Can find /dev/ttyTHS1

Issue Overview

Users are experiencing difficulty locating the UART2 interface (/dev/ttyTHS1) on the Nvidia Jetson Orin Nano Dev board when attempting to connect to the PX4 flight controller. The issue arises primarily during setup or configuration phases, specifically when users are trying to access UART functionalities via the 40-pin expansion header.

Symptoms and Errors

• Users report an inability to find the UART2 device file (/dev/ttyTHS1).
• The problem is often encountered while attempting to establish a serial connection with external hardware (e.g., PX4).

Context

• The issue is noted in both development kit and custom board configurations.
• Users have been prompted to provide details such as their Jetpack version, which may influence the availability of UART interfaces.

Frequency

• This issue appears to be sporadic, with some users successfully locating UART interfaces while others do not.

Impact

• The inability to access UART2 can severely hinder development efforts, particularly for projects requiring serial communication with peripherals like flight controllers.

Possible Causes

• Hardware Incompatibilities or Defects: If users are using a custom board rather than the official devkit, there may be discrepancies in pin mappings or hardware configurations that prevent access to UART2.

• Software Bugs or Conflicts: Certain versions of Jetpack may have bugs that affect UART device detection. Users need to ensure they are using a stable version.

• Configuration Errors: Incorrect configurations in the device tree or serial port settings may lead to unrecognized UART interfaces.

• Driver Issues: Missing or outdated drivers could prevent the operating system from recognizing the UART hardware.

• Environmental Factors: Power supply issues or overheating could lead to erratic behavior in hardware components, including UART interfaces.

• User Errors or Misconfigurations: Misunderstanding of which UART interface corresponds to which device file can lead to confusion and errors in accessing the correct ports.

Troubleshooting Steps, Solutions & Fixes

1. Check Hardware Configuration

   • Confirm whether you are using the official Nvidia Jetson Orin Nano Dev kit or a custom board.
   • If using a custom board, verify that the pin mappings match those expected for UART2.

2. Verify Jetpack Version

   • Ensure you are running a compatible and updated version of Jetpack. You can check your Jetpack version by running:

     dpkg-query -W | grep jetpack
     

3. Inspect Device Tree

   • Check if the device tree includes entries for UART2. You can view the device tree by executing:

     sudo cat /boot/dtb/tegra234-p3668-all-p3509-0000.dtb | dtc -I dtb -O dts -
     

   • Look for entries related to ttyTHS1 and ensure they are correctly configured.

4. Check Serial Port Availability

   • List available serial ports using:

     ls /dev/ttyTHS*
     

   • This will show all available UART devices. If /dev/ttyTHS1 is missing, further investigation is needed.

5. Driver Installation

   • Ensure all necessary drivers are installed and up-to-date. Reinstalling Jetpack can help resolve driver-related issues.

6. Test with Different Configurations

   • If possible, test with another known working setup or different Jetpack version to isolate whether the issue is hardware or software-related.

7. Consult Documentation

   • Review Nvidia’s official documentation for any specific instructions regarding UART usage on the Orin Nano Dev board.

8. Best Practices

   • Always ensure your development environment is properly set up with adequate power supply and cooling.
   • Regularly update software components and check compatibility before starting new projects.

Note on Unresolved Aspects

While several troubleshooting steps have been outlined, some users may still face challenges based on unique configurations or setups. Further investigation may be required if standard solutions do not resolve the issue.