Micron Technology Inc. et al.
`Ex. 1022, Cover-1
`
`

`

`Microcomputer
`Interfacing
`HAROLD S. STONE
`
`UNIVERSITY OF MASSACHUSETTS, AMHERST
`
`..,~ ADDISON-WESLEY PUBLISHING COMPANY
`READING, MASSACHUSETTS
`MENLO PARK, CALIFORNIA
`LONDON
`AMSTERDAM
`DON MILLS, ONTARIO
`SYDNEY
`
`Micron Technology Inc. et al.
`Ex. 1022, Cover-2
`
`

`

`This book is in the ADDISON-WESLEY SERIES IN ELECTRIC ENGINEERING
`
`SPONSORING EDITOR: Tom Robbins
`PRODUCTION EDITOR: Marilee Sorotskin
`
`TEXT DESIGNER: Herb Caswell
`ILLUSTRATOR: Jay's Publishers Service Inc.
`COVER DESIGN AND ILLUSTRATOR: T. A. Philbrook
`ART COORDINATOR: Joseph Vetere
`
`PRODUCTION MANAGER: Sue Zom
`PRODUCTION COORDINATOR: Helen Wythe
`
`The text of this book was composed in Times Roman on a Mergenthaler 202 by Information
`Sciences Corporation and was printed by R. R. Donnelley and Sons.
`
`Library of Congress Cataloging in Publication Data
`
`Stone, Harold S., 1938-
`Microcomputing interfacing.
`
`Bibliography: p.
`1. Interface circuits.
`I. Title. TK7868.158S76
`ISBN 0-201-07403-6
`
`2. Microcomputers-Circuits.
`621.3819'5835
`
`81-17619
`
`AACRZ
`
`Copyright © 1982 by Addison-Wesley Publishing Company, Inc.
`All rights reserved. No part of this book may be reproduced, st~~ed in a retrieval system, or transmitted, in any
`form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written
`permission of the publisher. Printed in the United States of America. Printed simultaneously in Canada.
`
`ISBN 0-201-07403-6
`ABCDEFGIIDK-00-898765432
`
`Micron Technology Inc. et al.
`Ex. 1022, Cover-3
`
`

`

`TO THE REVOLUTION
`
`"The old order changeth, yielding place to new ... "
`Alfred, Lord Tennyson
`To see a world in a grain of sand
`And a heaven in a wild flower,
`Hold infinity in the palm of your hand
`And eternity in an hour.
`
`William Blake
`
`Micron Technology Inc. et al.
`Ex. 1022, Cover-4
`
`

`

`INSTRUCTOR'S PREFACE
`
`In decades to come historians will look back to the 70s and 80s as the era of the Com(cid:173)
`puter Revolution. Just as the Industrial Revolution marks the period when people learned
`to harness energy to drive machinery, so the Computer Revolution marks the period when
`people have learned to harness microelectronics for control and for information process(cid:173)
`ing. Within of a decade of its introduction, the microprocessor made an enormous impact
`on the way we live and work. Who can recall the annoying difficulty of doing long divi(cid:173)
`sion by hand, to say nothing of such transcendental calculations as compound interest,
`square roots, and trigonometry? Today's electronic calculator places all of these calcula(cid:173)
`tions at your fingertips at essentially zero cost. But the calculators of the early 70s were
`only precursors of the innovations to come.
`The microprocessor has spawned the personal computer, the small-business com(cid:173)
`puter, the word processor, the data communications network, the automotive computer,
`and the intelligent telephone branch exchange. Yet this is still only a beginning. The
`microprocessor has been used in instruments and appliances in place of mechanical or
`discrete electric components. In such applications it yields lower cost, greater reliability,
`and greater functionality than former designs. But the microprocessor also makes possible
`a new technology that heretofore has not existed. In the laboratory, the logic analyzer is a
`microprocessor-controlled oscilloscope that enables the engineer to capture and analyze
`electronic waveforms in a manner that had never been possible before. In medicine, the
`microprocessor has led to the CAT-scanner and the ultrasonic scanner that have dramati(cid:173)
`cally improved the ability to diagnose illnesses. In merchandising, the point-of-sales ter(cid:173)
`minal that reads product labels automatically provides greater control of inventory, as
`well as faster, more accurate handling of sales. The microprocessor-controlled reading
`machine that automatically scans printed text and speaks the words it sees aloud has
`brought new vision to the blind. The main limitation on the innovative applications of
`microprocessors today is not technological, but rather one of imagination and skill.
`To help surmount the human limitation, this textbook is offered as one way to intro(cid:173)
`duce the student to basic principles of microprocessor technology. A primary goal is to in(cid:173)
`crease the pool of innovators. It is oriented to an undergraduate curriculum, and is ideally
`suited for juniors and seniors in a Computer Engineering, Electrical Engineering, or Com(cid:173)
`puter Science program. A course based on this text will give the student a strong founda(cid:173)
`tion in techniques for connecting computers to peripherals and communications devices,
`and in the methodology for programming the computer to control external devices in real
`time.
`The well-prepared reader has had instruction in hardware, software, electronics, and
`mathematics. But the material presented here is modular so that an instructor can skip por-
`
`v
`
`Micron Technology Inc. et al.
`Ex. 1022, p. v
`
`

