Basic Digital Electronics

231 Pages·1991·4.27 MB·English

by  J. A. Strong (auth.)

Basic Digital Electronics
'Contrariwise,' continued Tweedledee,
'if it was so, it might be; and if it
were so, it would be: but as it isn't,
it ain't. That's logic'
(Carroll: Alice Through the Looking Glass)
PHYSICS AND ITS APPLICATIONS
Series Editor
E.R. Dobbs
University of London
This series of short texts on advanced topics for students, scientists and engineers
will appeal to readers seeking to broaden their knowledge of the physics underlying
modern technology.
Each text provides a concise review of the fundamental physics and current
developments in the area, with references to treatises and the primary literature to
facilitate further study. Additionally texts providing a core course in physics are
included to form a ready reference collection.
The rapid pace of technological change today is based on the most recent scientific
advances. This series is, therefore, particularly suitable for those engaged in research
and development, who frequently require a rapid summary of another topic in physics
or a new application of physical principles in their work. Many of the texts will also
be suitable for final year undergraduate and postgraduate courses.
1. Electrons in Metals and Semiconductors
R. G. Chambers
2. Basic Digital Electronics
J. A. Strong
3. AC and DC Network Theory
Anthony J. Pointon and Harry M. Howarth
4. Nuclear and Particle Physics
R. J. Blin-Stoyle
Basic Digital
Electronics
J.A. 5trong
Reader in Experimental Physics
University of London
SPRINGER-SCIENCE+BUSINESS MEDIA, B.v.
First edition 1991
© 1991 J. A. Strong
Originally published by CHAPMAN AND HALL 1991
Typeset in 10/12 Times by Thomson Press (India) Ltd,
New Delhi
ISBN 978-0-412-39990-9
AII rights reserved. No part of this publication may be
reproduced Of transmitted, in any form or by any means,
electronic, mechanical, photocopying, recording or otherwise,
or stored in any retrieval system of any nature, without the
written permission of the copyright holder and the publisher,
application for which shall be made to the publisher.
The publisher makes no representation, express or implied,
with regard to the accuracy of the information contained in this
book and cannot accept any legal responsibility or liability for
any errors or omissions that may be made.
British Library Cataloguing in Publication Data
Strong, J. A.
Basic digital electronics
1. Electronics
I. Title II. Series
537.5
ISBN 978-0-412-39990-9
Library ofCongress Cataloging-in-Publication Data
Strong, J. A. (John A.), 1941-
Basic digital electronics / J. A. Strong.-lst ed.
p. cm.-(Physics and its applications; 2)
Includes bibliographical references and index.
ISBN 978-0-412-39990-9 ISBN 978-94-011-3118-6 (eBook)
DOI 10.1007/978-94-011-3118-6
1. Digital electronics. I. Title. II. Series.
TK7868.D5S79 1991
621.381-dc20 90-2689
CIP
Contents
Preface ix
Acknowledgements xi
1 Introduction 1
1.1 Preamble 1
1.2 History 2
1.3 Sentence analysis and truth tables 2
1.4 Number systems 4
1.5 Gates and memories 6
1.6 Integrated circuits 6
Problems 8
2 Basic gates 10
2.1 Introduction 10
2.2 Logic levels 10
2.3 Gating functions 12
2.4 Basic gates and symbols 12
2.5 Boolean algebra and truth tables 15
2.6 Universal logic elements 18
2.7 Gate minimization 20
2.8 NAND and NOR implementation 24
2.9 Limitations of the minimization process 25
2.10 Don't care and can't happen conditions 27
2.11 Hazards and glitches 28
2.12 Alternative symbols 31
2.13 Chip list 32
Problems 32
Practical exercises 35
vi Contents
3 Gating circuits 37
3.1 Introduction 37
3.2 Decoders 37
3.3 Decoders as logic elements 41
3.4 Multiplexers 42
3.5 Multiplexers as logic elements 45
3.6 Parity 46
3.7 Memories as logic elements 48
3.8 Programmable logic 49
3.9 Binary addition 54
3.10 Full-adder circuits 57
3.11 Look-ahead carry circuits 59
3.12 Decimal addition 60
3.13 Binary subtraction 62
3.14 Multiplication 64
3.15 Division 66
3.16 Chip list 66
Problems 67
Practical exercises 70
4 Latches and flip-flops 73
4.1 Introduction 73
