W83977ATF Datasheet, PDF (139/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
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).
CRF5 (Default 0x00)
FDD1 Selection: Same as FDD0 of CRF4.
TABLE A
Drive Rate Table
Select
DRTS1 DRTS0
0
0
0
1
1
0
Data Rate
DRATE1
1
0
0
1
1
0
0
1
1
0
0
1
DRATE0
1
0
1
0
1
0
1
0
1
0
1
0
Selected Data Rate
MFM
1Meg
500K
300K
250K
1Meg
500K
500K
250K
1Meg
500K
2Meg
250K
FM
---
250K
150K
125K
---
250K
250K
125K
---
250K
---
125K
SELDEN
CRF0 bit 0=0
1
1
0
0
1
1
0
0
1
1
0
0
Note:Refer to CRF2 for SELDEN value in the cases when CRF0, bit0=1.
TABLE B
DMOD0 DMOD1 DRVDEN0(pin 2) DRVDEN1(pin 3)
0
0
SELDEN
DRATE0
0
1
1
0
1
1
DRATE1
SELDEN
DRATE0
DRATE0
DRATE0
DRATE1
DRIVE TYPE
4/2/1 MB 3.5”“
2/1 MB 5.25”
2/1.6/1 MB 3.5” (3-MODE)
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Publication Release Date:April 1998
Revision 0.52