Hello,
Does the fan on the BBAI-64 work? I saw there was a fan connector…
Is this 5v or is it some other voltage that needs to be allocated to it?
Seth
It’s setup to be a pwm output, src/arm64/overlays/BONE-FAN.dts · v5.10.x-ti-unified · BeagleBoard.org / BeagleBoard-DeviceTrees · GitLab
It’s not only just set voltage output…
Regards,
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how to make PWM FAN work?
Can you please support thank you.
Hey @RobertCNelson! I hate to re-open a topic that has been answered, but I followed the GitLab link that you replied with and copied that code to my BBAI-64, then tried compiling it using this command:
dtc -@ -O dtb -o BONE-FAN.dtbo BONE-FAN.dts
But it gave me an error, saying:
Error: BONE-FAN.dts:9.1-9 syntax error
FATAL ERROR: Unable to parse input tree
Am I doing something wrong? As far as I understand, all I should have to do is compile it, then throw it in my /boot/firmware/overlays/ folder, then reference it in my /boot/firmware/extlinux/extlinux.conf file, then reboot. Is that correct, or am I missing a crucial component? And I apologize if this has been answered somewhere else. I am kind of a noob when it comes to the BBAI-64. And by the way, I am running a newer kernel. 6.12.17-ti-arm64-r33
Oh, and in case this is helpful, I made this little fan connector based on the documentation found here:
https://docs.beagle.cc/boards/beaglebone/ai-64/03-design-and-specifications.html#fan-header
Blue is PWM, yellow is tach, red is 5v and black is ground, obviously.
My issue at this point is just that the fan always runs full blast. I just haven’t figured out how to get the PWM fan overlay to work.
Yea, full blast is a good indicator that the PWM signal is either:
- Not being generated
or - Not being PINMUXed onto the connected pin.
Well considering I am stuck at trying to figure out how to compile the overlay that would generate the PWM signal, I’m going to go with, it’s not generating a PWM signal… Would you have any idea how I can compile the above referenced overlay and get it working?
Not personally, and since this question is already marked with a solution,
how about you open a new question with a more suitable title?
Also, I have seen people asking about this topic repeatedly,
so I would be very surprised if a search turned up zero results for you to pursue.
What fan and pwm connector are you using?
I just need to move this to be built-in like the BeagleY-AI and just assume a fan is connected…
But i want to make sure i use the same fan/etc… amazon link would help 
Regards,
It is not that straight forward to get the fan overlay working as the default debian image exports the pwm preventing the fan overlay working. I seem to recall there ia a udev rule or script that exports the pwm preventing the fan overlay grabbing the pwm.
To make the fan overlay work you need to disable the rule/script, not just in the Debian file system, but also in the init ram disk image.
Of course any updates that replace the init ram disk will break the fan again.
As the pwm is exported you should be able to control it via the /sys interface. Write a small python script that reads the cpu temp and adjust the fan accordingly.
There was… I’ve ripped the udev script out in newer build… The BeagleY-AI has a fan connector that’s compatible with the RPI fan, so that enables pwm fan out of the box… I then wrote a helper script for the BeagleY-AI to help export the correct directory:
sudo beagle-pwm-export --pin hat-08
https://docs.beagleboard.org/boards/beagley/ai/demos/beagley-ai-using-pwm.html
Saw this annoucment a few weeks back libpwm Making sure you're not a bot! maybe that’ll finally solve our problems…
Regards,