Self-diagnosing watchdog monitoring system

1. A self-diagnosing watchdog monitoring system, comprising:

a watchdog IC having an enable pin and a disable pin;

a microcontroller having a microprocessor and a digital input/output device with an enable pin and a disable pin, the enable pin of the digital input-output device being electrically coupled to the enable pin of the watchdog IC, the disable pin of the digital input-output device being electrically coupled to the disable pin of the watchdog IC; the microprocessor having an enable application and a disable application;

the enable application commanding the enable pin of the digital input-output device to transition from a high logic state to a low logic state at a first time that indicates an enable state has been initiated, and in response the watchdog IC starts an internal timer; and

the enable application monitoring the disable pin of the digital input-output device, and if the disable pin of the digital input-output device does not have the low logic state within a first predetermined amount of time after the first time indicating undesired operation of the disable application, then the enable application monitoring a contactor and if the enable application determines that the contactor has a closed operational position at a second predetermined amount of time after the first time indicating that the watchdog IC is malfunctioning, then the enable application generates a control message.

2. The self-diagnosing watchdog monitoring system of claim 1 , wherein the control message induces the microcontroller to transition a high voltage switch and a low voltage switch in a DC-DC voltage converter to an open operational state.

3. The self-diagnosing watchdog monitoring system of claim 1 , wherein the control message induces the microcontroller to transition the contactor to the open operational state.

4. The self-diagnosing watchdog monitoring system of claim 1 , wherein the contactor has a contactor coil electrically coupled to a high side voltage driver and a low side voltage driver; the microcontroller measuring a first voltage being output by the high side voltage driver, and a second voltage being output by the low side voltage driver; and

the enable application determining that the contactor has the closed operational position when either the first voltage is outside of a first voltage range or the second voltage is outside of a second voltage range.

5. A self-diagnosing watchdog monitoring system, comprising:

a watchdog IC having an enable pin and a disable pin;

a microcontroller having a microprocessor and a digital input/output device with an enable pin and a disable pin, the enable pin of the digital input-output device being electrically coupled to the enable pin of the watchdog IC, the disable pin of the digital input-output device being electrically coupled to the disable pin of the watchdog IC; the microprocessor having an enable application and a disable application;

the enable application commanding the enable pin of the digital input-output device to transition from a high logic state to a low logic state at a first time that indicates an enable state has been initiated, and in response the watchdog IC starts an internal timer;

the disable application commanding the disable pin of the digital input-output device to transition from the high logic state to the low logic state at a second time, and in response the watchdog IC stops the internal timer;

the enable application commanding the enable pin of the digital input-output device to transition from the low logic state to the high logic state at a third time, and to transition from the high logic state to the low logic state at a fourth time that indicates the enable state has been initiated; and

the enable application monitoring the disable pin of the digital input-output device, and if the disable pin of the digital input-output device does not have the high logic state at a fifth time within a first predetermined amount of time after the second time, then the enable application setting a first diagnostic flag to a first fault value indicating that the disable application is malfunctioning.

6. The self-diagnosing watchdog monitoring system of claim 5 , wherein if the disable pin of the digital input-output device does not have the high logic state at the fifth time within the first predetermined amount of time after the second time, then the watchdog IC transitions a contactor to the open operational state.