W83877TF Datasheet, PDF (40/154 Pages) Winbond – I/O chip disk drive adapter

INDEX (Bit 2):
This bit indicates the complement of INDEX output.
WP (Bit 1):
0 disk is not write-protected
1 disk is write-protected
DIR (Bit 0)
This bit indicates the direction of head movement.
0 inward direction
1 outward direction
W83877TF
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:
7 65 4 3 ²¹ 0
11
MOT EN A
MOT EN B
WE
RDATA Toggle
WDATA Toggle
Drive SEL0
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:
- 30 -
Publication Release Date: March 1998
Version 0.61