A controller for motor activation providing accurate and repeatable
position changes by pressing and releasing a push button switch.
Repeatable position changes are made in an advance direction by
triggering a digital counter for a predetermined number of cycles of a
reference clock signal. Backlash in retard motion of the motor is reduced
by similarly asserting a retard motor input for an amount of time
determined by another digital counter with a following advance correction
made automatically after the retard signal is applied, by applying a
predetermined retard-advance movement amount, as again counted by a
digital counter. The advance binary amount, the retard binary amount and
the retard-advance binary amount of set through binary switch inputs to
respective counters to count the respective time periods (TG3, TG1, and
TG2).