ajp166 wrote:
>
> Those parts were never cheap!
>
> You can also use 74289s for the '189s. The '382s are an improved version
> of the '182. A note, if you can tolerate a slower ALU you can omit the
> '382s
> and just use ripple carry.
If the 74289's are the non inverting 16x4 rams I would use them. I plan
to use 74ls382's (the ripple carry alu's).
> A sub for 74189s is some of the byte wide cache rams from an old 386/486
> PC as the faster ones were faster than the TTL 74189! You dont have to use
> the full space of the cache ram though having it would make afor an interesting
> register array.
Can't do that for three reasons
1) I am use a 16 x 12 ram ( 3 chips ) on two boards for a 8 x 24
register array.
2) I am using the 486 cache chips as main memory in my FPGA prototype
32k x 12 bits.:)
3) This was a TTL design on paper of what a computer designed in the
early 1980's
could have been like. That rules out 2901 bit slices.
> Allison
As it stands today I have a FPGA ( pat pat pat ) that is configured to
have a similar
layout as the ttl design and this lets me play around with the
configuration. Mind you a
larger TTL CPU with lights and switches is more impressive. If you like
lights
and switches here is a neat link
http://www.angelfire.com/scifi/B205/
'to the Bat Cave'
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 Thu Nov 01 2001 - 18:17:57 GMT