help - 11/34 console problem -- CNTRL key behaviour

[Tony Duell]

> 
> Tony wrote: 
> 
> > > 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
> 
> 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). 

> 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