Clearpoint DCME/Q4E configuration

Johnny Billquist bqt at
Sun Aug 16 04:14:57 CDT 2015

On 2015-08-16 02:52, Noel Chiappa wrote:
> Hi, does anyone know anything about the configuration of these boards?
> (The document on BitSavers only covers the Q4B; the jumper configuration
> on the Q4E is totally different.) They are 4MB quad QBUS memory cards;
> PMI capable, I'm pretty sure.
> I have two of them, one of which came out of an 11/84 (I never saw it in the
> machine, though), and is so probably configured to run PMI. The thing is that
> I stupidly mixed it in with the other one, and now I don't know which one is
> which - and they are jumpered differently.
> It doesn't have to be full (or any) documentation; if someone had one they
> _knew_ was jumpered for, say, PMI operation, I could copy their jumper setup
> (or see if one of mine already had the same).
> If not, I'm going to start in on drawing a picture of all the jumpers, and
> see what QBUS/PMI pins they are all connected to - looking at the card,
> there's a big row of jumpers next to the pins the PMI is on, and the jumpers
> are all 'on' on one card, and all 'off' on the other, so I suspect the one
> card is jumpered for PMI operation, and the other, not.
> So, even if there no documentation extant at all, we should be able to more of
> less figure out what many of the jumpers do, and start making use of these
> cards.
> But any help/info would be gratefully received!

Not a direct help, but DEC's memory boards never had any jumpers for PMI 
as such. It was automatically detected depending on where the board was 
placed on the backplane.

Jumpers/switches were only used to set the base address and the CSR 
address of the boards.


Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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