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Designing microprocessor-based instrumentation
F@vi@ws Introduction to the use of digital J N W Baldwin 'Microprocessors for Industry' Butterworth Scientific (1982) £7. 50 pp 149 This book is addressed to industrial and scientific users of automatic equipment in measurement and control. The author states that conversations with senior people in industry, commerce and education have revealed an ignorance of even the most rudimentary knowledge of digital electronics. The book has been written to enable such lay readers, in the electronic and computer sense, to investigate the subject in relation to their responsibilities. The aim is to provide a foundation of basic information to allow the reader to form a sound judgment on the use of digital electronics in his field. In a relatively short book which attempts to deal with all aspects of the subject from 'chips' to laser plotters and from assembly code to operating systems, it is inevitable that any particular subject is treated somewhat superficially, e.g. the Intel 8080 and Motorola 6800 are dealt with in one page each. In this context CAMAC has been treated at disproportionate length considering that, whilst it is widely used in the nuclear industry, particularly in the laboratories, it has not found acceptance in industry in general. The analog to digital converter (ADC) is an important part of most industrial data acquisition systems and is touched upon in several places. However, a short description of the two main classes, i.e. dual-slope integrating and successive approximation, and their characteristics would have been useful. The book covers digital techniques, hardware, software and peripherals. In the hardware section attention is drawn to the very important choice of at which level to commence system design, i.e. chip, board, or complete microcomputer system. A later chapter on 'The Quantity Problem' gives some qualitative guidance on this topic. A subject of importance to managers is system design documentation and project control. The
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former being required to achieve the latter. This is particularly relevant in software projects and is dealt with very briefly at the beginning of the chapter on 'Software Linguistics'. However, the importance of having complete documentation at the various stages of User Requirement Specification, Functional Specification, High Level Design, Low Level Design and Implementation cannot be over-emphasized. It would have been useful to have had this topic dealt with at greater length. The chapter on software linguistics also deals with machine code, assembly language, high level languages and operating systems. Amongst the high level languages Pascal and ADA are notable omissions. Also, the section on operating systems would have been enhanced by a mention of CP/M and Unix. Useful mention is made of the necessary test equipment required for the development of systems. This
includes logic analysers, pulse generators, pattern generators, and ICE in circuit emulation. A mention of signature analysis would have completed this section. The section on CAMAC is well covered including an interesting historical survey. A chapter on peripherals gives a brief but adequate summary of all important peripherals and includes some very useful data on data storage devices. The book concludes with a number of case studies, one of which is in quite reasonable depth. In conclusion, this is a readable, well produced book with an adequate index. Despite the various shortcomings mentioned in this review the book should be a useful introduction to the subject for busy managers who wish to get a quick appreciation of the main points involved.
Joe Gallacher
From binary and op amps to l i a r variable differential transformers and micro opcodes J J Carr Designing microprocessor-based instrumentation Prentice Hall (1982) £17.55 pp 323 This book is intended for practising (not necessarily electronic) engineers who are not too familiar with digital electronics, or with microprocessors. It attempts to cover a very wide field, from the inevitable description of binary arithmetic to operational amplifiers, and from linear variable differential transformers to tables of micro op-codes. The depth of explanation is mostly shallow due to the amount of material tackled for a book of this size, with only an occasional excursion into more detail. As a result, it can only be considered an introductory text to kindle the interest of the reader, at UK undergraduate level, and to apply seriously the ideas covered would require further reading. The text is weighted towards circuit design rather than micro topics only about one third seemed associated
with microprocessors, and I found it hard to believe that this was anything other than the author's preference. In fact, on occasions, some very hardwareintensive designs are described. For example, on interfacing pushbuttons to a micro, a TTL flip-flop is used to implement discrete logic which could easily have been internal to the microprocessor, a particularly cost-effective design example revealing a heavy hardware bias to systems design. The chapter devoted to transducers is fairly comprehensive in the types covered, which is good considering the aim of the book. Likewise, data conversion is adequately described and would point the avid reader in the right direction. The microprocessor aspect is disappointingly brief in its description, I felt. The author chooses to describe the micro with reference to two real products, the Z80 and 6502, rather than with generalizations. And what a relief not to be faced with the 6800
microprocessors and micros,vstems
yet again! The justification for this choice is sound, namely two very well established, high volume parts for which much software exists, which are not too antiquated, This device’s specific approach at least allows the novice to feel acquainted with particular chips, and permits the inclusion of vast quantities of material from the manufacturer’s data sheets. The various terms, microprocessor, microcomputer, single board computer etc, are defined to set the context, which is good, even if one does not personally agree with the definitions: is a microcomputer a chip or a board level product?
Perhaps the biggest deficiency is the minimal coverage given to software. After all, it is well known that the major, and ever-increasing, proportion of work in designing microprocessorbased systems is the software, yet in this book it hardly gets a mention. Perhaps it is beyond the scope of the book (the subject would certainly fill several other volumes), but then the title should perhaps reflect this more accurately. Another criticism I had was the complete lack of description of displays ot their interfacing. Most instrumentation has some form of electronic display, and the choice and variety of drive requirement is enormous.
The style of writing I found very readable, in typical American manner, and the illustrations and photographs are excellent. The contents and index are comprehensive, and each chapter also sets out the objectives for that chapter, with some self-test questions. To summarize, the book is a useful collection of a wide range of circuitry
techniques pertinent to instrumentation, but falls short in the areas of microprocessors software.
and particularly
in
I P Leslie Smiths Industries plc
Design notes Engineers - have you a design hint or trick of the trade you’d like to share with your colleagues, but cannot spare the time to author a full-scale refereed paper? Or do you have experience with a particular part or piece of equipment you feel may be of interest to others? Why not write a Design Note?
