Seeking control method using timer interruption for accelerating and

Abstract

A sled motor controlling method for shifting the position of an optical pickup a CD-ROM drive is disclosed. According to the inventive method, the number of tracks from an initial position of a pickup to a target position are counted. A timer interrupt, of a timer inside the CD-ROM, is enabled for acceleration to and rotation at constant speed of a sled motor which moves the pickup. The ennoblement of the timer interrupt is based on a number of reference clock pulses which correspond to the number of tracks to be traversed. A determination is made whether the pickup is approaching the target position. If it is determined that the pickup is approaching the target position, a timer interrupt is enabled for deceleration of the sled motor. Then, all timer interrupts are disabled if it is determined that the pickup has reached the target position. According to the sled motor controlling method in a CD-ROM drive of the present invention, the rotational speed of the sled motor is controlled by using an interrupt or time interval of the timer of a microcomputer in the drive unit. This reduces servo control errors due to mechanical errors. The cost of the drive unit is reduced by eliminating the need for a device for receiving an external reference signal to control the sled motor.