette Wa Ter compact controller ADVERTISING COORDINATOR Dan Gorsky STAFF RESEARC HERS Northeast signing with Hash Memory Eric Albert There a New Altemative to EEPROM and SRAM William Curlew by Markus A Levy Richard Sawyer Flash memory is the latest development in user programmable Ropert srek nonvolatile storage Midwest Jon Elson A PC bus desgn illus Tim McDonough trates techniques for West Coast interfacing and Frank Kuechmann programming Mark Voorhees Cover Illustation by Robert Tinney 2 CIRCUIT CELLAR INK DEPARTMENTS ee E A faces sls o Editors INK I ve Seen the Future by Curtis Franklin J r The times are a changing and so is our industry A recent industry conference provided a murky crystal ball for your editor Reader s INk Letters to the Editor NEWProductNews Firmware Fumace ANSI Contols and Fixed Points The Fumace Firmware Proj
170. nt Tools zero crossings of the waveform and the amplitude of the error becomes AV ta C Asin wt taA Q The resultant error as a fraction of the peak to peak full scale is For example the aperture time re quired to digitize a 10 kHz signal to 12 bits of resolution can be estimated as Ta z 0 000441 3 14159 x 10 0 x10 7 7x 10 that is 7 7 nanoseconds With num bers like these one begins to under stand the difficulty converting signals in the tens of gigahertz range where some of the latest scopes are now em ployed Also affecting the overall aper ture time is the sample and hold time COMPLETE 8096 DEVELOPMENT ENVIRONMENT ENV96 streamlines your design process by allowing you to bring your idea to prototype quickly and efficiently ENV96 is a plug in development board for Intel s 8096 80C196 microcontroller ENV96 includes an 8097BH or 80C197KB processor support hardware a shared 64K RAM module an interface to the PC a wirewrap area with digital and analog power and ground distributed throughout and wirewrap pins on the PC Bus and processor pins Easy to learn Debug software simplifies HW SW debugging nnapolis Micro Systems Inc Q der Serice 107 190 Admiral Cochrane Drive 304 841 2514 Annapolis MD 21401 FAX 301 844 2548 December WJanuary 97 2 Courtious Service Discount Prices Fast Shipping 1 New prepped power supply with wires end c
171. nterrupts that can be generated from all the possible sources These interrupts can be divided into two categories maskable and nonmaskable Fifteen of the interrupts can be masked with the condition code register 1 bit All the on chip interrupts are individually maskable by local control bits The software interrupt is nonmaskable The external input to the XIRQ pin is considered a nonmaskable interrupt because once enabled it cannot be masked by software however it is masked during reset and upon receipt of an interrupt at the XIRQ pin ANALOG TO DIGITAL CONVERTER The MCU contains an g channel multiplexed in put successive approximation analog to digital A D converter with sample and hold Two dedicated lines VRL and VRH are provided for the reference supply voltage input These pins are used instead of the device power pins to increase the accuracy of the A D conversion The g bit A D conversions of the MCU are accurate to within 1 LSB 1 2 LSB quantizing errors and 1 2 LSB all other errors combined Each conversion is accom plished in 32 MCU E clock cycles An internal control bit allows selection of an internal conversion clock oscillator that allows the A D converter to be used with very low MCU clock rates A typical conversion cycle requires 16 microseconds to complete at a 2 MHz bus frequency Four result registers are included to further enhance the A D subsystem along with control logic to control conversion activity
172. nual and wonder if a section has been left out Finally find some installation instructionsin Appendix4 6 A They say Copy contents of program disks to hard disk Set ruzs and uanptes for maximum performance Oh boy copy all of the disks into a subdirectory created type the program name hit ENTER and nothing Checking the program disk see subdirectories Inside the subdirectories are more subdirectories Finally pull out a DOS shell pro gram to automate the copying and over an hour later I m ready to start have to do some test runs to fine tune my autorxec and CONFIG settings but two hours after start at last have a working program Here s my guess The first program was developed with plenty of input from the marketing folks They in sisted on all of the pretty graphics which waste precious CPU cycles and they forced the programmers to sit with the tech writers for the manual construction The second 96 CIRCUIT CELLAR INK The Whole J ob program on the other hand had a team leader with a BSCS or BSEE They figured that anyone who used their soft ware ought to know their way around a computer so they decided not to waste time on making things pretty and inefficient Have you guessed which program would recommend to other engineers Just in case there s some doubt let me clear things up the marketing approach is the way to go Too many technical professionals feel that their job e
173. nvert a signal current into a voltage or extract a differential from common mode noise A filter typically a low pass antialiasing filter is often used to reduce man made electrical interfer ence noise reduce electronic noise and to limit the bandwidth of the 314 Full _ Scale 1 2 Full _ Scale 4 4 Full Scale 011 100 101 Input Code Word Figure 9 The transfer function of an ideal 3 bit DAC analog signal to less than half the sampling frequency in order to dimi nate frequency folding STUNG TIME An important aspect of any data acquisition system is called the set tling time That is the time elapsed from the application of a full scale step input to a circuit to the time when the output has entered and remained within a specified error band around its final value Its importance lies in the fact that our DAAC system is made up of sev eral analog operations which must be performed in a set sequence As such each operation must be accurately settled before the next operation can be initiated For example a buffer amplifierprecedinganA Dconverter must have accurately settled before the converter can do its thing An example of this settling time is shown in Figure 8 Here a full step input which has been submitted to an am plifier is followed by a small time delay afterwhichtheamplifieroutputslews or changes its maximum rate result ing from internal amplifier currents which must change internal c
174. ode provides maximum useof the pins for on chip peripheral functions and all address and data activity occur within the MCU This mode would not normally be used on the MC68HC11 Al because of no internal ROM EXPANDED MULTIPLEXED MODE The MCU can address up to 64K bytes of address space Higher orderaddress bits are output on the port B pins and lower order address bits and the data bus are multiplexed on the port C pins The AS pin provides the control output used in demultiplexing the low order address at port C The R W pin is used to control the direction of data transfer on port C bus BOOTSTRAP MODE AII vectors are fetched from the 192 byte on chip boot loader ROM This mode is very versatile and can be used for such functions as test and diagnostics on completed modules and for programming the EEPROM The serial receive logic is initialized by software in the bootloader ROM which pro vides program control for the serial communications interface SCI baud and word format In this mode a special control bit is configured that allows for self testing of the MCU TEST MODE Primarily intended for main production at time of manufacture however it may be used to program calibration or personality data into the internal EEPROM Inthis mode a specialcontrol bit isconfigured to permit access to a number of special test control bits CIRCUIT CHLAR INK BASIC 11 Version 1 54 Copyright c 1986 1990 by Gordon Doughman READY
