How to use two PWM fans on the Thor platform?

Robotics & Edge Computing Jetson Systems Jetson Thor
1

Hi Nvidia,

How can more PWM fans be added to the Thor platform?

As I knew, Jetson Thor provides PWM and tachometer functionality for controlling a fan as part of the thermal solution.

The FAN_PWM pin is configured as GP_PWM4
The FAN_TACH pin is configured as NV_THERM_FAN_TACH0

Can nvfancontrol.service recognise the new PWM fan if I want to add it?

4

hello pomelo.hsieh,

currently we don’t have any node for FAN_TACH1 enabled in the device tree.

5

Hi JerryChang,

I understand that the device tree does not include an additional FAN_TACH1 setting to read the fan RPM.

Does Nvfancontrol.service only recognize Nvidia’s native fan settings?
I don’t know how nvfancontrol knows the number of fans because it is not open source code.

If I need to add an additional PWM fan, does Nvidia have any suggestions?

Should I use the hwmon PWM fan driver to modify the thermal zone to include cooling maps and a cooling device for the PWM fan?

Thanks.

6

hello pomelo.hsieh,

please check Jetson Thor Series Modules Interface Design Guide for [Chapter 16. Fan].
FAN_PWM pin is configured as GP_PWM4, you may configure a GPIO pin as PWM for additional PWM fan.

7

Hi JerryChang,

Would nvfancontrol recognize the new fan if the GPIO pin is configured as PWM for an additional PWM fan?
Could I add a new fan setting to /etc/nvfancontrol.conf?
Following the above design, create two fan settings: one that follows the original NVIDIA design and can read/write PWM and read RPM values, and another that can only read/write PWM and but can’t read RPM values.
Does Nvidia have any suggestions for using more fans with the Jetson Thor platform?

Thanks.

8

hello pomelo.hsieh,

it’s per your use-case, see Jetson Thor Series Thermal Design Guide for reference.