I have a few questions about how PWM outputs vs relay outputs are handled on the Servo channels 9-16 with an Orange Cube in particular. It appears that the number of relay outputs can be altered with BRD_PWM_COUNT. By default it appears that AUX 5-6 are set as relays (BRD_PWM_COUNT=4).
Question 1. What is the status of Servo 15-16 in the default condition? The first rule of Servo 15-16 is not to talk about Servo 15-16 in documentation.
What I really need to do is pass RC channels 9-16 through the servo channels so that they appear on the SBUS out from the FC (controlling a gimbal etc.). I know about turning on the SBUS first and enabling the safety switch, if used.
The issue is that BRD_PWM_COUNT on the aircraft in question is set to 0 and RELAY_PIN_2 = 54 (AUX5). This relay controls a video feed switch and so is required.
Question 2. With no PWM outputs configured on AUX1-6 (see above), if I assign RC passthrough on Servos9-16, what happens? That is, does the relay still work when called for AUX5 but Servo13 is passing RC13 to the SBUS? It is unclear to me from reading the documentation what happens in the above case.
Question 3 is: Is the relay AUX5 now nothing to do with the Servo channels, or is it still linked in some way so that the RC13 channel messes with AUX5 relay or vice versa? I am seeing some strange behavior and trying to understand it.
Question 4: If one wanted to pass RC13 to Servo13 so that SBUS out channel 13 reflected RC13, is there any difference between SERVO13_FUNCTION being set to 1 (RC passthrough) and 63 RC13. Are there any circumstances when this setting results in different behavior?
Question 5: Does Ardupilot try to do anything ‘smart’ with renumbering servo channels if there are Relays set? in other words, normally SERVO13 corresponds to the AUX5 output, however, if AUX5 is a relay, is SERVO13 now mapped to CH15 (or the next spare channel)? If so, it might explain something I am seeing.
The above appears to be one of the issues with ArduCopter and the Orange Cube that cause the most confusion (mapping outputs) mainly because it is a mind bender (RC13, SERVO13, abstraction layer listening for RC13, SBUS 13 etc.), yet the documentation is a bit unclear to a novice and very scattered. For example the Relay page discusses BRD_PWM_COUNT, but makes no mention of what knock on effects it causes for Servos, if any.
Many thanks for your time.