Make Trainer port accept sbus (aswell as ppm)

[dahklfahdkghas]

Is there an existing issue for this feature request?

• I have searched the existing issues

Is your feature request related to a problem?

I want to hookup my headtracker to my Radiomaster Zorro via bluetooth. I use an esp32c3 or esp32s3 (really cheap and easy to program) to receive the data from the headtracker and generate a ppm signal fed to the trainer port (module bay is used by elrs tx). The problem is that the signal is jittery when bluetooth is active.

Describe the solution you'd like

Adding sbus support (or some other digital protocol) on the trainer port would make simpler interfacing with diy peripherals or any rx really. It adds options. Sbus would avoid the ppm signal and get rid of any jittering in my case.

Describe alternatives you've considered

1. Use the module bay (in use)
2. use a more powerful mcu (esp32s3) and run ppm generation on separate core. Didn’t work.
3. Use cable. Too many cables already.

Additional context

I think it expands the diy options for easily adding wireless trainer setups as well as my specific case. It expands the possible range of trainer channels which would increase options for more complex setups where two pilots control one plane.

Reading Sbus signals should already be in the codebase. Possibly easy to implement.

[raphaelcoeffic]

Adding sbus support (or some other digital protocol) on the trainer port

Most trainer ports are connected to timer pins, but not to UART pin. That would force us to use soft-serial, which is timing critical. On most radios however there are accessible serial ports that can be used for this.

On Zorro for instance, the external module bay allows for serial connections, so that you should be able to use it as a trainer input, if you don't use the external module otherwise.