27 Sep
2015
27 Sep
'15
5:07 p.m.
I have been through the ground up restoration of a full chassis version,
make sure the CPU is functioning correctly first. The best place to start:
http://www.psych.usyd.edu.au/pdp-11/hints.html
Try toggling in the "Line Time Clock Interrupt Test" from 001000, returned
the expected value of 000104.
Here is a pdf of the cabling for tty console, if you have no current loop
device an rs232 converter will work.
http://vintagecomputer.net/teletype/asr33/M9970_TTY.pdf
See also
http://www.pdp-11.nl/pdp11-05/cpu/boards/m7260.html
echo characters toggle-in program
005000 CLR R0
105737 TSTB @#177560
177560
100375 BPL -3
105737 TSTB @#177564
177564
100375 BPL -3
113737 MOVB @#177562,@#177566
177562
177566
105737 TSTB @#177564
177564
100375 BPL -3
110037 MOVB R0,@#177566
177566
105737 TSTB @#177564
177564
100375 BPL -3
000756 BR -16
On Sun, Sep 27, 2015 at 4:47 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:
[Second serial port on a PDP11/05]
--
Bill
vintagecomputer.net
Curious: what if the built in one were
faulty, or if you wanted to use rs-232
instead of current loop?
IIRC the 11/05S has a way to disable the built-in
console port (fit a wire link on one of the boards?)
the original 11/05 doesn't. There must be a way to do
it by cutting/jumpering but it is a mess....
Therefore, if the built-in port is faulty it is going to be
a lot less work to fix it than to disable it and add a DL11
Heck, the entire 11/05 CPU is only a couple of hundred ICs,
the serial port is going to be a small fraction of those. It is
not going to be hard to figure out.
As for the physical interface, firstly the OP mentioned a
teletype, which to me suggests current loop anyway. If
you need RS232 then either pick up TTL level signals on
the CPU board and add level shifters (very easy, but
makes the machine not original) or make a current loop
to RS232 interface (not exactly difficult either). I think
both are less work than disabling the built-in port.
-tony
- John