Cannot connect to Mission Planner through UART/Telem2 with FTDI

  1. Image and ArduPilot version. Latest vanilla Emlid Stretch running Plane 3.8

  2. Detailed problem description. How does observed behavior differ from the expected one?
    I cannot establish a connection to Mission Planner through Telem2 via the DF13 UART.

  3. Your step by step actions.
    Using a freshly burned image I have configured my wifi acess and GCS IP and have left the telem2 settings at default ( -C set to “/dev/ttyAMA0” ).
    I have no issue connecting to Mission Planner via UDP. I have set Telem 2 (Serial 1) to 57 through Mission Planner. I have attached an FTDI adaptor to the DF13 UART connector. It is correctly wired (but I have swapped Rx/Tx multiple times). I have selected the correct COM port in Mission Planner. It is not registering a heartbeat when I connect at 57600 through my FTDI COM port.

What am I missing? Connecting at 57.6k though the UART should be essentially the default configuration. Did I have to do anything else? I am at my wit’s end.

I should add this is my first steps in trying to use Dragonlink V3 at 19.2 through the UART.

Edit – did not see the # in front of -C !! Case closed.


I had a look at my Navio2. UART plug is Serial 1…

Edge Serial2ADC is also “serial1” in mission planner.


Thanks Marc.

I had actually set both Serial 1 and Serial 2 to 57.6 through Mission Planner params.

Essentially I am not incorrect in thinking that no further linux configuration needs to be done to get Telem2 through that UART DF13, right? If in Mission Planner I set Serial 1 to Mavlink (1) and Baud to 57600 (57) then with an FTDI I should be able to connect, right?

Do you have Edge or Navio?
I had success with Ftdi on both Navio2 UART and Edge Serial2ADC.

On Ftdi, I connect Ground, Rx an Tx. Speed 57600,



Yep, that is what I am doing. I just want to be sure that I am not missing anything. I am leaving the Telem2 setting ( -C set to “/dev/ttyAMA0” ) alone.

All I have done is set wpa_supplicant.conf so I connect to wifi and I have set my GCS IP. So I connect to Mission Planner fine. I cannot connect on my FTDI COM port at 57.6.

So there must be something missing. This is my second Emlid image, second FTDI, so I am assuming that is not the issue. It must be a physical connection issue somewhere.

-C /dev/ttyAMA0 is serial 1 UART. No problem with that.

It should work. On my Navio2 I now use UART for second GPS. Telemetry radio is on USB. I had a try with Ftdi when using Raspberry without wifi.


And that is a default setting so I could not exactly have it incorrect.

So odd. I have checked continuity on on the leads for Tx, Rx, and Gnd. I am not sure how else to test this. I guess I can plug in a 3DR radio and see what happens.

Thanks for confirming that my steps are ok. It must be something staring at me. Or I have a faulty Navio board with a dead UART. Which would be annoying as I purchased it months ago but have hardly used it.

Edit: My RFD 900X radio is not connecting either so I think I have exclude hardware connection as a possibility. This is a bummer. There must be something else going with my Navio2.

Marc – I did not notice that by default there is a # in front of the -C. What a plonker I am. Been a while since I spent any time in a Linux environment.

Thanks again for taking the time to reply. Not sure how to close this topic.

Have a nice flight