W83977AF Information Storage Devices, Inc, W83977AF Datasheet - Page 42

• Manufacturer Part Number: W83977AF
• Description: W83877TF Plus Kbc, Cir, RTC
• Manufacturer: Information Storage Devices, Inc

2.2 Register Descriptions
There are several status, data, and control registers in W83977F/ AF. These registers are defined
below:
This register is used to monitor several disk interface pins in PS/2 and Model 30 modes. In PS/2
mode, the bit definitions for this register are as follows:
INIT PENDING (Bit 7):
This bit indicates the value of the floppy disk interrupt output.
0
1
STEP (Bit 5):
This bit indicates the complement of STEP output.
This bit indicates the value of TRAK0 input.
DRV2 (Bit 6):
TRAK0 (Bit 4):
2.2.1 Status Register A (SA Register) (Read base address + 0)
A second drive has been installed
A second drive has not been installed
base address + 0
base address + 1
base address + 2
base address + 3
base address + 4
base address + 5
base address + 7
ADDRESS
OFFSET
7
6
5
DT (FIFO) REGISTER
4
SB REGISTER
MS REGISTER
SA REGISTER
TD REGISTER
DI REGISTER
3
READ
2
1
0
W83977F/ W83977AF
REGISTER
DIR
WP
INDEX
HEAD
TRAK0
STEP
INIT PENDING
DRV2
Publication Release Date: March 1998
DT (FIFO) REGISTER
DO REGISTER
DR REGISTER
CC REGISTER
TD REGISTER
PRELIMINARY
-31 -
WRITE
Revision 0.58