Jetson Nano Dev Kit PWM issue on JetPack 4.6.5

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Hello, @KevinFFF

I posted as below :

Now, I’ve got the solution how to work it.
There are 2 ways PWM is working with JetPack 4.6.3 ~ 4.6.5.

  1. Pinmux change
  2. Copy DTB File from JetPack 4.6.2

And only dtbs is built by make command.
The pwm is working correctly with this dtb file.
The pwm is already enabled on jetson-io.py when it boot .

  • Secnod solution - Copy DTB File from JetPack 4.6.2
    The dtb file is copied from JetPack 4.6.2 to JetPack 4.6.3 ~ JetPack 4.6.5
    After flash, I set enabling pwm on jetson-io.py.
    And then pwm is working correctly.

Those are works now with JetPack 4.6.3 ~ 4.6.5
I hope It will patch when the new version of jetpack will be released.
Jetson Nano Dev Kit is used well for education
Flashing with SDKManager is the best way for most students.

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2

Hello @sumin.lee1,

Thanks for sharing the solutions you found.

Now, with regards to your question.

What you want to find is an easier way to fix the issue or a way to distribute it to students? Are we understanding properly?

regards,
Andrew

3

Hi sumin.lee1,

Thanks for your sharing.

So the issue is caused from the pinmux register changed from JP4.6.3.
Would it work if you just flash clean the latest JP4.6.5 and use Jetson-IO tool to enable PWM?

4

Hello, @KevinFFF
Sorry, I couldn’t catch what you mean clearly.

5

It seems you pointed out that the issue is caused from the pinmux change between JP4.6.2 and JP4.6.3.
So, I would like to know if it could work if you use fresh JP4.6.5 and Jetson-IO tool to enable PWM on Jetson Nano?
Or you have to modify v1.01 pinmux spreadsheet of Jetson Nano to get it work.

6

PWM doesn’t work if I just use Jetson-IO with default BSP of JP4.6.3/JP4.6.4/JP4.6.5.
All of them. All latest 3 versions have same issue.
And solution is same for all 3 versions.

7

From the solution shared from you, it seems the issue caused from pinmux configurations.

Could you help to check the release of the pinmux dtsi in Jetpack 4.6.2 and Jetpack 4.6.3?

You can get the messages like the following in pinmux dtsi.

/*This dtsi file was generated by jetson_nano_module.xlsm Revision: 1.01 */

Or sharing the dtb of both Jetpack 4.6.2 and Jetpack 4.6.3 for further check.

8

The dtsi files is here.
nano_pwm_enable.zip (4.2 KB)

And I just downloaded JetPack 4.6.2 and JetPack 4.6.3 BSP from archive for DTB.

9 
			lcd_bl_pwm_pv0 {
				nvidia,pins = "lcd_bl_pwm_pv0";
				nvidia,function = "pwm0";
				nvidia,pull = <TEGRA_PIN_PULL_DOWN>;
				nvidia,tristate = <TEGRA_PIN_DISABLE>;
				nvidia,enable-input = <TEGRA_PIN_DISABLE>;
			};

From the pinmux you shared, it is expected to use pwm0(PV.00) for PWM usage.
No matter you are using which Jetpack release, please just use above pinmux configuration for PWM.

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