[BUG] Fysetc S6 PWM duty cycle too low

[Drachenkaetzchen]

Bug Description

When setting Fan1 speed to 100%, the PWM duty cycle is only 6% on the Fysetc S6.

Workaround

Use FAN_SOFT_PWM.

My Configurations

Configuration.h
Configuration_adv.h

Steps to Reproduce

1. Set Fan1 to 100%

Expected behavior:

PWM duty cycle of 100%

Actual behavior: [What actually happens]

PWM duty cycle of 6%

[Drachenkaetzchen]

When using FAN_SOFT_PWM the duty cycle is 100%, as expected.

[sjasonsmith]

This is similar to the SKR Pro behavior before the changes @LinoBarreca made, including the 20 kHz frequency you see here.

[LinoBarreca]

what kind of board is it? which architecture?

[LinoBarreca]

STM32... that's why. with 5.8.0 they should have fixed it. there was a bug in the duty cycle calculation which I think I saw being handled.

[LinoBarreca]

meanwhile you can just lower the PWM frequency, as I did in the skr-pro, to 1khz to have the correct duty cycle

[Drachenkaetzchen]

I think I tried that, but it had no effect. Maybe I messed something up, will try again later to verify

[Drachenkaetzchen]

I have found the relevant upstream issue:

stm32duino/Arduino_Core_STM32#790

So it's related to 8 bit to 12 bit mapping and not the frequency.

[boelle]

i just made an PR to fix scara printers and that made me think on other issues

so if you know how to fix this one just let me know what file to change or add (or remove) and i could submit the PR

sorry if this is bad formulated (not the sharpest pencil arround)

[Drachenkaetzchen]

i just made an PR to fix scara printers and that made me think on other issues

so if you know how to fix this one just let me know what file to change or add (or remove) and i could submit the PR

sorry if this is bad formulated (not the sharpest pencil arround)

it's an upstream issue, see link above

[boelle]

can marlin as project do anything about that?

[Drachenkaetzchen]

can marlin as project do anything about that?

yes, wait for a newer upstream release and update library refs then

[Drachenkaetzchen]

also, of course, test with the new upstream release and verify that it works correctly. If not, notify the upstream authors and see what we can do to make it work.