collins@mcosm.uucp (07/11/90)
AACK PFFFT!! I'm at my wits end!
I am building a Francis board for my A1000 and am having a bit of
trouble making it work.
For a while, it would hang with Francyc low and the RAS lines to the ram
inactie when I ran MODELOAD. If I forced Francyc high, the system
would start running again, but the RAS lines stayed inactive (ie no ram out
there...). I fooled around and finally got the thing working, by
running the clock (20Mhz) through a spare inverter on the lucas board
as suggested in the doc.
NOW, the darned thing gets through MODELOAD ok, with lots of activity on
the CAS lines to the ram, but after running for a brief period (from 1
to 10 seconds), the display goes berserk and then black. If I put the
logic probe on the francis *CS line, it seems to put out a blip now and then
during the boot process. Some of these blips are random. I get 1 every time
the head moves during kickstart load, and figure this: *CS blips with
nearly every keypress !
I figure that *CS should stay high unless I address the Francis board,
which should only happen during MODELOAD or direct memory manipulation
up at 0x400000. The crashes seem to be associated with the
first *CS blip following MODELOAD.
The only thing I can figure is that there must be noise or signal or
something on the address lines that go to making up *CS.
I've tried rerouting the jumper wires added to Lucas, with no effect.
Anyone have any ideas? should *CS be jumping up and down?
There is activity on A30 and A31, should there be?
Where could this noise be coming from? What should a fellow like me do?
Could this really be a problem of some other kind?
HELP HELP HELP....
--
* oij sp 0o9i8m[ sa []qwlkms[0934-9843p0gr-- - -0 9-032-2 +
% ?
& Steve Collins hacgate!trwind!mcosm!collins
$ A SHARP LOOKING SIGNATURE IS THE SIGN .
* OF A SICK MIND !!!
EE 2
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