internal pullup resistor when power off

[francois06]

Hello,

I wonder if I use the internal pullup resistor on an STM32F4 on an open-drain output, if the MCU is reset with the line NVIC_SystemReset(), does the internal pullup resistor with open drain output will still be seen by another IC connected to this pin ? Will it still be configured as open drain with pullup during and after reset ?

Thank you

[S.Ma]

Whatever is programmed by sw is lost when reset occurs as most peripheral registers have their reset values in the ref manual. Typically most gpio are input during reset to avoid electrical conflicts. For the progranmable pull up, check tge reset register value....

[AvaTar]

A reset will also set the peripheral config registers to their default values, which means powered-off.

The GPIO supposedly goes to a high-impedance state.

[francois06]

Okay thank you for your answers.