175. of Force to ADC 0 5V from DAC 0 5V Figure 5 The test setup consists ofan electromagnet IR transmit ter iR receiver support frame and contoller tional derivative mode for this project Here we have a process lag between the time the error is detected by the IR beam and the adjusted output voltage changes the magnetic field This process lag can if too long cause the sphere to drop If the lag didn t exist the proportional mode would provide adequate control Somewhere be tween the two extremes exists a cyclic condition where the ball merrily oscillates about the set point gradually rising in amplitude between the control extremes This generally leads to a loss of control In this case a bit of derivative mode control can make up for the process lag by adding additional error correction which is dependent on the error rate of change The equation for a combination proportional deriva tive mode would be E K E o Po Ka Ep E tp to where E output K proportional gain E present input 4 derivative gain E input att t time of last input t time of this input P set point 76 CIRCUIT CELLAR INK Let s assume that tt 0 001 s sample time P 0 no set point K K P 1 no gain 5Vin SVout Therefore E z KpEp 1 Kp Ep Fo 0 0 001 where E output K proportional gain ey 1 K derivative gain what s left after K E E change in input
176. of up to 1 MHz amp channd 8 bit A D converter 512 bytes of EEPROM Battery backed real time clock calendar Up to 64K of on board RAM EPROM 32K bytes of battery backed RAM Fivevolt only operation Small 3 5 x 4 5 form factor Compatible with RTC series I O expansion boards RIC HC 11 HARDWARE AnRTC HCi 1 computer control ler board is composed of the three distinct hardware subsystens shown in Figure 1 These include the MCU itself and its associated I O and reset circuitry external RAM EPROM and memory address decoding and the on board real time clock calendar with battery backup and write pro tect circuitry At the heart of the RTC HC11 board lies a PLCC packaged Motor ola MC68HC11A1 HCMOS microcon troller unit MCU This is a high speed low power fully static MCU design featuring over half a dozen sophisticated on chip peripherals In fact all of the on board I O devices with the exception of the real time dock areocated within the MCU and an RTC HC11 board can be stripped downto just twochips the68HC11A1 and the MAX232 and still be able to run small assembly language pro grams All of the MCU s subsystems can be accessed by a program executing from anywhere in the processor s MODA MODE RO IUA VgTgyt TIMER SYSTEM BUS EXPANSION AQORESS STROBE ANO HANDSHAKE PARALLEL VO SERIAL PERIPHERAL INTERFACE SERIAL COMMUNICATION INTERFACE NOT BONDED ON 48 PIN VERSIO
177. ommands and so on Just depends on how you want it to work These EPROM state machines are the thing to use where cost is an overriding factor in a design at least until the Creeping Features Creature shows its ugly head and you need the flexibil ity of aCPU Msg 31577 From DAVID M WILLIAMS SR To BOB PADDOCK Thanks for the suggestion just got an EPROM burner last month F1 look this over and see if can put one together My pad is the 3 x 4 type pressure film that supplies a ground or power through the key December 90 January 91 89 A prerequsite for any kind of telephone data communica tions is of course a modem What happens when you want to bring it along when traveling though Msg 31603 From BOB PADDOCK To ALL USERS One of my customers is on his way to the United Kingdom with a Hayes 2400 bps compatible modem internal modem for a Toshiba 5200 he wants to be able to call me with it when he gets there Has anyone here had any experience with making and receiving international modem calls What pitfalls should we be looking out for Msg 31765 From PELLERVO KASKINEN To BOB PADDOCK The main difficulties in international modeming seem to be covered as the modem is 2400 bps type and possibly even supports thedialingin the European network at least in the pulse dialing mode And in any case the dialing can be handled manually if the modem does not happen to comply What re mains is the
178. ommend obtaining a copy of either the 68HC11 Program me s Reference Manual or Volume II of the Motorola Microprocessor Microcontroller and Peripheral Databook The RTC HC11 processor board can decode up to three 8K blocks at addresses 8000 4000 and C000 for use by off board I O devices or RTC series expansion boards In ad dition a 1K I O block which is fixed at address 7C00 can be enabled to allow access to the on board real time dock calendar If one or more exter nal O blocks are enabled the chip select lines to the corresponding on Name Bit PORTA O 2 Input 3 6 output 7 Input Output PORTD O 5 PORTE O 7 IRQ XIRQ RESET Function Input Input Input Input f Fd for the upper conversion range limit Typically this ref erence will be set to 5 00 volts yielding aconverter resolution of 5 00 256 or 19 6 millivolts per steo for an 8 bit ADC Source impedance for each channel should not exceed ten thousand ohms and total sample ac quisition and conversion time for each channel is on the order of twenty two microseconds The ADC reference voltage is set by an LM 336 reference diode set at 5 00 V The LM 336 is powered from the positive voltage output of the MAX232 RS 232 nnector T3 1 T3 8 Input Output J1 1 3 5 7 2 J1 4 T3 10 J2 6 8 10 12 14 16 JP15 13 T3 9 JP15 11 JP6 1 Table i i7l compatible ports on fhe MC68HC TIA board RAM or EPROM are held hig
179. on STATES AND MODES Having defined the desired fea tures itis now possible to outline the operational environment in which ONDI will operate ON DI runs in one of three primary states idle local or remote When either local or remote ONDI can function in a transparent or command line mode Command line mode puts the user in direct commu nication with ONDI Transparent mode allows direct communications between the local and remote com puter Priority is given to the local interface so ONDI can transfer directly from remote to local operation if the switch is thrown to the local position The following rundown briefly de scribes the major operational states and modes that ONDI can assume Idle The idle state is entered on power on following system initializa tion and is the point of return follow ing the termination of most other states ONDI waits here for something better to do Remote state log on mode This modeallowstheuserattheremotesite to access ONDI in order to satisfy the log on requirements If successful ONDI proceeds to the remote com mand line mode Remote state command line mode In this mode the remote com puter isin direct communication with ONDI and has access to the remote command set Remote state transparent mode The computer s COM port is con nected to the modem ON DI monitors the modem transmit line If the escape sequence is detected control returns to the remote command lin
180. on from the previous channel which as sures that the two adjacent channels are never simultaneously connected together settling time defined the same as in our amplifier example except that it is referenced from the time the chan nel is turned on fhroughpuf rate the highest rate atwhichamultiplexercanswitchfrom channel to channel with the output settling to its specified accuracy cross talk the ratio of the output voltage to the input voltage with all channe s connected in parallel and off usually expressed as an input to output attenuation ratio in decibels To realize a large number of multi plexed channels you can connect analog multiplexers in parallel called single level multiplexing using the enable input to control each device It is also possible to connect the output of several multiplexers to theinputsof another called doubleleva multi plexing to expand the number of channels DIGITAL TO ANALOG CONVERTERS D A converters DACs are the devices used by computers for com munications with the real world They are employed in a variety of ways such as for CRT displays voice syn thesis automatic test systems digi tally controlled actuators and so on To understand how such a device works consider the transfer function for a 3 bit DAC shown in Figure 9 INDSEYE Converts your PC into Brainwave Entrainmen machine This unique new hardware software combination turns your PCXT AT 386 or clone
