I had been thinking for a while about making a gameboy speccy cartridge by plonking a z80, 48K of ram, and 16K rom on a cartridge, latching any writes to the screen ram area, and then feeding this to the gameboy's processor which would be running a program to pass the screen writes onto the gameboy screen. It didn't seem terribly feasible due to the size and colour depth of the gameboy screen.
However, I see that the gameboy advance has a 240x180 pixel screen, which is almost enough. It's being powered by a 60MHz ARM processor, so it might just be possible to emulate the z80... if not, we could hang a z80 on the cartridge port. Looking at the specification, I see it has both an ARM processor and an "8-bit CISC" processor, which I take to be the same processor as is used in the current gameboy (a stripped-down z80) to provide compatibility with earlier games. I wonder if a (non-mode 3) SAM emulator might be possible. We would have to put 512K ram on the cartridge port (I think the new GB will have only 32K user ram) Andy
