250
Western Digital Hard Disk Drive OEM Specification
11.46.6.5
Enable the EPC feature subcommand
Com m and Block Output Registers
Com m and Block Input Registers
Register
7
6
5
4
3
2
1
0
Register
7
6
5
4
3
2
1
0
Data
-
-
-
-
-
-
-
-
Data
-
-
-
-
-
-
-
-
Feature
0
1
0
0
1
0
1
0
Error
…See Below …
Sector Count
-
-
-
-
-
-
-
-
Sector Count
-
-
-
-
-
-
-
-
Sector Number
-
-
-
-
0
1
0
0
Sector Number
-
-
-
-
-
-
-
-
Cylinder Low
-
-
-
-
-
-
-
-
Cylinder Low
-
-
-
-
-
-
-
-
Cylinder High
-
-
-
-
-
-
-
-
Cylinder High
-
-
-
-
-
-
-
-
Device/Head
1
-
1
D
-
-
-
-
Device/Head
-
-
-
-
-
-
-
-
Command
1
1
1
0
1
1
1
1
Status
…See Below …
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC
UNC
0
IDN
0
ABT
T0N
AMN
BSY
RDY
DF
DSC
DRQ
COR
IDX
ERR
0
0
0
0
0
V
0
0
0
V
0
-
-
0
-
V
Table 217 Enable the EPC feature subcommand
On successful completion of this EPC subcommand, the device:
a)
enables the EPC feature set;
b)
sets IDENITFY DEVICE data word 120 bit 7 to one; and
c)
disables the APM feature set.
d)
if the Saved Timer Setting field is cleared to zero, then:
copy the value of the Default Timer Setting to the Current Timer Setting; and
e)
if the Saved Timer Setting field is non-zero, then:
copy the value of the Saved Timer Setting to the Current Timer Setting; and
f)
if the Current Timer Setting field is non-zero and the Current Timer Enabled is set to one,
then initialize and start the timer.
If the EPC feature set is enabled, then the EPC feature set remains enabled across all resets (i.e., power-on reset,
hardware reset, and software reset).
Output Parameters To The Device
Sector Number bit Description
7-4
Reserved
3-0
4h Enable the EPC feature subcommand (See Table 73)
Error Output
If the Extended Power Condition feature set is not supported then the device returns command aborted.