181. on a few square inches of PC board integration density and on chip attributes make 8K 32K RAM EPROM 36 CIRCUIT CELLAR INK Using the microcontroller chips very different While the RTC52 generally meets all my programming objectives and can be expanded to include lots of I O multiple boards cannot always be accommodated in every application still see the need for a more highly integrated very low power single board microcontroller for future proj ects Battery Backed Clock Calendar 256 bytes Watchdog Timer RAM MC68HC 11 Al Microcontroller 512 bytes EEPROM 8 Channel 8 Bit A D Converter RTC Stacking Expansion Bus Figure 1 Functional block diagram of the RIC HC 11 At first considered using the new Signetics 8031 based super chips and porting BASIC 52 to them but was advised that it would be an ordeal and that there were many incompatibili ties Instead thanks to a vocal group of Circuit Cellar BBSers who offered opinions ended up selecting the Mo torola 68H Cll The 68HCIIAI chip see sidebar is a wonderfully func tional microcontroller which offers considerable on chip attributes Motorola MC68HC11 A Venerable History and a Certain Future Serial Port RS 232 RS 485 Synchronous Serial Port TTL Using the 68HC11A1 we were able to put functions like parallel I O battery backed RAM EPROM EEPROM watchdog timer battery backed clock calendar se
182. onnectors soldered to inputs and outputs Open frame style Regulated Voltage end gt current adjustment trimmers 4 94 X 4 03 X 2 Rubicon CE photoflash capacitor 0 79 dia X 1 1 high These are new capacitors that have been prepped with 1 4 black and red wire leads soldered to the terminals CAT PPC 210 2 50 each 10 for 22 50 100 for 200 00 Large quantities available Call for pridng Airpax C82711 M1 17 Vdc 23 25 ohm dual coil permanent magnet stepper motor 7 5 degrees per step 2 25 dia X 91 thick 0 25 dia shaftis 0 6 bng Two hole mounting flange 2 625 canters 6 wire leads CAT SMT 6 6 00 each 10 for 50 00 Ainpax C 62710 12 Vdc 36 ohm dual coil permanent magnet Stepper motor 7 5 degrees per step 2 25 dia body X 0 93 high Mounts on 2 675 canters 6 wire i CAT S Rotron NC12E3 These are the same fans we have In our catalog for 9 00 each We just received another oad of them and want to move quantities at a special price Rated 12Vdc 0 16 amp 2 2 watts 41 69 square plastic housing X 1 25 thick 5 blade fan Two 9 pigtail leads CAT CF 122 00 100 for 500 00 Ivory RG 11 U terminated with heavy duty F connectors Also Includes a F 61 splicer and a 75 ohm terminator bad New cables manufactured for IBMpc networks UL listed Specs 75 ohm impedance Cable jacket 0 D 0 405 Dielectric 0 285 dia Center conductor 0 047
183. output states Q therefore repre sents the smallest analog difference which can be resolved or differentiated by the A D quantizer Asawtootherror func tion for the quantizer can be derived by running the input through its entire range while taking the difference between the output and input This is the irreduc ible error that results from the quanti zation process It can only be mini mized by increasing the number of output states the absolute resolution Typically for a given analog input level the output will vary anywhere from 0 to Q 2 with the error being zero only at points with analog values that correspond to the code center points This variation is defined as the quantization uncertainty or noise As a result the quantizer output can be thought of as a combination of the analog in and the Q noise where this noise has a peak to peak value of Q and an average of zero The RMS value can be computed from the triangular waveshape It is useful in analysis and is usually Q 3 464 SAMPLING THEORY No process is instantaneous Like most things the A D converter re quires a small but significant amount TIREQ OF WAITING FOR THE PROMPT Speed up with a ROM DRIVE Boots DOS and programs instantly Also used to replace mechanical drive completely in controllers or diskless workstations The anly perfect protection from viruses Easy to install half size card 95 WORLDS SMALLEST PC 3
184. pply requirements 5 digital interface required 6 nonlinearity error 7 output current drive 8 type of start stop and status signals 9 size and weight APPLICATIONS OF DAAC SYSTEMS Recently there has been marked enthusiasmforusingmicrocomputers for data acquisition and control It is currently estimated that nearly 40 of all computer applications require some form of analog I O And of that it s estimated that more than half use a PC in one form or another Of course the actual applicationdeterminesboth the type and number of analog signals in volved In most industrial process control or monitoring operations hundreds of control points are con tinuously processed These systems usually don t lend themselves to a PC Phillips 8xc552 based Hardware environment because of the large number of data channels and the need for fast multitasking environments However in simpler systems where the number of data channels is less than 100 the PC has comeintoits own This is where the steadily increasing computing power of the PC has made consistent inroads Systems with fewer analog channels allow having the analog circuity located directly on the same printed circuit board as the I O interface logic The card is made to just drop into any of your 16 bit or 32 bit slots with the analog input coming directly from the amplifier or your transducer A multiplexer in front of the card enables the PC to handle mu
185. protection They require a 5 V and a motor power supply Typically the control signals are a DIREC TION and a NOT ENABLE line The use of a NOT EN ABLE line prevents the motors from running when the control lines are disconnected Remember that TTL inputs float high It isalso possible to drive the NOT ENABLE line with a PWM signal to allow speed torque independence have successfully used these to control some small DC motors DC motors have an overrun problem when stopped In order to minimize this added a relay and some logic which would short the motor winding when stopped This provides very quick dynamic breaking The motor is acting as a generator into a short circuit and therefore stops rather rapidly Ron Dozier Wilmington DE ON ANOTHER LEVEL have been into computing for quite a few years now My first computer job was in 1957 preparing data for the IBM computer operated by Hughes Tool in Houston worked on mainframes IBM 7094s 360s 370s and HW 2000s for several years while wanting a computer of my own finally managed to graduate to micros in 1981 when my boss got me an Apple at last a computer of my own have been mostly a software person for many years application and systems programmer and systems ana lyst currently teaching programming at a community college but have occasionally messed around with elec tronics yes Know my way around a soldering iron my call
186. r These eight states are referenced by a sequence of binary numbers which range from000 to 111 over an analog input range of O 10 volts The absolute resolution of the quantizer circuit is specified by the number of output states defined in bits or in terms of a binary coded quantizer power 2 where n is that number of bits Thus an 8 bit quan tizer has 256 output states and an 24 bit quantizer has 1 677 220 output states M ost applications call for a 2 2 or 4096 output format In our example diagram there are 2 analog decision points or thresh old levels within the transfer function at 0 625 1 875 3 125 4 375 5 625 6 875 and 8 125 These de dsion points are precisely set halfway between the code word center points 1 25 2 50 etc in order to divide the analog voltage range into correct quantized values So when an analog signal level is submitted the quan tizer circuit determines what thresh old level has been obtained and as signs the binary code corresponding to it Keep in mind for anyone output code word there exists a small range of voltage differential about its center point where an input voltage can be assigned the same code This range between any two adjacent decision points is known as the analog quantization size quantum Q For our ex ample shown in Figure 2 the quantum is Q 1 25 V In general it can be de termined by dividing the full scale analog range by the number of
