Configuring GPIO Output on Nvidia Jetson Orin Nano

Issue Overview

Users are experiencing difficulties when attempting to configure a specific GPIO pin (PQ02) as an output on the Nvidia Jetson Orin Nano development board. The issue occurs during the flashing process when trying to apply custom pinmux configurations. After successfully flashing the board, the GPIO pin remains in input mode instead of the desired output mode. This problem impacts the ability to control external hardware or signals connected to the GPIO pin.

Possible Causes

1. Incorrect pinmux configuration file:
   The generated or modified DTSI file may contain errors or incompatibilities with the specific board revision.

2. Flashing process errors:
   Issues during the flashing process may prevent the custom pinmux configuration from being applied correctly.

3. Software conflicts:
   Existing software or drivers may be overriding the pinmux settings after boot.

4. Hardware limitations:
   Certain GPIO pins may have restrictions on their configuration due to hardware design.

5. User error:
   Mistakes in the configuration process or misunderstanding of the required steps could lead to improper setup.

Troubleshooting Steps, Solutions & Fixes

1. Generate correct pinmux configuration:

   • Use the official Nvidia Jetson pinmux spreadsheet to generate the DTSI file.
   • Ensure the generated file is named correctly and placed in the proper directory:

     <Linux_for_Tegra>/bootloader/generic/BCT/pinmux.dtsi
     

2. Create and place the GPIO configuration file:

   • Generate a GPIO configuration file named gpio.dtsi.
   • Place it in the following directory:

     <Linux_for_Tegra>/bootloader/gpio.dtsi
     

3. Modify the board configuration file:

   • Edit the file <Linux_for_Tegra>/p3701.conf.common.
   • Locate the line specifying the pinmux configuration and update it:

     PINMUX_CONFIG="pinmux.dtsi";
     

4. Flash the board with updated configurations:

   • Run the flashing command with the modified files in place.
   • Example command:

     sudo ./flash.sh jetson-orin-nano-devkit mmcblk0p1
     

5. Verify GPIO configuration after boot:

   • Use the gpioinfo command to check the current state of GPIO pins.
   • Look for the PQ02 pin and verify its configuration.

6. Control GPIO using libgpiod:

   • Install libgpiod tools if not already present:

     sudo apt-get install gpiod
     

   • Set the GPIO pin as output:

     gpioset --mode=time -s 1 $(gpiofind PQ.02)=1
     

7. Implement a custom driver or service:

   • For permanent GPIO control, consider writing a custom kernel driver.
   • Alternatively, create a systemd service that sets the GPIO state on boot.

8. Use Device Tree Overlay:

   • Create a Device Tree Overlay file to set the GPIO as output.
   • Apply the overlay during boot using the bootloader configuration.

9. Check for conflicting software:

   • Review running processes and services that might interfere with GPIO settings.
   • Disable or modify any conflicting software.

10. Consult Nvidia documentation:

    • Review the latest Jetson Linux Developer Guide for any updates or known issues related to GPIO configuration.
    • Check the Nvidia Developer Forums for community solutions to similar problems.

If the issue persists after trying these steps, consider reaching out to Nvidia support or the Jetson developer community for further assistance. Provide detailed information about your setup, the steps you’ve taken, and any error messages encountered during the process.