micro_ros_agent serial not working?

[fzoric8]

micro_ros_agent, serial on rPi 4

• Hardware description: raspberry Pi 4 Model B
• Installation type: micro_ros_setup
• Version or commit hash: humble

Steps to reproduce the issue

Hi, I've managed to install, setup and run micro_ros_agent. I start it with:

ros2 run micro_ros_agent micro_ros_agent serial --dev /dev/ttyAMA0 -b 115200

And output of that command is:

[1701676721.257899] info     | TermiosAgentLinux.cpp | init                     | running...             | fd: 3
[1701676721.260238] info     | Root.cpp           | set_verbose_level        | logger setup           | verbose_level: 4

Which means that agent is running.

I've tested my serial port /dev/ttyAMA0 and when I run:

echo "test" > /dev/ttyAMA0 

I recieve echoed string on my serial port.

However, when I publish message on the certain ros 2 topic, such as /cmd_vel, nothing is propagated to the serial port.

So, after running micro_ros_agent and testing serial port, when I publish ROS 2 message on the /cmd_vel nothing gets to the serial port.

Expected behavior

I expect to have something on my serial port if I published message to the topic. So for example if I publish something on the /cmd_vel topic, I should at least see some bytes being sent to the serial port or: /dev/ttyAMA0. However, currently, nothing gets to the serial port.

Actual behavior

micro_ros_agent is running. And serial port is opened. However, when I publish message on the /cmd_vel topic, nothing gets through.

Additional information

Let me know if you need anything more!

[pablogs9]

Which is your micro-ROS Client code?

[fzoric8]

Well currently, client is running on nucleo. It is custom written code that reads /cmd_vel and republishes it to individual motors.

It was tested with micro_ros_agent on another PC with USB2UART connection. Now I'm trying to setup the same thing with the rPI4, and in this case, I looped back GPIOs of the rPI for the UART, and serial works, however, I'm not able to get anything on the serial when running micro_ros_agent.

Maybe I'm missing something. Tnx for the help!

[pablogs9]

I do not understand why you are looping back GPIOs... The micro-ROS Agent must be connected to a micro-ROS Client to operate.

Does your setup work when you connect a micro-ROS Agent to a micro-ROS Client? Does your micro-ROS Agent print logs when you open it with flag -v6 and connect your board?

[fzoric8]

Hi @pablogs9

You're right. I've run the micro_ros_agent with the -v6 and I get all the output. Especially after connecting with the client code on the nucleo.

I've had a little bit of trouble enabling serial port on the raspberry Pi4 for Ubuntu 22.04, that's why I used loopback. I've thought that I could see something on the serial port only running server side of the micro_ros_agent.

However, now things run smoothly. Output of the -v6 is nice:

Example:

ros2 run micro_ros_agent micro_ros_agent serial --dev /dev/ttyAMA0 -b 115200 -v 6
[1701679248.690618] info     | TermiosAgentLinux.cpp | init                     | running...             | fd: 3
[1701679248.691381] info     | Root.cpp           | set_verbose_level        | logger setup           | verbose_level: 6
[1701679249.071156] info     | Root.cpp           | create_client            | create                 | client_key: 0x153E537A, session_id: 0x81
[1701679249.073321] info     | SessionManager.hpp | establish_session        | session established    | client_key: 0x153E537A, address: 0
[1701679249.073746] debug    | SerialAgentLinux.cpp | send_message             | [** <<SER>> **]        | client_key: 0x153E537A, len: 19, data: 
0000: 81 00 00 00 04 01 0B 00 00 00 58 52 43 45 01 00 01 0F 00
[1701679249.082618] debug    | SerialAgentLinux.cpp | recv_message             | [==>> SER <<==]        | client_key: 0x153E537A, len: 44, data: 
0000: 81 80 00 00 01 07 22 00 00 0A 00 01 01 03 00 00 14 00 00 00 00 01 00 20 0C 00 00 00 6E 75 63 6C
0020: 65 6F 5F 67 34 39 31 00 00 00 00 00

Problem was with the serial of the raspberry Pi4 :)

Thanks!