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Power Conditions log descriptor
Offset
Type
Description
0
Byte
Reserved
1
Byte
Power Condition Flags
Bit
7
6
5
4
3
2
1-0
2-3
Byte
Reserved
4-7
DWord
Default Timer setting
The Default Timer field is set at the time of manufacture.
The Default Timer Setting field is valid if the Power Condition Supported bit is set to one,
regardless of whether EPC is enabled or disabled. A value of FFFF_FFFFh indicates that the
time is greater than or equal to 429_496_729_500 milliseconds.
Measurement Units: 100 milliseconds.
8-11
DWord
Saved Timer setting
The Saved Timer Setting field is a value that has been saved by a SET FEATURES Set
Power Condition Timer subcommand. The Saved Timer Setting field is valid if the Power
Condition Supported bit is set to one, regardless of whether EPC is enabled or disabled. A
value of zero indicates that this power condition is disabled if the EPC feature set is enabled.
A value of FFFF_FFFFh indicates that the time is greater than or equal to 429_496_729_500
milliseconds.
Measurement Units: 100 milliseconds.
Table 163 Power condition log description
Description
Power Condition Supported
The Power Condition Supported bit is valid if the EPC feature set is supported,
regardless of whether EPC is enabled or disabled. If the Power Condition Supported
bit is set to one, then the power condition is supported. If the Power Condition
Supported bit is cleared to zero, then the power condition is not supported.
Timer Savable
The Timer Savable bit is valid if the Power Condition Supported bit is set to one,
regardless of whether EPC is enabled or disabled. If the Timer Savable bit is set to
one, then the power condition is savable if EPC is enabled. If the Timer Savable bit is
cleared to zero, then the power condition is not savable.
Timer Changeable
The Timer Changeable bit is valid if the Power Condition Supported bit is set to one,
regardless of whether EPC is enabled or disabled. If the Timer Changeable bit is set
to one, then the power condition is changeable if EPC is enabled. If the Timer
Changeable bit is cleared to zero, then the power condition is not changeable.
Default Timer Enabled
The Default Timer Enabled bit is valid if the Power Condition Supported bit is set to
one, regardless of whether EPC is enabled or disabled.
Saved Timer Enabled
The Saved Timer Enabled bit is valid if the Power Condition Supported bit is set to
one, regardless of whether EPC is enabled or disabled.
Current Timer Enabled
If EPC is disabled, then the Current Timer Enabled bit shall be cleared to zero. If EPC
is enabled and the Current Timer Setting field is non-zero and the Current Timer
Enabled bit is set to one, then the power condition timer is enabled. If EPC is enabled
and the Current Timer Enabled bit is cleared to zero, then the power condition timer
is disabled.
Reserved
Western Digital Hard Disk Drive OEM Specification
188
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