W83977A Winbond Electronics Corp America, W83977A Datasheet - Page 39

• Manufacturer Part Number: W83977A
• Description: Winbond I/O
• Manufacturer: Winbond Electronics Corp America

INDEX (Bit 2):
This bit indicates the complement of INDEX output.
WP (Bit 1):
0
1
This bit indicates the direction of head movement.
0
1
2.2.2 Status Register B (SB Register) (Read base address + 1)
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:
Drive SEL0 (Bit 5):
This bit indicates the status of DO REGISTER bit 0 (drive select bit 0).
WDATA Toggle (Bit 4):
This bit changes state at every rising edge of the WD output pin.
RDATA Toggle (Bit 3):
This bit changes state at every rising edge of the RDATA output pin.
WE (Bit 2):
This bit indicates the complement of the WE output pin.
MOT EN B (Bit 1)
This bit indicates the complement of the MOB output pin.
MOT EN A (Bit 0)
This bit indicates the complement of the MOA output pin.
In PS/2 Model 30 mode, the bit definitions for this register are as follows:
DIR (Bit 0)
disk is not write-protected
disk is write-protected
inward direction
outward direction
7
1
6
1
5
4
3
-31 -
2
1
0
MOT EN A
WDATA Toggle
MOT EN B
WE
RDATA Toggle
Drive SEL0
Publication Release Date: April 1998
W83977TF
PRELIMINARY
Revision 0.62