Dissimilar microcontrollers for outflow valve

1. A cabin pressure control and monitoring system comprising:

an outflow valve;

a first motor configured to operate the outflow valve to release fluid from a cabin;

a second motor configured to operate the outflow valve to release fluid from the cabin;

a first microcontroller configured to automatically control the first motor based on a pressure of the fluid in the cabin; and

a second microcontroller configured to:

drive the second motor at a first speed greater than zero in response to sensing a user input, and

increase the second motor from the first speed to a second speed greater than zero in response to sensing the user input for more than a predetermined duration, wherein the second speed is faster than the first speed; and

wherein a type of the first microcontroller is different than a type of the second microcontroller.

2. The cabin pressure control and monitoring system of claim 1 ,

wherein a design of the first microcontroller is different than a design of the second microcontroller, and

wherein the first microcontroller operates independently of the second microcontroller.

3. The cabin pressure control and monitoring system of claim 1 , further comprising monitoring circuitry separate from the first microcontroller and the second microcontroller,

wherein the monitoring circuitry is configured to monitor the pressure of the fluid in the cabin, and

wherein the first microcontroller is further configured to:

detect a fault condition in the first microcontroller or the first motor;

receive a signal from the monitoring circuitry indicating that the monitoring circuitry detected a fault condition in the first microcontroller or the first motor; and

output an indication of the fault condition to disable the first microcontroller and the first motor in response to detecting the fault condition and receiving the signal from the monitoring circuitry.

4. The cabin pressure control and monitoring system of claim 1 ,

wherein the first microcontroller is configured to receive power from a first power supply, and

wherein the second microcontroller is configured to receive power from a second power supply, the second power supply being different than the first power supply.

5. The cabin pressure control and monitoring system of claim 1 , wherein the second microcontroller is configured to output a signal indicating that an altitude limit operation is active.

6. The cabin pressure control and monitoring system of claim 1 , wherein the outflow valve is a first outflow valve, the cabin pressure control and monitoring system further comprising:

a second outflow valve;

a third motor configured to operate the second outflow valve to release fluid from the cabin;

a fourth motor configured to operate the second outflow valve to release fluid from the cabin;

a third microcontroller configured to automatically control the third motor based on a pressure of the fluid in the cabin; and

a second microcontroller configured to:

control the fourth motor based on user inputs; and

monitor the pressure of the fluid in the cabin,

wherein a type of the third microcontroller is different than a type of the fourth microcontroller.

7. A method for controlling a pressure of a fluid in a cabin, the method comprising:

automatically controlling, by a first microcontroller and based on the pressure of the fluid in the cabin, a first motor to operate an outflow valve to release the fluid from the cabin;

controlling, by a second microcontroller and based on a user input, a second motor to operate the outflow valve to release fluid from the cabin, wherein controlling the second motor comprises:

driving the second motor at a first speed greater than zero in response to sensing the user input, and

increasing the second motor from the first speed to a second speed greater than zero in response to sensing the user input for more than a predetermined duration, wherein the second speed is faster than the first speed; and

monitoring, by the second microcontroller, the pressure of the fluid in the cabin,

wherein a type of the first microcontroller is different than a type of the second microcontroller.

8. The method of claim 7 ,

wherein a design of the first microcontroller is different than a design of the second microcontroller, and

wherein the first microcontroller operates independently of the second microcontroller.

9. The method of claim 7 , further comprising:

transmitting, by the first microcontroller, a signal to the second microcontroller;

self-testing, by the second microcontroller, the second microcontroller in response to receiving the signal; and

outputting, by the second microcontroller, an indication of a fault condition in response to self-testing the second microcontroller.

10. The method of claim 7 , further comprising:

monitoring, by monitoring circuitry separate from the first microcontroller and the second microcontroller, the pressure of the fluid in the cabin, and

detecting, by the first microcontroller, a fault condition in the first microcontroller or the first motor;

receiving, by the first microcontroller, a signal from the monitoring circuitry indicating that the monitoring circuitry detected a fault condition in the first microcontroller or the first motor; and

outputting, by the first microcontroller, an indication of the fault condition to disable the first microcontroller and the first motor in response to detecting the fault condition and receiving the signal from the monitoring circuitry.

11. The method of claim 7 ,

performing, by the second microcontroller, an altitude limit operation by closing the outflow valve in response to determining that the pressure of the fluid in the cabin is less than a threshold level;

performing, by the second microcontroller, a dump operation by opening the outflow valve in response to a user input;

receiving, by the second microcontroller, an input signal;

causing, by the second microcontroller, the altitude limit operation to override the dump operation in response to a first value of the input signal; and

causing, by the second microcontroller, the dump operation to override the altitude limit operation in response to a second value of the input signal.