It is not 100% clear to me if the 3.3V pull-up is provided by the Cube as long as the AUX pin is configured correctly, or should I provide the voltage from somewhere else. The resistor has to be external, this is clear from the documentation.
Follow-up question: if external voltage for pull-up is required, can we use 5V, are the GPIO / AUX pins tolerant? Does it matter if Cube Black / Orange, if I remember correctly the PWM OUTPUT can be changed 5V with the Orange Cube (there is a parameter for this).
This topic concerns output functions, but it is not helpful to me, since I am using the GPIO / AUX signal pins as inputs. I think I will do some testing to see if the 3.3V is present in the pin after it is configured as an input.
When AUX OUT is being used as GPIO, it doesn’t need external pull-up.
3.3-5V is okay for the input PWM signal. There is a voltage converter inside which scales the input signals to 3.3V before feeding to MCU.
OK, Thank You. I think this should be explained in more detail in both ArduPilot and Cube documentation.
For future reference and interest I post the parameters I am planning to use:
BRD_PWM_COUNT = 4 (default) // AUX 6 & 5 reserved for GPIO or relay
RELAY_PIN = -1 (default 55) // disabled, AUX 6 is not relay
RELAY_PIN2 = -1 (default 54) // disabled, AUX 5 is not relay
BATT3_MONITOR = 11 (default 0) // fuel flow = 11
BATT3_CURR_PIN = 55 // AUX 6 used as input from fuel flow sensor