10 Nov
2005
10 Nov
'05
7:53 p.m.
Tony wrote:
Ok, so the CNTRL key behaviour analysis is a good point to start with.
Well, it's a definite fault. I would guess the firmware is doing the
wrong thing (I can't see how a hardware fault in the keyboard or display
could do this).
just a
short question, I have seen so much that I start doubting
everything :-( After you pressed the CLR key on the 11/34
console (to get a clear start point), if you *only* press the
CNTRL key, nothing should happen, right?
Right. The CNTRL key is a bit like a shift key, and should do
nothing on its own.
To answere one of your other posts, I would expect data to be
written ot the display latch quite frequently (of the order of ms)
_but_ the write pulse will be narrow (a few us at most), and if
you've got the analyser set up to sample for long enough to display
several display scans, you might well miss some of the write pulses
because they occur between analyser samples. I think the K100D has
'gltich capture' for just this sort of problem, try selecting it for
the input you use for the write pulse.
-tony But I will first inspect the two RAM chips! 4-bit data
in, 4-bit data
What are the RAMs? From the description, they sound like the little TTL
RAMs that DEC also used for register storage on some of the '11 CPUs
-tony