AMD2901s (was e: Inside old games machines,was: Re: Simulated CP/M-68K?)

[e.stiebler]

Allison wrote:
>> On 6/19/07, woodelf <bfranchuk at jetnet.ab.ca> wrote:
>>> Providing the word length is a multiable of 4 bits that is.
>> It sure would be "fun" to debug microcode issues with nine of those
>> puppies chained together.
> 
> Ignoring race conditions 9 of them are no harder than one.
> The nasty is propagation delays.  A machine that you can 
> microcode single step or slow step makes life easier.
> 
> I did an "improved 8080" a bunch of years ago using 2 and 
> it was fun.  I have a dozen or so 2901Cs that were supposedly
> the fastest of the TTL flavor. Though the ECL parts were much 
> faster.

I'm toying with the idea of a uCode testbench for a while already.
To have an FPGA(yes, I know, not everybody likes them) and a SRAM which 
is at least 64 bit wide for microcode. The uCode gets downloaded via V24 
or SD-Flash, then just the standard set of periperals like V24 (2), and 
a bus interface, probably with some SDRAM already.
But, as usual, I can do it only in my spare time ;-)