Matek F405-WING Telemetry radio on UART 4

I’m trying to wire up an F405 with the following accessories:
FrSky Rx on SBUS + S.Port
Telemetry Radio (Tried on UARTs 3 and 4)

FrSky Rx and telemetry working fine, but I can’t get the secondary 915MHz telemetry radio to work. It’s bonded with a solid green light, and wired to UART4. I set SERIAL3_PROTOCOL = 2, but still not working.

Any tips or hints appreciated!

Thank you

For Matek f405 wing we have:

  • SERIAL1 = Telemetry1 = USART1
  • SERIAL2 = empty, USART2 used for RCInput
  • SERIAL4 = GPS2 = UART4
    So, if you have radio wired to uart4 you need to configure serial4 instead of serial3

I saw a SERIAL0 and assumed it was a different count order. Tried that and didn’t work.

I’ve re-installed it in UART1, but still not able to get a MAVLink connection. Lights up green solid on both units, but times out trying to connect.

In Mission Planner, when I go to setup the SIK Radio, it fails when I click “Load Settings”. If I disconnect and just load settings with the USB base station receiver local and remote populate ok.

Not sure what I’ve got wrong.

Did you have correct serial protocol and baud settings correct for serial 1?

Also some radios does not support mavlink2. Please try mavlink 1

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I solved it! Tx/Rx reversed in the documentation from cheap amazon radio.

I was plugging Tx to Rx and Rx to Tx on the UARTs like one should, but their labeling was backward.

Mavlink 2 works as well.


Damn, I had the same problem… I probably have the same cheap radio. Thank you so much for sharing your solution, I wouldn’t have thought of inverting them.

So the Matek F405-Wing will work with FRSky S.Port. Which protocoll did you use? Number10 (FrSky FPort Passthrough)?
Is it possible to connect the F405 direct to the S.Port or will i need an inverter?

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Same setup here. Have you find a solution ? Need inverter or not? Fw version of ardu 4.0.6 or 4.1x dev?

Not possible without inverter.