Read CRSF Telemetry Mirrored to Radio Aux Ports

[matt-nolan11]

Is there already an issue for this?

• I have searched the issues and there is no existing issue for this feature request.

Is your feature request related to a problem?

I'm looking for more control over my existing RC radio, without having to build a custom one from scratch. Critically, I'm interested in keeping the existing radio hardware in-the-loop. I'm currently using a microcontroller to send an SBUS trainer signal to one of the radio's AUX ports control some of the RC channels. This approach works, but is incomplete because it doesn't give me access to the radio's telemetry information. I want to use that same microcontroller to read the radio's telemetry as it's being mirrored to the other AUX port.

Describe the solution you'd like

I'd like to be able to connect the TX line of one of my radio's AUX ports to a microcontroller and read the CRSF telemetry that is being mirrored to that port. This is likely similar to an RX-only version of #88.

Describe alternatives you've considered

I have considered using USB-VCP telemetry mirroring to read the telemetry on a PC using Python (example). However, this requires additional (and relatively large) hardware and is inconvenient.

I could also potentially use the above method with MicroPython on a microcontroller, but that will likely come with a large speed penalty, as well as implementation issues with other areas of my project that depend on Arduino libraries.

Additional context

I am using a Radiomaster TX16S running EdgeTX, and would prefer to use a Xiao RP2040 as the microcontroller.

[ZZ-Cat]

Can do. =^/.^=

Your request has been added to #111, and it's in my "To-Do" list.
As you can tell, there is a lot on my plate with this version, particularly regarding security (the xz utils backdoor incident is what has brought this to my attention), and the Serial Transmitter Interface.
So, it may be some time before I get around to implementing your request.