`

`vi
`
`Instructor's Preface
`
`tions of the text that refer to topics that students at particular institutions will not yet have
`mastered. A breakdown of the prerequisites is as follows:
`
`1. All Chapters: The student should have some exposure to microprocessors and logic
`design through such textbooks as Blakeslee (1979), Klingman (1977), Kraft and Toy
`(1979), Krutz (1980), or Peatman (1977). This general type of textbook introdu~es
`the student to the logic components, design techniques, and the structure of digital
`computers. The student should be comfortable 'with assembly language, but need not
`have extensive skills in this area. It is desirable for the student to have read such text(cid:173)
`books as Gear (1980) or Wakerly (1981) that cover assembly language for many dif(cid:173)
`ferent machines.
`2. Chapter 2, Transmission Lines. Prior exposure to transmission-line theory is helpful
`for Chapter 2, but not absolutely necessary. The chapter is self-contained in that all
`background required to support the physical concepts is developed within the
`chapter. In curricula in which the electronic aspects of interfacing have been omitted,
`the instructor may choose to skip portions of Chapter 2 (grounding, shielding, and
`transmission lines), Chapter 3 (bus interconnections), and Chapter 7 (magnetic(cid:173)
`recording techniques).
`3. Chapter 7, Linear Systems. Some results and equations in this chapter are cited from
`other sources rather than derived in the chapter. A student should know Laplace
`transforms and transfer functions for full appreciation of this material. The exercises
`require a knowledge of electronics as well. The material may be skipped at institu(cid:173)
`tions that teach microprocessor interfacing earlier than linear systems.
`4. Chapter 9, High-Level Language Programming. The student should be familiar with
`sorne high-level language such as Pascal, ALGOL, Ada, PL-I, FORTRAN, or
`COBOL. The notation in the chapter is basically Pascal, but should be quite under(cid:173)
`standable for readers familiar with any of the first four languages cited here. Where
`the only high-level language in the curriculum is FORTRAN or COBOL, before the
`students read Chapter 9, the instructor may wish to incorporate a brief tutorial on a
`block -structured language.
`
`The presentation of material in the text is three-tiered. Each chapter contains
`
`1. Basic principles.
`2. Applications of the principles in present technology.
`3. Specific examples of the use of the principles.
`
`Principles are stressed by necessity. Principles tend to be the foundation of expertise.
`They tend to change very slowly, if at all, over long periods of time. Details and specific
`facts quickly become obsolete. In the microprocessor industry, new generations of
`memory and microprocessors appear every two to three years. This means that details
`taught to a sophomore will be obsolete by the time that sophomore graduates. A curricu(cid:173)
`lum must, therefore, rest on the principles that support the technology. The student must
`master these first, and must learn to apply them. As the industry advances and the specific
`details change, the student must be able to adapt to these new details without outside in-
`
`Micron Technology Inc. et al.
`Ex. 1022, p. vi
`
`

