is provided via line 516 from the power supply circuit 503 a low voltage reset circuit 518 monitors the voltage vdd on line 516 and applied to the microprocessor 514 the reset circuit 518 selectively resets the microprocessor 514 when the voltage vdd applied to the microprocessor via line 516 transitions from below a predetermined threshold to above the predetermined threshold the threshold is generally the minimum voltage required by the microprocessor 514 to operate therefore the purpose of the reset circuit 518 is to maintain operation and re establish operation of the microprocessor in the event that the voltage vdd supplied via line 516 drops below the preset minimum required by the microprocessor 514 to operate optionally to save power the hall sensor 508 may be intermittently powered by a hall strobe 520 controlled by the microprocessor 514 to pulse width modulate the power applied to the hall sensor the microprocessor 514 has a control input 522 for receiving a signal which affects the control of the motor 500 for example the signal may be a speed select signal in the event that the microprocessor is programmed to operate the rotor such that the stator is commutated at two or more discrete speeds alternatively the motor may be controlled at continuously varying speeds or torques according to temperature for example in place of or in addition to the hall sensor 508 an optional temperature sensor 524 may be provided to sense the temperature of the ambient air about the motor this embodiment is particularly useful when.