w83977ctf Winbond Electronics Corp America, w83977ctf Datasheet - Page 42

• Manufacturer Part Number: w83977ctf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

2.2 Register Descriptions
There are several status, data, and control registers in W83977EF/CTF. 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.
DRV2# (Bit 6):
0
1
STEP (Bit 5):
This bit indicates the complement of STEP# output.
TRAK0#(Bit 4):
This bit indicates the value of TRAK0# input.
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
-33 -
2
1
0
REGISTER
DIR
INDEX#
WP#
HEAD
TRAK0#
STEP
INIT PENDING
DRV2#
Publication Release Date: March 1999
W83977EF/ CTF
DT (FIFO) REGISTER
DO REGISTER
DR REGISTER
CC REGISTER
TD REGISTER
PRELIMINARY
WRITE
Revision A1