PWM on pin32 with J401 board + Jetson Orin Nano

Products & Technology Single Board Computers
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Hi. How do I configure pin 32 to be PWM for J401 board together with Jetson Orin Nano?

I read through article at https://www.seeedstudio.com/blog/2020/05/27/configure-pwm-output-on-jetson-nano-m/ but that is only for Jetson Nano. It does not work for Jetson Orin Nano.

Are there any parts different? I found documentation on how to change 40 pin header configuration for Jetson Nano from Nvidia (here) but there does not seem to be any documentation on how to do this for Jetson Orin Nano.

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Any help would be appreciated.

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Hi! Yes, the Jetson Orin Nano differs slightly from the original Jetson Nano in how it handles pin multiplexing and PWM configuration — especially with expansion boards like the Seeed J401.

Here’s how you can approach it:

Differences from Jetson Nano:
While the blog you referenced (PWM on Jetson Nano) is great for Nano, the Jetson Orin Nano uses a different device tree structure and pinmux configuration.

Steps to Enable PWM on Pin 32 (J401 + Orin Nano):

1. Confirm Pin Mapping on J401 for Orin Nano

Pin 32 corresponds to GPIO3_PQ.05 (on Orin Nano) — not the same as Nano.
Use this reference:

2. Edit Pinmux Configuration

You’ll likely need to modify the device tree using the Jetson Linux Customization Guide ( [Welcome — Jetson Linux
Developer Guide 34.1 documentation]).

  • Generate the pinmux spreadsheet via NVIDIA tools

  • Set pin 32 (PQ.05) to PWM mode

  • Compile DTB and flash using SDK Manager or manual flashing

  1. Check Jetson PWM Driver

Load the driver if it’s not already:

sudo modprobe pwm-fan
  1. Use /sys/class/pwm/ Interface

After enabling, you should see:

/sys/class/pwm/pwmchip0/

Export and control PWM via:

echo 0 > export
echo 1000000 > pwm0/period
echo 500000 > pwm0/duty_cycle
echo 1 > pwm0/enable

Extra Resources:

  • NVIDIA Jetson Orin Nano Developer Kit Docs

  • Jetson Linux Pinmux Reference

  • Robocraze’s Nvidia Jetson Nano Page (good for kits & guides if you’re in India)

If I manage to test this setup on the J401 in the next few days, I’ll report back. Let me know if you’ve tried any specific DT overlay or Jetpack version — that can affect compatibility.

Cheers!