Needed: Help disassembling Williams Test ROM

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OK, I know Williams doesn't like this, however Ted Estes hasn't got the
info I need so here is my problem:

Williams produced a Test ROM (2532) that covered system 3 - through 7 and
the image is split in two.
0000 - 07FF is for the earlier games (two LED indicators)
0800 - 0FFF is for System 7 (seven segment display)

Using this in a game like Black Night (second image used) shows a count
from 0 - 9, and then the display blinks twice and shows a steady 0. All the
tests from 0 - 9 seem to emulate the same tests that BK shows in the little
book, however what is NOT documented is the double blink! I thought it
might be an interrupt test, but the IRQ timing is correct...

What I have is two seemingly identical boards - one that boots fine and the
test shows the correct sequence, and a second that counts correctly but
won't do the double blink nor does it boot.

Fluke 9010A claims RAM ROM and I/O are fine. (in case you were curious)

So what I am left with it trying to figure out what the double blink
portion of the test was. Ted Estes thought it had no meaning - but he had
never been able to find the docs on this test Eprom when he worked at
Williams (seems to have done a thorough search!) - but now he is not so
sure. So I am trying to disassemble the Eprom image (800 - FFF) in an
effort to find what that test might be. Unfortunately I am NOT any good at
this and was hoping that someone with experience in this would be
interested in helping document this Test Eprom.

Sections of it make sense to me, like RESET clears all the PIAs, but then
it wanders off to check the contents of assigned RAM locations and I don't
know how to track this efficiently...but am happy to provide a table of
ROM/RAM and I/O ports.

This is a 6800 based system (6808) with five 6821's, one IRQ generator
(1k077hz) running at 1Mhz.

I have the Test ROM from Two Bit, it is the same Williams program for the
1st half (0-7FF), the second (800-FFF) is different though, and not very
well documented...

Thanks if anyone can help...

John :-#)#
Thanks!

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Received on Fri Jun 06 14:13:42 2003