W83977EF Datasheet, PDF (100/150 Pages) Winbond – WINBOND I/O

W83977EF
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
0
0
0
0
0
1
1
DPYTE0
0
0
0
0
1
0
1
DRATE1
1
0
0
1
X
X
0
DRATE0
1
0
1
0
X
X
1
SELDEN
1
1
0
0
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.
Bit 4 - 3: DRTS1, DRTS0: Data Rate Table select (Refer to TABLE A).
= 00 Select Regular drives and 2.88 format
= 01 Specifical application
= 10 2 Meg Tape
= 11 Reserved
Bit 2: Reserved.
Bit 1:0: DMOD0, DMOD1 : Drive Model select (Refer to TABLE B).
Publication Release Date: April 2003
-94 -
Revision 1.1