PWM Configuration Issue on Nvidia Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties configuring and using PWM (Pulse Width Modulation) on the Nvidia Jetson Orin Nano Developer Kit. The primary symptoms include:

• No PWM output detected on the oscilloscope when connected to pins 33 or 15
• No error messages when running the Python script using Jetson.GPIO library
• The issue persists across different software environments (Linux JetPack 5.1.1 and custom Yocto image)
• Initial attempts to use jetson-io for PWM configuration resulted in errors

The problem affects the functionality of PWM-dependent applications and hinders development efforts on the Jetson Orin Nano platform.

Possible Causes

1. Improper Pin Configuration: The PWM pins may not be properly enabled or configured in the device tree.

2. Software Library Issues: The Jetson.GPIO library might not be fully compatible with the Orin Nano board or may require additional setup.

3. Hardware Limitations: There could be hardware-specific limitations or differences in the Orin Nano that affect PWM functionality.

4. Incorrect Pin Mapping: The code might be using incorrect pin numbers for the Orin Nano board.

5. Device Tree Overlay Problems: Issues with the device tree overlay file or its application could prevent proper PWM configuration.

6. Permission Issues: Lack of proper permissions when running configuration tools or scripts.

Troubleshooting Steps, Solutions & Fixes

1. Enable PWM Pins Using Jetson-IO:

   • Run Jetson-IO with root permissions:

     sudo /opt/nvidia/jetson-io/jetson-io.py
     

   • Use Jetson-IO to enable the desired PWM pins.

2. Verify Device Tree Overlay:

   • If Jetson-IO fails, manually decompile the device tree overlay:

     sudo dtc -I dtb -O dts -o jetson-io-overlay.dts /boot/tegra234-p3767-0000-p3509-a02-hdr40.dtbo
     

   • Inspect the resulting .dts file for PWM-related configurations.

3. Check Pin Compatibility:

   • Verify that the pins you’re using (33 and 15) are indeed PWM-capable for the Orin Nano board.
   • Consult the Jetson Orin Nano GPIO Header Pinout documentation for accurate pin information.

4. Update Jetson.GPIO Library:

   • Ensure you have the latest version of the Jetson.GPIO library installed.
   • Check for any Orin Nano-specific instructions or patches.

5. Modify Python Script:

   • Double-check that the output_pins dictionary in your script includes the correct entry for ‘JETSON_ORIN_NANO’.
   • Verify that the selected pin (33) matches the physically connected pin.

6. Test with Different Frequencies:

   • Modify the PWM frequency in your script (currently set to 50 Hz) to rule out frequency-related issues.

7. Verify Power and Ground Connections:

   • Ensure proper power and ground connections to the Jetson Orin Nano board and any connected devices.

8. Check for System Logs:

   • Examine system logs for any PWM or GPIO-related errors:

     sudo dmesg | grep -i pwm
     sudo dmesg | grep -i gpio
     

9. Yocto Integration:

   • For integrating PWM functionality into a custom Yocto image:
     • Include necessary PWM drivers and Jetson.GPIO library in your Yocto recipe.
     • Ensure the device tree overlay for PWM is properly applied during boot.
     • Consider creating a custom layer for Jetson Orin Nano-specific configurations.

10. Seek Community Support:

    • If issues persist, consult the NVIDIA Developer Forums or community channels for Jetson development.
    • Be aware that custom environments like Yocto may not be officially supported by NVIDIA.

By following these steps, users should be able to resolve most PWM configuration issues on the Nvidia Jetson Orin Nano Dev Board. If problems persist, further investigation into hardware-specific details or consultation with NVIDIA support may be necessary.