Specifications

5.7.4 Enable/Disable Auto Standby command
This command (command code E2
H
) enables and disables the automatic
standby feature of the drive. When the drive receives this command, it
sets BSY and makes a transition to Standby mode. Depending on the
value placed in the Sector Count register, the drive either enables or
disables the standby timer. The drive then clears BSY and generates an
interrupt.
Placing a zero value in the Sector Count register disables automatic
Standby. Placing a nonzero value in the Sector Count register enables
the standby timer to count down in 5-second increments. For example,
a value of 12 sets the standby timer to sixty seconds (after which time,
the Standby routine is initiated). A value of 13 sets the timer for 65
seconds. The delay timer is reset by the drive whenever a read, write or
seek command is issued. The default power-on condition is that auto-
matic standby is disabled.
5.7.5 Idle Immediate command
This command (command code F8
H
) causes the drive to enter Idle mode
immediately. When the drive receives this command, it sets BSY, makes
a transition to Idle mode, clears BSY and generates an interrupt. The
drive generates this interrupt when it completes its transition to Idle mode.
If the drive is already in Idle mode, it ignores this command.
5.7.6 Ready and Enable/Disable Auto Idle command
This command (command code FB
H
) is the functional equivalent of the
Enable/Disable Auto Idle command (command code FA
H
). However, this
command always forces the drive into the Active state. It then enables
or disables the idle timer based on the value in the Sector Count register.
5.7.7 Ready and Enable/Disable Auto Standby
command
This command (command code E3
H
) is a functional combination of the
Ready Immediate and the Enable/Disable Auto Standby commands.
Refer to the individual commands for a detailed description.
When the drive receives this command, it sets BSY, enters Active mode,
sets the standby timer if necessary, clears BSY and generates an
interrupt. If the spindle is already up to speed when the command is
received, the spinup sequence is not executed.
ATA Interface Reference Manual, Rev. C 63