Issue coming out of standby mode using RTC

[SSmit.13]

Hi

 I am having issues coming out of standby mode using RTC timers. I am using both timers and the periodic counter, all at different times. If I dont go into stanby mode all works as expected, and the interrupts are generated for each clock and timer. If I go into standby , then one interrupt wakes the processor, but the other interrupts dont wake the processor.   I am using the stm32L433 processor.

I setup the RTC clocks :

void RTC_Set_Periodic(void)
{
RTC->ISR |= RTC_ISR_INIT;

RTC->WPR = 0xCA;
RTC->WPR = 0x53;

RTC->CR &= ~RTC_CR_WUTE; //clear wakup timer
while ((RTC->ISR & RTC_ISR_WUTWF) != RTC_ISR_WUTWF)

RTC->CR &= ~RTC_CR_WUCKSEL;
RTC->CR |= RTC_CR_WUCKSEL_2;
RTC->WUTR=9; //wakeup every 10 seconds

EXTI->RTSR1 |= EXTI_RTSR1_RT20;
EXTI->IMR1 |= EXTI_IMR1_IM20;
EXTI->EMR1 |= EXTI_EMR1_EM20;
EXTI->PR1 |= EXTI_PR1_PIF20;

RTC->CR |= RTC_CR_WUTIE;
RTC->CR |= RTC_CR_WUTE;

RTC->ISR &= ~(RTC_ISR_WUTF);

NVIC_EnableIRQ(RTC_WKUP_IRQn);
NVIC_SetPriority(RTC_WKUP_IRQn,3);

RTC->ISR &=~ RTC_ISR_INIT;
RTC->WPR = 0xff;
}

void RTC_WKUP_IRQHandler(void)
{

if(RTC->ISR & RTC_ISR_WUTF)
{

while(!(RTC->ISR & RTC_ISR_RSF))
;

}

EXTI->PR1 |= EXTI_PR1_PIF20;
}

////////////////////////////////////////

 void RTC_Set_ClockA()
{
unsigned long Alarm=CalcNextAlarm(ClockAPeriod); //calculate next time

RTC->ISR |= RTC_ISR_INIT;
RTC->CR &=~RTC_CR_ALRAE;

RTC->WPR = 0xCA;
RTC->WPR = 0x53;

RTC->CR &= ~RTC_CR_ALRAE;
RTC->CR &= ~RTC_CR_ALRAIE;
RTC->ISR &= ~(RTC_ISR_ALRAWF); //clear any pending Interupts

while((RTC->ISR & RTC_ISR_ALRAWF)==0);

RTC->ALRMAR =Alarm;

RTC->CR |= RTC_CR_ALRAE;
RTC->CR |= RTC_CR_ALRAIE;

EnableRTCStoreAndSendTimer();

RTC->WPR = 0xff;
RTC->ISR &=~ RTC_ISR_INIT;
}

void RTC_Set_ClockB()
{
unsigned long Alarm=CalcNextAlarm(NodeTimesAlarmsStruct.SampleRate); //simply get next alarm...RTC->ISR |= RTC_ISR_INIT;
RTC->CR &=~RTC_CR_ALRBE;

RTC->WPR = 0xCA;
RTC->WPR = 0x53;

RTC->CR &= ~RTC_CR_ALRBE;
RTC->CR &= ~RTC_CR_ALRBIE;
RTC->ISR &= ~(RTC_ISR_ALRBWF); //clear any pending Interupts

while((RTC->ISR & RTC_ISR_ALRBWF)==0);

RTC->ALRMBR =Alarm;

RTC->CR |= RTC_CR_ALRBE;
RTC->CR |= RTC_CR_ALRBIE;

EnableIRQs();

RTC->WPR = 0xff;
RTC->ISR &=~ RTC_ISR_INIT;
}

//Enable Interupts
void EnableIRQs()
{
EXTI->RTSR1 |= EXTI_RTSR1_RT18;
EXTI->IMR1 |= EXTI_IMR1_IM18;
EXTI->EMR1 |= EXTI_EMR1_EM18;
EXTI->PR1 |= EXTI_PR1_PIF18;

NVIC_SetPriority(RTC_Alarm_IRQn,0);
NVIC_EnableIRQ(RTC_Alarm_IRQn);
}

//interupt routines

void RTC_Alarm_IRQHandler(void)
{
//check for AlarmA,
if(RTC->ISR & RTC_ISR_ALRAF)
{
RTC->ISR &= ~(RTC_ISR_ALRAF);
}

//check for AlarmB
if(RTC->ISR & RTC_ISR_ALRBF)
{
RTC->ISR &= ~(RTC_ISR_ALRBF);
}

EXTI->PR1 |= EXTI_PR1_PIF18;
}

All the above works as expected in normal mode, but when I put in the lines

HAL_PWREx_EnableSRAM2ContentRetention()
 HAL_PWR_EnterSTANDBYMode();

The processor goes into standby mode and gets woken only by one interupt.

In Main I have:

if(__HAL_PWR_GET_FLAG(PWR_FLAG_SB)!=RESET)
{
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);
if(RTC->ISR & RTC_ISR_WUTF) //check for periodic timer
{

PeriodicSet=1;
RTC->ISR &= ~(RTC_ISR_WUTF);
}

if(RTC->ISR & RTC_ISR_ALRAF)//check for clock A
{

ClockASet=1;

RTC->ISR &= ~(RTC_ISR_ALRAF);
}

//check for AlarmB, sample results
if(RTC->ISR & RTC_ISR_ALRBF)
{

ClockBSet=1;

RTC->ISR &= ~(RTC_ISR_ALRBF);

}

}

If any of the above is set (clockBSet etc), I go into standby mode again. But only ever 1 wakens up the processor. I assume all timers can wakeup the processor as above?

Best Regards

Scott

[Sarra.S]

Hello @SSmit.13, 

When the processor wakes up from standby, it will execute the interrupt with the highest priority, in your case, it is it is the RTC_Alarm_IRQn (priority 0, and priority 3 for the RTC_WKUP_IRQn) 

This interrupt will clear the  RTC_ISR_ALRAF and RTC_ISR_ALRBF flags so the other interrupt will not be executed when it occurs.