Allison wrote:
> The 74289 is also the same part/pinout save for instead of open collector
> they are
> tristate outputs.
OK I would have used a generic 16x4 non inverting memory.
> The 74382 is not an ALU, it's a carry look ahead generator. The 74381 is an
> ALU.
I have a 74F382 data sheet -- this is a ALU.
> BZZZT!!! By ealy 1980 the 2901 was already passe', as were TTL cpus.
> I presume by that you really meant early (very early) 1970s as the 2901
> is a 1970s part.
That is hard to say what era my cpu is from as I have to fake it from
what
I would of built in 1980's. LS TTL was just becoming popular. 8 bit
micros
where the big thing.I used a PDP8/e and a PDP8/S in 1983.
> Also the 2901 is directly traceable to 74181, 74189 like parts.
The 2901 is a nice bit slice chip. If I had used it in my alu I would
have
fewer states per instruction, but then I would have needed to go to
micro-code
style architecture. This design was random logic where no PROMS need
ever be
programed.
>I already have a real PDP-8. ;)
I should have known :)
> Allison
Ben Franchuk.
--
Standard Disclaimer : 97% speculation 2% bad grammar 1% facts.
"Pre-historic Cpu's" http://www.jetnet.ab.ca/users/bfranchuk
Now with schematics.
Received on Fri Nov 02 2001 - 09:14:56 GMT