W83877TF Datasheet, PDF (102/154 Pages) Winbond – I/O chip disk drive adapter

W83877TF
8.2.8 Configuration Register 7 (CR7), default = 00H
When the device is in Extended Function mode and EFIR is 07H, the CR7 register can be accessed
through EFDR. The bit definitions are as follows:
76 5432 10
FDD A type 0
FDD A type 1
FDD B type 0
FDD B type 1
FDD C type 0
FDD C type 1
FDD D type 0
FDD D type 1
FDD D type 1, 0 (Bit 7, 6):
These two bits select the type of FDD D.
00 Selects normal mode. When RWC = 0, the data transfer rate is 250 Kb/s. When
RWC = 1, the data transfer rate is 500 Kb/s.
Three mode FDD select (EN3MODE = 1):
01 RWC = 0, selects 1.2 MB high-density FDD.
10 RWC = 1, selects 1.44 MB high-density FDD.
11 Don't care RWC, selects 720 KB double-density FDD.
FDD C type 1, 0 (Bit 5, 4):
These two bits select the type of FDD C.
00 Selects normal mode. When RWC = 0, the data transfer rate is 250 kb/s. When
RWC = 1, he data transfer rate is 500 kb/s.
Three mode FDD select (EN3MODE = 1):
01 RWC = 0, selects 1.2 MB high-density FDD.
10 RWC = 1, selects 1.44 MB high-density FDD.
11 Don't care RWC, selects 720 KB double-density FDD.
FDD B type 1, 0 (Bit 3, 2):
These two bits select the type of FDD B.
00 Selects normal mode. When RWC = 0, the data transfer rate is 250 Kb/s. When
RWC = 1, the data transfer rate is 500 Kb/s.
Three mode FDD select (EN3MODE = 1):
01 RWC = 0, selects 1.2 MB high-density FDD.
10 RWC = 1, selects 1.44 MB high-density FDD.
11 Don't care RWC, selects 720 KB double-density FDD.
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Publication Release Date: March 1998
Version 0.61