
5.3 Host Commands
*2) Advanced Power Management (APM)
The host writes the Sector Count field with the desired power management level and executes this command with the Features field X’05’, and then Advanced Power Management is enabled.
The drive automatically shifts to power saving mode up to the specified APM level when the drive does not receive any commands for a specific time. The sequence in which the power management level shifts is from Active Idle to Low Power Idle. The Mode 0 level requires the longest shifting time, depending on the APM level settings. The settings of the APM level revert to their default values
APM Level | Sector Count Field | |
|
| |
Mode 0 Active Idle → Low Power Idle | ||
Mode 1 Active Idle → Low Power Idle | ||
Mode 2 Active Idle → Low Power Idle | ||
Reserve (State Keep) |
| 00h, FFh |
|
|
|
Active Idle: | The spindle motor rotates, and the head is loaded on | |
| the most inner position on media. |
Low Power Idle: The spindle motor rotates, and the head is unloaded.