4.2 Aims 73
4.3 The set-reset flip-flop 74
4.4 The set-reset flip-flop as a switch debouncer 77
4.5 The data latch 77
4.6 The data flip-flop 80
4.7 Synchronization of external signals 83
4.8 The JK flip-flop 84
4.9 The T flip-flop 86
4.10 Multivibrators 87
4.11 Chip list 90
Problems 90
Practical exercises 92
5 Registers and counters 95
5.1 Introduction 95
5.2 Aims 96
5.3 Basic register 96
Contents VB
5.4 Shift register 97
5.5 Ring counters 100
5.6 Counters 103
5.7 Asynchronous counters 104
5.8 Modulo-n asynchronous counters 107
5.9 Synchronous counters 110
5.10 Synchronous system design 115
5.11 Modulo-5 counter using JK flip-flops 115
5.12 Modulo-5 counter using T flip-flops 118
5.13 Modulo-3 up/down counter using JK flip-flops 120
5.14 Decade counter using D flip-flops 123
5.15 Chip list 125
Problems 126
Practical exercises 130
6 Memories 131
6.1 Introduction and aims 131
6.2 Memory types and uses 132
6.3 Memory architecture 133
6.4 Memory arrays and buses 137
6.5 Memory read and write cycles 138
6.6 A practical memory circuit 141
6.7 Chip list 142
Problems 143
Practical exercises 144
7 The analogue connection 146
7.1 Introduction 146
7.2 Aims 147
7.3 Digital-to-analogue conversion 148
7.4 The R -2R ladder 149
7.5 Practical DACs 152
7.6 A microprocessor-compatible DAC 152
7.7 A multiplying DAC 154
7.8 Uses for DACs 157
7.9 Accuracy and resolution of DACs 157
7.10 Analogue-to-digital conversion 159
7.11 Integrator ADCs 159
7.12 Single-slope conversion 160
7.13 Dual-slope ADC 162
viii Contents
7.14 Other ADCs using integrators 164
7.15 Analogue-to-digital conversion using DACs 165
7.16 The tracking ADC 165
7.17 The successive-approximation ADC 167
7.18 Flash ADCs 170
7.19 Chip list 172
Problems 173
Practical exercises 174
Appendix 1 Boolean algebra 178
AU Rules 178
At.2 Algebraic minimization 179
At.3 Minimization in product-of-sums form 181
Appendix 2 Logic families 182
A2.1 TTL circuits 182
A2.2 Open-collector output 185
A2.3 Tri-state output 186
A2A Schmitt trigger inputs 187
A2.5 Schottky TTL 189
A2.6 Emitter-coupled logic (ECL) 190
A2.7 MOS logic 191
A2.8 Conversion between TTL and CMOS 193
A2.9 A CMOS oscillator circuit 195
Appendix 3 Designing and testing 196
A3.1 Designs and diagrams 196
A3.2 Proto typing methods 198
A3.3 Testing 199
Answers to problems 201
Further reading 210
Index 212
Preface
Modern electronics is the most visible result of research in solid state
physics. Transistors and integrated circuits are used everywhere in
ever increasing numbers. The microprocessor controlled coffee-pot
exists.
Most experimental physicists, and, indeed, experimental scientists
in most disciplines, study their subject with the aid of apparatus
containing significant amounts of electronics and much of that
electronics is digital. In order to design experiments and apparatus
or simply to understand how a piece of equipment works, an under
standing of electronics has become increasingly important. In
recognition that electronics has pervaded so many areas, courses in
digital electronics are now a recommended part of physics and many
other science degree courses.
At the introductory level, digital electronics is, primarily, a
practical subject with relatively few basic concepts and any complex
ity arises from the coupling together of many simple circuits and the
extensive use of feedback. Designing an electronic circuit and then
getting it to work correctly provides an experience, and a sense of
achievement, which is significantly different from most undergradu
ate work as it more closely resembles project work than standard
laboratory practicals.
For many years, I have been convinced of the value to students of
understanding electronics and have taught a number of courses at
different levels. This book is based on the introductory material given
to physics and computer science students over several years but with
extensive updating in an attempt to keep pace with rapid changes in
the field. I have concentrated on the basic ideas and provided
examples of the circuits and techniques used together with a