Unexpected data reception on UART

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
1

Hi,

When writing data to ttyTHS1, it will get data out of nowhere.
Python one-line reproducer for this:

sudo python -c 'from periphery import Serial; s = Serial("/dev/ttyTHS1", 115200); s.write(b"\xFF"); print(s.read(32, 0.1)); s.close()'

1375×385 61.4 KB

System information

AGX Orin devkit

nvidia@ubuntu:~$ cat /etc/nv_tegra_release
# R36 (release), REVISION: 4.0, GCID: 37537400, BOARD: generic, EABI: aarch64, DATE: Fri Sep 13 04:36:44 UTC 2024
# KERNEL_VARIANT: oot
TARGET_USERSPACE_LIB_DIR=nvidia
TARGET_USERSPACE_LIB_DIR_PATH=usr/lib/aarch64-linux-gnu/nvidia

Both UART1_TX and UART1_RX are connected to nothing.

4

Hi 5d867a92b9bdd01df324966db,

What do you mean about this?
Is there any error showing in dmesg at this moment?

How about you connect them together to perform loopback test?

5

Hi KevinFFF,

What do you mean about this?

It means that RX is not connected but still receive data.

Is there any error showing in dmesg at this moment?

No.

How about you connect them together to perform loopback test?

It will work as expected. But is the behavior described above normal?

6

What data do you receive? \x00?

It seems the issue relating to python script.
You can also get a scope to check if there’s any data from RX when you send 0xFF from TX but TX/RX is disconnectd.

8

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