Problem with PWM setup

[Superposition]

Hello,
I'm just a begginer with embedded and STM32 so bare with me please.

I was trying to follow a program tutorial to periodically blink an LED using a timer channel in PWM generation mode. I have an STM32 Nucleo h755zi-q board, I set the integrated LED on pin PB0 to it's alternate function which is timer 3 channel 3, I assigned timer 3 to core C7 turned on internal clock as source and set channel 3 to PWM generation. I used different setups but for example 200 Mhz on the clock, prescaler 19999, autoreload 9999, pulse 5000. I left everything else as default and generated the code and only added this line

"HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_3);"

right before the infinite loop in the main function. This should make the user LED on pin PB0 blink periodically with 1 Hz frequency I think. But the LED isn't doing anything at all.

I'm using CubeIDE obviously and using just a basic timer with interrupt works flawlessly, so where is the mistake?

Sorry for low details, I'm currently in a rush, will provide any details you ask for later.
Thanks in advance for all the suggestions :)

[Saket_Om]

Hello @Superposition 

Please refer to the below material as starting point: 

• Custom signal generation using PWM and DMA - STMicroelectronics Community.
• Projects/STM32H745I-DISCO/Examples/TIM/TIM_DMA.
• Projects/NUCLEO-H743ZI/Examples/TIM/TIM_PWMOutput.

[Superposition · Accepted solution]

Thanks for the reply and help, however I finally managed to solve the problem myself.
If anyone ever needs it, what I had to do was turn off the "human machine interface".

I don't really know what it is but whenever starting a project, a box called human machine interface pops up and asks to configure some pins for me, I also don't really know if this is intended or a bug, but if I leave it turned on, timer channels literally don't work and I can't even turn UART on.

So in short my problem was solved by clicking "unselect all" in the human machine interface thus turning it off.