PDP-11/84 SLU problem?
pete at dunnington.plus.com
Mon Dec 15 13:40:06 CST 2014
On 15/12/2014 18:47, Noel Chiappa wrote:
>> From: John Rollins it doesn't appear to transmit data from the
>> console port on the back. I have tried ... every conceivable switch
>> setting on the PDP with nothing
> I asssume you've tried setting the baud rate with the switches on the
> CPU card (in case the cable to the back panel is damaged - or, more
> likely, the rotary baud select switch has a bad contact due to
> corrosion over time)?
The normal setting is all 8 switches in the pack at E83 (beside the
LEDs) off. Switch 1 is to do with the console SLU (see below). 2, 3
and 4 set the boot device (all off means boot according to the settings
in the EEPROM; all on means power up in ODT providing switch 1 is off).
Switch 5 is the "force dialog mode" switch - on an 11/83, setting 1
and 5 on is used to "disable customer access to setup", to prevent the
most common cause of the not booting correctly problem. If switch 5 is
on, the CPU won't go into dialog mode. 6, 7, and 8 set the baud rate,
providing the rotary switch on the panel is either disconnected or set
to 7 or set to 15. For 9600 set 6 and 8 on, 7 off; for 1200 set 7 on, 6
and 8 off. All on is 38400; all off is 300.
> If you have the parts, fabricating a substitute serial interface
> cable would also be something to try.
Always a a useful device for QBus machines. The same cable fits
KDF11-B, KDJ11-B, DLV11-J, MXV11-A, MXV11-B, etc.
> The next step would normally be to disable the on-board serial
> interface, and provide a substitute console interface, out on the
> bus. _Alas_, as far as I can tell from reading the KDB11-B User's
> Guide (EK-KDJ1B-UG-001), there is no way to disable the on-board
> serial interface.
Actually, setting switch 1 (in the pack at E83, beside the LEDs) on
should disable the console, but I know that at least on early boards it
doesn't (wasn't implemented) and I can't remember if that's a hardware
issue or a ROM function.
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