[BUG] Layer cooling fans only works with 100% of pwm speed (ATMEGA2560)

[Henyckma-Sensei]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

The layer cooler only works when the power percentage is at 100%, otherwise it does not activate, I use ramps 1.4 so I don't know if it happens on other boards
to make sure it was not an electrical problem, I went back to the previous version and everything worked perfectly.

Bug Timeline

This is a new bug but have some related bug #25018

Expected behavior

I was expecting the printer to set the fan speed expressed by the slicer

Actual behavior

The layer fan not are turning on while printing, doesn't do anything, I activate it at 75% in the menu and it doesn't turn on either... only if i turn at 100% can turn on but, only at full power.

Steps to Reproduce

1. I compiled and flash new marlin
2. After flashing it, I started to print several objects
3. I realize that the layer fan doesn't work
4. I try to activate it from the lcd it doesn't work either (30%, 50%, 75%)
5. I increase it to the maximum speed and it works at full flow
6. flashed again with the old firmware
7. works normally, no problems

Version of Marlin Firmware

2.1.2 and Bugfix

Printer model

Custom prusa i3

Electronics

Ramps 1.4 (EFB)

Add-ons

none

Bed Leveling

None

Your Slicer

Prusa Slicer

Host Software

None

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

Marlin.zip

[ellensp]

not current bugfix configs...

Updated to current bugfix for testing
bugfix 2.1.x Configuration.zip

[Henyckma-Sensei]

not bugfix configs...

not current bugfix configs...

Updated to current bugfix for testing bugfix 2.1.x Configuration.zip

thanks, I used the bugfix only to to see if the fan worked so i left everything blank and just changed the motherboard section

[ellensp]

Issue seem to be the frequency, pwm is working.

bugfix 2.1.x pin D9 62.5 khz
bugfix 2.0.x pin D9 980.4hz

[ellensp]

I have a fix, 3 related bugs, works for fans. Got to check it doesn't break pwming leds.. but that will have to wait.. its 4:30am.

[Henyckma-Sensei]

I have a fix, 3 related bugs, works for fans. Got to check it doesn't break pwming leds.. but that will have to wait.. its 4:30am.

I can wait as long as you want!, I appreciate your hard work, thank you!

[ellensp]

@Henyckma-Sensei please test this PR

[Henyckma-Sensei]

@Henyckma-Sensei please test this PR

Works great!

[ellensp]

Ok then, closing this as solved. PR will get merged into bugfix soon

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.