C141-E090-01EN 5 - 43
(22) IDLE (X'97' or X'E3')
Upon receipt of this command, the device sets the BSY bit of the Status register, and enters
the idle mode. Then, the device clears the BSY bit, and generates an interrupt. The device
generates an interrupt even if the device has not fully entered the idle mode. If the spindle of
the device is already rotating, the spin-up sequence shall not be implemented.
If the contents of the Sector Count register is other than 0, the automatic power-down function
is enabled and the timer starts countdown immediately. When the timer reaches the specified
time, the device enters the standby mode.
If the contents of the Sector Count register is 0, the automatic power-down function is
disabled.
Enabling the automatic power-down function means that the device automatically enters the
standby mode after a certain period of time. When the device enters the idle mode, the timer
starts countdown. If any command is not issued while the timer is counting down, the device
automatically enters the standby mode. If any command is issued while the timer is counting
down, the timer is initialized and the command is executed. The timer restarts countdown after
completion of the command execution.
The period of timer count is set depending on the value of the Sector Count register as shown
below.
Sector Count register value Point of timer
0 [X'00'] Disable of timer
1 to 240 [X'01' to X'F0']
(Value ×5) seconds
241 to 251 [X'F1' to X'FB']
(Value – 240) ×30 minutes
252 [X'FC'] 21 minutes
253 [X'FD'] 8 hours
254 to 255 [X'FE' to X'FF'] 21 minutes 15 seconds
At command issuance (I/O registers setting contents)
1F7
H
(CM) X'97' or X'E3'
1F6
H
(DH)
× × ×
DV xx
1F5
H
(CH)
1F4
H
(CL)
1F3
H
(SN)
1F2
H
(SC)
1F1
H
(FR)
xx
xx
xx
Period of timer
xx