C128 PLA dumped!

From: Nicolas Welte (welte_at_chemie.uni-konstanz.de)
Date: 1999-01-19 10:54:17


This weekend I finished a little project, an almost complete memory dump
of the C128 PLA chip. This little beast has 27 inputs and 18 outputs,
but e.g. the C128DCR only makes use of 24 intputs and 14 outputs. This
is the configuration I dumped into a file, which still is 32MB in size.
But due to the nature of such data, it compresses very well to about

Since I have no experience at all with techniques to reduce this truth
table to a set of equations, I want to leave this task to others. Maybe
there will be a little competition who solves this first.

The file is only available from my own server right now, but I'll upload
it to funet as well. I think I will also make an announcement in
comp.sys.cbm, since there was a little discussion about this subject a
while ago.


BTW, I can still be talked into providing a more complete dump, with 26
inputs and 16 outputs. But this would involve a redesign of my little
interface card and therefore I need some good reasons for it. It
actually would be more of some historical interest, because the extra
lines were never actually used in the C128 system. Might just be funny
to see what they were meant to do. And I'm not going to dump all 18
output bits, because the use of the extra two is pretty obvious. There's
an input which selects if the ROM select lines are generated for 128k (4
needed) or 256k ROMs (2 needed). 

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