Hi from a newbie.
I got this running without any initial difficulty, not having see it since 1980, but when I got interested in making it control the temperature of my home-brew (beer) I found a very strange problem: Channel 0 in the CTC will happily interrupt the main program, but not Channels 1, 2 or 3.
This is very odd, because you don’t have direct control over the channel registers, the CTC is supposed to insert the correct information, given that you, for instance, sent the SAME CTC set-up words to “CTC1” at 41H per the MPF-1 Users Manual at page 36.
I typed in the code for the MPF-1 project “Clock with CTC Interrupts” as provided, which works perfectly on Channel 0. However, trying to use Channel 1, the program crashes instantly, with the display showing address-data E5C6 FF every time Channel 1 is selected, and other data for Channels 2 & 3
I tried a new CTC IC without success, got the same address-data on the display, and even tried replacing the decoder IC U9 (74LS139) to see if that would cure it. (My CRT oscilloscope at 15 MHz bandwidth is not really up to it, but the various waveforms look believable). Next and possibly final step is to replace the Z80 CPU in the hopes that some internal gate in it has died after 41 years.
Otherwise I’m out of ideas.
Any comments will be welcome!