I'd noticed that the 8271 appeared to allow step speeds in ms to be specified by a complete byte. The effect of using zero wasn't immediately obvious but I didn't see why a 1ms setting shouldn't work. So I did a few byte searches in a suitable DFS ROM but didn't find anything obvious. Plan B was to hook up some digital probes to the 8271 control signals and data bus, trigger on writes, figure out where the op codes and data were coming from and also look at the step pulses. But when I dug out the machine with the 8271 it wasn't working, so the project was put on hold.
Statistics: Posted by ctorwy31 — Tue May 27, 2025 10:23 pm