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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment. |
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19th Nov 2020, 3:04 am | #1 |
Octode
Join Date: Mar 2011
Location: North Yorkshire, UK.
Posts: 1,087
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Motorola MC6802 repro (1978)
Another 'lockdown 2020' Retro-Computing project
https://www.youtube.com/watch?v=j6D_KIOQbsI Back around 1980 I worked in BT's Measurement & Analysis Centre, which was a GEC2050 computer that made test-calls and collated results to improve the telephone service. In each exchange was a TRT302 printer, which contained a 6802 microprocessor board, which we robbed from any faulty printers. I was a Z80 user and this was my first 6800 project, but I hand-wrote a monitor for it and me & pal Steve made development systems from these boards. 40+ years on, I still have that original board, but its forever breaking and I thought I'd make a reliable reproduction using the same hardware and the same monitor program. It has display memory, modify memory, goto program, a serial loader for 'S' records, breakpoint & register display, NMI handling etc... quite complex for a hand-coded project in 1978. The Repro is much smaller and neater but works exactly like the old one. The noughts-&-crosses game is embarrassingly simple by todays software standards, but its typical of hand-coded, amateur efforts back in the day - of course, its unbeatable, it may be over 40 years old but it never loses! Getting a micro to play a tune, or to calculate prime numbers was an achievement then, this was all fascinating new territory for the electronics hobbyist. Cheers Phil (PS not sure about 1978 - may have been early 80s) Last edited by Phil__G; 19th Nov 2020 at 3:16 am. |
19th Nov 2020, 11:33 pm | #2 |
Octode
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,362
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Re: Motorola MC6802 repro (1978)
Cool project - never done anything with 6800 series machines although the S68 from ETI is obviously on my radar...
Someone sent me a mail the other day and said that this stuff was so amazing because it was new... perhaps that is why I find it so absorbing as I was aware of it but never got involved at the time. |