Control method of spindle motor

A method for controlling spindle motor of a disk drive that includes a tray for carrying a disk, a detect switch, a DC motor, a spindle motor, a traverse module and a firmware, wherein during tray retraction operation, a voltage is applied to the DC motor to move the tray in sequence through a first position, a second position, a third position to a fourth position meanwhile the detect switch is correspondingly shifted in sequence through a first inclined position, a second inclined position, a third inclined position to a fourth inclined position, wherein a first signal is transmitted to the firmware when the detect switch is shifted to the second inclined position, and a second signal is transmitted to the firmware when the detect switch is shifted to the third inclined position, the spindle motor control method comprising the following steps:

• moving the tray from the fourth position to the third position, wherein the traverse module is disposed at a lower position;
• receiving the first signal;
• moving the tray from the third position to the second position, wherein the traverse module is raised from said lower position to an upper position;
• receiving the second signal;
• determining whether the disk is present on the tray or not;
• starting up the spindle motor;
• and
• moving the tray from the second position to the first position, wherein the traverse module is disposed at said upper position, the traverse module being retained at said upper position during movement of the tray from the second position to the first position.