`

`Instructor's Preface
`
`vii
`
`struction. Therefore, a college curriculum should prepare the student for self-education in
`the future. To do so requires a thorough foundation in basic principles.
`The nine chapters in this text are more than sufficient for a semester course in micro(cid:173)
`processor interfacing. The instructor can easily select a subset of material to adapt the text
`to any particular curriculum. Core material that should be in all curricula consists of
`
`Chapter 1, basic microcomputer structure
`Chapter 3, bus interconnections
`Chapter 5, serial interfacing
`Chapter 6, parallel interfacing
`Chapter 9, software development
`
`Curricula in which electronic design and logic design is stressed should add
`
`Chapter 2, grounding, shielding, and transmission-line techniques
`Chapter 4, memories
`
`Curricula that stress the use of the microcomputer as a control element should incorporate
`
`Chapter 7, magnetic-recording techniques
`Chapter 8, CRT-controller design
`
`Now let's tum to methods of instruction for the material. Lectures should be coupled
`with a computer laboratory in which the student can perform simple interfacing experi(cid:173)
`ments including the development of elementary control software. The experimental la(cid:173)
`boratory in conjunction with the course should occupy roughly three hours per week and
`should be followed later in the curriculum by one or more project-design laboratories de(cid:173)
`voted to microprocessor-based designs. The project-design laboratory gives the student an
`opportunity to integrate information from many subject areas, such as interfacing tech(cid:173)
`niques, software development, and communications.
`The experiments in the text are sufficient for a full semester of laboratory work. The
`reason for an experimental orientation instead of a design orientation is that the informa(cid:173)
`tion is passed quickly and efficiently when the student does not have to design and debug
`the bulk of the experimental apparatus. The student uses existing equipment and commer(cid:173)
`cially available boards to learn the principles of interfacing. The student exercises the
`equipment through small digital project boards and simple interfacing software. By ob(cid:173)
`serving the behavior of the equipment on oscilloscopes and logic analyzers, the student
`learns about such basic notions as noise reduction, electrical loading, timing, hysteresis,
`handshaking, skew, etc. The experiments in a laboratory should demonstrate various
`phenomena and should illustrate preferred approaches for dealing with fundamental prob(cid:173)
`lems. After completing the experimental lab, the student should be well prepared for sub(cid:173)
`sequent project-design labs.
`It would be rather ironic in this age of high technology to approach microprocessor
`education in a totally traditional form. This textbook is an example of a technology that is
`centuries old. Obviously, the printed word is an effective way for presenting information
`because it would not have survived to this day if it were not. But can we do better? In par-
`
`Micron Technology Inc. et al.
`Ex. 1022, p. vii
`
`

`

`viii
`
`Instructor's Preface
`
`ticular instances, new technology enables one person to do in one day what formerly took
`four people to do in a week. Can new technology help the academic community educate
`students more effectively and efficiently? The search for a better way has led this author
`to develop an instructional syste~ for this course consisting of this text plus a set of color
`video tapes. Tapes are produced by the Association for Media-Based Education for En(cid:173)
`gineers (AMCEE) at Georgia Institute of Technology in Atlanta, Georgia. The tap(;!s may
`be ordered by writing to Addison-Wesley Publishing Company, Reading, MA 01867; At(cid:173)
`tention: Tom Robbins, Acquisitions Editor, Computer Engineering.
`The instructional system is modular in that the text stands on its own and can be used
`in the traditional ways. The tapes too are self-contained and can be used independently.
`Together, the tapes and the text make up an instructional system that is far more effective
`than either medium by itself.
`To see how the two work together, consider the material on transmission lines in
`Chapter 2. The student is told about reflections on transmission lines and how ~ermina­
`tions can remove or reduce reflections. The student has to see this to appreciate the ideas
`fully. Experiments illustrating the ideas are demonstrated on the video tapes. Because the
`experiments show waveforms changing in time, and show them with their normal spikes
`and jitter rather than as idealized waveforms, the student gains experience with the real
`world rather than an artificial one. The key here is that there is information in the dynam(cid:173)
`ics of the video image as it changes in time. That information is lost when the image is
`photographed or drafted as a figure in a textbook. When specific comparisons are made on
`the videotape, the images appear in rapid succession so that the student can quickly grasp
`what similarities and differences exist. The behavior of a phase-locked loop acquiring
`phase lock appears vividly on video as a sudden change of frequency of a voltage(cid:173)
`controlled oscillator. The jitter in the oscillator at the threshold of acquisition is clearly
`visible. How can this information be displayed in a textbook? For waveforms changing in
`time, the video image is clearly superior to the printed image.
`This author has often prepared classroom or laboratory demonstrations to illustrate
`basic ideas. The effort involved in setting up a demonstration is considerable and notal(cid:173)
`ways successful. Some demonstrations work well on the bench, but fail when the equip(cid:173)
`ment is moved to the classroom. A probe may fall off, or a connection might not be tight,
`or a noise "glitch" may cause the logic to latch in a failure mode. The experiments on the
`video tape all work correctly. They were carefully set up and video taped in operation so
`that the course instructor need not repeat the effort in the setup nor take the risk of the ex(cid:173)
`periment failing.
`The video medium leads to a better presentation of the waveforms than does the ac(cid:173)
`tual physical equipment. The physical size of an oscilloscope or logic-analyzer display is
`only 10 to 20 em square, which is too small for a classroom of 30 students. This forces the
`instructor to set up the experiments in a laboratory and demonstrate them to small groups
`of students so that each has an opportunity to study the principles being demonstrated.
`Apart from the inefficiency of this method, it does not resolve the basic difficulty of
`pointing to specific places on a small display screen. Pointing at the images is not very
`effective because the instructor's hand tends to block large portions of the display from
`
`Micron Technology Inc. et al.
`Ex. 1022, p. viii
`
`

