88
Western Digital Hard Disk Drive OEM Specification
9.18.3.3
Feature Control Command (action code : 0004h)
Inputs: (Key Sector)
Word
Name
Value
Description
0
Action Code
0004h
Set or return the state of drive features described in Table 67
1
Function Code
0001h
Set state for a feature
0002h
Return the current state of a feature
0003h
Return feature option flags
2
Feature Code
Word
See Table 67 for a list of the feature codes
3
State
Word
Feature code dependent value
4
Option Flags
Word
Bit15:1 = Reserved
If the function code is 0001h, setting bit 0 to one causes the
requested feature state change to be preserved across power
cycles.
If the function code is 0001h, setting bit 0 to zero causes the
requested feature state change to be volatile. A hard reset
causes the drive to revert to default, or last non-volatile
setting.
255:5
reserved
0000h
Table 65 Feature Control Command (Inputs)
Outputs: (TF Data)
Command Block Input Registers (Success)
Error
00h
Sector Count
If Function Code was 0002h, then this is the LSB of Feature State.
If Function Code was 0003h, then this is the LSB of Option Flags.
Otherwise, this field is reserved.
Sector Number
If Function Code was 0002h, then this is the MSB of Feature State.
If Function Code was 0003h, then this is the MSB of Option Flags.
Otherwise, this field is reserved.
Cylinder Low
reserved
Cylinder High
reserved
Device/Head
reserved
Status
50h
Table 66 Feature Control Command (Outputs)
