Quoted from Ilikewires:On my end, still beavering away.. my board runs EPROM code, but the CTC chip does not generate any timing (a zero cross interrupt and a 2.5mS interrupt are supposed to be generated on the board). And yet the code is sending bytes to the chip. That is where I am at the moment. Solve that and I should be on the downhill slide.
Are they using vectored interrupts? One of coolest features in the Z80 systems.