Unable to Set PWM on Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties in configuring PWM (Pulse Width Modulation) on the Jetson Orin Nano Dev Board, specifically with pins 32 and 33 of the expansion header. The issue arises after attempting to set these pins for PWM control using the Jetson.GPIO library.

Symptoms

• Users receive a ValueError indicating that the specified channels (32 and 33) are not recognized as PWM channels when executing the following code:

  import Jetson.GPIO as GPIO
  GPIO.setmode(GPIO.BOARD)
  test_pwm = GPIO.PWM(33, 100)
  

• The error message returned is:

  ValueError: Channel 33 is not a PWM
  

Context

• The issue occurs after users have run the command sudo /opt/nvidia/jetson-io/jetson-io.py to configure the pins, expecting that this would enable PWM functionality.
• The problem persists even after verifying the configuration through system files, where users report no reference to the expected PWM devices.

Hardware and Software Specifications

• Device: Jetson Orin Nano Dev Kit (8GB)
• Software: JetPack 6 (L4T R36.2)

Frequency and Impact

• This issue appears to be consistent among users attempting similar configurations.
• The inability to set PWM affects projects relying on precise control of hardware components, thus impacting user experience and functionality.

Possible Causes

1. Hardware Incompatibilities or Defects

   • Pins may not be properly configured or may be defective, leading to failure in recognizing them as PWM channels.

2. Software Bugs or Conflicts

   • There may be bugs in the Jetson.GPIO library or conflicts with other installed packages that prevent proper PWM operation.

3. Configuration Errors

   • Incorrect configuration steps may have been followed when setting up the pins for PWM, leading to their unavailability.

4. Driver Issues

   • Outdated or incompatible drivers may not support the desired functionality for PWM on the specified pins.

5. Environmental Factors

   • Power supply issues or overheating could affect the performance of the board and its ability to handle PWM signals.

6. User Errors or Misconfigurations

   • Users may inadvertently misconfigure settings or fail to reboot after making changes, resulting in persistent issues.

Troubleshooting Steps, Solutions & Fixes

1. Verify Pin Configuration

   • Ensure that pins are correctly configured for PWM using:

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

   • Select "Configure Jetson 40pin Header" and manually check that pwm5 (33) and pwm7 (32) are selected. Save changes and reboot.

2. Install Required Packages

   • Make sure all necessary packages are installed:

     sudo apt update
     sudo apt install git python3-pip pip
     

3. Clone and Install Jetson.GPIO Library

   • Clone the library from GitHub and install it:

     git clone https://github.com/NVIDIA/jetson-gpio.git
     cd jetson-gpio
     sudo python3 setup.py install
     

4. Test with Sample Code

   • Navigate to sample scripts and run a basic PWM test:

     cd samples
     sudo python simple_pwm.py
     

5. Check System Files for PWM Devices

   • Verify if the expected PWM devices are listed under /sys/devices/platform/. Use:

     ls /sys/devices/platform/
     

   • Look for entries like 32c0000.pwm which should indicate proper configuration.

6. Review System Logs for Errors

   • Check system logs for any related errors during boot or operation:

     dmesg | grep pwm
     

7. Reboot After Changes

   • Always reboot the device after making configuration changes to ensure they take effect.

8. Seek Further Documentation

   • For additional guidance, refer to NVIDIA’s official documentation on configuring GPIO and PWM on Jetson devices.

Recommended Approach

Multiple users have successfully resolved similar issues by following the steps outlined above, particularly ensuring that pin configurations are saved properly and that all necessary software dependencies are installed.

Unresolved Aspects

While many users have shared solutions, some aspects remain unclear, such as specific driver compatibility issues or potential hardware defects that could lead to these errors. Further investigation may be required in those areas if problems persist despite following troubleshooting steps.