tel 8080 and the Motorola 6800 and relies heavily on material produced by the respective manufacturers. A short final chapter entitled 'Looking ahead...'.
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Book Reviews Microprocessors and microcomputers: hardware and software RJ. Tocci and L.P. Laskowski Prentice-Hall, 1979, 323pp. £10.75
book and covers i.o. control, u.a.r.t.s, keyboard scanning, magnetic-storage devices and c.r.t.s. The text ends with a section on microcomputer programming. The Rockwell 6502 is used as an example processor and, although some atMicroprocessors: theory and ap- tempt is made to justify the inclusion of plications some of the addressing modes that the 6502 provides, in general the treatment G.A. Streitmatter and V. Fiore conforms to the usual technique of just Eeston, 1979, 456pp. £11 describing the chosen processor's instruction set. Streitmatter and Fiore follow their A clear majority of the numerous books aimed at introducing readers to the con- general introduction by sections on 'incepts required to permit the develop- structions' and an introduction to softment of microcomputer-based products ware. The latter section at least makes a conform to a well established pattern of gesture towards the concept of procontents: a review of number systems viding a high-level description of the and digital logic, a lengthy section on solution to a problem, although the 16pp. microprocessor hardware and finally a dedicated to this subject still represent shorter section on simple assembly- only a very small percentage of the total language programming. Usually, the lat- text. This section is followed by chapters ter two sections draw on examples from on bus structure, i.o. concepts and the 'industry standard' microprocessors memory devices, drawing examples to illustrate their points, with a greater from the products of both Intel and emphasis typically being placed on one Motorola. Next comes a chapter on 'advanced particular device. Whilst this approach may leave the reader with an insight into software' which outlines assembler how a particular microcomputer system functions, debugging using a simple operates, it unfortunately leaves several monitor and arithmetic operations. Most questions unanswered — questions of the remainder of the main text (almost which need answering before an effec- 150pp.) is dedicated to describing, in tive approach to a system design can be some detail, the operation of both the Inmade. tel 8080 and the Motorola 6800 and Perhaps the most obvious examples relies heavily on material produced by of these shortcomings are in the treat- the respective manufacturers. A short ment of programming. Most authors are final chapter entitled 'Looking ahead...' content with describing the instruction describes briefly some of the more reset of a processor in terms of its various cent Intel and Motorola products and operation codes and addressing modes, outlines the development aids produced broadly illustrated by sample programs by Motorola for its 6800 family of to solve 'typical' problems, such as devices. Streitmatter and Fiore end their generating a time delay, multiplying two book with five appendixes covering numbers etc. What is not usually includ- number systems, ASCII code, available ed is why particular instructions and ad- integrated circuits, standard logic symdressing modes are provided and how bols and instruction sets. The last appenthey may be used most effectively. More dix on instruction sets is over 100pp. importantly, in general no reference long and is derived by 'lifting' sections whatsoever is made to the problems of directly out of the manufacturers' program design and testing or to the publications on the two processors solution of those problems by modern covered, the Intel 8080 and Motorola techniques such as structured program- 6800. These two books are neither ming, step-wise refinement and so on. This is surely what most engineers need significantly better nor significantly in an introductory text on micro- worse than the majority of texts on processors rather than just the usual microprocessors — indeed the deficienregurgitation of the manufacturers' cies highlighted are typical of most texts assembly-language definitions and data on this subject. Thus, whilst it is difficult to strongly recommend their purchase sheets. Both the books by Tocci and by either students or practising Laskowski and by Streitmatter and Fiore engineers, most alternative texts would unfortunately fall into the standard pat- invariably pose the same difficulty. tern just described, starting, of course, P.G. DEPLEDGE with a general treatment of number systems and digital logic! Tocci and Laskowski then proceed to outline the Digital filters: analysis and operation of a simple computer, subse- design quently relating this to the operation of a microcomputer in terms of a.l.u. and A. Antoniou register structure, memory accessing McGraw-Hill, 1979, 524pp. £17.95 and i.o. operation. This is treated in a general nature and does not rely on one Many disciplines contributed to the specific microprocessor family for ex- development of digital filters in the early amples. Following this is a comprehen- days, but the fundamental principles of sive and lucid introduction to the pro- this discipline lie in the area of circuit blems of interfacing peripheral systems theory and design. Indeed the potential to a microprocessor system. This sec- and limitations of digital filters become tion is undoubtedly the best part of the evident from a circuit-theoretic basis.
There are currently many books one can choose from to study digital filters in some depth, but until recently there has been no book to present this very important area from an alternative basis. The book by Prof. A. Antoniou gives an alternative presentation with a circuittheoretic flavour, and it does so most ably and effectively. The scope of the book is to introduce the reader to the area of digital filters both from the analysis and the synthesis points of view. The first 170pp. out of a total of approximately 500pp. are devoted to the tools of analysis where sampling, z-transform and signal-flow-graph ideas are included with copious worked examples and problems at the end of each chapter. The rest of the book is given over to the very important questions of design methods and techniques. Both recursive and nonrecursive digital filters are examined in considerable detail, and the author does include a chapter on the effects of finite wordlength. Wave-digital-filter structures, their alternatives and their derivations form a novel aspect. A further novel characteristic of the book is the treatment and inclusion of elliptic-filter approximation. The chapter on hardware implementation starts from elementary ideas which are soon developed into complete hardware organisation specifically geared to digital filtering. The appendix includes a large collection of programs (in HPL language), useful for the analysis and design of recursive and nonrecursive filters, with typical runs illustrating the outputs from these programs. This is, indeed, a splendid book, recommended to the student as well as the practising engineer. However, those who actively research the area of digital filters will find something useful in the book, of this I am sure. It is perhaps a pity that the author has not devoted some of his not inconsiderable talent to the inclusion of two-dimensional digital filters, a subject whose importance has become more evident recently. In a second edition of the book I feel that the computer programs should be changed from HPL to a more widespread language e.g. Fortran or Basic. A.G. CONSTANTINIDES
Errata
April issue, p. 330 The price of 'Microprocessors — principles and applications' by M.J. Debenham is £3.90 in paperback and £7.75 in hardback March issue, p.263 In the review of 'Active filters for communication and instrumentation' by P. Bowron and F.W. Stephenson, the second sentence of the second paragraph should read 'Chapter six to eight present active filters proper and are grouped according to controlled source realisation, realisation using single operational amplifiers, and realisation by analogue simulation'.
