W83977EF Winbond Electronics Corp America, W83977EF Datasheet - Page 39

• Manufacturer Part Number: W83977EF
• Description: Description = W83877TF Plus Kbc, GP I/O, Wake-Up, Power Fail Resume ;; Package = QFP 128
• Manufacturer: Winbond Electronics Corp America

2.2 Register Descriptions
There are several status, data, and control registers in W83977EF. 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.
HEAD (Bit 3):
This bit indicates the complement of HEAD# output.
0
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
side 0
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
-33 -
READ
2
1
0
REGISTER
DIR
WP#
INDEX#
HEAD
TRAK0#
STEP
INIT PENDING
DRV2#
Publication Release Date: April 2003
DT (FIFO) REGISTER
DO REGISTER
DR REGISTER
CC REGISTER
TD REGISTER
WRITE
W83977EF
Revision 1.1