RTC alarm handler does not want to work

[hitsumen]

Posted on February 13, 2014 at 09:34

Good day,

Like topic said, the alarm handler does not to work, but if I do like this:

while (!RTC_GetITStatus(RTC_IT_ALRA));printf(''\nALARM''); //it works

Here is my code: int main(void){  NVIC_InitTypeDef  NVIC_InitStructure;    STM_EVAL_PBInit(BUTTON_USER , BUTTON_MODE_EXTI);    STM_EVAL_LEDInit(LED3);  STM_EVAL_LEDInit(LED4);  STM_EVAL_LEDInit(LED5);  STM_EVAL_LEDInit(LED6);      /* Turn LED2 ON */  STM_EVAL_LEDOn(LED3);   DBGU_Init();     RTC_Config();    RTC_TimeShow();  RTC_AlarmShow();    NVIC_InitStructure.NVIC_IRQChannel = RTC_Alarm_IRQn;  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  NVIC_Init(&NVIC_InitStructure);  while (!RTC_GetITStatus(RTC_IT_ALRA));printf(''\nALARM''); //works  while(1);}and handler:

void RTC_Alarm_IRQHandler(void)

{  if(RTC_GetITStatus(RTC_IT_ALRA) != RESET)  {    STM_EVAL_LEDToggle(LED6);    RTC_ClearITPendingBit(RTC_IT_ALRA);    EXTI_ClearITPendingBit(USER_BUTTON_EXTI_LINE);  } }

[chen]

Posted on February 13, 2014 at 10:18

Hi

You have not said which STM32 Discovery board you are using. You have not shown your code for ''

RTC_Config();

'' Have you done this : ''All RTC interrupts are connected to the EXTI controller. To enable the RTC Alarm interrupt, the following sequence is required: 1. Configure and enable the EXTI Line 17 in interrupt mode and select the rising edge sensitivity. 2. Configure and enable the RTC_Alarm IRQ channel in the NVIC. 3. Configure the RTC to generate RTC alarms (Alarm A or Alarm B). To enable the RTC Wakeup interrupt, the following sequence is required: 1. Configure and enable the EXTI Line 22 in interrupt mode and select the rising edge sensitivity. 2. Configure and enable the RTC_WKUP IRQ channel in the NVIC. 3. Configure the RTC to generate the RTC wakeup timer event.'' (Take from the reference manual)

[hitsumen]

Posted on February 13, 2014 at 10:30

Why do I need EXTI line for that? I use STM32F4-DISCOVERY.

static void RTC_Config(void)

{  RTC_DateTypeDef RTC_DateStructure;    /* Enable the PWR clock */  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);  /* Allow access to RTC */  PWR_BackupAccessCmd(ENABLE);    RCC_LSEConfig(RCC_LSE_ON);  /* Wait till LSE is ready */    while(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)  {  }  /* Select the RTC Clock Source */  RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);  /* ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)*/  uwSynchPrediv = 0xFF;  uwAsynchPrediv = 0x7F;  /* Enable the RTC Clock */  RCC_RTCCLKCmd(ENABLE);  /* Wait for RTC APB registers synchronisation */  RTC_WaitForSynchro();    /* Configure the RTC data register and RTC prescaler */  RTC_InitStructure.RTC_AsynchPrediv = uwAsynchPrediv;  RTC_InitStructure.RTC_SynchPrediv = uwSynchPrediv;  RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;  RTC_Init(&RTC_InitStructure);    /* Set the alarm 05h:20min:30s */  RTC_AlarmStructure.RTC_AlarmTime.RTC_H12     = RTC_H12_AM;  RTC_AlarmStructure.RTC_AlarmTime.RTC_Hours   = 0x05;  RTC_AlarmStructure.RTC_AlarmTime.RTC_Minutes = 0x20;  RTC_AlarmStructure.RTC_AlarmTime.RTC_Seconds = 0x05;  RTC_AlarmStructure.RTC_AlarmDateWeekDay = 0x31;  RTC_AlarmStructure.RTC_AlarmDateWeekDaySel = RTC_AlarmDateWeekDaySel_Date;  RTC_AlarmStructure.RTC_AlarmMask = RTC_AlarmMask_DateWeekDay;    /* Configure the RTC Alarm A register */  RTC_SetAlarm(RTC_Format_BCD, RTC_Alarm_A, &RTC_AlarmStructure);    /* Enable RTC Alarm A Interrupt */  RTC_ITConfig(RTC_IT_ALRA, ENABLE);    /* Enable the alarm */  RTC_AlarmCmd(RTC_Alarm_A, ENABLE);    RTC_ClearFlag(RTC_FLAG_ALRAF);    /* Set the date: Friday January 11th 2013 */  RTC_DateStructure.RTC_Year = 0x13;  RTC_DateStructure.RTC_Month = RTC_Month_January;  RTC_DateStructure.RTC_Date = 0x11;  RTC_DateStructure.RTC_WeekDay = RTC_Weekday_Saturday;  RTC_SetDate(RTC_Format_BCD, &RTC_DateStructure);    /* Set the time to 05h 20mn 00s AM */  RTC_TimeStructure.RTC_H12     = RTC_H12_AM;  RTC_TimeStructure.RTC_Hours   = 0x05;  RTC_TimeStructure.RTC_Minutes = 0x20;  RTC_TimeStructure.RTC_Seconds = 0x00;     RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);   }

[chen]

Posted on February 13, 2014 at 10:41

''Why do I need EXTI line for that?''

The Reference manual says so. ''

  /* Enable RTC Alarm A Interrupt */

  RTC_ITConfig(RTC_IT_ALRA, ENABLE);'' Check this does what the reference manual says.

[chen]

Posted on February 13, 2014 at 10:46

Hi

Also, just spotted you are missing this :     NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4); Since your project is so simple - it does not matter which group you pick.

[hitsumen]

Posted on February 13, 2014 at 11:29

Actually you were right I need EXTI, and handler worked

/* EXTI configuration */

EXTI_ClearITPendingBit(EXTI_Line17);EXTI_InitStructure.EXTI_Line = EXTI_Line17;EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;EXTI_InitStructure.EXTI_LineCmd = ENABLE;EXTI_Init(&EXTI_InitStructure);And I do not need this:NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);About alarms, can I do it on other day? I just saw that I could only set up alarm time..Thank you,//Nikolaj

[chen]

Posted on February 13, 2014 at 12:08

Hi

I have not used the RTC peripheral myself (yet). Looking at the RTC registers, it implies you can set any day and time. By implication : ''About alarms, can I do it on other day? I just saw that I could only set up alarm time..'' Yes - you should be able to set the alarm for another day. It CANNOT set an alarm in another month or year.