Patent ID: 7791306

Claim:
An apparatus for controlling a stepping motor, comprising: an angle address register storing a start angle address representing a start angle of the stepping motor, as well as an end angle address representing an end angle of the stepping motor; a pointer register holding an angle address representing a rotation angle of the stepping motor; an acceleration control starter that initializes the pointer register with the start angle address stored in the angle address register upon receipt of a control start signal; a duty cycle memory storing duty cycles corresponding to different angle addresses including the start angle address stored in the angle address register; a duty cycle selector that looks up the duty cycle memory to select duty cycles corresponding to the angle address held in the pointer register; a pulse generator that produces pulse signals having the duty cycles selected by the duty cycle selector to drive the stepping motor; an angle address calculator that updates the pointer register with a new angle address calculated by adding a given address increment to the angle address held in the pointer register; a revolution detector that detects one revolution of the stepping motor by comparing the angle address of the pointer register with the end angle address and produces a detection result signal indicating the detection of one revolution of the stepping motor; a count trigger generator that generates a trigger signal based on the detection result signal from the revolution detector; and an acceleration constant calculator that changes the address increment each time the trigger signal is received from the count trigger generator.