187. ransition of DSR going from off to on which would indicate either the con nection or powering up of the mo dem For ease of implementation the modems result codes will be disre garded and the modem s CD line will be used to find the state of carrier To simplify the user interface the operational state of ONDI will be controlled by a single three position 12 CIRCUIT CELLAR INK toggle switch which will enable or disable auto answer or put the systen into a local mode of operation ON DI will have the capability of being seri ally accessed either locally or remotely where remote access will be used for control purposes and local access for configuration check out and down loading Interactive communications will be carried out using a command line format which will handle buff ered input with echo and a transpar ent mode of operation will release the communications lines to the modem computer An escape sequence will be used to return to the command line A timeout facility monitors the modem line for periods of inactivity Abort times will be set at two minutes during log on and five minutes for normal remote operation and will ter minate the session on expiration With the power to access the re sources of a computer remotely there is a potential for problems so pass word access protection will also go on our list Finally we will twiddle some LEDs on ONDI to indicate these vari ous states and modes of operati
188. rd and cables High reliability 1600 or 6250 BPI capability may be used for disk backup as well as ta data interchange Discover the big AT amp T advantage 9 track tape has over other IBM UNISYS micro mainframe links AEN MAINFRAMES APOLLO e oeccecececeecec Simply exchange data files on a reel of g track tape Call us today FOR DETAILS AND TO ORDER Jt ALSTAR PHONE 810 852 3822 9621 Irondale Ave Chatsworth CA 91311 1989 Qualstar Corp All product and company names and trademarks are the exclusive property of their respecti 1 Selling Track Systems on the Desktop ive owners Reader Service 178 DSTN Film STN TFT 4 8 1 6 10 1 18 1 12 1 40 1 200 ms 250 ms 250 ms 250 ms 40 ms 0 13 w 0 3 7 w 7W 3w 6 15 W 35 deg 40 deg 45 deg 60 deg gt 60 deg 5 12mm 7 28 mm 28 mm 7mm 30mm 25 150 g 150 1800 g 1600 g 800 g 1090 g Low Med High Med Med Mono Mono Mono Color Mono Mono Color 0 5x 0 7x 1x Ix 2 5x Figure 4 A summary of LCD technologies shows the benefits and drawbacks of each would be glad to junk their CRTs in favor of a TFT LCD today The problem is cost and a look at how TFT LCDs are made will shed some light on the million dollar question namely why do they cost a million dollars THE WORLDS BIGGEST DRAM Let s take a look at a state of the art TFT LCD the Hitachi TM26D01VC The TFT LCD is a cross between a regular LCD and aDRAM as shown in
189. ren t many people talking about 8 bit processors at the show Intel mentioned the 8051 saying that they have now shipped over 100 000 000 of them but that came as a passing statement at their press conference announcing the latest mem bers of the 80960 family Motorola was ready and willing to talk about 68030 and 88000 applications National was discussing the 32000 and everyone was announcing the arrival of the 32 bit future Once in a while I heard talk about 16 bit chips like the 80186 and 8096 but there was a noticeable absence of discussion on anything having to do with 8 bit applications All of the predictions I ve talked about are fine and probably true if you are involved in building avionics for the B 2 or automating a nuclear power plant If on the other hand you re working on building automation data logging or day today process control 32 bit processors and million line applications running under UNIX may be a bit of overkill CIRCUIT CELLAR INK So what are we going to do We re going to renew our commitment to 8 and 16 bit applications with a special empha sis on stretching the limits of the possible with 8 bit processors There are new 8 bit processors coming onto the market and we will let you know about them If you need more power there is alot of activity in 16 bit processors and we ll keep you up todate there Operating systems will play a part in both 8 and 16 bit applications as will high level lang
190. respondence with the input There are many different ap proaches used for DAC implenenta tion but most in use are of the parallel type where all bits change simultane ously upon application of an input code word Serial type converters on the other hand produce an analog output only after receiving all digital input data in sequential form To employ a DAC within our process control application see Fig ure 1 have chosen to describe a 28 CIRCUIT CELLAR INK configuration that provides a deglitched analog signal to our feed back control device actuator of the pressure valve or heating element All D A converters produce output spikes or glitches They are most seri ous at transitions of 1 4 1 2 and 3 4 of the full scale fs An example of this is shown in Figure 10 They are caused by the small time differences between current sources being turned off and on within the D A converter Take for example the major code tran sition at half scale from 0111 1111 to 1000 0000 Here the MSB leftmost bit in the converter current source tumson while all othercurrent sources are off As a result the small differ ence in switching time causes a nar row half scale spike which could cause a hiccup in a finely tuned actuator To overcome this problem the digital input to the DAC is controlled by an input register while the con verter output is stored on a sample and hold When the digital input is upgraded by t
191. rial ports and an A D converter in a low cost 3 5 x 4 5 form factor Combined with high level languages cross assem blers and a monitor this RTC HC11 board offersa formidable platform for many future Circuit Cellar projects Of course we have to start some place and can t just drop an RTC HC11 into some project without detail ing the design of it for you beforehand After you familiarize your self with the 68H Cll from the sidebar l Il fill you in on the specifics of the RTC HC11 board architecture at tributes and memory map Finally with help from Burt l Il address some software devd opment tools and pro gramming examples for the RTC HC11 THE BASICS The RTC HC11 is a single board 8 bit compute controller based on the Motorola MC68HC11A1 MCU Like the 8031 and V25 based designs previously presented in the pages of Circuir CELLAR INK Editor s Note See Creating a Network Based Embed ded Controller Crrcurr CELLAR INK 8 and PC Programming Comes to Embed ded Control Circut CELLAR INK 17 the RTC HC11 uses the same dual vertical stacking I O expansion bus took advantage of the 68HC11A1 to build the following features onto the board M otorola MC68HC11A1 MCU running at 8 00 MHz Up to 21 bits of TTL level O 8 bits are shared with ADC Asynchronous Serial port eather full duplex RS 232 or half duplex RS 485 Synchronous serial port withdata transfer rate
192. rms the result Either the light did in fact go on or it was on and you turned it off Possibly it is burned out or even worse another slip of paper gets added to your job jar So you can see that closed loop feedback can not only show the process is operating correctly but just asimportantly what has to be done to correct any errors in the output December 90 January 91 71 Hysteresis Band Rising Temperature Control Path 4 Falling Temperature i Control Path 72 74 76 78 F ae Point Figure 1 Hysteresis is offen used to prevent jitter on the control output BALANCE OF POWER Equilibrium can only take place when the strength of the magnetic field the electromagnet can overcome the force of gravity the weight of the sphere at the defined distance IR beam to magnetic source This defined dis tance must be less than the maximum distance at which the electromagnet can overcome the force of gravity The distance the sphere can travel between the mini mum and maximum IR beam interruption is about 1 mm The Law of Falling Bodies illustrates how long it will take the sphere to travel 1 mm 1 g S gt gt where S is the distance in feet g is the acceleration of gravity and tis time in seconds Rearranging and insert ing numbers with S 10 m and g 9 8 m s we get t 1 4 x 10 s or t 14 ms Worst case if the control loop can t respond in less than 14 milliseconds the sphere