`

`Instructor's Preface
`
`ix
`
`view. However, the image of the same display on the video tapes is superior to the oscillo(cid:173)
`scope because the image is enlarged. Moreover, electronic superposition techniques per(cid:173)
`mit the instructor to point to and label the most highly detailed parts of a waveform with
`no obstruction of view to other parts of the image. The video tapes relate the wavefmm to
`a schematic by using zoom and pan to illustrate various regions of the schematic, with
`those images juxtaposed between images of waveforms that appear at selected points on
`the schematic. The information is presented at an extraordinarily fast pace compared with
`classroom discussion, yet is easily comprehensible because of the way the video medium
`is used to advantage. Should the student wish to review specific waveforms, it is a very
`simple matter to rewind to the point of interest and play the material again. Consequently,
`the video tapes are an extremely attractive solution to the laboratory demonstration prob(cid:173)
`lem. There is no setup overhead, the equipment is inexpensive, and video is more effec(cid:173)
`tive than the laboratory equipment itself for reaching large groups of people. The tapes,
`like the text, are prepared in a modular fashion so th;1t the instructor can select specific
`material to support lectures and laboratory work.
`Because of rapid changes in microprocessors still to come, we anticipate future edi(cid:173)
`tions of the textbook and video tapes to be issued at regular intervals with new chapters
`incorporated to cover various technological advances and to maintain a blend of basic
`principles and current technology. To find out what new material or supplementary texts
`are available, write to Tom Robbins at the address on page x.
`
`Many people beside the author have made substantial contributions to the textbook
`and video tapes: The author owes a deep debt of gratitude in particular to John Wakerly
`for his timely and thoughtful comments throughout the project development. Other
`manuscript reviewers have added their unique perspectives and have helped to create a
`better textbook than the author could have done in their absence. Among the many re(cid:173)
`viewers were Jack Lipovski, Martha Sloan, Jacob Abraham, Ed Brockert, and Dominique
`Thiebaut. 'fhrough John Fitch's skills in video production and direction, I was able to
`develop the accompanying video-tape course, but he deserves the bulk of the credit for
`showing the author the power of the medium and the techniques for tapping its unique
`capabilities. Tom Robbins, the acquisitions editor for the project, maintained his
`enthusiasm for the project from our very first phone conversation through the difficult
`times of final book production. His management activities behind the scenes freed the au.,.
`thor from many frivolous problems, and let the author focus his activity on the textbook
`itself. Marilee Sorotskin's gift for the details of editing and consistency added materially
`to the quality of the exposition. Finally, the dislc operating-system for the word processor
`on which the book was developed was written by my wife, Jan Stone. Her support both as
`a spouse and as a live-in systems programmer was extraordinary, and was a critical in(cid:173)
`gredient in the project development.
`
`Amherst, Massachusetts
`May1982
`
`H.S.S.
`
`Micron Technology Inc. et al.
`Ex. 1022, p. ix
`
`

