W83787IF Datasheet, PDF (34/123 Pages) Winbond – WINBOND I/O WITH SERIAL-INFRARED SUPPORT

W83787IF
Status Register 3 (ST3)
765
43
210
US0 Unit Select 0
US1 Unit Select 1
HD Head Address
TS Two-Side
TO Track 0
RY Ready
WP Write Protected
FT Fault
2.3.5 Digital Input Register (DI Register) (Read 3F7H/377H)
The Digital Input Register is an 8-bit read-only register used for diagnostic purposes. In a PC/XT or
AT only Bit 7 is checked by the BIOS. When the register is read, Bit 7 shows the complement of
DSKCHG, while other bits of the data bus remain in tri-state. Bit definitions are as follows:
76 54321 0
xxxxxx x
x ^{Reserved for the hard disk controller}
During a read of this register, these bits are in tri-state
DSKCHG
DSKCHG (Bit 7):
This bit indicates the complement of the DSKCHG input.
Bit 6-3: These bits are always a logic 1 during a read.
2.3.6 Configuration Control Register (CC Register) (Write 3F7H/377H)
This register is used to control the data rate. In the PC/AT and PS/2 mode, the bit definitions are as
follows:
7 6 5 ⁴ 3 ²¹ 0
xxxx xx
DRATE0
DRATE1
X: Reserved
Bit 7-2: Reserved. These bits should be set to 0.
DRATE1 DRATE0 (Bit 1, 0):
These two bits select the data rate of the FDC.
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Publication Release Date:Sep 1995
Revision A1