STM32L071CBT6 GPIO PB15 Input Not Responding to 5V Signal from Buck Converter
Hello everyone,
I'm using the STM32L071CBT6 microcontroller and facing an issue with reading a digital input on GPIO pin PB15.
What I'm Trying to Do:
I’m using a buck converter with a 5V output to indicate the power status. The 5V output from the buck converter is connected to PB15, which is configured as a digital input on the STM32.
Setup:
Buck converter 5V output = GPIO PB15
Measured with multimeter: PB15 shows 5V when buck converter is ON
PB15 is configured in firmware as an input pin (floating or pull-down)
Problem:
Although PB15 is reading 5V on the pin when measured, the firmware logic that depends on PB15 being HIGH doesn't work.
What I’ve Checked:
The GPIO pin is correctly configured as input
Measured 5V directly at PB15
Tried enabling internal pull-down or external pull-down resistor
No response or logic change in the code when the 5V signal is applied
Why does PB15 show 5V physically (confirmed via multimeter) but the STM32L071 doesn't detect it as a logic HIGH in firmware?