`

`READER'S PREFACE
`
`This book is intended for both the undergraduate and the professional reader. Undergradu(cid:173)
`ates should be majors in a computer engineering or enrolled in a computer science pro(cid:173)
`gram that has exposed them to logic design, assembly-language programming, and a
`high-level language prior to using this textbook. The professional reader with training in
`electrical engineering, computer science, or other technical areas is likely to have a sound
`technical background but needs to brush up on microprocessor technology. This reader
`will find it useful to browse through the book to learn the major subject areas discussed,
`and then to concentrate on the unfamiliar material.
`Topics are covered three different ways. Each chapter opens with a discussion of
`basic principles, followed by methods for applying these principles. The chapters close
`with detailed examples of the principles put to use. The principles are the foundations of
`microprocessor technology and will continue to be as important in the next decade as they
`are today. However, the devices available change rapidly as technology advances. The
`processors, memories, and I/0 ports that a student learns about in a sophomore laboratory
`are obsolete by the time student graduates. Only the principles remain relatively stable
`within this time frame.
`To put this textbook to best use, the reader should learn the principles first, then how
`to apply them using current technology. The examples in the textbook illustrate practical
`designs that use real devices available in 1982. Armed with detailed specifications of new
`devices and with the basic information contained in this textbook, the reader should no
`difficulty adapting to the most modem devices.
`An essential part of the undergraduate learning experience is the experimental lab as(cid:173)
`sociated with the textbook. The experiments clarify the principles. Practice in applying
`the principles can come in the experimental lab or in a later project-design laboratory.
`The professional reader undoubtedly has had some laboratory experience. Although
`having an experimental lab while reading is useful, it may not be necessary for those
`readers who have older degrees in Computer Engineering or Computer Science and who
`wish to use this book to bring themselves up to date. These readers should focus on very
`specific topics. They will probably be able to absorb the material through reading without
`conducting the lab experiments. Some readers may have sufficient equipment at their
`disposal in their companies to be able to conduct selected·experiments where the experi(cid:173)
`ments are central to the learnivg process. Several demonstrations are available on color
`video tapes and may be accessible to the professional through a company library or short(cid:173)
`course. In any case, the professional reader should have the experience and maturity to
`recognize what topics in the textbook must be mastered and to devise a strategy for mas(cid:173)
`tering them.
`
`X
`
`Micron Technology Inc. et al.
`Ex. 1022, p. x
`
`

`

`Reader's Preface
`
`xi
`
`There are several reader objectives that this book addresses. Readers who are or who
`wish to become professional designers will find the material to be quite relevant to their
`work. These readers need a thorough background in electronics and logic design in addi(cid:173)
`tion to the material taught in this text. Additional background in transmission lines (for
`Chapter 2) and linear systems (for Chapter 7) may also be useful. Another group of
`readers will be concerned with connecting microcomputers to I/0 devices or to other
`microcomputers, and will probably use existing interfaces instead of designing new ones.
`This group of readers should focus attention on Chapters I (microprocessor structures), 5
`(serial interfacing), 6 (parallel interfacing), and 9 (software development). Chapter 2
`(shielding, grounding, and transmission lines) may be helpful if the reader must specify
`the physical connections between systems. Chapter 3 (bus interconnections) covers proto(cid:173)
`cols and timing questions that may also be important issues when configuring complex
`systems.
`Another reader of the textbook may be strong in software and relatively weak in elec(cid:173)
`tronics. A typical reader of this type may wish to control VO through software without
`becoming expert in logic design. This reader will find Chapter 9 (software development)
`especially illuminating, and will also find topics of interest in Chapters 1 (microprocessor
`structures), 4 (memories and DMA), 5 (serial interfacing), 6 (parallel interfacing), 7
`(magnetic-recording techniques), and 8 (CRT-controller design).
`The color video tapes associated with the textbook are an extremely effective way of
`observing the principles in action. We particularly recommend the tapes for readers who
`have limited access to experimental equipment because they provide vivid demonstrations
`of several of the more important experiments. The professional may find a short-course
`environment with video tapes to be an effective means of learning the material, not only
`as a way of observing experiments, but as an opportunity to raise and answer questions
`through class discussions.
`I am most interested in the readers' reactions to this textbook. The intended audience
`is quite broad with diverse skills and backgrounds. Discussions that are over the head of
`some readers may be too basic and trivial for others. Comments on the strengths and
`weaknesses of the material in the context of its use are greatly appreciated and may
`strongly influence future revisions of the material.
`
`Amherst, Massachusetts
`Mayl982
`
`H.S.S.
`
`Micron Technology Inc. et al.
`Ex. 1022, p. xi
`
`

