Idle (97H,E3H); Idle Immediate (95H,E1H); Initialize Device Parameters (91H); Table 6-8 Automatic Standby Timer Periods - Samsung SP0401N Product Manual

DISK DRIVE OPERATION

6.4.8 Idle (97h,E3h)

This command causes the drive to set BSY, enter the Idle Mode, clear BSY, and generate an interrupt. The
interrupt is generated even though the drive may not have fully transitioned to Idle Mode.
If the drive is already spinning, the spin-up sequence is not executed.
If the Sector Count register is non-zero, then the automatic Idle Mode sequence is enabled, and the timer
begins counting down immediately. If the Sector Count register is zero, the automatic power down sequence
is disabled.
After the drive enters Idle Mode, it automatically transitions to Standby Mode upon expiration of a prescribed
1 minute spin-down timer.
Sector Count Register Contents
1-240 (01h-FOh)
241-251 (F1h-FBh)

6.4.9 Idle Immediate (95h,E1h)

This command causes the drive to set BSY, enter Idle Mode, clear BSY, and generate an interrupt. The
interrupt is generated even though the drive may not have fully transitioned to Idle Mode.

6.4.10 Initialize Device Parameters (91h)

This command enables the host to set the number of sectors per track and the number of heads minus 1, per
cylinder. Upon receipt of the command, the drive sets BSY, saves the parameters, clears BSY, and generates
an interrupt.
The only two register values used by this command are the Sector Count register which specifies the number
of sectors per track, and the Drive/Head register which specifies the number of heads minus 1. The DRV bit
designates these values to Drive 0 or Drive 1, as appropriate.
SpinPoint P80 Product Manual Rev. 01

Table 6-8 Automatic Standby Timer Periods

0 (00h)
252 (FCh)
253 (FDh)
254 (FEh)
255 (FFh)
Corresponding Time-out Period
Timeout Disabled
(value * 5) seconds
(value - 240) * 30 minutes
21 minutes
8 hours
Reserved
21 minutes 15 seconds
64