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2 min interrupt using RTC

shwetafree2fly
Associate
Posted on September 04, 2012 at 02:47

Hi all,

I am new to programming. I wanted some help regarding rtc coding. I am using stm32l1 discovery board(and IAR workbench), and want to generate interrupt after every 2 mins. I think using timers for this will be tricky. I tried one vague attempt using std periph examples, and obviously it din work.. I donno the format that i should give for 2 mins interrupt generation. 

void RTC_Config(void)

{

  RTC_InitTypeDef RTC_InitStructure;

  RTC_TimeTypeDef  RTC_TimeStruct;

 

  /* Enable the PWR clock */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

  /* Allow access to RTC */

  PWR_RTCAccessCmd(ENABLE);

  /* Reset RTC Domain */

  RCC_RTCResetCmd(ENABLE);

  RCC_RTCResetCmd(DISABLE);

  /* Enable the LSE OSC */

  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);

  /* Configure the RTC data register and RTC prescaler */

  RTC_InitStructure.RTC_AsynchPrediv = 0x7F;

  RTC_InitStructure.RTC_SynchPrediv  = 0xFF;

  RTC_InitStructure.RTC_HourFormat   = RTC_HourFormat_24;

  RTC_Init(&RTC_InitStructure);

 

  /* Set the time to 00h 00mn 00s AM */

  RTC_TimeStruct.RTC_H12     = RTC_H12_AM;

  RTC_TimeStruct.RTC_Hours   = 0x00;

  RTC_TimeStruct.RTC_Minutes = 0x00;

  RTC_TimeStruct.RTC_Seconds = 0x00;  

  RTC_SetTime(RTC_Format_BIN, &RTC_TimeStruct);

    /* Enable the RTC Clock */

  RCC_RTCCLKCmd(ENABLE);

 

  /* Wait for RTC APB registers synchronisation */

  RTC_WaitForSynchro();

}

/**

  * @brief  Configures the RTC Alarm.

  * @param  None

  * @retval None

  */

void RTC_AlarmConfig(void)

{

  EXTI_InitTypeDef EXTI_InitStructure;

  RTC_AlarmTypeDef RTC_AlarmStructure;

  NVIC_InitTypeDef NVIC_InitStructure;

 

  /* 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);

 

  /* Enable the RTC Alarm Interrupt */

  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);

 

  /* Set the alarmA Masks */

  RTC_AlarmStructure.RTC_AlarmMask = RTC_AlarmMask_NONE;

  RTC_SetAlarm(RTC_Format_BIN, RTC_Alarm_A, &RTC_AlarmStructure);

  RTC_AlarmStructure.RTC_AlarmTime.RTC_Minutes = 2;

 

  /* Enable AlarmA interrupt */

  RTC_ITConfig(RTC_IT_ALRA, ENABLE);

 

  /* Enable the alarmA */

  RTC_AlarmCmd(RTC_Alarm_A, DISABLE);

 

}

Any help is highly appreciated.

Thanks

2 REPLIES 2
shwetafree2fly
Associate
Posted on September 04, 2012 at 12:26

hi all..,

Or can anyone suggest me any alternative to generate interrupt after each 2mins??

frankmeyer9
Associate II
Posted on September 04, 2012 at 14:17

Without timer or rtc, this is hardly possible.

However, a simpler approach is to use the Systick timer.

Configure it, for instance, for one interrupt each second, and count up the seconds.

A SysTick example application is provided in the PeripheralDriver libs.