PDP-8 /e/f/m memory

vrs vrs at msn.com
Mon Aug 14 02:04:38 CDT 2006

From: "Allison" <ajp166 at bellatlantic.net>
> Looking for information on a QUAD width omnibus RAM card.
> Not interested in hex wide as it doesn't fit the older 
> Omnibus 8E or F boxes.  I used to have a 4kx12 card that
> used 2102 type rams but had no data for it. That went to
> and earlier 8E I had.
> Even schematics would help.  In the end I may do my own as 
> a pair of 61256s will certainly fit the bill and barely fill
> a corner of a board.

I looked at doing one of these, but got kind of lost about how 
the timing signals are used.  I looked at the MOS RAM for the 8/A, 
but there's all this cruft for refresh in there, some stuff about 
suppressing access during ROM access, etc.  And then it looks like 
the memory timing signals are derived somehow from the memory 
refresh stuff??

Is there a nice place where the Omnibus memory interface control 
signals are explained somewhere?


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