Jetson Orin Nano DevKit – No data on /dev/ttyTHS2 (UART2 at J14)

Robotics & Edge Computing Jetson & Embedded Systems Jetson Orin Nano
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Hi all,

I’m using a Jetson Orin Nano DevKit (carrier board v1.3) and trying to interface aGPS module via UART2 (/dev/ttyTHS2).

Here’s what I’ve done:

  • Wired the GPS to the J14 (Button/Debug header) as per the datasheet:

    • J14-3 → UART2_RXD (connected to GPS TX)

    • J14-4 → UART2_TXD (connected to GPS RX)

    • J14-7 (or 9/11) → GND

  • GPS module outputs standard NMEA at 3.3 V TTL.

  • Verified that:

    • serial-getty@ttyTHS2.service is inactive.

    • Kernel cmdline (/proc/cmdline) has no console=ttyTHS2.

    • /dev/ttyTHS2 opens fine in Python or cat.

  • On /dev/ttyTHS1 (J12 pins 8/10), the same GPS works and I get NMEA data.

  • On /dev/ttyTHS2 (J14 pins 3/4), I get no data at all, even when trying multiple baud rates (9600, 115200).

My questions

  1. Is UART2 on J14 really usable as a general-purpose UART, or is it reserved for debug only?

  2. If it is usable, do I need to make any device tree or pinmux modifications to enable RX/TX on J14?

  3. Has anyone successfully received data from a peripheral on /dev/ttyTHS2 on the Orin Nano DevKit?

Environment

  • Jetson Orin Nano DevKit Carrier Board v1.3

Any guidance from NVIDIA or community members would be really helpful. Right now I only see NMEA on /dev/ttyTHS1 (UART1 at J12), but not on /dev/ttyTHS2 (UART2 at J14).

Thanks!

5

Hi khamkarvedant33,

I’ve moved your topic to the correct category for Orin Nano.

What’s the Jetpack version in use?

It seems you want to connect the GPS module to the debug UART.
Actually, we don’t suggest and verify for this use case.
It is a debug UART (Tegra Combined UART), which means that it will output logs from several firmwares.
You cannot disable them completely as some configurations are included in the firmware itself.
As a result, UART2(debug UART) can only be used for debug purpose only.

Please also share the full dmesg for further check.

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Thanks for replying @KevinFFF

My Jetson Orin Nano is running JetPack 6.0 / L4T R36.4.4.

Is it totally impossible to use UART2 ? Can we reconfigure it using pinmux spreadsheet and changing DT ?

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Jetpack 6.0 includes L4T r36.3.0
Jetpack 6.2.1 includes L4T r36.4.4
Could you share the result of the following command on your board?

$ cat /etc/nv_tegra_release

We have not verified it and think it will be unstable even if you’ve configured it correctly.
Have you considered using USB-to-Serial or SPI-to-Serial module to get more UART interfaces?

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