datasheets for 82S21 - Signetics 32x2 SRAM?

Tony Duell ard at
Thu Sep 8 15:57:29 CDT 2005

> >What device uses this RAM, and what are the control pins conencted to?
> It's used in the MIT CADR lisp machine, for the m-memory, which is a
> high speed scratch pad used by the microcode.

Oooh... very nice...

> I wrote some programs to convert the original CAD files (in SUDS) into
> verilog and I've been (slowly) working on getting them to simulate.  I
> want to boot one under simulation and eventually put one in a simple
> fpga (hah, by the time I'm 75 at this rate).  I figure they'll make nice

My experience with simulators suggests that's a massive _underestimate_ 
of the time it would take. 

> christmas gifts :-)
> I've got it fetching microcode from the prom.  Most of the problems have
> been with 74 style 'parts' I have made - in some cases I had to guess
> because I have no data sheet but I'm slowly fixing that.

FWIW< I have a reasonably complete set of TTL databooks from several 
manufactueres. Let me know if there's any 74-series part you want me to 
look up.


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