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 (Mode-1) when power-on or COMRESET occurs for the drive.

APM Level

Sector Count Field

 

 

Mode 0 Active Idle → Low Power Idle

C0h-FEh

Mode 1 Active Idle → Low Power Idle

80h-BFh

Mode 2 Active Idle → Low Power Idle

01h-7Fh

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.

C141-E249

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Fujitsu MHW2120BS, MHW2100BS, MHW2080BS, MHW2040BS, MHW2060BS manual Advanced Power Management APM