[vcf-midatlantic] Workshop this weekend - Thoughts?

Douglas Crawford touchetek at gmail.com
Sun Jan 31 15:36:19 EST 2016


Another question related to this:
>>> If anyone has an older 'breadbox' c64 (not c64c) with the signetics 
>>> 82s100
>>> PLA in it (only used for the first year or so before being replaced 
>>> with
>>> the MOS PLA) let me know, I'd like to try to read the fusemap out 
>>> with an
>>> 82s100 programmer. There exists a reverse engineered fusemap of the 
>>> 82s100,
>>> but it was done "by hand" using an eprom programmer to probe all the 
>>> inputs
>>> and look at outputs like a giant truth table, and based on an interview
>>> with Bil Herd a few years ago, I now know that this will not produce an
>>> accurate dump of the chip, because the engineeres at commodore 
>>> played some
>>> tricks by adding extra/unnecessary gates to certain outputs to
>>> intentionally 'slow down' the edges of certain signals to prevent 
>>> glitches.


Any real risks to the PLA in reading in this fashion?



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