Newnes Microprocessor Pocket Book PDF
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Other Pocket Books from Heinemann Newnes Newnes Radio Amateur and Listener's Pocket Book Steve Money Newnes Audio and Hi-Fi Engineer's Pocket Book Vivian Capel Newnes Computer Engineer's Pocket Book Michael Tooley Newnes Data Communications Pocket Book Michael Tooley Newnes Radio and Electronics Engineer's Pocket Book Keith Brindley Newnes Television and Video Engineer's Pocket Book Eugene Trundle Newnes Engineering Science Pocket Book J O Bird Newnes Electronics Pocket Book E A Parr Newnes Electrical Pocket Book E A Reeves (ed) Newnes Physical Science Pocket Book for Engineers J O Bird and P Chivers Newnes Mathematics Pocket Book for Engineers J O Bird In preparation Newnes Mechanical Engineer's Pocket Book Roger Timings and Tony May Newnes Refrigeration Pocket Book Michael Boast Newnes Engineering Materials Pocket Book W Bolton Newnes Microprocessor Pocket Book Steve Money Heinemann Newnes Heinemann Newnes An imprint of Heinemann Professional Publishing Ltd Halley Court, Jordan Hill, Oxford OX2 8EJ OXFORD LONDON MELBOURNE AUCKLAND SINGAPORE IBADAN NAIROBI GABORONE KINGSTON First published 1989 © Steve Money 1989 British Library Cataloguing in Publication Data Money, Steve A. Newnes microprocessor pocket book. 1. Microprocessor system I. Title 004.16 ISBN 0 434 91290 5 Typeset by Electronic Village Ltd, Richmond, Surrey Printed and bound in Great Britain by Courier International, Tiptree, Essex Preface During the past ten years the microprocessor has become an integral part of many pieces of electronic equipment ranging from domestic appliances to industrial control systems. Compared with more conventional electronic systems using discrete components or integrated logic circuits the micro- processor has the advantage that it is versatile and can readily be adapted to perform a number of different functions merely by altering its program- ming. Another major advantage is that a micro- processor-based system often requires fewer components than the equivalent system based on more conventional electronic circuits. The engineer involved in developing a system based around the use of a microprocessor needs to have some knowledge of programming as well as the usual knowledge of electronics circuit design. In a micro- processor system most of the functions that would normally be performed by logic circuits can be implemented by suitable instructions in the computer program or software. The result is that most of the hardware design is concerned with interfacing between the microprocessor and the outside world whilst the overall operation of the equipment is largely controlled by the software. In this book the basic hardware operation of a microprocessor is explained and the actions of the various types of instruction that can be executed are described. In practice the instruction sets for the various types of microprocessor follow much the same pattern although the data sheet for the processor being used will generally need to be consulted to see exactly how the instruction is executed and which address modes are available. A section of the book is devoted to a summary of the characteristics of many of the popular micro- processors in current use. There are in fact hundreds of types of microprocessor available and there are many variants of the ones described. In many cases the difference between types is in the speed of opera- tion. Sometimes the alternative types may use a different fabrication technology or provide a few additional instructions or extra hardware features. To Vil give details of every processor type would require a much larger book than this so coverage has been restricted to the basic processors of the more popular ranges. Details given include pin connections, signal functions, instruction set summary and details of timing and interrupt operation. Apart from the popular 8- and 16-bit micro- processors some details are also given of the popular single chip microcomputers and of the more recently developed reduced instruction set computer (RISC) type processors such as the Transputer, Novix FORTH processor and Acorn ARM processor. For most practical applications the microprocessor acts as a controller for the rest of the equipment but it could also be used for taking measurements in an instrumentation system. Usually a combination of these two basic functions is performed. In either case the connection or interface between the processor and the rest of the electronics is important. In this book the principles involved in both parallel and serial input-output interfaces are discussed. Details are given of the common standards used for parallel and serial input-output systems. Although discrete logic can be used for input- output interfaces, most microprocessor-based systems use specially developed integrated circuits for this purpose. Examples of these special interface chips are described with details of their internal arrangement and the basic techniques for programming their modes of operation. This covers parallel and serial input-output chips, counters and timers as well as one or two of the multifunction peripheral chips that are available. The development of a microprocessor-based system can be made easier by the use of a good micro- processor development system (MDS) which provides facilities for writing and testing the software. Most development systems also provide diagnostic tools, such as In Circuit Emulation, for testing the hard- ware design. The principles of development systems are described in this book. Although most systems use mnemonic assembly language for programming other higher level languages such as BASIC, FORTH and C are also used. The principles of these assembler, interpreter and compiler type languages are discussed together with the use of diagnostic routines such as debuggers. Many microprocessor-based systems are designed viii around the use of popular personal computers such as the IBM PC so the arrangement of the expansion bus for this machine is given. For industrial applica- tions a system using standard cards plugged into a backframe bus system is often used. Typical buses are the STD, STE and Intel Multibus and details of these buses are given. In this book I have tried to present a wide selection of information likely to be of general use to the engineer involved in developing a micro- processor-based system. It will also be of interest to anyone involved in designing, servicing or just wishing to learn