Success
Reworked the code for the new board. Added a patch for the schematic error.
Here it is working:
And here are the boards:
Debugged
Had some problem with the Flash ROM chips from my MyCP/M V2. The chips (both W29C020Bs) had corrupted pages 0x001680, 0x001700, 0x001780, 0x001800, 0x001880, 0x001900 and 0x001A00. They even had exactly the same bad memory locations and values. It took me long time to believe the problem was the chips rather than my firmware. In the end I tried a new chip and it programmed fine. I suspect that when My CP/M crashed it was endlessly writing to these locations on both chips causing failure. The bad segments were in my CBIOS. So no wonder I could not understand what was happening.
Here is a happy MyCPM V2 and the Flash ROM Programmer:
AlanX
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