Solved
How to read state of SYS WKUP pin ?
I am using the Nucleo-L433RC-P board and have configured pin PC13 as SYS WKUP (for the blue top button).
How can I read the state of this pin when the processor wakes up, because HAL_GPIO_ReadPin will not work.
I am sure I used a function or macro to read the state of this pin before, but can't remember how I did it.
I need to distinguish between an RTC wake or a pin wake from shutdown.
I use wake markers stored in an RTC backup register to detetc an RTC wake. I write to the backup register just before calling shutdown in the function SCH_mcuSleep....
void SCH_mcuSleep (void){
/* The Following Wakeup sequence is highly recommended prior to each Standby mode entry
mainly when using more than one wakeup source this is to not miss any wakeup event.
- Disable all used wakeup sources,
- Clear all related wakeup flags,
- Re-enable all used wakeup sources,
- Enter the shutdown mode.
*/
// write value to RTC backup register to indicate mcu was in sleep
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR2, WAKE_FROM_SLEEP_RTC);
// Disable all used wakeup sources
HAL_RTCEx_DeactivateWakeUpTimer(&hrtc);
HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, RTC_WAKE_SEC, RTC_WAKEUPCLOCK_CK_SPRE_16BITS);
// Clear all related wakeup flags
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
Enable_PC13_Wakeup();
// Call sleep (note that the terms 'sleep' and 'powerdown' are only used for readability, both call shutdown mode)
HAL_PWREx_EnterSHUTDOWNMode();
}
Then in main I call this function for when the processor wakes...
void MAN_checkWake (void)
{
// read wake marker from RTC backup register to determine if woken from sleep or shutdown
wake_marker = HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR2);
if (wake_marker == WAKE_FROM_SLEEP_RTC)
{
// woken from sleep (RTC wake)
// check if elapsed time is greater then shutdown time
if (elapsedSeconds >= RTC_SHUTDOWN_S)
{
SCH_mcuShutdown();
}
}
else if (wake_marker == WAKE_FROM_SHUTDOWN_WKUP)
{
// woken from shutdown (power switch pressed during shutdown)
wakeConfigReset(); // reset time and date and set default reference pressure
}
else
{
// woken from reset
wakeConfigReset(); // reset time and date and set default reference pressure
// store value in RTC backup register to indicate mcu was reset
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR2, WAKE_FROM_RESET);
}
}
There is a seperate function to shutdown that only uses pin wake (does not require RTC wake)...
void SCH_mcuShutdown (void){
// write value to RTC backup register to indicate mcu was in shutdown
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR2, WAKE_FROM_SHUTDOWN_WKUP);
// disable RTC wakeup
HAL_RTCEx_DeactivateWakeUpTimer(&hrtc);
// enable pin wakeup
Enable_PC13_Wakeup();
// Call power down (note that the terms 'sleep' and 'powerdown' are only used for readability, both call shutdown mode)
HAL_PWREx_EnterSHUTDOWNMode();
}