There stuff already made that can be used for that. There's the MSX computer, which uses pretty standard (old) Western Digital (WD) floppy controllers, or the Magic drive , which control code runs in the Z80/SMS mode on the mega drive.
The advantages of MSX drive interface is that it's 100% dos compliant, but is limited to 2DD discs (Only 720k)
So it's best hack the drive routines from magic drive. But it uses a weird motorola FDC which I don't know a shit about ... but it's a idea anyway ...