193. rocessor Systems INTROL C Cross Compilers INTRO L Mc dula 2 Cross Compilers INTROL Relocating Macro Cross Assemblers COMPILER PACKAGES INCLUDE Compiler Assembler Linker Runtime library including a multi tasking executive Support utilities Full year s maintenance TO SIMMO SOCKET TARGETS SUPPORTED 6301 03 6801 03 e 6809 68HC11 68000 08 10 12 68020 030 881 851 e 32000 TO SIMM1 SOCKET 32 81 82 AVAILABLE FOR FOLLOWING HOSTS VAX and MicroVAX Apollo SUN Hewlett Packard Macintosh Gould Power Node IBM PC XT AT and compatibles INTROL CROSSDMLOPMENT SYSTEMS are proven accepted and will save you time money and effort with your develop ment All INTROL products are backed by full oon igue 3 Using separate chip enables trades off board complexity for IOW power usage meaningful technical support CALL or WRITE for facts NOW TO SIMM2 SOCKET TO SIMM3 SOCKET 74x245 TO SIMMO go z irani G f TO SIMM1 MEMDECODE S Ha lt ODECODES lt IBHEX WRL ENABLE FA TO SIMM3 gt ENABLE WRLO 3 and WRHO 3 TO SIMM2 9220 W Howard Avenue Mihuaukee WI 53220 414 327 7171 FAX 414 327 7734 Quality Software Since 1979 Figure 4 A smple buffering scheme is used to connect the memory to the system bus Reader Service 146 52 CIRCUIT CELLAR INK IOW 10 PAGE NUMBER trom VO decode dreutny PCMCIA STANDARD MEMORY CARD
194. rogram This inter nal variable can be changed by setting the fifth and sixth bytes of the on chip EEPROM to a value other than FF These new EEPROM values represent the memory address at which BASIC 11 will attempt to store an ESAVEd program Since the RTC HC11 has a Dallas Semiconductor DS1210 RAM backup protection circuit we can use some of BASIC s normal program RAM for the esave storage area This isaccom plished by setting jumpers JP8 11 so that backup power is supplied to U9 from the on board battery and the read write line is routed through the DS1210 s power down protection cir cuitry This effectively creates an on board EEPROM into which we can store retrieve a BASIC I 1 program byusingthe save and ELOAD com mands If we also issue the auvrosr command the ESAVEed program will automatically execute on reset or power up The stored program can be copied back to user RAM for editing by using the ELoap command As a bonus the user RAM area can be used by the ESAVEd program for data stor age ASSEMBLY LANGUAGE The assembly language memory map see Figure 5 is inspiring and uncluttered kind of like pulling onto a fivelane freeway at three o dock in the morning in a Porsche Each of the RTC HC11 s memory sockets can be decoded for an 8K or 32K memory block U9 covers 0000 7FFF and U8 covers 8000 FFFF Three small memory blocks are decoded for peripheral devices 1000 103F for on chip I O and
195. rter made from Linear Technology s LTI072 supplies e712 V necessary for programming page number through an I O port to a latch accomplishes the same page se lection aS before but now the data translates directly into memory card address inputs A16 A23 This elimi nates the entire decoding structure 10uF 2N3904 CONVERTOR Veco MUR120 SZ 150uH VSW 6 Vpp 12V 200mA TY 100uF GND GNO ik LT1072 BOOST RESET from system bus Vec RESET J MC34064P UNDERVOLTAGE SENSING CIRCUIT shown in Figure 2 or 3 The IC card itself also contains the B transceiver buffering This results in the hard ware reduction shown in Figure 5 You will want to purchase a spring loaded connector from Fujitsu AMP PROCESSOR Board 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 x4 5 package al areasonableprice Featuring thepopular Motorola MC68HC11 8 bit microcontroller the RTC HCI 1 gives you up to 21 lines of TTL compatible i FO an 8 bit 8 channel analog to digital converter two serial ports a real time _ Clock calendar with battery backup 512 bytes of nonvolatile EEPROM and up to 64K of on board RAM or EPROM 32K of which can be battery _ backed og Software development can be done directly on the RTC fe HC11 target system using BASIC 1 1 an extremely fast integer BASIC interpret
196. rts for the board Seems 3M had some chips tailored made and no one induding 3M or Harris who made the chips has replacements If you know of some plans would appreciate some info Msg 31566 From BOB PADDOCK To DAVID M WILLIAMS SR Well if your keypad is a 2 of 7 or 2 of 8 type and not the multiplexed type I was just about to send a message to Ed about the overlooked virtues of the 2 of x keyboards you can make a simple electronic lock What you need is a 2 of x keyboard a 27 C 512 EPROM a 74 HC 273 8 amp bit edge clocked latch and a 74 CHC 14 which is used for reset and a slow oscillator Feed the outputs of the EPROM into the inputs of the 273 feed the outputs of the 273 into AO A7 of the EPROM Connect your keyboard to A8 A15 Use the 14 to make an oscillator and reset for the 273 Connect D7 from the EPROM to one of the 14 s inverters and use that to drive a 2N2222 or equivalent that will in turn drivea relay What you have just built is a state machine where the 273 represents the current state with the keypad supplying the next state information What you put in the EPROM will determine what the thing does For example with 256 states you could have use a 128 digit number to turn the output on witl a 128digit number to turn the output off a bit unrealistic for us grown ups to renember but the kids can handle it Another way to program it is for 32 4 digit on commands with 32 4 digit off c
197. s 16 TTL CMOS digital I O lines lt Six layered construction Dedicated GND adjacent lo each analog signal Supports twisted pair or ribbon cable Call today for our new catalog featuring the following hardware software and much more AD1000 8 S E channels 12 bit 20 us A D sample amp hold three 8 MHz timer counters 24 TTL CMOS digital I O lines 275 ADA1100 AD1000 with 2 channel D A and resistor configurable gain essees 365 AD2000 8 Diff 16 S E channels 20 us A D sample amp hold three 8 MHz timer counters binary programmable gains of 1 2 4 8 amp 16 16 TTL CMOS digital I O lines 359 ADA2000 AD2000 with 2 channe D A and 40 TTL CMOS digital T O lines 489 AD100 AD500 Single channel 8 channel S E 12 bit integrating A D programmable gains of 1 10 amp 100 sss 1591259 ADA100 Single channel differential input 12 bit integrating A D X bit D A output pro grammable gains of 1 10 amp 100 Plus 10 TTL CMOS digital 1 O lines 219 ADA300 8 channel R bit 25 us A D single 8 bit D A 24 TTL CMOS digital YO __ 199 DA600 DA700 Fast settling 2 4 6 8 channel 12 bit D A double buffered 1921359 DG 24 48 72 96 TTL CMOS digital I O cards with up to 96 lines 8255 based Opt buffers and pull up resistors 110 256 TC24 Five 5 MHz timer counters uses pow erfulAM95 13A chip 24digital I O lines from TTL CMOS compatible PPI chip 218 ATLANTIS PEGASUS High performance da
198. second polarizer and thus not reflected Low power operation is a re sult of the fact that theliquid crystal requires little power to retain orien tation and likea CRT need only be refreshed periodically Using a row column addressing scheme only a fraction of the panel s pix as as few as 1 100 or 1 200 are energized at any point in time Thus the basic good of LCDs is that power consumption is tiny typi cally0 025 1 Wdependingonpand size Contrast this to the 75 W or so for a typical CRT The only intrinsic bad for LCDs is that the liquid crystal like any other liquid acts up when exposed to temperature extremes Most panels are speci fied to operate in a range of 0 50 C but some are limited to even a narrower range e g 10 40 C For thenonmetric out there suffice it to say you shouldn t expect your LCD widget to work in a snowstorm or a heat wave The basic TN reflective LCD described so far the typical calculator watch type display does suffer from a variety of ugly problems Most basic is the reliance on ambient light The solution is backlighting A variety of Z280 Z80 64180 8085 Advanced Relocating Macro Cross Assembler e Includes linker librarian and cross reference utility Generates full source level debugging information Automatically bank switches program greater than 64K using MMU Linker allows code placement at both physical
