W83627DHG Datasheet, PDF (145/268 Pages) Winbond – WINBOND LPC I/O

W83627DHG
10.2.8 Digital Input Register (DI Register) (Read base address + 7)
The Digital Input Register is an 8-bit, read-only register used for diagnostic purposes. In PC/XT or
PC/AT mode, only bit 7 is checked by the BIOS. When the register is read, bit 7 shows the complement
of DSKCHG#, while the other bits remain in tri-state. The 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-stat
DSKCHG
In PS/2 mode, the bit definitions are as follows:
765 43 21 0
11 1 1
HIGH DENS#
DRATE0
DRATE1
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.
DRATE1 DRATE0 (Bit 2, 1):
These two bits select the data rate of the FDC. See DR register bits 1 and 0 (Data Rate Register (DR
Register) (Write base address + 4)) for how the settings correspond to individual data rates.
HIGHDENS# (Bit 0):
0
500 KB/S or 1 MB/S data rate (high-density FDD)
1
250 KB/S or 300 KB/S data rate
In PS/2 Model 30 mode, the bit definitions are as follows:
-133-
Publication Release Date: Aug, 22, 2007
Version 1.4