PDP-11 with real ADV11-C board still unhappy

From: Tom Leffingwell <tom_at_sba.miami.edu>
Date: Sun Jan 20 13:52:09 2002

Thanks. I tried all that, and then I moved the system home. (It was
stored about 20 miles away before, and I was getting tired of driving back
and forth, but that finally overcame my laziness of loading it all into my
truck). Anyway, when I got home I noticed it got just slightly further
than before. I took out all the modules and checked for the fourth time
that they were set correctly. I found that one of the zero ohm
resistor-style jumpers on the DRV11 had been cut even with the board, so
it looked very much like it was still connected, and I managed to miss
this before. I soldered a jumper around it, but still the same problem.
Remembering that it got further than it did before, I decided to hook back
up the external hardware that talks to the DRV11 and DRV11-B. (I hadn't
attached it since I got home). Sure enough, it worked. I assume the
vector address on the DRV11 had something to do with it, but why it got
that little bit futher with nothing but hauling the equipment around still
bothers me. Anyway, hopefully it will stay that way.

Thanks very much again for all your help, as well as everyone elses.


On Sat, 19 Jan 2002, Pete Turnbull wrote:

> Probably, but I'm not sure what :-) You could try halting it and see if i
> always halts in the same place(s). If so, it would be worth looking to see
> if you can figure out what instructions it executing at that point. It
> might be a WAIT or a polling loop. Also look at the vectors in low memory
> (from locations 0 to about 20), and the vectors for the devices you have in
> the system. They should point to somewhere in the program.
> Sounds like you have it set up correctly, at least as far as addressing is
> concerned.
> The order of the modules shouldn't matter, though it's best to have
> CPU-memory-serial followed by whatever device needs highest priority
> response. I expect the DSD RX02 controller works just like a DEC one as
> far as addresses and interrupts are concerned, so that's unlikely to
> matter. The BDV11 is another story, though. It includes a line-time
> clock, and your system may need that. IIRC, it's controlled by a
> combination of a switch on the BDV11, a bit in a register on the BDV11, and
> the LTC switch on the front panel. All of those have to be enabled, and
> the BDV11 must be present, for the clock to run. I have seen systems that
> boot but then hang if the software needs a clock but it's not present or is
> disabled.
> --
> Pete Peter Turnbull
> Network Manager
> University of York
Received on Sun Jan 20 2002 - 13:52:09 GMT

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