OSWORD &FB

OSWORD &FB (251) - WD1770/2 Floppy Disk Control 80x86 DOS

The control block is ignored, so for speed, set XY?0=0 and XY?1=0.
Commands are sent from the 80x86 via Tube register 2. These are:
0 - Finish
1 - Master FDC command; register 2 sends 4-byte address low to
    high, R/W command, Write flag, Interrupt mask, number of
    sectors, FDC command.
2 - BBC B/B+ command; as for command 1.
3 - Claim Tube and NMI.
4 - Release Tube and NMI.
5..&FF - Write byte sent though register2 to &FExx.

See Also

• http://mdfs.net/Docs/Comp/BBC/Oswords

Jgharston 14:27, 26 May 2009 (UTC)