Datasheet

4.1 Control/Sense Commands
C141-C008 4-81
It is possible to select the disk drive's spindle motor starting mode through the
extrnal setting terminal. If prohibition of motor starting control is set by this
command at the setting terminal, the spindle motor starts automatically when the
IDD's power is switched on. It is possible to delay the starting time by the value
of SEL_ID. When the setting terminal is being set to perform motor starting
control by command, the IDD's spindle motor will not start even when the power
is switched on. In this case, it is necessary for the INIT to issue a command to
start the spindle motor.
The setting terminal specifies only the spindle motor starting
method at power on time, and whichever mode is set, this command
is valid.
The INIT can issue this command whenever it is desired and stop or
start the spindle motor regardless of the state of the setting terminal.
Depending on the value specified in the "Immed (immediate)" bit, bit 0 of CDB
byte 1, the timing of completion (status byte report) of this command differs as
shown below.
a. In the case of the start specification ("Start" bit = "1")
− When the "Immed" bit is "1," simply by instructing starting of the
spindle motor, a GOOD status is reported without waiting until the disk
drive is in the Ready state, and command execution is completed.
− When the "Immed" bit is "0," the status byte is reported, and command
execution is completed, at the point when the disk drive has entered the
Ready state after the spindle motor has started.
b. In the case of the stop specification ("Start" bit = "0")
− When the "Immed" bit is "1," simply by instructing stopping of the
spindle motor, the GOOD status is reported and command execution is
completed.
− When the "Immed" bit is "0," the status byte is reported, and command
execution is completed, after the spindle motor is in the stopped state.