Frsky pass though telemetry issues on ArduPlane?

ArduPlane
1

Hello,

I just upgraded my firmware to ArduPlane 4.0 and saw that the pass through telemetry which I use on Pixhawk1 / Frsky X8R / Craft & Theory combo stopped working.

After fiddling with things, it looks like there is an issue with the Power Module of the Pixhawk. If I pull it off and power the Pixhawk through the servo rail or with the usb port, then the telemetry data starts flowing though to my transmitter immediately . As soon as I connect the power module back, things freeze up and the transmitter warns that the telemetry signal was lost.

By the way, i tried things with a new power module and the issue persists. I also tried to use a different script from Craft & Theory and it is clear that there is just no data coming through…

I know that in the ArduPlane 4.0 firmware, there was a bug fix associated with the Frsky pass through telemetry, so may be, there is a change in the configuration / protocol? I will downgrade back to 3.8 firmware tomorrow to see if the issue is indeed firmware related…

Any insights would be helpful.

Thanks

2

just to bring closure to this topic, my issue was with high voltage level on my passthrough telemetry circuitry. For some reason over time the circuitry stoped tolerating a voltage level above 5V. Thanks to Alex, leading Yaapu, I was able to resolve the issue by adding 2 diodes to the V++ line to reduce the input voltage to the circuitry.