one more question about pdp8/e console switches behaviour

From: Gooijen H <GOOI_at_oce.nl>
Date: Thu Nov 11 01:32:29 2004

  Hello all,

I have the pdp8/e *including* the console running on the Core
6809 Board (plus one I/O Board)! But ...
I have one more question about the behaviour of the pdp8/e.

If the HALT (or SING STEP) switch is down, you can use the EXAM
and DEP momentary switches. If I press EXAM, I want to see the
12-bit word contents of the address currently on display in the
top row (memory address) of the console.
That 12-bit word is displayed on the 12 lights below the memory
address lights. Is it correct that the position of the selector
switch (the rotary knob) must be on "AC" to see the contents of
the active address? Or is its position not relevant while HALT
(or SING STEP) is active which seems odd to me because you want
to be able to see more than just the AC when you HALTed the CPU?

The answer seems easy, I just want to hear confirmation.
The current implementation shows the contents briefly after I
pressed EXAM *and* the knob is on "AC". Just *very briefly*,
then the simulation shows the actual AC content again.
So, on a real pdp8/e I assume that when the knob is on "AC" you
see the contents of AC when HALT is active?
In that case, after the user pushed EXAM once (and the memory
contents is displayed as I described above), how does he get to
see contents of the "AC" again?

Hope I made myself clear why I asked the question ...

TIA,
- Henk, PA8PDP.
Received on Thu Nov 11 2004 - 01:32:29 GMT