`

`CONTENTS
`
`Instructor's Preface
`Reader's Preface
`1 Microcomputer Structures
`
`1.1 Basic microcomputer structure
`1.2 The memory interlace
`1.3 The I/0 interlace
`I/0 port structure and I/0 transactions
`Interrupts
`The interrupt interlace
`Device identification
`I/0 port addressing
`1.4 The DMA interlace
`1.5
`I/0 strategy: Program-controlled versus interrupt -driven
`1. 6 Memory and I/0 interfaces for typical microprocessors
`History and background reading
`
`2 Shielding, Grounding, and Transmission-Line
`
`Techniques
`
`2.1 Grounding and shielding
`Shielding techniques
`Balanced interconnections
`2.2 Transmission-line techniques
`Point-to-point transmission
`Applications
`Graphical methods
`2.3 Putting the techniques into practice
`Intra-board connections
`Backplane connections
`Board-to-board connections
`Chassis-to-chassis connections
`Other source material
`Experiments
`Problems
`
`xii
`
`v
`X
`
`1
`
`1
`6
`11
`11
`15
`19
`21
`23
`25
`28
`31
`39
`
`42
`
`43
`45
`51
`54
`55
`61
`68
`71
`71
`72
`78
`82
`82
`83
`86
`
`Micron Technology Inc. et al.
`Ex. 1022, p. xii
`
`

`

`3 Bus Interconnections
`
`3.1 Bus functions
`3.2 The bus handshake
`Synchronous buses
`Asynchronous buses
`Semisynchronous buses
`3.3 Arbitration protocols
`3.4 Asynchronous timing difficulties
`3.5
`Interrupt -request arbitration
`3.6 Examples of existing bus protocols
`3.7 Examples of bus arbitration
`Other reading
`Experiments
`Problems
`
`4 Memories
`
`4.1 Types of memory
`General characteristics of semiconductor memory
`Static random-access memory (RAM)
`Read-only memory (ROM)
`Dynamic RAM
`4.2 Memory systems
`Arbitration policy
`Synchronization
`4.3 DMA controllers
`4.4 Examples of DMA controllers
`The i8257 DMA controller
`The Am9517 DMA Controller
`The MC6844 DMA controller
`Other reading
`Experiments
`
`5 Serial Interfacing
`
`5.1 Serial I/0 protocols
`5.2 Asynchronous protocols
`The RS-232-C interface
`The 20-rnilliampere current interface
`The RS-422, RS-423, and RS-449 interfaces
`5.3 Synchronous interfaces
`The BISYNC protocol
`The IIDLC protocol
`
`Contents
`
`xiii
`
`88
`88
`90
`91
`95
`98
`100
`107
`109
`110
`115
`121
`123
`124
`
`126
`126
`127
`134
`134
`136
`143
`143
`146
`148
`152
`152
`154
`155
`157
`157
`
`161
`163
`165
`167
`171
`174
`178
`181
`182
`
`Micron Technology Inc. et al.
`Ex. 1022, p. xiii
`
`

`

`xiv
`
`Contents
`
`5.4
`
`5.5
`
`Implementations of serial interfaces
`Rise-time control for cross-talk reduction
`Isolation
`Flow control on serial1inks
`Interface devices
`Asynchronous interfacing with the MC6850
`The BISYNC interface
`The i8251 for asynchronous and synchronous links
`HDLC interfacing
`Other reading and source material
`Experiments
`Problems
`
`6 Parallel Interfacing
`
`6.1 Parallel port characteristics
`Open-collector outputs
`Tri-state outputs
`Control lines
`6.2 The IEEE-488 instrument bus
`Functional description of the IEEE-488 bus
`Integrated circuits for parallel interfaces
`Interface chips for the IEEE-488 bus
`Other reading and source material
`Experiments
`Problems
`
`6.3
`
`7 Magnetic-Recording Techniques
`
`7.1 Tape interfaces
`Principles of phase-locked loops
`Example of an interface with a phase-locked loop
`7.2 Magnetic-disk recording techniques
`Disk-controller design
`Examples of practical disk interfaces
`Other reading and source material
`Experiments
`Problems
`
`8 CRT -Controller Design
`
`8.1 System description of a typical CRT controller
`The controller software
`Keyboard scanning
`CRT timing considerations
`
`185
`185
`187
`190
`192
`192
`194
`194
`197
`201
`202
`204
`
`206
`207
`207
`212
`215
`215
`218
`227
`233
`240
`240
`243
`
`245
`246
`252
`261
`265
`271
`276
`289
`289
`290
`
`292
`292
`295
`296
`300
`
`Micron Technology Inc. et al.
`Ex. 1022, p. xiv
`
`

