Reason for not being able to use UAVCAN and MAIN output at the same time

I know, that it is not possible to use MAIN PPM out and UAVCAN actuators at the same time. I know many threads where people ask this. (UAVCAN esc and PWM OUT - #3 by michmich, …) And I also know a workaround to use AUX PPM outputs of autopilot. And I’m not really familiar with this. Which means I will lose some failsafe modes. Because of this, the servos (and other PPM actuators) will be controlled from FMU (instead of IO MCU).

And my question is what is the reason that you cannot use UAVCAN and MAIN PPM at the same time?

(this question was asked also on the slack. But without an answer.)


Please let me know if you get an answer

Please can anyone advise me on this problem? Or give reasons why this is so?

Now we get CUAV NANO and it has only 3 AUX outputs. Which is not enough for us. And I would like to use UAVCAN VESC ESC, because other important information is logged there.