1、开发平台：

STM32L1-Discovery Keil 4

2、RTC Calendar和wake up

STM32L152RC 带有一个硬件的实时时钟模块(RTC),可为用户提供日历功能，RTC也可以提供一个自动定时的功能，相当于是一个睡眠定时器，下面就看看该如何配置日历和定时：

 void SYS_RTCInit(void)

{

    static NVIC_InitTypeDef  NVIC_InitStructure;

    static EXTI_InitTypeDef  EXTI_InitStructure;

    static RTC_InitTypeDef RTC_InitStructure;

    static RTC_TimeTypeDef RTC_TimeStructure;

    static uint32_t AsynchPrediv = 0, SynchPrediv = 0;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

    /*!< Allow access to RTC */

    PWR_RTCAccessCmd(ENABLE);

    /*!< 使能外部低速时钟 */

    RCC_LSEConfig(RCC_LSE_ON);

    /*!< 等待外部低速时钟就绪 */

    while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)

    {}

    /*!< 配置RTC时钟来源 */

    RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);

    /*!< 使能RTC时钟 */

    RCC_RTCCLKCmd(ENABLE);

    /*!< Wait for RTC APB registers synchronisation */

    RTC_WaitForSynchro();

    //配置日历

    /* 配置RTC数据寄存器以及时钟分频 */

    SynchPrediv = 0xFF;

    AsynchPrediv = 0x7F;//分频为1Hz

    RTC_InitStructure.RTC_AsynchPrediv = AsynchPrediv;

    RTC_InitStructure.RTC_SynchPrediv = SynchPrediv;

    RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;//24小时制

    /* 检查RTC初始化 */

    if (RTC_Init(&RTC_InitStructure) == ERROR)

    {

        printf("\n\r        /!\\***** RTC Prescaler Config failed ********/!\\ \n\r");

    }

    //配置时间 9点15分01秒

    RTC_TimeStructure.RTC_H12     = RTC_H12_AM;

    RTC_TimeStructure.RTC_Hours = 0x09;

    RTC_TimeStructure.RTC_Minutes = 0x15;

    RTC_TimeStructure.RTC_Seconds = 0x01;

    RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);

    //配置自动定时功能

    /* 中断配置 *******************************************************/

    EXTI_ClearITPendingBit(EXTI_Line20);

    EXTI_InitStructure.EXTI_Line = EXTI_Line20;

    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;

    EXTI_InitStructure.EXTI_LineCmd = ENABLE;

    EXTI_Init(&EXTI_InitStructure);

    /*使能 RTC Wakeup Interrupt */

    NVIC_InitStructure.NVIC_IRQChannel = RTC_WKUP_IRQn;

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

    NVIC_Init(&NVIC_InitStructure);

    /* RTC 唤醒中端配置: Clock Source: RTCDiv_16, Wakeup Time Base: 4s */

    RTC_WakeUpClockConfig(RTC_WakeUpClock_RTCCLK_Div16);

    RTC_SetWakeUpCounter(0x1FFF);//0x1FFF = 8191; 4s = (8191+1)*(1/(32768/16))

    /* 使能 the Wakeup Interrupt */

    RTC_ITConfig(RTC_IT_WUT, ENABLE);  

}

使能了RTC的定时中断，那么就要编写中断服务子程序，如下：

void RTC_WKUP_IRQHandler(void)

{

  if(RTC_GetITStatus(RTC_IT_WUT) != RESET)

  {

    RTC_ClearITPendingBit(RTC_IT_WUT);

    EXTI_ClearITPendingBit(EXTI_Line20);

  } 

}