I wish I had time to finish the software....
All the test fixture can do is report what it can see from the CPU side.
Often a stuck IRQ can be caused by a bad CPU but usually identified with a bad RIOT.
The QS80 will exercise all RAM and Registers that are writeable AND readable and will report a RIOT as good or bad depending on values returned. If the test fixture can clear the IRQ then it will set them one at a time to see if any go awry. If that works then it starts up a series of rapid IRQ tests for each IRQ.
For those wondering about the 10M oscillator on my board -
One 'thing' that made the QS80 difficult to design is the fact that there are quite a few Rockwell 6502 CPUs out there that do not meet the 6502 timing specifications. With the incredibly slow circuitry on the Gottlieb boards, nothing is affected by this timing issue. However, the registers on the QS80 are blindingly fast in comparison and are affected by the Rockwell timing anomaly. Not sure how the French guys get around this (or if they do) but I had to resort to retiming the CPU signals to work with fast logic.
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