Z80 Porting Question

I could probably answer if I understood the question. It's possible to port songs from some other Megadrive games into Sonic games, yes.

 

In theory the sound driver can be taken across, but it often requires more work than most people are willing to undertake. It depends on the sound driver you're porting. Some are custom-made and aren't compatible at all with the Sonic driver, while others use the same makeup and require only minor changes; it depends on the game.

 

You'd either have to disable the 68k part of the driver, or ensure that you're porting a DAC-only Z80 driver. For the latter, you may also have to modify the 68k part to put values where the new Z80 driver expects them (for example, S1's 68k driver writes to Z80 $1FFF to determine the sample to be played).

 

It's not possible to just transfer z80 ram between S1 and other Sonic games, because they work differently. You have to change a few things in the game to make it work correctly.