STM32L562CET6 won't enter EXTI callback function.

[LOlhe.1]

I am quiet new to STM32 programming and can't get the external interrupt to work.

I started with the NUCLEO-L011K4 and wrote my programm without any issues. I switched to my own board (pdf included) and weren't able to get extrenal interrupts to work.

I use the STM32CubeIDE 1.5.1 and the ST-Link/V2 to programm.

The goal of the code is to change the PWM outputs frequency and duty cycle with incoming 5V high signals on pin "Change" and pin "Laser_On". The Controller itself gets 3,3V.

I can see in debug mode that the Callback function isn't entered when i provide the high signals.

Am I missing some crucial code? Help is appreciated.

[LOlhe.1]

VDD of 3,3V is present at all times. I measure 0V on the pin when the programm is loaded on the MCC. Before the programm is transfered I measure 3V on PB6.

[LOlhe.1]

Signal directly on PB6 after phototransistor.

[LOlhe.1]

I manually sodered a 10k pull-down resistor between PB6 and GND but Change_Pin is still constantly reporting 64 instead of 0.