bit 2 = 0
Except for bit 8, other bits are 1. It is not known which bits are decoded by the interaceinterface.
Bit 8 is 1 or 0, maybe it can't be either, but if it is set it could clash
Ports used and their function:
FBFA - wd1010 sdh head/select (SDH) register (read/write)
FBFB - wd1010 write command (write)/wd1010 read status register (read)
F9F8 - WD1010 data register (read/write)
F9F9 = wd1010 precomp precompensation register (write)
F9FA = wd1010 sector count register (read/write)
F9FB = wd1010 sector number register (read/write)
wd1010 documentation says head select/drive select not available as outputs.
"Description" sector:
(incomplete)
byte 0: checksum of bytes 1 to 255 in sector
byte 7: ? not 0x0fe
byte 240: !=0 => no password, 0 => password
byte 241: password length in characters
byte 242: password characters CPLed (up to 10 characters?)
byte 252: drive id (0=a, 1=b, 2=c etc)
Furthur details:
* MFM