24 Jan
2013
24 Jan
'13
2:13 p.m.
From: "John Wilson" <wilson at dbit.com>
Sent: Thursday, January 24, 2013 7:17 PM
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: pdp11/34 strange problem indeed.
On Thu, Jan 24, 2013 at 09:07:43AM -0600, Roe Peterson
wrote:
As I said, the way how I remember it might be a bit hazy ... and at this
moment I can not start up my 11/34C (I could have just 4 weeks ago ...).
When you press CNTRL/INIT, you (the monitor) gets control and the
RUN LED should be off. If it stays on, it's typical a bus grant issue.
The numbers, LAD, CLR etc. all operate while the RUN LED is off.
When you press start after 165020 LAD (IIRC) you start the monitor
which itself will start with executing some hardware tests. There is
another address that will start without the HW tests.
This monitor is in the ROM in the middle of the M9312 module board.
greetz,
- Henk.
At poweron, the system starts the M9312 console
emulator software; I
can use it to deposit a small program into memory with no problem.
Attempting to use the "S" command to actually start the program
causes the RUN light to come on; the program never executes, hitting
CTRL/HALT on the front panel causes BUS ERR, the RUN light stays on,
and the only way to regain control of the system is power off. For
example:
@ L 1000
@ D 000777
@ L 1000
@ S
If I knew how to debug the 11/34a front panel, then *I* wouldn't have
similar problems with CNTRL/INIT etc. causing unwanted results. **But**,
if you're talking to the M9312 serial console, then you already *are*
executing PDP-11 code, so the "run" light should already be on. So maybe
whatever's driving the LED is confused but the CPU itself is executing
code more or less OK?
John Wilson
D Bit