1/ I'm seriously torn on how best to implement the Quantel DPB-7000's Size Card in MAME. It uses a gang of 8 Am2901B bitslice processors driven by a set of PROMs. At the lowest level, I could just emulate the Am2901Bs themselves, and I've already made a skeleton device.
There could be differences, but it's really doubtful. There aren't enough PROM pins to go around. If you want to verify, though, probe out pins 5, 6, 27, and 28 on each Am2901B. They should be tied to 0V.
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As it is, the one thing that I *thought* was a schematic error (which bits on the disc sync byte are inverted) turned out to be an error in my understanding.
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Sorry, I misspoke. Pins 6, 27, and 28. Pin 5 is tied to the PROM banks as it should be.
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