W83977F Datasheet, PDF (136/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
CRF1 (Default 0x00)
PRELIMINARY
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.
DTYPE1 DPYTE0 DRATE1 DRATE0 SELDEN
0
0
1
1
1
0
0
0
0
1
0
0
0
1
0
0
0
1
0
0
0
1
X
X
0
1
0
X
X
1
1
1
0
1
0
Note: X means don't care.
CRF4 (Default 0x00)
FDD0 Selection:
Bit 7 : Reserved.
Bit 6 : Precomp. Disable.
= 1 Disable FDC Precompensation.
= 0 Enable FDC Precompensation.
Bit 5 : Reserved.
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Publication Release Date: March 1998
Revision 0.58