I had planned to do ore work on this by now, but I have managed to spend some time working through the next bits.

The USB interface is starting to come to life, and I can now reliably read back from the EEPROM and RAM. Writing to the EEPROM is proving to be a bit more challenging however - firstly, my write protect code seems not to be working, but it seems writing in general isn’t incredibly reliable. I suspect the timing is a bit off. Shouldn’t be too hard to fix but it might taking a bit of figuring out.

Once I get that figured out, I can actually start working on the Z80 side a bit more while carrying on to work on the programmer side to tidy it up.

It’s beginning to come together though!