W83977F-A Datasheet, PDF (134/182 Pages) Winbond – WINBOND I/O

W83977F-A/ W83977G-A/ W83977AF-A/ W83977AG-A
= 0 No Swap (Default)
= 1 Drive and Motor sel 0 and 1 are swapped.
Bit 3-2 Interface Mode
= 11 AT Mode (Default)
= 10 (Reserved)
= 01 PS/2
= 00 Model 30
Bit 1 : FDC DMA Mode
= 0 Burst Mode is enabled
= 1 Non-Burst Mode (Default)
Bit 0 : Floppy Mode
= 0 Normal Floppy Mode (Default)
= 1 Enhanced 3-Mode FDD
CRF1 (Default 0x00)
Bit 7-6 : Boot Floppy
= 00 FDD A
= 01 FDD B
= 10 FDD C
= 11 FDD D
Bit 5 : Media ID1 Polarity
= 0 Non-Inverse
= 1 Inverse
Bit 4 : Media ID0 Polarity
= 0 Non-Inverse
= 1 Inverse
Bit 3-2 : Density Select
= 00 Normal (Default)
= 01 Normal
= 10 1 ( Forced to logic 1)
= 11 0 ( Forced to logic 0)
Bit 1 : DISFDDWR
= 0 Enable FDD write.
= 1 Disable FDD write(forces pins WE, WD to stay high).
Bit 0 : SWWP
= 0 Normal, use WP to determine whether the FDD is write protected or not.
= 1 FDD is always write-protected.
CRF2 (Default 0xFF)
Bit 7-6 : FDD D Drive Type
Bit 5-4 : FDD C Drive Type
Bit 3-2 : FDD B Drive Type
Bit 1:0 : FDD A Drive Type
When FDD is in enhanced 3-mode(CRF0.bit0=1),these bits determine SELDEN value in TABLE A
of CRF4 and CRF5 as follows.
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