Vintage Computer TTL

ben bfranchuk at
Wed Oct 14 15:36:25 CDT 2015

On 10/14/2015 12:12 PM, Mouse wrote:
>> The hardest part is finding parts for the FPGA, sure I can use 74XXX
>> but was it out in 1975-76?
> If you mean some specific 74-series part, well, it depends on which
> one.
> But, if you mean 74-series logic in general, I think so.  Sometime
> within a year or so of '78, I was working with the stuff, and it was as
> an undergrad, so I doubt I would have been working with just-released
> logic.

The design uses 74LS for low power and more drive, but nothing off hand
not found in regular TTL, since this version uses random logic.
A microcoded CPU needs 512 x 8 roms and 5 input Nor's (LS) something
not found in the mid 70's I am guessing. Most of timing is ball park
but still a good feel for TTL logic. Now pricing is harder to find
... surplus 3 7400's for 10 cents to $30 for prime new chips.

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