199. ser to the potential deleterious effects of electron bom bardment and or low frequency EMF Note that am certainly not qualified to say whether or not a safety problem really exists with the CRT How ever in the absence of hard evidence the belief that a safety problem exists will be enough to indict the CRT Make no mistake the issue of CRT safety has the potential of becoming a big economic political legal Medical technical emotional battle unless studies can conclusively prove it s not a problem Of course you ve probably guessed by now that the LCD doesn t have the CRT emission and radiation problems although I m not sure about the backlight Assuming performance and price advantages of the CRT are slowly but surely eroded by the TFT LCD isn t it only a matter of time before the safety issue comes to the fore OK now you can go move your CRT back a tad Contact Hitachi America Ltd Electron Tube Division 300 N Martingale Road Suite 600 Schaumburg IL 60173 708 517 1144 Tom Cantrell holds a B A in economics and an M B A from UCLA H owns and operates M icrofuture Inc and has been in Silicon Valley for ten years involved in chip board and system design and marketing IRS 42 1 Very Useful 422 Moderately Useful 423 Not Useful Radio Shack DAK fasten your seat belts HCC is unleashing the industry s most incredible BLOWOUTSUPE
200. t gt 0 IF TB gt LL THEN 32200 LL TB CK 0 PRINT Si PRINT HEX2 LL 3 32180 32190 32200 32210 32220 32230 32240 32250 32260 32210 32275 32280 32290 32300 32310 32320 32330 32340 SA SAtLL 32350 ENDWH 32360 RETURN PRINT HEX SA 0F FOR X 0 TO LL 1 SD PEEK SA X PRINT HEX2 SD CK CK SD TB TB 1 NEXT X CK CK LL 3 CK CK SA OF AND ff CK CK EOR Sffff PRINT HEX2 CK AND Sf f listing P continued tively an IBM PC using a communica tions program can be substituted The console device you choose must be ca pable of being configured for 9600 baud 8 data bits 1 stop bit and no parity if you will be using either the ROM monitor BUFFALO 3 4 or BASIC I 1 The console device is con nected to the RTC HC11 through J2 Once everything has been con nected and double checked turn on the power to the terminal and allow it CK CK SA OF AND f 00 256 AND ff to warm up Net apply power to the RTC HC11 If the ROM monitor is installed and everything is connected properly you should see the message BUFFALO gt 3 4 ext Enter a for a list of BUFFALO commands If you re using BASIC 1 and everything is working properly your display should look like this LEARN TO WRITE AND_TEST PROGRAMS FORTHE 8051 The 8051 Microcontroller Architecture Programming and Applications by Kenneth Ayala This new text shows you how to program the 8051 micro
201. t 7 as it did for charac ters from the serial port The piezo beeper sounds off only when charac ters come from the keypad On the other side of the user inter face sending a character to the LCD firmware as well as the serial port is so simple we don t even need a listing to explainit if the LCbEcho controlbit is set just call LCDSendChar from putch after sending the character to the serial port As you saw in CIR CUIT Cerar INK 15 LCDSendChar handles the common control char acters LF CR FF and BS As long as PROC PUBLIC _getch _getch lt lt lt startup code omitted gt gt gt your application can use TTY style output you re in good shape However you probably want to treat the LCD pane as a static display screen write some fixed information then move the cursor around to up date selected values This improves output speed because fewer charac ters are sent and depending on the LCD controller may also eliminate display glitches But because TTY style output can t handle cursor posi tioning this trick is impossible With the putch interface so far you ge check for a char from the serial L wait MOV JNZ A RRing_cLevel L fetch ge check for keypad char JNB CALL JNC CALL SJMP KbdTestChar L wait KbdGetChar L polish PadConsole L wait skip pad if not enabled none have one fix it up so continue waiting get it zee get char from s
202. ta acquisition analysis software foreground background operation maximum 25 KHz rate supports hard disk streaming pull down win dows interactive graphical data andtysis hypertext help scsssseeeeeeees 150 250 Custom OEM designs on request Real Time Devices Inc 820N University Drive P O Box 906 State College PA 16804 Phone 814 234 8087 FAX 814 234 5218 Reader Service 182 December 90 January 91 39 ADDRESS BUS E JP eee E 45 WOS mony DATA BUS MC34054 ui wee e i RESET GND 3 tigure 3b0 ine second halt ot the RIC HC 1 schematic includes the extemal memory real time clock calendar and power supervisor circuitry Position and or Velocitv Motion Control TT 8 Axis Programmable Motion Controller State of the art Digital Multifunction 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 code included A Precision Micro
203. te away from work pastimes include home remodeiing swimming and parenting 412 Very Useful 413 Moderately Useful 414 Not Useful multitasking executive Stack size up to 64K per task EACH Protected heaps amp task reentrant calls lv25 register bank support for REAL TIME EMBEDDED SYSTEMS new features Full MS DOS compatibility _ 80x87 amp math emulator Support for reentrancy L 80x86 family G ROM able Q preemptive scheduler Q libraries for all memory models g works with Microsoft and Turbo c assembler and debugger 70 microsecond task switch 10MHz 60188 Q 15 microsecond interrupt TO MOST EPROM PROGRAMMERS AVAILABLE FOR MOST 8 BIT MICROPROCES SORS AND 680001010 CALL OR WRITE FOR TECHNICAL BULLETIN 30 DAY MONEY BACK GUARANTEE MC V AE Micro Dialects Inc DEPT C PO BOX 30014 CINCINNATI OH 45230 513 271 9100 PER SHIPMENT 5 CONTIGUOUS USA 10 CANADA AK HI 20 INTERNATIONAL Reader Service 160 58 CIRCUIT CELLAR INK pc demo source code Fast pipe macros Dev Kit amp No Royalty License 1995 Source Code 1000 Evaluation Kit amp PC demo 95 User s Guide amp demo disk 25 latency Q 5KB to 25KB code size 1 year free support amp updates a 30 day money back guarantee MICRO DIGITAL Cypress CA 90630 5630 1 800 366 2491 FAX 714 895 2164 Reader Service 161 ANSI Controls and Fixed Points The Fumace Firmware Project Contin
204. te programmers for PLCC 2764 thru 27512 PA3232 adapts for 2701 0 27020 27040 PLCC PA280 44 adapts 16 bit wide PLCC EPROMs EP 751 PA51 FC PA552 68 PA51 44 87C51 PLCC adapter i PA280 44 16bit PLCC EPROM 115 00 PA28 32 2764 thru 27512 PLCC adapter 90 00 CALL 315 478 0722 FAX 315 475 846 Logical Systems Corporation P O Box 6184 Syracuse NY 13217 USA Reader Service X15 Principles of PC based Data Ac quisition and Control Systems FEA TURE ARTIC LE C hris Ciarcia lei start this article with some sweeping statement like PC based data acquistion and control systems provide the greatest versatility and flexibility etc etc but most of you are already sold on that idea If you ve spent any time reading past issues of this magazine then you appreciate how many different things your PC can do Instead I d like to discuss the basic principles behind the application instrumentation used in those articles In other words want to discuss how your PC is able to interact so effectively with the real word and what pitfalls you may encounter as you try to control your environment Figure 7 Process DAAC System Physicalparame ten and process charac teristics are derived from pressure iransducer and temperature thermo couple measurements which are amplified and digitized and then fed to a PC for status monitoring and decision input The PC then analyzes the process respons
205. to 3 000 for some of the specialized embedded prod ucts It s a different type of overhead but substantial overhead increase all the same Finally an operating system adds another level of complexity to any debugging exercise You can t just worry about how your software is interacting with the hardware you have to consider how the passions in the hardware OS application software triangle are affecting one another The time involved is still more overhead that must be absorbed by the project All of this overhead is starting to add up unless you re writing a truly large application LARGE APPLICATIONS You know the 8K EPROM I mentioned in the last section Well you can forget putting code into it You re going to be writing embedded software that needs 500 000 1 000 000 lines of code Stop for a moment and let that sink in Are you still with me If you re going to spend the time money and effort to develop a million lines of embedded code the overhead of an operating system gets lost in the background noise Furthermore I m willing to say that if you have a million line program you need an operating system to support your code You also need a high level language heavy duty libraries and support programs and a debugger that will work with you in a most intimate fashion Oh yes you also need a processor that will let you get to that much code EDITOR S INK Curtis Franklin J r 32 BIT PROCESSORS There we
