- March
- 5th
- 2008
Desktar P7K500 powersave using APM
Posted by MaEl in: Bits-and-Bytes Comments (0)
When the value in the Feature register is 05h (=Enable Advanced Power Management), the Sector Count
Register specifies the Advanced Power Management level.
FFh — Aborted
C0 – Feh — The deepest Power Saving mode is Normal Idle mode
(the same as Disable Advanced Power Management)
80 – BFh — The deepest Power Saving mode is Low power Idle mode
01 – 7Fh — The deepest Power Saving mode is Low RPM standby mode
00h — Aborted
Low Power Idle mode
Additional electronics are powered off, and heads are unloaded on the ramp, however the spindle is still rotated
at the full speed.
Low RPM standby mode
The heads are unloaded on the ramp, and the spindle is rotated at the 60-65% of the full speed.
When Feature register is 85h (=Disable Advanced Power Management), the deepest Power Saving mode becomes normal Idle.
The idle time to Low power idle mode and Low RPM standby mode vary according to the value in Sector Count
register as follows:
When Low power idle mode is the deepest Power Saving mode,
YB1B=(x-80h) * 5+120 [sec] (120<= YB1B<=435)
YB2B=N/A(the device does not go to Low RPM standby mode)
When Low RPM standby mode is the deepest Power Saving mode and the value in Sector Count register is
between 40h and 7Fh,
120<=YB1B<=435 [sec] (default: 120 [sec])
YB2B=(x-40h) * 60 + 600[sec] (600<=YB2B<=4380)
When Low RPM standby mode is the deepest Power Saving mode and the value in Sector Count register is
between 01h and 3Fh,
120<=YB1B<=435 [sec] (default: 120 [sec])
YB2B=600 [sec]