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Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Editor Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Rick Walters Reader Services Ann Jenkinson Advertising Manager Brendon Sheridan Phone (03) 9720 9198 Mobile 0416 009 217 Regular Contributors Brendan Akhurst Garry Cratt, VK2YBX Julian Edgar, Dip.T.(Sec.), B.Ed John Hill Mike Sheriff, B.Sc, VK2YFK Ross Tester Philip Watson, MIREE, VK2ZPW Bob Young Photography Glenn A. Keep SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. A.C.N. 003 205 490. All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $54 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 34, 1-3 Jubilee Avenue, Warrie­ wood, NSW 2102. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. PUBLISHER'S LETTER Windows of opportunity in the kit business To a casual observer, the electronics business has been fairly static over the last few years. The pace at which new semiconductors are being introduced might seem to have slowed or at least, the semiconductor manufacturers appear to be making less noise about their new products. But in fact, while semicon­ ductor companies, with the exception of those such making micro­processors, don’t seem to promote their products much, the pace of change is rapidly accelerating. Two projects featured in this month’s issue highlight these changes. The first of these is the Teletext decoder for PCs and the second is the NTSC-to-PAL converter. Both of these use custom chips as the key devices rather than chips you can find in data books (or can’t find in data books, as they become harder to get). The same trend was evident last month with the Picture-in-Picture Adaptor. Why is this happening? The first point is that custom devices such as PGAs (pro­grammable gate arrays), PLAs (programmable logic arrays) and all their generic equivalents make it possible to design circuitry with far fewer chips than could be achieved with conventional logic chips. Second, the use of these custom devices and OTP (one-time programmable) ROMs makes it possible to protect a design from being copied. Third, designers and manufacturers are finding it impossible to rely on mainstream semiconductor manufacturers to provide the chips they want. And even if the manufacturers do make a particular device which could be of use, the reliability of delivery times is becoming increasingly in jeopardy. Fourth, and probably the most important factor of all, semiconductor manufacturers cannot be relied upon to keep manu­facturing the devices in their range. They seem to be increasing­ly capricious in deciding to discontinue semis, some of which may have been introduced only a few years ago. For the semiconductor manufacturers it does not matter that some of their smaller customers may be cut off without a second source for key devices; they have such a demand on their production that they can make these decisions with impunity. You can expect to see this trend increase. In one respect it is good because these customised chips do mean that designs are cheaper to make. The three projects mentioned above are pretty cheap after all and they would be much more involved and expensive if conventional chips had been used. On the other hand, they probably won’t be available for more than about 12 months or so because production runs are becoming much shorter, across the entire field of electronics. All of which means that if a high-tech project appeals to you, you should buy and build it soon. If you wait too long, the “window of opportunity” will close and you will miss out. Leo Simpson ISSN 1030-2662 WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. 2  Silicon Chip