Fujitsu MPF3XXXAT manual

(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)

1F7H(CM)					X'97' or X'E3'
1F6H(DH)	×	×	×		DV	xx
1F5H(CH)					xx
1F4H(CL)					xx
1F3H(SN)					xx
1F2H(SC)				Period of timer
1F1H(FR)					xx

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