Industrial Design with Microcomputers
by Steven K. Roberts, 1981


There was a time, not so long ago, when it was possible to speak of “the mighty microprocessor” as a relatively isolated phenomenon. Although the devices were supremely flexible replacements for random logic, they had not quite changed the world. Not yet, anyway.

But it was inevitable. Such concentrated and cheap processing horsepower couldn’t help but endow everything it touched with new energy, and the infant technology became, within a few years, an essential part of the environment in which every other industry functions.

This caused as many problems as it solved. Not the least of these was the supreme difficulty of learning what it was all about: where most other technolo­gies have a rich heritage on which to draw, this one had only the obscurest of roots in the vast body of engineering literature. Device data was readily available from the manufacturers, of course, but there was little or no established art that could serve as the basis for the creative efforts of individual system designers.

The most frequent question I heard during eight years of consulting, design­ing industrial systems, and selling small computers was, “How can I learn to design with microprocessors? What book do you recommend?”

I always had a hard time coming up with an answer, even when, in the late 1970s, the market became flooded with literature. There were books on languages, the micros themselves, interfacing, logic design, communications, and even engineering management — but none that adequately integrated the whole field of microcomputer-based design into a cohesive whole that could serve as the basis for detailed and task-specific information.

It was with awareness of this void that this book was written. With a real-world emphasis gleaned from (often painful) experience, I have attempted to bring together the widely diverse ideas that must be assimilated before creative system design can be effectively undertaken. Far from being another “how-to” text that starts with binary numbers and the author’s favorite instruction set, this book is designed to provide the philosophical underpinnings for the wealth of in­ formation that can be found elsewhere.

Part I opens with an exploration of industrial system design requirements, and then sets the stage for an overview of microcomputer technology with a real application context. Next, avoiding product-specific data as much as possible, I sketch both the chip- and board-level tools that will be used as “black boxes” throughout the text. Our discussion of reality begins with the consideration of a wide range of interfacing techniques, after which the bad news is revealed: the ideal textbook world is not what is really out there.

Part II brings a sharp shift of emphasis with an introduction to the concepts of software design and a discussion of the various tools and methods that have evolved to make programming not only possible but productive as well. In this context, I take the time to consider industrial applications of artificial intelligence techniques, as well as the more prosaic but eminently worthwhile principles of structure, hardware/software balance, and system design philosophy. Part II ends with a close look at the development environment, including emulation and de­bugging techniques.

Part III is designed to apply everything covered so far by tracing the develop­ment and operation of a distributed industrial control system. This leads us into network communications, application of real-world design ideas, interfacing, hu­man factors, software engineering, and a concrete system integration example. The book closes with a look at digital signal processing, a few relatively esoteric design techniques, and a brief potpourri of applications.

But as important as the specific subjects discussed is the attitude of respect for the reader’s creativity and awareness that permeates the entire book. I have made the text casual — not in a trite or “underground” sort of way, but in the same fashion that would characterize correspondence with an intelligent friend. Much of the true meaning is between the lines, where ideas too delicate for bla­tant exposition are gently explored. While the classic textbook places a formal dis­tance between the author and the student, this one invites readers to relax, kick off their shoes, and share understanding.


A book, like any human creation, springs not from the author alone. This one is no exception: many people have touched my life in ways which have had a profound effect (directly or indirectly) upon these words. Although an exhaustive list is impossible, I would like to thank certain friends, associates, mentors, author and machines.

First, I am deeply indebted to Bob Phare, who not only devoted hundreds of evening and weekend hours to the creation of the illustrations, but also partici­pated strongly in the refinement of the text. His penciled notes in the manuscript more than once spotlighted clumsy structure and logical gaps, and the text is scat­tered with the echoes of countless midnight tea-sodden brainstorming sessions.

Bob Phare working on drawings for this book – Dublin, Ohio – 1981

(Bob, in turn, thanks Rita, who somehow put up with all this.)

This book has also profited immeasurably from the close involvement of Lori Opre (editor par excellence), whose loving touch guided it through the pro­duction process and held the enemies of quality at bay.

I would like to thank Steve Orr for over a decade of close and stimulating friendship, general consultation, insights into digital signal processing, and the PACK macro. Steve is very much a part of this book.

Steve Orr in 1980

My parents, Phyllis and Ed Roberts, are also represented here: by nurturing my childhood fascination with all things electronic, by representing an attitude of quality in workmanship and expression, and by supporting me even through times of disagreement, they have shaped my work in ways for which I shall be forever grateful.

At this point, I quickly encounter the problem of implied prioritization em­bedded in anything other than arbitrary sequencing. That would be intolerable, so I now alphabetically thank the following:

Doug Bucheit of Robinson-Nugent Company, for the original concept behind the insertion-withdrawal force system.

David Caudill, for his inspired participation in this project through creation of the cover art.

Jim Dudick, for general consultation and the PL/I word count program.

David Heiserman, for introducing me to Prentice-Hall.

Doug Hofstadter, for his magnificent book, Gödel, Escher, Bach — an end­lessly stimulating and thought-provoking volume if ever there was one.

Jim Jenal, for assistance in understanding UNIX, insights into the Al field, and off-site file backup facilities.

Jency Kelly, for CROMIX assistance and a long-desired system renovation.

Dan Landon, for his excellent work on the data collection system and for many hours of enthusiastic home-computer interaction during those exciting pre-kit years.

Al Messing, for his major creative role in the IDAC system and his subse­quent efforts in helping me market it.

Susan Mowers, my meta-assistant, for dedicated proofreading, broad­ spectrum support, and boundless enthusiasm.

Sylvia Nelson and Ron Pearson, for passing along the spark.

Vince Phillips of the Alkon Corporation, for contributing strongly to my understanding of structured design and software engineering.

Debra Roberts, for proofreading, frequent encouragement, superhuman tolerance, and much more.

David Wright, for creative assistance in a variety of microcomputer-based projects which helped shape this book.

I also thank the following for a variety of reasons far too diverse and com­plex for elaboration here:

John Barnard, Jim Berkey, David Boelio, Judy Borsuk, S. Jerome Clarke, Sam Cooke, Jim Dome, Glenn Glassner, Bill Godbout, Jim Helton, Roy Humphress, Ernest Kent, Brad Lizotte, Dick Lorimor, David Martin, Edgar Marven, Dan Meinerz, Jyll Matheny, Cheryl Miller, Chris Morgan, Phil Morgan, Alan O’Neill, John Raffauf, Tom Rouse, Frank Sharp, John Stork, and the Dublin Ohio Police Department.

Last and most certainly not least, I want to thank BEHEMOTH, my reliable and 100% dedicated computer system, for tirelessly and heroically manipulating the text of this book and for potentiating a writing career by obsoleting the type­writer.

Dublin, Ohio
Steven K. Roberts

The author – Dublin, Ohio – 1981

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