Motor control circuit and method of use

1. A motor control circuit, comprising:

a first circuit configured to conduct an analog tachometer output signal;

a second circuit configured to conduct an analog control input signal; and

a microcontroller coupled to said first circuit and said second circuit, said microcontroller configured to transmit and receive serial data other than the analog tachometer output signal and the analog control input signal over a serial channel comprising said first circuit and said second circuit.

2. The motor control circuit of claim 1 further comprising a power circuit comprising a ground conductor, a motor power voltage input conductor, and a control power voltage input conductor.

3. The motor control circuit of claim 1 , wherein the serial data comprises motor speed and motor torque.

4. The motor control circuit of claim 1 , wherein said analog control input signal represents a speed control voltage input.

5. The motor control circuit of claim 1 , wherein said microcontroller is further configured to receive the serial data on said second circuit.

6. The motor control circuit of claim 1 , wherein said microcontroller is further configured to transmit the serial data on said first circuit.

7. The motor control circuit of claim 1 , wherein said microcontroller is further configured to switch from an analog mode to a serial mode when a valid serial command is received over said serial channel.

8. A method of operating a motor, said method comprising:

receiving an analog control input signal from an analog input circuit;

operating the motor according to the control input signal;

transmitting an analog tachometer output signal to an analog output circuit, the analog tachometer output signal indicative of an operating speed for the motor;

receiving serial data other than the analog control input signal on a serial channel comprising the analog input circuit and the analog output circuit; and

transmitting serial data other than the analog tachometer output signal on the serial channel.

9. The method of claim 8 further comprising providing power to the motor using a ground conductor, a motor power voltage input conductor, and a control power voltage input conductor.

10. The method of claim 8 further comprising determining to operate in one of an analog mode using the analog control input signal and the analog tachometer output signal, and a serial mode using the serial channel.

11. The method of claim 10 , wherein determining to operate in one of the analog mode and the serial mode comprises:

detecting a valid serial command using the analog input circuit as a serial receive line; and

switching from the analog mode to the serial mode.

12. The method of claim 8 , wherein transmitting serial data on the serial channel comprises:

generating serial data including motor speed; and

transmitting the serial data using the analog output circuit as a serial transmit line.

13. The method of claim 8 , wherein transmitting serial data on the serial channel comprises:

generating serial data including motor torque; and

transmitting the serial data using the analog output circuit as a serial transmit line.

14. The method of claim 8 further comprising:

executing a motor control program on a microcontroller coupled to the serial channel; and

operating the motor according to received serial data and the motor control program.

15. A motor comprising:

a stator;

a rotor configured to turn within said stator;

a wiring interface comprising:

an analog input circuit; and

an analog output circuit;

a motor controller coupled to said wiring interface and configured to:

cause said rotor to turn according to an analog control input signal received over said analog input circuit;

transmit an analog tachometer output signal over said analog output circuit, the analog tachometer output signal indicative of an operating speed for the motor; and

transmit and receive serial data over a serial channel comprising said analog input circuit and said analog output circuit.

16. The motor of claim 15 , wherein said wiring interface consists of five wires, said five wires including:

said analog input circuit;

said analog output circuit;

a ground conductor;

a motor power voltage input conductor; and

a control power voltage input conductor.

17. The motor of claim 15 , wherein said motor controller comprises a microcontroller.

18. The motor of claim 15 , wherein said motor controller is further configured to receive serial data including a serial speed control input.

19. The motor of claim 15 , wherein said motor controller is further configured to transmit serial data including a serial tachometer output.

20. The motor of claim 15 , wherein said motor controller is further configured to switch from an analog mode using the analog control input signal and the analog tachometer output signal, to a serial mode using said serial channel upon receiving a valid serial command over said serial channel.