80-Bus News


May–June 1983 · Volume 2 · Issue 3

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On Schedule

Well, it looks as though we’ve done it!! Having produced the last issue somewhat late, it looks as though we have got back on schedule with this one. Mind you, I’d better not make too much of it, or some law or other will prevail, and it will be six months to the next issue!

Some of you who have subscriptions will probably be receiving this issue in the same post as the previous one. Sorry if this comes as rather a shock, but as I doubt that we will have got all of the last issue in the post by the time we get this one back from the printers, it seems silly to double up on postage costs. If you don’t want to read two issues at once, then put this one away for three or four weeks! Bye, bye for a while.......

Some time later

Hello there. And what has been happening since you received the last issue of this wonderful magazine? It seems like only yesterday! Well, for a start, I am afraid that I have to report that despite further letters to Lucas/​Nascom and to IO Research we have still NOT heard from them about the I/O mapping of their 80-BUS/​Nasbus boards. Now, the questions asked were not too tasking, and went along the lines of:

  1. What boards have you/do you/​will you produce that occupy Z80 I/O ports?
  2. What are the recommended standard addresses for these boards, what alternatives are there, and how are these options achieved (links/​PROM/​etc.)?
  3. Are NASIO and DBDR provided (necessary for Nascoms)?
  4. Can the boards be used with Nascom 1/2/3, Gemini GM811 & GM813?
  5. Are there any special restrictions that we should know about?

Answering this lot should take about 10 minutes per board, and nobody makes that many boards that this should produce a serious problem. And why an I making all this fuss? Well, there are now about 25 80-BUS compatible boards available, all fighting for 256 ports. Not a serious problem yet? Well, unfortunately there have already been clashes. Gemini brought out the GM812 IVC some time before the Lucas/​Nascom AVC. And yet the IVC uses ports B1, B2 and B3, and guess what? – the AVC uses ports B0, B1 and B2. Yes, the AVC and IVC can both be located elsewhere if necessary, but the standard software support for both of them assumes these port addresses. And why should someone who may well want both boards be hampered by this restriction? Another example of this clashing is between the Climax colour board and another board being produced by a new manufacturer. The Climax uses C0-D0, and the first release of the new board (which I can say no more about – tease, tease!) uses C0-CF. It looks as though they’ll have to change it before going into full production. And we all know that IO Research have already shown a prototype of their Pallette board, and have announced two other forthcoming products as well. What ports do these use, and what will they clash with? This is my reason for the third part of question (a) above. I am not expecting all existing and potential manufacturers to send me full details of their yet-to-be-released products, but it would be nice if they sent a note saying “New board, available approx 3 months, uses ports 40-9F”! In order not to prolong the agony, awaiting the reply of obviously disinterested parties, you will find in this issue a VERY brief summary of current port usage. If you know of any boards that I have missed, any mistakes that I have made, and any boards that are under development (no need to say what), then PLEASE drop me a note.

Well, that’s all there is space for. Material and ads. for the next issue by July 30th please. And until then, TTFN.

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