206. to trigger the interrupts of a 6502 microprocessor part of an AIM 65 board from a sanity timer to restart the system in case the processor got off track and wasn t executing properly We had the same problem Once we got the microprocessor s attention how would we get it to go back to restart instead of back to where it left off when the interrupt occurred without causing stack problems The 4 CIRCUIT CELLAR INK Letters to the Editor only logical thing to do was to modify the return address on the stack This method while very practical would probably be frowned upon by those adhering to strict structural tech niques especially those who develop software for military applications per standards like DOD STD 2167 How ever if it is viewed as a form of exception handling then it would probably be considered respectable I m not sure however that this method helps dis cover where your code has been as your subtitle to the article suggests but rather it changes where your code is going to Kenneth J Ciszewski Overland MO LEGO CONTROL I d like to comment on the letter Keep those Legos Moving in Circuit CeLLaR INK 16 The little motor driver circuit that was described is essentially available as Spra gue U DN 2952B or UDN 2952W full wave bridge motor drivers They are available from Circuit Specialists Mesa Arizona They are capable of 3 5A of output current and feature thermal
207. tor C which has low leakage and low dielectric absorption charac teristics typically MOS type S is an electronicswitch usuallyaFET which is rapidly switched on or off by a driver circuit which interfaces with TTL inputs The sampleand hold works in two modes sampling or tracking when S is dosed and holding when the switch is open When used with an A D converter the device is kept in ahold mode until a new input sig nal is required This is the case for a sample and hold used in a data ac quisition system following a multi Figure 6 When the frequency spectrum shown in a is sampled andrec onstucted ata rate less than twice f_ frequency folding or aliasing results b plexer see Figure 1 While with an D A converter it is used as a deglitcher Here the device is used to continuously track the input signal then switched into the hold modeonly at specified times THE SAMPLING THEOREM In most DAAC systems analog signalsare sampled on a periodic basis similar to that demonstrated in Figure 5 Here the sinusoidal input signal 5a is sampled on a periodic basis de termined by a train of sampling pulses 5b which represent a fast acting switch that connects the signal to the sample and hold for a very short pe riod of time then disconnects it for the remainderofthesamplingperiod The result of this operation is identical to multiplying theanalogpulsebya train of sampling delta functions of unity amplitude
208. ts in this page memory board design The 74x521 comparator sinputsbeginwith A3 to simplify the decoding circuitry for the I O port addresses This places the base I O port on an even 8 byte boundary Use discretion when set ting the switch to avoid conflictin the AT environment recommend using I O addresses between 300H and 318H because this area is assigned for prototype cards Listed in the order in which they appear on the 74x138 decoder in Fig ure 6 the eight I O ports in this design are BIO BI3 accesses the board s iden tifiers the window address within the system s memory space the SIM M s presence detect the V pp ena bling register and the page number reading and writing ports didn t diagram the board s iden tifier circuitry because the implemen tation is extremely simple It consists of four identical units made up of a 74x244 and an8 input DIP switch The four enables BIO B13 from the I O decoder connect to the corresponding unit s enable The I O space is scanned for the identifiers to locate the board The user selectable page window address can be placed on any 64K byte boundary within the DOS 1 megabyte range but only the adapter ROM area between COOOOH and EOOOOH will alleviate compatibility problems Using additional inputs on the Memory Decode Enable 74x521 and an 8 input DIP switch allows window placement above 1M byte Simply connect address lines A20 A23 to input pins P
209. uages so we ll look at how both can affect the project you work on Finally we ll remember that one of the reasons most of you read C IRCUIT CELLAR INK is that we take the road less traveled in our approach to applica tions We re going to be going a little farther down those less traveled paths in upcoming issues A NOTE Scott Ladd s Practical Algorithms is taking a one issue va cation It will be back in Circuit CELLAR INK 19 December 90 January 91 1 FOUNDER EDITORIAL DIRECTOR sone CIRCUIT CELLAR I N K oi faa Fal Daniel RONG THE COMPUTER Issue cera APPLICATIONS oe MANAGING JOURNAL EDITOR Ken Davidson PUBLISHING jones FEATURES ENGINEERING STAFF Jeff Bachiochi ONDI The ON Line Device Interface Part 2 Edward Nidey Software for Remote PC Control CONTRIBUTING by J ohn Dybowski EDITORS A complete computer remote control system wraps up with a look at Thomas Cantrell the software for remote control operation and display Christopher Ciarcia NEW PRODUCTS Principles of PC based Data Acquisition and EDITOR Control Systems Harv Weiner by Chris Ciarcia CONSULTING Writing control software can t start until you understand the problems EDITORS A lesson in control theory can save you hours in wasted design time Mark Dahmke Lany Loeb An Interface for Portable Battery Backed RAM CIRCULATION Using the Mitsubishi BEE Card for Non COORDINATOR volatile Data Storage Rose Ma
210. ues L winter when I laid out the Furnace Firmware project forgot about Serious Heat and Humidity right now it s 90 F at 90 and have no intention of firing up the furnace for a code check So this column in dudes the ANSI LCD driver and a fixed point math package Never fear when the heating season rolls around again you will get the final wrapup PARALLEL CHARACTERS The Furnace code so far indudes keypad input and LCD output rou tines but they are entirely distinct from the normal C console O rou tines Wouldn t It Be Nice lf the C getch function returned charac ters from the keypad and putch sent output to the LCD pang in addi tion to the normal C serial console support The keypad firmware in Circurr CELLAR INK 16 produces a character for each key press using the timer tick to control polling Listing 1 shows the few lines of code needed to splice those characters into getch A similar addition to kbhit which is not shown here indicates when a charac ter is available from the keypad The PadConsolebitcontrolsthenew code in each routine so you can disable the connection and process keypad char acters separately by calling Kbas etChar when needed The keypad translation table now includes the CR ESC Ctrl C BS and hyphen characters needed for nor mal console input Because the three remaining function keys still return characters above 80 hex get c h no longer clears bi
211. ured temperature t set temperature h half the hysteresis Discontinuous mode may in fact have multiple set points As each point is passed the controller outputs a new level In a three position discontinuous mode the output may take ona third intermediate value of say 50 in addition to on or off As the number of set points increase you begin to approach a continuous controller Photo 1 The results of the hardware software combination de scribed later in this article clearly show the samples leading the input sine wave There are typically three kinds of continuous modes proportional integral and derivative A proportional output has a direct linear relationship to the error input It is used when system load changes are small because a per manent offset error occurs which limits the usable error span A proportional output may be described as follows P KE P P P 0 where P output i K proportional constant gain E_ input measurement P nominal set point P Ep Kp lt t P Ep Kp 1 P Ep Kp gt 1 V KpVp Vo where Kp R1 R2 Figure 2 The proportional control output has a direct linear rela tionship fo the error input An integral mode output changes faster for larger rates of error input and drives the output at a slower rate as the error input approaches zero This mode is normally used in combination with other modes where the process lag is short Integral mode is def
