More Bringing up a CPM

From: Allison J Parent <allisonp_at_world.std.com>
Date: Tue Jun 1 21:59:02 1999

<Even if you don't intend to use PROMs in your final device, I'd certainly
<recommend you build a few PROMS which make the processor do rudimentary
<things and perhaps which make the DMAC do the same things. You then have
<simple tools with which to troubleshoot your memory interfaces.

that can be helpful. I just use the CPU executing junk FF/00 or whatever
else the bus lets it see,

<After reading about the problems you're having, I think I'll fetch the 124
<LA out onto the patio as well.

I troubleshoot 90% of my s100 problems with a good logic probe and
a DVM. The rare case I've dragged out the scope it was handy but usually
because I missed something stupid. The recent NS* bring up required the
logic probe, its where I spotted a missing Mwrite/ (jumper smeared off the
cpu board).

With rare exception and all if a board doesn't work scoping it may or may
not help. just follow the logic with a logic probe as likely it's a chip
or socket failure. The reason is the board worked, was sold working and
if it were good it should still work. The exception is when you have bus
incompatability problems and a scope will not help unless your going to
alter the board to make it work assuming it was not also broken.


Allison
Received on Tue Jun 01 1999 - 21:59:02 BST

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