Unable to Control Multiple GPIO Pins on Nvidia Jetson Orin Nano Dev Kit

Issue Overview

Users of the Nvidia Jetson Orin Nano Developer Kit are experiencing difficulties when attempting to control multiple GPIO pins simultaneously. The issue occurs specifically when trying to manipulate GPIO pins 9 and 12 using custom Python code. While single-pin control works as expected, the multi-pin control script fails to function properly. This problem impacts the ability to develop more complex GPIO-based applications on the Orin Nano platform.

Possible Causes

1. Incorrect Pin Numbering: The code uses BOARD numbering (29 and 7), which may not correspond to the desired GPIO pins 9 and 12.

2. Syntax Errors: There are minor syntax errors in the provided code, such as using a comma instead of a period in GPIO,LOW and GPIO,HIGH.

3. Improper GPIO Setup: The GPIO.setup() function might not be correctly configuring multiple pins for output.

4. Software Version Incompatibility: The issue could be related to the specific Jetpack version (5.1.3) or L4T version (35.5.0) being used.

5. Hardware Limitations: There might be restrictions on simultaneous control of certain GPIO pins on the Orin Nano Dev Kit.

Troubleshooting Steps, Solutions & Fixes

1. Correct Pin Numbering:

   • Verify the correct BOARD numbering for GPIO pins 9 and 12.
   • Update the channels list in the code accordingly:

     channels = [21, 32]  # BOARD numbers for GPIO 9 and 12
     

2. Fix Syntax Errors:

   • Correct the comma to a period in the GPIO.output() calls:

     GPIO.output(channels, [GPIO.HIGH, GPIO.LOW])
     GPIO.output(channels, [GPIO.LOW, GPIO.HIGH])
     

3. Proper GPIO Setup:

   • Ensure each pin is set up individually:

     GPIO.setup(21, GPIO.OUT)
     GPIO.setup(32, GPIO.OUT)
     

4. Use NVIDIA’s Example Code:

   • Test with the NVIDIA-provided example script:

     jetson-gpio/samples/simple_out.py
     

   • Modify this script to control multiple pins if it works for a single pin.

5. Check GPIO Library Version:

   • Ensure you have the latest Jetson.GPIO library installed:

     pip install --upgrade Jetson.GPIO
     

6. Verify Hardware Connections:

   • Double-check that the GPIO pins are properly connected to your external components.
   • Ensure there are no short circuits or loose connections.

7. Test Individual Pin Control:

   • Create a script to control each pin separately to isolate any pin-specific issues.

8. Use Alternative GPIO Control Method:

   • Try using the gpiod library instead of Jetson.GPIO:

     import gpiod
     import time
     
     chip = gpiod.Chip('gpiochip0')
     lines = chip.get_lines([9, 12])
     lines.request(consumer='test', type=gpiod.LINE_REQ_DIR_OUT)
     
     while True:
         lines.set_values([1, 0])
         time.sleep(1)
         lines.set_values([0, 1])
         time.sleep(1)
     

9. Check for Conflicting Processes:

   • Ensure no other processes are trying to control the same GPIO pins:

     sudo lsof /dev/gpiochip0
     

10. Consult Official Documentation:

    • Review the Jetson Orin Nano Developer Kit documentation for any known GPIO limitations or required configurations.

11. Community Support:

    • If the issue persists, consider posting a detailed description of your problem, including your code and any error messages, on the NVIDIA Developer Forums or the Jetson community on GitHub.