212. us the ability to change algorithms easily through software which really beats getting out the old soldering iron and attacking the hardware to alter the Model 250 for Algorithm Development Data Acquisition Instrumentation Audio TMS320C25 DSP at 10 MIPS Up to 192 Kwords RAM Multi Channel Analog IO 250K Samples sec Development Software including Assembler amp Debugger Applications Software includes FFT Signal Display Data Acquisition amp Wavefomm Editor No Gap Sampling to from Disk at Very High Rates Supports Multiboard amp Standalone EPROM Operation From 1095 Other DSP Products Available DALANCO SPRY 89 Westland Avenue Rochester N Y 14618 716 473 3610 Reader Service 17 P Kp lt t P Kp 1 1 4 LM1458 ucc V kets where Ky R2xC t Figure 4 7he output of a derivative mode controller is driven by how fast the enor input is changing offset gain integral or derivative parameters every time we want to adjust the system APPLYING THE MAGIC OF MICROPROCESSOR CONTROL Process control with a simple input and output doesn t require a microcontroller However using a simple proc ess allows one to easily grasp the basics and the advan tagesof using this approach on a more cost effective basis With a small amount of signal processing the position error input of the process load ball can be transferred to a m
213. ut strobe function in the expanded multiplexed mode it provides R W read write function The R W is used to control the direction of transfers on the external data bus AS STRA Provides two different functions depending on the operating mode In single chip mode the pin provides STRA input strobe function and in the expanded multi plexed mode it provides AS address strobe function The AS may be used to demulti plex the address and data signals at port C INPUT OUTPUT LINES PA9 PA7 PBO PB7 PCO PC7 PDO PD5 PEO PE7 These I O lines arearranged into four 8 bit ports A B C and E and one 6 bit port D All portsserve more than one purpose depending on the operating mode Port functions are controlled by the particular mode selected In the single chip mode and bootstrap mode four ports are configured as parallel I O data ports and port E can be used for general purpose static inputs and or analog todigital converter channel inputs In the expanded multiplexed mode and test mode ports B C AS and R W are configured as a memory expansion bus PORT A In all operating modes port A may be configured for three input capture func tions four output compare functions and pulse accumulator input PAD or a fifth output compare function Each input capture pin provides for a transitional input which is used to latch a timer value into the 16 bit input capture register External devices provide the transitional inputs and inter
214. vices The batch command language allows users to create and simulate an entire DSP system complete with user input breakpoints and single step Source code ex amples are provided for the popular MathPak87 and Numerical Recipes in C analysis routines Interfaces are currently available for most signal processing boards based on the AT amp T DSP32 DSP32C devices and others will be available soon Other features include context sensitive help cross referenced for ease of use pull down menus detailed parameter setup up to eight display windows and color UNIVERSAL ANALOG TEST INTERFACE BOARD A universal analog interface that is controlled by a single 24 bit TTL digital I O has been announced by Latel Engineering The FB 1000 Analog Test Interface Family board is an 8 x 12 printed circuit board de signed to provide a conven ient and flexible interface between a Device Under Test DUT and the test system controller or microcomputer It features a variety of signal interface and control func tions and includes locations for 64 raays two analog output device support An introductory version is available for 250 The full rdease with additional hardware and software interfaces sells for 495 The demo disk can also be downloaded from the DspH q bulletin board at 301 8383205 Modem parameters are 300 1200 2400 N 8 1 The is devoted to Digital Signal Processing
215. ware on Disk or Circuit Cellar BBS on Disk send check or money order to Circuit Cellar INK Software or BBS on Disk P O Box 772 Vernon CT 06066 or use your MasterCard or Visa and call 203 875 2199 Be sure to specify the issue number of each disk you order CIRCUIT CELLAR COLLECTIBLES PROJECT COMPONENTS AT BLO WOUT PRICES Item Chip IS 32 Optic RAM SN76849 SN76832ANIR REC AY 3 1350 Synthesizer TMS9918AN Sprite Gen TMSS 18AN Sprite Gen TMS99532AN Modem TMS1121 Real Time Ct Chip SP1000 Voice Recog Chip HD6802P Processor NCR5380 SCSI Controller ADC0831 8 bit A D Ceramic Mike Acoustic Modem Rubber Cups 4 032 MHz Xtal 10 738 MHz Xtal 7 16 MHz Resonator BT450 Video DAC Z8613RS Z8 P rotopac Minimum order 25 00 Prices do not include shipping CCC Project Micro D Cam Sound Generator IR Remote Control Whimsi Bell Color Video Display 3 Chip Color Video Display Single chip 300 bps Modem RTC 4 Fimer Controller Lis ner Voice I O HCS 6802 Processor COMM180 SB180 SCSI Lis ner Voice I O Acoustic Modem Acoustic Modem For TMS99532 Modem Chip For Sprite Chips For SP1000 Chip GT180 Analog Video Driver Piggyback EPROM Z8 Chip Blowout Price 25 00 5 00 1 00 3 50 5 00 9 00 5 00 6 00 10 00 1 50 15 00 2 00 1 00 2 00 pair 0 75 0 75 0 75 25 00 15 00 CIRCUIT CELLAR KITS 4 Park Street Vernon CT 06066 203 875 2751 Fax 203 872 2204 Reader Serv
216. will drop beyond the range of magnetic attraction Although process control brackets a wide variety of durations most industrial proc esses are in the range of minutes rather than fractions of a second as shown here CONTROLLER PRINCIPLES Process control has three main parts the process load measurement error input the controller analog or digi tal and the control element correction output The proc ess load measurements can come from oneor more sources each having its own range about a nominal value The control output can go to one or more control elements each having a maximum and minimum effect on the process The controller must make decisions based on the process load measurements to adjust the control elements and return the process load to normal Different algorithms may be used by the controller depending on the type of process being controlled Each control mode has its own associated algorithm 72 CIRCUIT CELLAR INK There are two main types of process control loops discontinuous and continuous The simplest is the discon tinuouscontroller mode Two position controlin this mode is simply on or off like the thermostat which controls the furnace in your house Your thermostat measures the air temperature makes a decision based on the temperature and hysteresis setting and signals the furnace for more heat if necessary P OFF P ON ifE gt t h ifE lt t h where P output to furnace E meas
217. y life at 4 years when operated at 25 C A write protect switch located on the end of the card can be used to protect data from being accidentally overwrit ten if desired A 32K BEE card was chosen for several reasons First using the BEE card as a mass storage device is very straightforward It can be read from and written to justlikeany other RAM device in the computer s memory map There are no special disk drive interfaces to build and no disk BIOS to write as there would be had we incorporated a disk drive Se lecting the32K sizeallowed us to place some conventional EPROM and SRAM on the board and still address the BEE card within the 8031 s 64K addressspace withoutaddingany sort of a bank switching scheme The second reason for using the BEE card is it has no moving parts such as drive motors that generate heat collect dirt and make noise or heads to go out of alignment Since the BEE card is all solid state battery backed SRAM it has none of these shortcomings Most of the flexibility of toting around a floppy disk is re tained although in our case not quite as much data storage is available Photo 1 The Datalog R allows the user to become familiar wi fhe use of the Mitsubishi BEE card without spending a lot a 8031 TO THE RESC UE A schematic of our design is shown in Figure 1 The size of the fin ished board without the BEE card inserted is4 5 by 6 0 A34 pin header provides a

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