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12.56 Standby (E2h/96h)
The Standby command causes the device to enter the Standby Mode immediately and set auto power down timeout
parameter (standby timer).
When the Standby mode is entered, the drive is spun down but the interface remains active. If the drive is already
spun down, the spin down sequence is not executed.
During the Standby mode the device will respond to commands, but there is a delay while waiting for the spindle to
reach operating speed.
The automatic power down sequence is enabled and the timer starts counting down when the drive returns to Idle
mode.
If the EPC feature set is enabled, device enters into the Standby_Z power condition.
Standby timer
period
Timeout Parameter. If zero, the timeout interval (Standby Timer) is disabled. If non-zero, then
the automatic power down sequence is enabled, and the timeout interval is shown below:
Value
Description
-----------
-------------------------------
0
Timer disabled
1-240 Value * 5 seconds
241-251 (Value-240) * 30 minutes
252
21 minutes
253
8 hours
254
Aborted
255
21 minutes 15 seconds
When the automatic power down sequence is enabled, the drive will enter Standby mode
automatically if the timeout interval expires with no drive access from the host. The timeout
interval will be reinitialized if there is a drive access before the timeout interval expires.
Table 243 Standby Command (E2h/96h)
Command Input
Field
Description
FEATURE
N/A
COUNT
Standby timer period
LBA
N/A
DEVICE
Bit Description
7 Obsolete
6 N/A
5 Obsolete
4 Transport Dependent
3:0 Reserved
Command
7:0 E2h or 96h
Normal Outputs
See Normal Outputs in Section 12.7 Flush Cache (E7h)
Error Outputs
See Error Outputs in Section 12.12 Idle (E3h / 97h)
322
Hard Disk Drive Specification