UART on RPi-CM4-IO with Radxa CM3

ROCK 3 Series CM3
21

The firm im working in is looking for a replacement for the RPi CM4.
The CM3 is connected to one of our controllers which sends data every second to the uart but cat /dev/ttyS2 has no output. And we only use baudrate 115200, thats why im asking.

I tried that with multiple ways but it never seems to change the baudrate.
Things that I tried:

  1. stty
  2. setserial
  3. Linux Serial Ports Using C/C++ | mbedded.ninja
  4. Setting non-standard baud rate to Serial Port (embeddedguruji.blogspot.com)

could you help me here aswell?

22

stty should work, so in your case

stty -F /dev/ttyS2 speed 115200

set the baudrate and prints the old one. Then

cat /dev/ttyS2

will use it.

However, are you sure your connected HW works without RTS/CTS? Did it worked before on a SBC, the RPi for instance?

1 Like
23

Maybe CuteCom is what you need. It’s a a GUI program to communicate over serial lines. It can configure the port (including baudrate) too and you will have bidirectional communication. Or, use

screen /dev/ttyS2 115200

24

I used hTerm and got it working now.
The problem was that when I was sending something it allways came back
instead of cat printing it.
So I had to add more Settings to the stty and then it worked.

Thank you so much for the help!