The SKR Mini E3 V2 uses the STM32F103RCF6 MCU based around ARM.
I want to control the pin PC12 with PWM. However, this pin is not working as the Laser PWM signal. It never gets triggered actually with G0/G1 S0-255, although I am absolutely sure, that this is not an issue with the laser configuration itself. When manually setting the pin state with G-code I can only set it to 0 V with S0 or to 3.3V with S1 to S255. It is not doing any kind of PWM at all. The same can be observed with PC6 vs PC7. PC6 is the parts cooling fan and it outputs PWM signals. PC7 is the controller fan and it does not output PWM. I have checked the 2 main Configs of Marlin and the Pins BTT... and BTT...common for any clues, however regarding the definition of these pins I see no difference.
After looking up the pins using the PDF of the manufacturer, I cannot see a difference between PC6 and PC7 - both are paper-wise supporting the same features and just have a different index - which is kind of obvious. So how is it possible, that one pin can be set to PWM states, while the other pins (without exception) only react digitally with a 0 or 1 state?
Please do not consider the version, which is 2.0.9.1, quite outdated. I have to stick to the version for like a dozen of reasons. It is a fork anyways, so what gives? I do not actually want to ask about firmware version things, but how it is possible, that there is a difference on this level at all? If I set the pin state whilst disabling firmware protection of this pin I would expect the pin to react as PWM, if I ask it to. I mean, using the thermistor pins as output is possible, which works as expected. From the chip datasheet and the configuration files I cannot see a reason, why the pins would behave differently. The circuit between PC6 and PC7 is absolutely identical, so this is out of the question already.
Is there any function, that needs to be called or a setting that needs to be made for PWM to be even loaded/initialized at all? I see many people struggling to set PWM to any pin other than the parts cooling fan, so it is not a new issue. I never saw a real fix for this, only suggestions like Buck converter for manual adjustments.
I want to control a laser, so this is out of the question. Any idea?
