9 Mar
2003
9 Mar
'03
5:32 a.m.
Learned: If you plug in a G727A bus grant card
backwards, the processor will
not halt. :-)
Mainly because the grant chain is then open, so the M9302 terminator
asserts SACK. This means that the 11/34 can't be halted from the panel
(it gets tied up trying to remove the grant that's causing the SACK...)
To do: My only existing cable that plugs into a DL11-W is for 20mA current
loop. I have a current loop VT52 that I haven't yet tested. I'll see if I
can do that tomorrow. After all, it would be nice to know if the register
printout is actually occurring.
Almost all DL11-Ws have the RS232 driver/receiver chips on them, and if
you've got one of the few that haven't. it's not hard to add them (1488
and 1489 IIRC).
It's also not hard to make up the RS232 cable. I've done it many times.
Let me know if you want to do this and need pinouts, etc.
I don't know what test gear you have, but if you have a logic probe, then
you could monitor the TX output of the UART (I assume you have the
printset). It should blip low (actually a fairly complex pulse train if
you have a logic analyser) when it's doing the register printout. That
would at least tell you if the unit was working at all.
-tony