Building a BA08 for a pdp8/L

Chris Zach cz at alembic.crystel.com
Sat Jan 22 18:07:28 CST 2022


There's a couple of MC8/L manuals on bitsavers, this might jog your memory.

http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp8/pdp8l/

Anyway, the timing seems to be for the read core, transfer into MB, 
write back into core (because reads are destructive) then send the 
completed signal. On MOS memory you probably just need to see the state1 
line go high (I have something on the address lines) then just put the 
data into the MB and go straight to signal 4 (since you don't need to 
rewrite).

On a positive note the 8/L will be able to run as fast as it can as it 
doesn't have to wait for the core memory. Hm.

C

On 1/22/2022 11:19 AM, pbirkel at gmail.com wrote:
> I have absolutely no idea!  Jameco would have likely been my source for most components although we did have a Hamilton-Avnet in town and it's possible that ordered some components from them (I still have a NS databook with their sticker on it).  It's entirely possible that I fiddled with some TTL gate-delays to derive a good-enough approximation.  Where are you getting your circuit schematic from?  Maybe if I look at it a bit something will come back to mind ...


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