Darnit! UDA50 problem.

From: Tony Duell <ard_at_odin.phy.bris.ac.uk>
Date: Tue Nov 4 04:28:18 1997

On Mon, 3 Nov 1997, Daniel A. Seagraves wrote:
> > Given that you're getting a BUS ERR, I'm willing to bet that you don't
> > have bus continuity done up right. Which slots are the UDA50 cards in?
> > What are in the other slots? Which slots have the NPR jumpers removed?
> >

Remember he has an M9302 terminator. That card will lock up the bus
(actually it asserts SACK and keeps it asserted) if the grants are not
continuous.

On the other hand, having an NPG jumper (the little wire-wrap between pins
CA1 and CB1) where you shouldn't have one will cause all sorts of
problems. I'm pretty sure that a UDA50 is an NPR (== DMA) device - did you
cut the jumper when installing it?

Tim : Can you remember which of the 2 UDA50 cards needs to have the NPG
jumper cut? Does the other one short CA1 to CB1 anyway?

>
> Oh, crud. The UDA is in slots 14 and 15. There are 18 slots, as follows:

Tracing grants is something you'll get good at if you mess about with
PDP11's...

> 18 M9302 + GCJ

-tony
Received on Tue Nov 04 1997 - 04:28:18 GMT