EDITOR’S INK CASE is Coming Curtis Franklin, Jr. I t’s fun to watch events come together to form a trend. A and the programmer’s “quality of life” improved. Finally, there while back, I told you that events were coming together that came the trend that would tie everything together. would result in a trend toward using “PC-compatible” platforms Intel pushed to merge desktop microcomputer and embed- for control applications in ever-increasing numbers. Things are ded controllerarchitectureswiththe80186. Here wasa micropro- still rolling along with that trend, and I feel pretty good about the cessor that was code-compatible with the popular 8088 and 80% prediction. I feel so good, in fact, that I’m going to hit you with microprocessors, yet had I/O features more typical of embedded another prediction this time: I predict that most of the people controllers. Through time, the price of IBM PC/XT-clone moth- reading this will be using CASEKomputer-Aided Software erboards dropped to a point where the same I/O, operating Engineering-within the next five years. It doesn’t matter whether system, and memory architectures could be economically used most of your programming time is spent on desktop computer for both desktop computing and control applications. Engineers applications or embedded control, I believe you will start using and control programmers have been introduced to the wonders CASE tools. I’m making this prediction based, not on any sort of of the modern desktop development environment, and the steps blazing insight, but on the logical progression of several industry are short between (for example) the Borland Turbo-language trends. environment and CASE. The first important trend is pretty obvious: Programmers In CASE, the programmer writes no code, but a detailed are moving away from assembly language and toward high- specification of the program required. All of the unpleasant (and level languages for programming. No one who does most of their time-consuming) details of interrupt servicing, I/O generation, programming for personal computers will be surprised at this, and housekeeping are handled by the CASE software. While the but assembly programming is still SOP for much embedded and most obvious current applications of CASE are in GUI-software control application software. The trend really started quite a few development (where the programmer does not want to spend years ago, when BASIC and FORTH were put into on-processor endless time re-creating the graphical shell for each program), ROM for the Z8. They weren’t, of course, “real” programming the tools are rapidly progressing to the point where they will be languages, and most people only used them for prototyping, but coveted by most programmers. Why? The basic reasons are that their relative ease-of-use was seductive. Before long, engineers they save programmer time and take some of the repetitive were looking for excuses to use BASIC rather than assembly tedium out of programming. language, and trying to extend the higher-level languages for It’s no longer news that engineering and programming time greater flexibility. A bit of time passed, and separate high-level- is more valuable than hardware. The trouble is that the gap is language compilers and interpreters began to appear for tradi- becoming so wide that employers and clients will push for any- tional controller chips. These were all cross-compilers, most with thing that cuts down on time required for a project. CASE fits that limited libraries, and almost all had user interfaces that were bill nicely. Now, the support for CASE is not universal. On our abysmal by any standards but their own. Nonetheless, they engineering staff, Ed Nisley tells me that it takes as much time to worked, after a fashion, and they helped to separate the program- write a detailed specification as to write the code. He’s right, of mer from time-consuming tedium. The difficulty and frustration course, but it just doesn’t matter. CASE will come to your encountered in using these tools were see by many engineers as software environment, and I’m betting that you’ll be glad when a sort of “ennobling pain,” a badge of honor for those intellectu- it does. The force of history is on my side, and (ultimately) we’ll ally macho enough to tolerate them. In the mean time, program- see better and more creative applications because of it. ming tools for personal computers were developing along some- what different lines. Personal computers tended to have increasing levels of processor power and memory capacity. These were used by compiler, debugger, and editor writers to support greater num- bers of functions and higher levels of integration. Rather than viewing struggle with tools as an honorable pursuit, desktop ap- plication programmers saw primitive tools as impediments to greater productivity and better software. They were particularly interested in seeing software development tools keep pace with the rising levels of power and functionality available from their hardware. Compiler and development tool vendors responded, October/November lpP0 1 FOUNDER/ EDlTORIAL DIRECTOR Steve Ciarcia PUBLISHER Daniel Rodrigues EDITOR-in-CHIEF Curtis Franklin, Jr. PUBLISHING CONSULTANT John Hayes ENGINEERING STAFF Ken Davidson Jeff Bachiochi Edward Nisle y Multichannel Digital Voltmeter Interface MAX134 Chip Adds High-Performance ADC to Embedded Control CONTRIBUTING 43 by Steve Ciarciu EDKOR q An autoranging DVM interface is the first step in Ciarcia’s newest Thomas Cantrell building automation plans. NEW PRODUCTS EDlTOR Control Theory for Embedded Controllers Hunt Weiner 58 An introduction to the Basics of Computerized Control CONSULTlNG q by Thomas Mosteller EDlTORS Knowing how a system should work is the key to building working Mark Dahmke embedded svstems. Larry Loeb Using C For Embedded C ClRCUlATlON Building a 6805-Based COORDINATOR Darkroom Timer Rose Mansella by Ashok Pate/ & Walter Bunks ClRCUlATlON A high-level language can CONSULTANT make your development Gregory Spitzfaden time more productive. ART % PRODUCTION DIRECTOR Tricia Dziedzinski PRODUCTlON Functions of Complex Variables ARTlST/ILLUSTRATOR Lisa Ferry Generating Biomorphs on Personal Computers by Saim Ural BUSINESS Fractal-like methods can create beautiful MANAGER “biomorph’ patterns and images. Jeanneffe Walters ADVERTlSlNG COORDINATOR Creating Fractal Images Dan Gorsky Using the Power of Fractals for Realistic Planetary Images STAFF RESEARCHERS by Chris Ciarciu Northeast Extend fractal techniques to model realistic Erfc Albert planets and landscapes. William Curlew Richard Sawyer Robert Stek Midwest Running VGA on an IBM Professional Graphics Display Jon E/son by J.Contad Hubert ?7m McDonough 38 You can connect affordable workstation monitors to VGA adapters West Coast q Fran& Kuechmann with a simple hardware addition. Mark Voorhees The Second Circuit Cellar INK Design Contest Winners Cover Illustration by Robert Tinney 2 ClRCU/l CELLAR INK Circuit Cellar BBS-24 Hrs. 300/1200/2400bps,8bits,no parity, 1 stop bit, (203) 871- Editor’s INK 1988. CASE is Coming The schematics provided by Curtis Franklin, Jr. in Circuit Celbr INK are drawn using Schema from Omation Inc. All programs and schematics in Circuit Reader’s INK-Letters to the Editor Cellar INK have been care- fully reviewed to ensure that 5 their performance is in bc- rl cordance with the spectfit cations described, and pro- NEWProductNews gramsarepostedontheCir- 10 cuit Cellar BBS for electronic rl transfer by subscribers. Circuit Celbr INK makes Firmware Furnace no warrantii and assumes The Furnace Firmware Project, Part 3 no responsibility or Ilability of any kind for errors in these light Code Meets the C Monster programs or schematics or by Ed Nisley fortheconsequencesofany The Furnace Firmware project continues with additions to the such errors.. Furthermore, be- cause of the possible varit acquisition and display hardware. ation in the quality and con- dition of materials and work- manship of reader-as- sembled projects. Circuit From the Bench Cellar INK disclaims any re- sponsiblity for the safe and PC Programming Comes to Embedded Control proper function of reader- V25...An 8088 with all the good stuff assembled projects based upon or from plans, descrip- by Jeff Bachiochi tions, or information pub A new processor board! Jeff shows how to build an 8088-compatible liihed in Circuit Cellar INK. (V25-based) controller. 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