`

`8.2 The CRT-controller chip
`The clocking and timing functions
`Cursor functions
`Scrolling
`Other Controller Functions
`8.3 A sampling of CRT -controller chips
`A basic controller: The SMC 5027
`The Intel8275 CRT controller
`The Signetics 267X CRT chip set
`A video display controller: The 6847/68047
`Other reading and source material
`Experiments
`
`9 Software Development
`
`9.1 Software development methodology
`Top-down design and iterative refinement
`An example: File merging
`Translation to assembly language
`Pragmatics of assembly language
`9.2 Software for l/0 control
`Coroutines: Structure and implementation
`File filters: An application of coroutines
`Coroutines for l/0 control
`A detailed example of an l/0 controller
`Other source material
`
`Bibliography
`Appendix A: The ASCII Code
`Appendix B: The RS-232-C Standard
`Appendix C: The RS-449 Standard
`Appendix D: IEEE-4881nterface Messages
`Index/ Glossary
`
`Contents
`
`XV
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`304
`305
`307
`308
`309
`310
`310
`312
`313
`315
`317
`318
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`320
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`321
`321
`322
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`333
`336
`336
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`347
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`368
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`370
`372
`373
`
`Micron Technology Inc. et al.
`Ex. 1022, p. xv
`
`

`

`1 I MICROCOMPUTER STRUCTURES
`
`This chapter reviews the general characteristics of microcomputer systems. We focus here
`on the functional description of the major components and on the system structure. By
`understanding these facets of microcomputers, we will be able to select among several al(cid:173)
`ternative approaches to interfacing and to work easily with both software and hardware to
`put together complex systems. The functional descriptions in this chapter treat data and
`control flow exclusively, and ignore specific details of timing and electronics. Later
`chapters carefully delve into these details and should be sufficient to prepare the reader for
`practical interface design. This chapter, like those that follow, opens with a general
`description of the major concepts presented and ends with specific examples to illustrate
`actual implementations of the concepts.
`
`1.1 BASIC MICROCOMPUTER STRUCTURE
`
`A very simple microcomputer system is composed of three types of modules typically
`connected as shown in Fig. 1.1. The components are
`
`1. a microprocessor, which contains the control logic and arithmetic unit of the system,
`2. a memory, which holds programs and data, and
`3. an input/output (VQ) system, which contains one or more pmis that connect to such
`external devices as terminals, disks, printers, and communications modems.
`
`Fig. l.l(a) shows a single bus system through which the memory and VO system com(cid:173)
`municate with the processor. In this system the processor is the master controller. It ini(cid:173)
`tiates all activity on the bus by issuing commands to the memory and I/0 systems. The
`bus carries only one transaction at a time, s.o that commands are issued sequentially, one
`at a time. The memory and VO syste]lls respond to the commands, but do not issue com(cid:173)
`mands in turn. If we monitor what happens on the bl.ls over a period of time, we see the
`processor issuing a sequence of commands, with each command directed to a particular
`port or memory cell. One type of command instructs the destination to accept data from
`the processor, and the data from the processor accoqJ.panies the command. Another type
`of command tells the destination to return data to the processor, and the destination replies
`by sending the requested data back to the processor. So the flow of information is from the
`processor to memory and VO, with flow in the reverse direction in response to processor
`cbmmands.
`A slightly different fUTangement is shown in Fig. l.l(b). Here the I/0 and memory
`systems have independent paths to the processor rather than a shareq path as in Fig.
`
`Micron Technology Inc. et al.
`Ex. 1042, 1
`
`

`

`2
`
`Microcomputer Structures
`
`Microprocessor
`
`I
`
`Memory
`
`I
`
`I/0
`port
`
`I
`
`I
`
`I/0
`port
`
`I
`
`External
`device
`
`External
`device
`
`Microprocessor
`
`I
`
`Memory
`
`(a)
`
`(b)
`
`FIGURE 1.1 The basic structure of microcomputer: (a) One-path system; (b) two-path system.
`
`1.1(a). Because the paths are separate and independent, two different transactions can be
`active at the same time, one on each bus. That is, the processor can issue commands to
`memory while simultaneously issuing commands to the I/0 system. This form of mi(cid:17