A control apparatus for a motor having a rotor includes a resolver, a processor, a decoder, a sensor, and a motor driver. The resolver outputs waveforms sensed from a rotation of the rotor. The decoder generates an absolute angle signal and an incremental angle signal in response to the waveforms from the resolver and provides the absolute angle signal and the incremental angle signal to the processor. The sensor estimates a positioning angle of the rotor and provides an estimated angle signal in response to the positioning angle of the rotor to the processor. When one of the absolute angle signal, the incremental angle signal, and the estimated angle signal is transmitted to the processor, the processor executes a predetermined program associated with the respective absolute angle signal, the incremental angle signal, and the estimated angle signal, to control the motor driver to rotate the rotor.