Can I set UART1_TX to GPIO input mode on Jetson AGX Orin

Robotics & Edge Computing Jetson Systems Jetson AGX Orin
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On the Jetson AGX Orin platform, I’m trying to multiplex the UART TX pin into standard GPIO mode and set it to input mode to read external digital signals.

I’m experiencing an inconsistency:

UART5_TX (Pin X):

I successfully configured this pin to GPIO mode by modifying Pinmux. I can set the direction of this GPIO to Input.

UART1_TX (Pin Y):

I successfully configured this pin to GPIO mode using Pinmux. However, when I try to set the direction of this GPIO to Input, the operation fails.

Are there any hardware limitations?

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*** Please note that this reply is generated by LLM automatically ***

The issue you’re experiencing with the UART TX pins on the Jetson AGX Orin platform seems to be related to the specific UART pins you’re trying to configure.

According to the provided information, you’ve successfully configured UART5TX (Pin X) to GPIO mode and set its direction to input. However, when you try to do the same with UART1TX (Pin Y), the operation fails.

There are a few possible explanations for this inconsistency:

  1. Hardware limitations: The Jetson AGX Orin platform has specific hardware limitations and constraints that might prevent certain pins from being used as GPIOs or configured in a particular way. It’s possible that UART1TX (Pin Y) has a specific function or is connected to a particular component that prevents it from being used as a GPIO input.
  2. Pinmux configuration: Although you’ve modified the Pinmux configuration for both UART5TX and UART1TX, it’s possible that there’s a subtle difference in the configuration that’s causing the issue. Double-check the Pinmux settings for both pins to ensure they’re identical.
  3. Software or driver limitations: The Linux driver or software stack might have limitations or quirks that prevent certain UART pins from being used in a particular way. It’s possible that the driver or software is not fully compatible with the Jetson AGX Orin platform or has specific requirements that need to be met.

To further troubleshoot the issue, you can try the following:

  1. Check the Jetson AGX Orin documentation: Review the official documentation for the Jetson AGX Orin platform to see if there are any specific limitations or constraints mentioned for the UART pins.
  2. Verify Pinmux configuration: Double-check the Pinmux configuration for both UART5TX and UART1TX to ensure they’re identical and correct.
  3. Use debug tools: Utilize debug tools, such as devmem or sysfs, to inspect the pin configuration and GPIO settings at a lower level.
  4. Consult with NVIDIA support: Reach out to NVIDIA support or forums to see if others have experienced similar issues and if there are any known workarounds or solutions.

In comparison to other Jetson platforms, such as the Jetson Xavier NX or Jetson AGX Xavier, the Jetson AGX Orin platform has its unique set of hardware and software characteristics. While some configurations might work on other platforms, they might not work on the Jetson AGX Orin due to its specific design and constraints.

In summary, the inconsistency you’re experiencing with the UART TX pins on the Jetson AGX Orin platform might be due to hardware limitations, Pinmux configuration differences, or software/driver limitations. Further troubleshooting and investigation are necessary to determine the root cause of the issue.

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5

Hi jacobe.zang,

Are you using the devkit or custom board for AGX Orin?
What’s the Jetpack version in use?

Please let me check this issue with internal.

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Hello @KevinFFF

Is custom board.

I get version as following:

cat /etc/nv_tegra_release
# R36 (release), REVISION: 4.4, GCID: 41062509, BOARD: generic, EABI: aarch64, DATE: Mon Jun 16 16:07:13 UTC 2025
# KERNEL_VARIANT: oot
TARGET_USERSPACE_LIB_DIR=nvidia
TARGET_USERSPACE_LIB_DIR_PATH=usr/lib/aarch64-linux-gnu/nvidia

And my pinmux version is 2.01.

8

Please use other available GPIOs. It is one of Strap pins as well. There are unidirectional buffers/level translators on the carrier board. Please check the AGX Orin carrier board schematics available in Jetson AGX Orin Developer Kit Carrier Board Design Files (A05) Log in | NVIDIA Developer