I love the strong open source current in the RC community. Some of the best stuff comes out of it, and the power and economy of much of it is truly great.
That said, the documentation is often minimal if not cryptic, and chronically out of date. I also have a fondness for underdog platforms (in this case the 9XR Pro and Cleanflight). This combination has meant some things have taken me months to figure out. So: here is a recipe for FrSky telemetry with a Naze32 or Naze clone board running Cleanflight.
A lot of the Naze32/Baseflight tutorials you’ll find out there will instruct you how to use the FrSky telemetry pins that are on the Naze32 board. There is a better way – softserial. The pins on the Naze32 board for FrSky telemetry are shared with the USB port, so you’ll only get telemetry once armed, and you can run into conflicts if you want to use an OSD as well as telemetry. There’s really no good reason to run the board this way – the pins predate the improved softserial code.
So, first, here’s how to wire a Naze32 board for softserial FrSky telemetry. Solder the green Rx pin from your FrSky telemetry-equiped receiver to pin 6 on the underside of your Naze32 board. Here’s what that looks like:
Now here’s how to do the same wiring on a Naze32 clone (such as Flip32, Dragonfly32, etc.):
These two examples look different, but they’ve accomplished the same thing – connect input pin 6 to the green FrSky telemetry receiver RX pin. All the other pins on the FrSky telemetry input on your receiver are optional. (In one case I wired in the ground, in another I did not. I did say I struggled with this for a while, remember?)
So that should cover the hardware end, for whatever board type you have.
Now here’s how to set up the software end in Cleanflight. Enter the following commands in the CLI:
set serial_port_3_scenario = 4
set serial_port_1_scenario = 5
At this point, FrSky telemetry should be available to your radio.
A number of the above commands are exactly how you’ll find the defaults set, but it won’t take you long to enter them all anyhow.
Here’s the original documentation for the serial port modes above listed above: https://github.com/cleanflight/cleanflight/blob/master/docs/Serial.md. I honestly found it pretty confusing, but hopefully it will improve.
Next I hope to cover how to set up a 9XR Pro to receive this telemetry.