Snapdragon Flight Fixed-Wing Mixer

I am trying to implement a PX4-based autopilot for a fixed-wing UAV, similar to TBS Capirinha. It turns out that the easiest alternative is to use the 4 PWMs output on port J13 which uses snapdragon_pwm_out module (https://github.com/PX4/Firmware/tree/master/src/drivers/snapdragon_pwm_out).

As we can observe in the source code, it tries to parse the mixer file into a MultirotorMixer object. In practice, I am having the following error from the mini-dm

[08500/00]  01:50.030  HAP:34:Trying to initialize mixer from config file /dev/fs/myfixedwing.main.mix  0166  snapdragon_pwm_out.cpp
[08500/03]  01:50.032  HAP:34:Unable to parse from mixer config file  0181  snapdragon_pwm_out.cpp
[08500/03]  01:50.032  HAP:34:Mixer initialization failed.  0337  snapdragon_pwm_out.cpp```
even if I used the example mixer file given in the DevGuide (https://dev.px4.io/airframes-adding-a-new-frame.html).

Does it have any link with the class `MultirotorMixer`? Could I initialize the fixed-wing mixer without using a `.mix` file, setting up the `MultirotorMixer` directly?

Did you make any progress? I might be able to help if you get stuck on any fixed wing issues.

I’m working on it right now.

The idea is to switch the MultirotorMixer by a MixerGroup, allowing it to accept any mixer file structure.