MEM11 update

Guy Sotomayor ggs at
Mon Feb 8 15:18:58 CST 2016

> On Feb 8, 2016, at 1:08 PM, Ian S. King <isking at> wrote:
>> See above re: gold edge fingers.  I was originally thinking that if I do
>> have to
>> split the board up, that I’d make them completely independent.  But that
>> has
>> the issue of requiring 2x the number of UNIBUS transceiver parts (which are
>> all but unobtainium as of now).  One of the things that drives up the
>> power (and
>> board area) are said transceivers (and level shifters, etc).  If I could
>> come up
>> with a reasonable alternative for the SPC version, that may work.  But
>> that’s
>> all in the future at the moment.
>> TTFN - Guy
> A thought: would a second quad board necessarily need transceivers?  I'm
> thinking of the top-block connectors used in the PDP-8, and the top-plugged
> ribbon cables for e.g., MicroVAX II CPU-to-memory connection.  You might
> still want to grab power through a few fingers, but that's an
> implementation detail.  — Ian

I’m not a particular fan of that because some of the signals I’m running are
pretty fast between the FPGA and some of the other components (~40ns
cycle time for the FRAMs for example).  I wouldn’t want to run those signals
very far and certainly not across any sort of cabling.

It’s not clear to me (yet) how I could partition the design across 2 SPC boards.

TTFN - Guy

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