hello
Description:
I'm currently working with the STM32U585 and encountered an issue related to GPIO behavior after waking up from standby mode.
Before entering standby, I configure certain GPIO pull-up:(No external pull-down resistors on the affected pins)
HAL_PWREx_EnableGPIOPullUp(PWR_GPIO_D, PWR_GPIO_BIT_14);
HAL_PWREx_EnablePullUpPullDownConfig();However, after the MCU wakes up from standby (via wakeup pin), I observe a brief voltage drop on those previously GPIOs, about 300ms. This drop occurs before the firmware reinitializes the GPIO configuration:
i added a delay(implemented with i--)before calling the HAL_Init() function, and the voltage drop became less pronounced:
Questions:
Is this behavior expected due to the standby mode reset mechanism?
Is there a recommended way to retain GPIO output levels across standby wakeup?
Could this be related to the IO pull settings or the boot configuration?
Are there any hardware-level workarounds to avoid this voltage dip?
- Why does delay have such an impact
