How to Control the Power LED on the Nvidia Jetson Orin Nano Dev Board Using GPIO

Issue Overview

Users are experiencing difficulties in controlling the power LED on the Nvidia Jetson Orin Nano Dev Board via a Python script. The specific symptoms include:

• The power LED, identified as GPIO04, is not controllable by default.
• Users are seeking to modify the device tree to enable control over this pin.
• Confusion arises regarding the naming conventions used in the Jetson.GPIO library and how to access GPIO04.

The issue typically occurs during attempts to set up or run scripts intended to manipulate the LED. Users have reported varying levels of success with different commands and configurations, particularly when using Jetpack version 5.1.2. The problem impacts user experience by limiting functionality and usability of the GPIO pins, specifically for those looking to integrate the LED control into their applications.

Possible Causes

The following potential causes may lead to the inability to control GPIO04:

• Hardware Incompatibilities or Defects: If there are any issues with the board itself or its connections, it may prevent proper GPIO functionality.

• Software Bugs or Conflicts: Bugs in the Jetson.GPIO library or conflicts with other installed libraries could hinder access to GPIO pins.

• Configuration Errors: Incorrect settings in the device tree or misconfigured scripts can lead to failures in pin control.

• Driver Issues: Outdated or incompatible drivers may result in GPIOs not being recognized or controlled as expected.

• Environmental Factors: Power supply issues or overheating may affect board performance and GPIO functionality.

• User Errors or Misconfigurations: Mistakes in command execution or misunderstanding of library functions can lead to unsuccessful attempts at controlling GPIO pins.

Troubleshooting Steps, Solutions & Fixes

To address the issue of controlling GPIO04, users can follow these troubleshooting steps and solutions:

1. Check Jetpack Version:

   • Ensure that you are using Jetpack version 5.1.2, as this has been confirmed by multiple users.

2. Control GPIO Using Sysfs:

   • Execute the following commands to control GPIO04:

     sudo su
     cd /sys/class/gpio
     echo 329 > export
     echo out > PCC.01/direction
     echo 0 > PCC.01/value
     echo 1 > PCC.01/value
     

3. Modify Device Tree for GPIO Access:

   • To enable access to GPIO04, add the following line to the appropriate Python script:

     (13, 'PCC.01', "tegra234-gpio-aon", 4, 1, 'GPIO04', 'GP07_SPI2_MISO', None, None)
     

   • This line allows for control via the Jetson.GPIO library.

4. Understand Naming Conventions:

   • Familiarize yourself with different naming modes available in Jetson.GPIO:
     • GPIO.BOARD
     • GPIO.BCM
     • GPIO.CVM
     • GPIO.TEGRA_SOC
   • Use pinmux spreadsheets available from NVIDIA to understand pin mappings.

5. PWM Capabilities Check:

   • To determine if a pin has PWM capabilities:
     • Refer to the pinmux configuration template provided by NVIDIA.
     • Use the command:

       cat /sys/kernel/debug/pwm
       

   • This command helps identify which PWM IDs are available for use.

6. Documentation and Resources:

   • Consult the official NVIDIA documentation and GitHub repository for Jetson.GPIO for further guidance and updates.

7. Preventive Best Practices:

   • Regularly update your software and libraries.
   • Verify connections and power supply stability before running scripts.
   • Maintain backups of working configurations for easy recovery.

By following these steps, users should be able to successfully control the power LED on their Nvidia Jetson Orin Nano Dev Board through GPIO04. If issues persist, further investigation into hardware status and software configurations may be necessary.