FUJITSU MHV2120AT - Manual (Page 113)

5.3 Host Commands
C141-E218 5-37
(13) 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 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.
By using this command, the APS (Automatic Power Standby) timer function is
enabled and the timer immediately starts the countdown. When the timer reaches
the specified value, the device enters standby mode. The APS timer is set to
prohibition if the Sector Count register's value was "00h" when device has
received this command.
The APS timer allows the device to change to the standby mode automatically
after specified period. When the device enters the state which is waiting Host
Command, 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’] Timeout disabled
1 to 240 [X’01’ to X’F0’] (Value
× 5) seconds
241 to 251 [X’F1’ to X’FB’] ((Value-240)
× 30) min
252 [X’FC’] 21 minutes
253 [X’FD’] 8 hrs
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) x x x DV xx
1F5
H
(CH)
1F4
H
(CL)
1F3
H
(SN)
1F2
H
(SC)
1F1
H
(FR)
xx
xx
xx
Period of timer
xx