Jetson TX2 can transmit data but can not receive data via port /dev/ttyS0 (UART pin 8 and 10 on J21 header))

Hi everyone!
I got a problem when connecting Jetson TX2 to my laptop.
I use port /dev/ttyS0 to transmit data from Jetson TX2, it’s ok. But when i enter data form my laptop to send back Jetson TX2, i got an error:
“Error: device reports readiness to read but returned no data (device disconnected or multiple access on port?)”
Is that system related error? How can i fix it?
Thanks everyone!!!

hello daohieudaica,

it’s by default UART serial console, may I know how you access to it?
please see-also Serial Console - NVIDIA Jetson TX2 - JetsonHacks. thanks

I just add user to tty and dialout group then run UARTDemo code

After adding user to group i run command:
sudo chown $USER: /dev/ttyS0

Never add your user to group tty. I’d remove that.

The “/dev” files are not “real” files, they are pseudo files. This means they exist in RAM and are actually drivers pretending to be a file. Their ownership is not changed in the usual manner, and typically it is the udev system which makes those changes. The fact that the ttyS0 is tty and not dialout means something else owns it (serial console program). Changing permissions does not change the fact that the terminal software is still trying to user that UART. You now have two programs fighting over one UART, and neither of them will now have correct permissions.

The addition of your user to group “dialout” is correct. You would then disable serial console, and this would cause the permission to revert to dialout group without you needing to change anything else. Anything you are sending is basically going to a login prompt somewhere (and anything you might receive is a login response).

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.