@lawrie If you have a working implementation on Mister to guide you, maybe it is not all that difficult to add mouse and disk.
The wikipedia page for the original Mac's describes the mouse, including its wiring across chips:
The disk hardware is essentially the same as the disk hardware on an Apple ][:
I think once the registers that the controller presents to the software are known, doing a verilog replacement can be similar to what you did for the QL.
Oh - just found the ultimate hardware description here:
And a ROM disassembly is here:
On the Mac, the rom just contains start-up code and device drivers. On the QL, it contained the whole operating system. The biggest part of Mac Plus rom seems to be the file system implementation.
I'm not sure that is correct. See below link for some details:
floppy.vin the source code archive on that page). It seems this project was doing exactly what you are aiming for: a quick fix to get something running. It also has a preprocessed system disk image in the archive).
@lawrie Had a second look. Complexity looks manageable, but I'm not sure it translates 1:1 to the ULX3S.
The essence of the floppy stuff is in two files: iwm.v (this implements the logic of the drive controller 275 lines) and floppy.v (this implements a model of the floppy drive, 375 lines). If I understand the code correctly, it skips (de-)serialising the data and passes bytes between the two instead - which makes sense. The floppy model implements a fake motor speed signal, which I guess is needed for the Mac ROM code to work.
The floppy model gets its data from a parallel flash chip on the Altera DE1 board - for which we do not have a direct equivalent on our board. I think the iwm.v code can be used more or less in tact (probably it is also in the Mister code). The floppy.v code would need the flash rom replaced by an interface to the ESP32. Doable, but not a 10-line fix.