Wake-up circuit

1. An apparatus, comprising:

a vehicle; and

a control system located in the vehicle, the control system comprising:

a processor,

a wake-up circuit coupled to the processor;

a program utilized by the processor during a standby mode of operation, the program configured to:

provide a voltage to the wake-up circuit for a first time period once an interrupt is received by the processor;

monitor the wake-up circuit for a second time period; and

recalibrate the voltage to the wake-up circuit if a response of the wake-up circuit exceeds at least one predetermined limit.

2. The apparatus, as set forth in claim 1 , wherein the control system comprises a remote keyless entry system.

3. The apparatus, as set forth in claim 2 , wherein the control system comprises a lock actuator in communication with the processor, wherein the lock actuator is configured to engage and disengage a door lock.

4. The apparatus, as set forth in claim 3 , wherein the remote keyless entry system comprises a transceiver module that is coupled to the processor and adapted to receive a signal from a transmitter to activate the lock actuator to unlock the door lock.

5. The apparatus, as set forth in claim 1 , wherein the control system comprises a window system.

6. The apparatus, as set forth in claim 5 , wherein the window system comprises a motor coupled to the processor and a window, wherein the motor moves the window.

7. An automotive control system, comprising:

a microprocessor,

a wake-up circuit coupled to the microprocessor;

a memory coupled to the microprocessor;

a program within the memory and utilized by the microprocessor, the program configured to:

apply a voltage to the wake-up circuit for a first time period;

measure a response of the wake-up circuit for a second time period;

determine if the response is within a predetermined limit; and

recalibrate the voltage if the response is not within the predetermined limit.

8. The automotive control system, as set forth in claim 7 , wherein the program accesses a plurality of stored parameters to determine the voltage.

9. The automotive control system, as set forth in claim 8 , wherein the plurality of stored parameters are stored in the memory.

10. The automotive control system, as set forth in claim 7 , wherein the recalibration of the voltage updates at least one of a plurality of stored parameters.

11. The automotive control system, as set forth in claim 7 , wherein the microprocessor comprises a first port and a second port coupled to the wake-up circuit; and wherein the voltage is provided to the wake-up circuit through the first port and the response is measured from the first port.

12. The automotive control system, as set forth in claim 7 , wherein the wake-up circuit comprises:

a first resistor having a first terminal and a second terminal, wherein the first terminal is coupled to ground;

a second resistor having a third terminal coupled directly to the second terminal at a node and a fourth terminal coupled to a first port; and

a capacitor having a fifth terminal coupled to each of the second terminal, the third terminal, and a second port and a sixth terminal coupled to ground.

13. One or more tangible computer readable mediums encoded with a computer program for operating and recalibrating a wake-up circuit, the program comprising:

a routine for applying a voltage to a wake-up circuit for a first time period in response to an interrupt;

a routine for measuring a response of the wake-up circuit for a second time period;

a routine for determining if the response is within a predetermined limit; and

a routine for recalibrating the voltage if the response is not within the predetermined limit.

14. The computer program, as set forth in claim 13 , wherein the tangible medium is a memory.

15. The computer program, as set forth in claim 13 , comprising a routine for accessing a plurality of stored parameters to determine the voltage.

16. The computer program, as set forth in claim 13 , wherein recalibrating comprises updating the voltage if the response is not within the predetermined limit.

17. The computer program, as set forth in claim 13 , wherein the routine for applying the voltage is activated by the interrupt received at a processor.

18. The computer program, as set forth in claim 13 , wherein the routine for applying the voltage to the wake-up circuit is utilized when a standby mode is indicated by a processor.

19. A method of monitoring a control system, the method comprising the acts of:

providing an interrupt signal to a microprocessor;

measuring a first voltage on a port of the microprocessor connected to a wake-up circuit;

generating an output voltage for a time period on the port;

measuring a second voltage on the port once the output voltage generation stops;

comparing the first voltage and second voltage to at least one stored parameter;

determining if the comparison is within or equal to a predetermined limit; and

recalibrating at least one of the output voltage and time period, if the comparison exceeds the predetermined limit.

20. The method, as set forth in claim 19 , comprising providing an interrupt signal to another port of the microprocessor connected to the wake-up circuit.

21. The method, as set forth in claim 19 , wherein recalibrating comprises:

reducing the time period stored in memory, if the comparison is greater than the predetermined limit; and

increasing the time period stored in memory, if the comparison is less than the predetermined limit.

22. The method, as set forth in claim 19 , wherein the acts are performed in the order recited.

23. The method, as set forth in claim 19 , wherein the predetermined limit is stored in a memory coupled to the microprocessor.

24. The method, as set forth in claim 19 , comprising recalibrating at least one of the output voltage and the time period once a predetermined number of interrupts have been performed.

25. A method of manufacturing a control system comprising the acts of:

providing a processor;

coupling a wake-up circuit to the processor;

encoding an program to:

provide a voltage to the wake-up circuit for a first time period if a standby mode is indicated;

stop providing the voltage at the end of the first time period;

monitor a response of the wake-up circuit for a second time period; and

recalibrate the voltage if the response exceeds at least one of a plurality of predetermined limitations.

26. The method, as set forth in claim 25 , comprising coupling a memory to the processor.

27. The method, as set forth in claim 26 , comprising storing the encoded program in the memory.

28. The method, as set forth in claim 25 , wherein coupling the wake-up circuit comprises:

coupling a first resistor to a first port and a second port of the processor;

coupling a capacitor and a second resistor in parallel between the first port and a lower voltage potential.

29. A method of monitoring a control system, the method comprising the acts of:

providing an interrupt signal to a microprocessor;

operating the microprocessor to detect a state change for a control system when the interrupt is provided;

determining whether a threshold event has occurred;

recalibrating an output voltage associated with a wake-up circuit, so that the output voltage is within a predetermined limit, if the threshold event has occurred; and

waiting for another interrupt to be provided to the microprocessor, if the threshold event has not occurred.

30. The method, as set forth in claim 29 , comprising accessing a switch component to determine whether the state change has occurred.

31. The method, as set forth in claim 29 , wherein the threshold event comprises counting the number of times an interrupt has been provided to the microprocessor connected to the wake-up circuit.

32. The method, as set forth in claim 29 , wherein the threshold event comprises measuring a time period from the previous calibration of the wake-up circuit.