K6602637
Rev.3
02.27.01
- 53 -
(2) Active Idle Mode/Low Power Idle Mode
The device supports two kind of sub-Idle modes called Active Idle mode and Low Power Idle mode.
Selecting the APM mode, the power consumption can be reduced.
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Active Idle mode: Heads are loaded, and kept on outer cylinder.
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Low Power Idle mode: Heads are unloaded outside of the disk platters and the spindle motor
is rotating. This mode is lower power mode than Active Idle mode.
(3) Low Power Consumption Mode Transition
Table 6.10 Low Power Consumption Mode Transition Time
Operation Mode
APM
Value *1
Operation
APM Mode 0
C0h - FEh
Move to Low Power Idle mode
APM Mode 1
A0h – BFh
Move to Low Power Idle mode
APM Mode 2
80h – 9Fh
Move to Low Power Idle mode
(Power on Default)
APM Mode 3
20h – 7Fh
Move to Standby mode *2
APM Mode 4
01h – 1Fh
*1: This value is set by Sector Count register of Enable Advanced power management sub-command.
If non-defined values 00h and FFh are set, the device returns Aborted command.
*2: APM function does not affect on the Standby timer value. The Standby timer and the Standby mode
transition control of APM function is operated independently.
6.3.2.6.3 Check Power Mode [98h, E5h]
This command posts the power mode of the device. If the device is in, going into, or recovering from
the Standby Mode, it shall set BSY and set the Sector Count Register to 00h. The device then clears
BSY and generates an interrupt. If the device is in the Idle Mode, the device shall set BSY, set the
Sector Count Register to FFh, clear BSY, and generate an interrupt. If the device is in the Active
Mode or Low Power Active Mode, the device shall set BSY, set the Sector Count Register to FFh,
clear BSY, and generate an interrupt.