Configuring PWM on Jetson Orin Nano with Non-Nvidia Carrier Board

Issue Overview

Users are experiencing difficulties configuring the 40-pin header on the Nvidia Jetson Orin Nano System on Module (SoM) when used with a non-Nvidia carrier board, specifically the J401 from Seed Studio. The primary issue involves enabling Pulse Width Modulation (PWM) on pin 32 of the 40-pin header. Users have reported that attempts to change pin functions using the jetson-io.py utility have been unsuccessful, as it appears to only support Nvidia’s official development kits. The lack of documentation specific to the Jetson Orin Nano for third-party carrier boards exacerbates the problem, leading to confusion and frustration among users trying to adapt their hardware for specific applications.

Possible Causes

1. Hardware Incompatibility: The jetson-io.py tool may not be compatible with non-Nvidia carrier boards, which could prevent users from successfully changing pin functions.
2. Software Bugs: There may be unresolved bugs in the software tools provided by Nvidia that affect functionality when used with third-party hardware.
3. Configuration Errors: Users may not be following the correct procedures for configuring pin functions, particularly if they are relying on documentation meant for other Jetson models.
4. Driver Issues: Outdated or incorrect drivers could lead to failures in recognizing or configuring GPIO pins.
5. User Misconfigurations: Incorrect settings or commands entered by users may lead to unexpected results when attempting to configure the pins.

Troubleshooting Steps, Solutions & Fixes

Step-by-Step Instructions

1. Verify Hardware Compatibility:

   • Ensure that the J401 carrier board is designed to work with the Jetson Orin Nano SoM.
   • Check if there are any known limitations or compatibility issues documented by Seed Studio.

2. Check Software Installation:

   • Confirm that you have installed the latest version of JetPack that supports the Jetson Orin Nano.
   • Update your system and ensure all dependencies are installed:

     sudo apt update
     sudo apt upgrade
     

3. Use jetson-io.py Tool:

   • Launch the tool with:

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

   • If this does not work, consider that it might only function with Nvidia’s reference boards.

4. Modify Pinmux Configuration:

   • If jetson-io.py fails, you may need to manually edit the pinmux configuration files.
   • Documentation for generating these files can be found here.
   • Follow instructions carefully to ensure correct pin settings.

5. Testing and Isolation:

   • Test PWM functionality using a simple script after making changes:

     import RPi.GPIO as GPIO
     import time
     
     GPIO.setmode(GPIO.BOARD)
     GPIO.setup(32, GPIO.OUT)
     
     pwm = GPIO.PWM(32, 50)  # Set frequency to 50Hz
     pwm.start(0)  # Start PWM with 0% duty cycle
     
     try:
         while True:
             for dc in range(0, 101, 5):  # Increase duty cycle
                 pwm.ChangeDutyCycle(dc)
                 time.sleep(0.1)
             for dc in range(100, -1, -5):  # Decrease duty cycle
                 pwm.ChangeDutyCycle(dc)
                 time.sleep(0.1)
     except KeyboardInterrupt:
         pass
     
     pwm.stop()
     GPIO.cleanup()
     

6. Consult Documentation and Community Forums:

   • Refer to Nvidia’s official documentation for additional insights into hardware configurations and troubleshooting.
   • Engage with community forums for shared experiences and solutions from other users facing similar issues.

7. Best Practices for Future Prevention:

   • Always check for compatibility before purchasing third-party hardware.
   • Keep firmware and software updated to minimize bugs and improve compatibility.
   • Document any changes made during configuration for future reference.

Recommended Approach

If multiple users report success with modifying pinmux configurations directly rather than using jetson-io.py, prioritize this method as a recommended approach.

Unresolved Aspects

There remains a lack of comprehensive documentation specifically addressing how to configure non-Nvidia carrier boards for use with Jetson Orin Nano modules. Further investigation into community contributions or Nvidia’s updates may be necessary to resolve these gaps effectively.