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.
Jgharston 14:27, 26 May 2009 (UTC)