Pulsed-motor driving apparatus and pulsed-motor driving method

A pulsed-motor driving apparatus including a frequency-divided clock generating section for generating a frequency-divided clock having a predetermined driving frequency by dividing a base clock having a base frequency based on a set frequency-division ratio, the apparatus comprising:

• a division-ratio calculating section calculating a real number ratio of the driving frequency relative to the base frequency and setting a rounded frequency-division ratio obtained by rounding the real number ratio as the frequency-division ratio and calculating a rounding error in the rounding of the real number ratio;
• an accumulated error calculating section adding the rounding error to an accumulated error when the frequency-divided clock generating section generates a frequency-divided pulse which is a one cycle of frequency-divided clock;
• and
• a division-ratio correcting section that uses the rounded frequency-division ratio as the frequency-division ratio if the accumulated error does not exceed a threshold value and that uses, as the frequency-division ratio, a value obtained by correcting the rounded frequency-division ratio based on the threshold value and subtracting the threshold value from the accumulated error if the accumulated error exceeds a threshold value.