more about microprocessor-based systems. Steve Money 1 Integrated circuits Integrated circuits are circuits composed of trans- istors, diodes, resistors and capacitors fabricated on a single chip of semiconductor material which is typically silicon. The circuits may be analogue types, such as amplifiers, or digital types such as logic gates, switches and memory devices. Integrated circuits can be broadly classified into a series of scales of integra- tion according to their complexity. Scales of integration Early designs for digital integrated circuits contain the equivalent of up to about ten simple logic gates and are generally referred to as small scale integration (SSI) circuits. Examples of SSI chips are the basic transistor transistor logic (TTL) gates such as the 7400, 7410 and 7420. As techniques improved larger devices with some 10 to 100 gates were produced. These are called medium scale integration (MSI) circuits. Examples of MSI circuits are the 4-bit binary counter devices such as the 74190, 74194 and 74196. Further development of fabrication techniques allowed the production of large scale integration (LSI) circuits containing up to 1000 gates. Examples of LSI devices include the 8-bit microprocessors such as the Motorola 6800 and Zilog Z80. This level of integration also covers most of the microprocessor support chips and the smaller capacity memory devices. More recently even larger circuits with more than 1000 gates have been produced. These are referred to as very large scale integration (VLSI) circuits and include the modern 16- and 32-bit microprocessors such as the Intel 8086 and Motorola 68000. Also included in this category are many of the large memory chips and some logic array chips which are used for custom designed digital circuits. Normally a large array of separate integrated circuit chips is produced on a silicon wafer of perhaps 7.5 to 10 cm in diameter. The wafer is then cut up to produce separate chips which are packaged as individual integrated circuits. The latest development 2 is wafer scale integration in which the array of chips on the wafer is left intact. Individual chips on the wafer are tested and those which work properly are wired together to form a complete system. This scheme allows the production of a memory array with enormous capacity in a single package. Alter- natively a large array of interconnected micro- processors could be produced as a single integrated circuit. Fabrication technologies A variety of different fabrication technologies has been employed for making digital integrated circuits. These fall into two major groups: bipolars and metal oxide semiconductors (MOS). Bipolar logic devices This type of device uses conventional npn or pnp type junction transistors fabricated on a silicon wafer. They have the advantage of high switching speed but tend to require quite large levels of supply current and are not very tolerant of variations in the power supply voltage. Diode transistor logic (DTL) The gate structure for DTL uses diodes for the actual logic function with a transistor buffer amplifier to drive the output, as shown in Figure 1. Figure 1 Circuit of a DTL-type AND gate Typical of these devices were those in the 930 series which was produced by a number of different manufacturers. DTL is now obsolete although 930 series chips may be found in some older computer and industrial control equipment. 3 Supply voltage 4.5-5.5 V Supply current (per gate) typical 4 mA Gate delay time 30 nS max. Input low + 1.1 V max. —1.4 mA high +2.0 V min. 5 μΑ Output low +0.45 V max. 12 mA high + 2.6 V min. -120 μΑ Transistor transistor logic (TTL) The gate structure of TTL devices typically uses multi-emitter transistors for the gate action followed by a transistor amplifier to drive the output, as shown in Figure 2. This widely used logic family has device type numbers which start with the code 74. Most of the simpler circuits in the series, such as gates and flip-flops, have numbers in the series 7400 to 7499. Many more complex devices have numbers ranging from 74100 up to numbers in the region of 74900. Originally introduced by Texas Instruments, the TTL 74 series is now available from a large number of different manufacturers. Figure 2 Circuit of a TTL-type AND gate TTL devices have the advantage of quite high speed with typical gate delay times of the order 15 ns. When an input is held in its low or Ό' state the circuit driving the input must be able to sink about 1.6 mA of current flowing from the gate input circuit. The output of a typical TTL device can sink a current of about 16 mA and will drive the inputs of up to ten other TTL gates. The main disadvantage of standard TTL is that it requires a stable power supply, within 5% of the nominal +5 V which even for a relatively small system may have to supply currents in the order of amperes. Decoupling of the supply is also important and a 0.1 ^F decoupling capacitor should be included 4 across the supply lines close to every group of four to five TTL chips. Supply voltage +4.75 V- + 5.25 V Supply current (per gate) typical 4 m A Gate delay time 15 ns Input low +0.8 V max. -1.6 mA high +2.0 V min. 10 μ,Α Output low +0.4 V max. 16 mA high +2.4 V min. -400 μΑ Low power TTL (LPTTL) To overcome the power demands of standard TTL a modified version known as low power TTL was developed. These circuits offer a supply current demand much lower than that of standard TTL devices but this results in a lower switching speed. Gate delay for a typical 74L series gate is around 90 ns. Logic signal levels for LPTTL are the same as for TTL but input and output current levels are much lower. This range of circuits has type numbers prefixed with the code 74L and have equivalent func- tions to the corresponding 74 series device. Thus a 74L00 is the low power equivalent of the 7400. Supply voltage +4.75 V- + 5.25 V Supply current (per gate) typical 0.5 m A Gate delay time 90 ns Input low +0.7 V max. -0.18 mA high +2.0 V min. 10 μA Output low +0.3 V max. 2 mA high + 2.4 V min. -100 μΑ Schottky TTL (STTL) By incorporating Schottky diodes into the input circuits of a TTL device it was found that the switch- ing speed could be increased to give a typical gate delay of around 7 ns and flip-flop switching speeds up to 125 MHz. This type of logic provides equivalent devices to those in the standard TTL range but the type numbers are prefixed by the code 74S. The Schottky equivalent of a 7400 quad NAND gate is the 74S00.
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