> This happens on all microcontrollers btw. Random charge accumulates and pushes the voltage on your pin to some arbitrary point. The way you fix this normally

> This happens on all microcontrollers btw. Random charge accumulates and pushes the voltage on your pin to some arbitrary point. The way you fix this normally is by providing a path for that charge to escape in the form of a pull-down resistor. Usually you need something in the 100k range. Because of this bug you need something more in the 5k range. Many microcontrollers provide an internal, selectable pull-up or pull-down resistor (or neither). For example, on the STM32, it's a 30-50k, and individually selectable on a per-pin basis: https://www.keil.com/dd/docs/datashts/st/stm32f10xxx.pdf#G11.1154906 https://www.keil.com/dd/docs/datashts/st/stm32f10xxx.pdf#G11... It's normal for pins to float, it's not normal for them to both lack an internal bias option and to float to a condition where they source significant current. You don't typically put a very low impedance external pull-down resistor on every single input pin.