It can be as short as you like - consistent with clarity - and we can reproduce your software listings straight from printer output. Send us your sketches and our studio will turn them into works of art (although we would prefer unlettered tracings). At present we can offer rapid typeset publication - which can be turned quickly and simply into glossy reprints for use by your company.
Send your ideas (or ring for more advice) to Simon Middelboe Microprocessors and Microsystems Butterworth Scientific Limited - Journals Division PO Box 63 Westbury House Bury Street Guildford Surrey GU2 5BH UK Telex: 659556 SCITEC G Telephone: 0463 31261
vol 7 no 3 april 1983
727
126
tronics for managers in industry
former being required to achieve the latter. This is particularly relevant in software projects and is dealt with very briefly at the beginning of the chapter on 'Software Linguistics'. However, the importance of having complete documentation at the various stages of User Requirement Specification, Functional Specification, High Level Design, Low Level Design and Implementation cannot be over-emphasized. It would have been useful to have had this topic dealt with at greater length. The chapter on software linguistics also deals with machine code, assembly language, high level languages and operating systems. Amongst the high level languages Pascal and ADA are notable omissions. Also, the section on operating systems would have been enhanced by a mention of CP/M and Unix. Useful mention is made of the necessary test equipment required for the development of systems. This
includes logic analysers, pulse generators, pattern generators, and ICE in circuit emulation. A mention of signature analysis would have completed this section. The section on CAMAC is well covered including an interesting historical survey. A chapter on peripherals gives a brief but adequate summary of all important peripherals and includes some very useful data on data storage devices. The book concludes with a number of case studies, one of which is in quite reasonable depth. In conclusion, this is a readable, well produced book with an adequate index. Despite the various shortcomings mentioned in this review the book should be a useful introduction to the subject for busy managers who wish to get a quick appreciation of the main points involved.
Joe Gallacher
From binary and op amps to l i a r variable differential transformers and micro opcodes J J Carr Designing microprocessor-based instrumentation Prentice Hall (1982) £17.55 pp 323 This book is intended for practising (not necessarily electronic) engineers who are not too familiar with digital electronics, or with microprocessors. It attempts to cover a very wide field, from the inevitable description of binary arithmetic to operational amplifiers, and from linear variable differential transformers to tables of micro op-codes. The depth of explanation is mostly shallow due to the amount of material tackled for a book of this size, with only an occasional excursion into more detail. As a result, it can only be considered an introductory text to kindle the interest of the reader, at UK undergraduate level, and to apply seriously the ideas covered would require further reading. The text is weighted towards circuit design rather than micro topics only about one third seemed associated
with microprocessors, and I found it hard to believe that this was anything other than the author's preference. In fact, on occasions, some very hardwareintensive designs are described. For example, on interfacing pushbuttons to a micro, a TTL flip-flop is used to implement discrete logic which could easily have been internal to the microprocessor, a particularly cost-effective design example revealing a heavy hardware bias to systems design. The chapter devoted to transducers is fairly comprehensive in the types covered, which is good considering the aim of the book. Likewise, data conversion is adequately described and would point the avid reader in the right direction. The microprocessor aspect is disappointingly brief in its description, I felt. The author chooses to describe the micro with reference to two real products, the Z80 and 6502, rather than with generalizations. And what a relief not to be faced with the 6800
microprocessors and micros,vstems
yet again! The justification for this choice is sound, namely two very well established, high volume parts for which much software exists, which are not too antiquated, This device’s specific approach at least allows the novice to feel acquainted with particular chips, and permits the inclusion of vast quantities of material from the manufacturer’s data sheets. The various terms, microprocessor, microcomputer, single board computer etc, are defined to set the context, which is good, even if one does not personally agree with the definitions: is a microcomputer a chip or a board level product?
Perhaps the biggest deficiency is the minimal coverage given to software. After all, it is well known that the major, and ever-increasing, proportion of work in designing microprocessorbased systems is the software, yet in this book it hardly gets a mention. Perhaps it is beyond the scope of the book (the subject would certainly fill several other volumes), but then the title should perhaps reflect this more accurately. Another criticism I had was the complete lack of description of displays ot their interfacing. Most instrumentation has some form of electronic display, and the choice and variety of drive requirement is enormous.
The style of writing I found very readable, in typical American manner, and the illustrations and photographs are excellent. The contents and index are comprehensive, and each chapter also sets out the objectives for that chapter, with some self-test questions. To summarize, the book is a useful collection of a wide range of circuitry
techniques pertinent to instrumentation, but falls short in the areas of microprocessors software.
and particularly
in
I P Leslie Smiths Industries plc
Design notes Engineers - have you a design hint or trick of the trade you’d like to share with your colleagues, but cannot spare the time to author a full-scale refereed paper? Or do you have experience with a particular part or piece of equipment you feel may be of interest to others? Why not write a Design Note?
It can be as short as you like - consistent with clarity - and we can reproduce your software listings straight from printer output. Send us your sketches and our studio will turn them into works of art (although we would prefer unlettered tracings). At present we can offer rapid typeset publication - which can be turned quickly and simply into glossy reprints for use by your company.
Send your ideas (or ring for more advice) to Simon Middelboe Microprocessors and Microsystems Butterworth Scientific Limited - Journals Division PO Box 63 Westbury House Bury Street Guildford Surrey GU2 5BH UK Telex: 659556 SCITEC G Telephone: 0463 31261
vol 7 no 3 april 1983
727