14 Mar
2007
14 Mar
'07
5:28 p.m.
Guy wrote....
One of the easiest things to do is to use the LTC (on
the M7856) and write
a small program that counts at 60Hz (or any sub-multiple) on each "tic".
The counter (if in R0) will be displayed on the console lights when you're
in a WAIT.
Or just have the M7856 interrupt on a single character input. No
software
required, I think this could all be set up from the front panel.
As I recall, the problem was that the moment any device interrupted, the
system would always trap to location X. No matter which device was
interrupting. I forget what "X" was... I think it may have been 3. But at
the same time, it would boot xxdp from an RL pack just fine so the system
must have been SOMEWHAT sane.
One thing you want to check is to make sure that your
backplane is *not*
wired to have an M787 be the LTC (mainly for the grant chain). Otherwise,
you'll have to use the M787 and disable the LTC function on the M7856.
I
don't think this system ever had a M787, it doesn't now in any case. I
think I checked the backplane wiring for this once (a jumper needs to be
added or removed when the M787 is installed) and I think I found it was set
up to not have a M787. I will double check this now.
Along those same lines... The system did have a KW11-P. According to the
docs the LTC needs to be connected to that slot for the KW11-P to use. I
should also see if it was wired for that. Isn't there some issue like you
can't have multiple cards connected to the LTC? Something about overloading
the circuit that generates it in the power supply? I recall something about
it being very critical no more than ONE M7856 was set for LTC use. If that
is the case, I assume you couldn't also have the KW11-P set to use LTC if
one of the M7856's was set to use it? Foggy memory here...
Jay