It’s been 2 months since I wrote about setting up the SPI connection between the supervisor and FPGA. That time hasn’t been idle, but I still don’t quite yet have a proven SPI connection. What I do have is a Z80 CPU running a program to exercise the SPI connection in a simulation. Valuable lessons were learned along the way that I hope you’ll find useful. Let’s start with a nice picture of the simulation waveforms!
Simulation Waveform, click for bigger image