pdp8/e Problems: KE8-E EAE debugging
Charles H. Dickman
chd_1 at nktelco.net
Wed Mar 9 20:09:26 CST 2005
I wanted to try out my VC8/I Point-Plot Display with PDP8 spacewar.
I added support to SPCWR3.PA for the VC8/I.
This requires an EAE and now I find out that my untested EAE does not work.
The first sign of problems was that the processor paused while running
and the only way to stop it was to turn off power. The HALT switch did
I got a copy of MAINDEC-8E-D0LB-D which is EAE test 1 and it locked up
pretty much the same way. I removed the EAE and the diagnostic halted at
a reasonable place insteading of locking up.
The EAE stops the main processor sequencer and then does it's thing and
when it is finished, restarts the processor sequencer. I seems to me
that this handoff is not occuring properly. The front panel shows that
the processor is stuck in Execute (E) State with a 7 in the IR and the
PC within one of an EAE instruction.
This not gonna be easy to fix. The over-the-top connectors prevent the
use of an extender card, so I can't probe anything easily.
Since the MAINDEC tests won't run, I will try to figure out which if any
of the EAE instructions function and which to not. Since, so far,
everything seems to hang, it might be something fundamental, and that
might be easier to find.
Suggestions, comments please.
If this is an extra post, my apologies.
The rules have changed, and I respect that.
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