User manual
Hitachi hard disk drive specifications
193
Y
2
=(x-40h) * 60 + 600[sec] (600<=Y
2
<=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<=Y
1
<=435 [sec] (default: 120 [sec])
Y
2
=600 [sec]
where x is the value in Sector Count register, y
1
is the idle time to Low Power Idle mode, and y
2
is the idle time
to Low RPM standby mode.
If Low power idle mode has already been enabled (i.e., y
1
has been set) before Low RPM standby mode is
enabled, y
1
is preserved. If Low power idle mode is disabled (i.e., y
1
has not been set yet), y
1
becomes 120[sec]
when Low RPM standby mode is enabled.
Enabled Power Saving mode and idle time (y
1
and y
2
) are preserved until Advanced Power Management is
disabled, the deepest Power Saving mode becomes Normal Idle mode, or new time is set. They are initialized
with a hard/soft reset unless Reverting to power on defaults is disabled and the device receives a soft reset.
11.37.5.1 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.
11.37.5.2 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.
11.37.6 Set Maximum Host Interface Sector Time
Sector Count
Typical PIO Mode Host Interface Sector Time (7:0)
LBA Low
Typical PIO Mode Host Interface Sector Time (15:8)
LBA Mid
Typical DMA Mode Host Interface Sector Time (7:0)
LBA High
Typical DMA Mode Host Interface Sector Time (15:8)
Subcommand code 43h allows the host to inform the device of a host interface rate limitation. The typical Host
Interface Sector Times have the same units as Identify Device word 96 for DMA and word 104 for PIO. A value of
zero indicates that the host interface shall be capable of transferring data at the maximum rate allowed by the
selected transfer mode. The Typical PIO Mode Host Interface Sector Time includes the host‟s interrupt service
time.