Help with uXRCE-DDS to serial connection - Pixhawk 6c

Hi @jlab , glad to hear that. Try increasing the baudrate please.

On the mavilink console, you can use

listener "name of the topic"

see in real time the topics you are interested in.

Hi @Benja ,

I forgot to mention in the previous posting that I increased the baudrate to 921600. Is that too high?

I will try that command you shared. Thank you!

Hi @Benja ,

I am publishing OffBoardControlMode messages to the /fmu/in/offboard_control_mode topic on the Jetson. Unfortunately, nothing is picked up on the mavlink console (it does not even detect the topic). There is an error when the topic tries to get created (see attached images).

Jetson publishing and confirmed by echoing
image

There are several errors saying topics could not be created (including /fmu/in/offboard_control_mode). And I highlighted that the topic is not found.

Consistently get topic creation errors (even when I adjust baudrate).

Thanks in advance!

Reviving the issue to add my experience. I had problem getting /fmu/out messages registered on MicroXRCEAgent (v2.4.3) in serial mode with Raspberry Pi 4 (ubuntu 22.04) and PX4 6C (v1.15). It turned out that error was low BAUD rate (57600 did not work where as 115200 did, as per @Benja 's suggestion).

I figured out after seeing this on nuttx terminal:

[timesync] RTT too high for timesync 11ms

Also, it does not work on emulated arm64 container as companion either. I suspect it has to do with emulation increasing RTT as well.

So do not assume that lower baud rate must be a better default value, trying multiple levels is apparently better.

uxrce_dds_client stop
uxrce_dds_client -t serial -d /dev/ttyS3 -b 115200

can be run on nuttx shell to manually restart the client for TELEM2. Cheers!