PCs that support only one floppy drive in hardware
ard at p850ug1.demon.co.uk
Sun Oct 9 07:51:07 CDT 2005
> But does that work without digging in further? Does a PC/XT-era floppy
> card replicate a PC-AT diskette controller? I am asking, since I've
> never tackled such a project.
Sort-of. It uses the same I/O addresses and DMA channel for the 765 and
the drive select register (the drive select and motor-on bits for drives
2 and 3 are documented as 'reserved' in the PC/AT docs :-)). What it
doesn't have is the data rate register, the PC/XT controller is fixed at
250kbps only. And the data separator is strictly MFM only I think.
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