W83977AF Information Storage Devices, Inc, W83977AF Datasheet - Page 44

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

This bit indicates the value of HEAD output.
0
1
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
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.
DIR (Bit 0)
Status Register B (SB Register) (Read base address + 1)
side 1
side 0
disk is not write-protected
disk is write-protected
inward direction
outward direction
7
1
6
1
5
4
3
2
1
W83977F/ W83977AF
0
MOT EN A
MOT EN B
WDATA Toggle
WE
RDATA Toggle
Drive SEL0
Publication Release Date: March 1998
PRELIMINARY
-33 -
Revision 0.58