关于stm32断电后时间不能保存的问题

玉珊瑚

问题现象：
我用的芯片是stm32F103VCT6，在VBAT脚加了3.3V电池，断电后，该引脚确实有电压
但是断电后，再上电，时间从新开始了，不能记录我之前修改好的

我看了一下寄存器，RTC_CNTH这个里面是用来存放断点之前的时钟数据的，但是断电之后再上电，这个里面的数据都没有了
但是软件复位就可以，依然有记录。
这是怎么回事呢？

void RTC_Configuration(void)
{
      /* Enable PWR and BKP clocks */
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
   
      /* Allow access to BKP Domain */
      PWR_BackupAccessCmd(ENABLE);
   
      /* Reset Backup Domain */
      BKP_DeInit();
   
      /* Enable LSE */
      RCC_LSEConfig(RCC_LSE_ON);
      /* Wait till LSE is ready */
      while (RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET)
      {}
   
      /* Select LSE as RTC Clock Source */
      RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);
   
      /* Enable RTC Clock */
      RCC_RTCCLKCmd(ENABLE);
   
      /* Wait for RTC registers synchronization */
      RTC_WaitForSynchro();
     
      /* Wait until last write operation on RTC registers has finished */
      RTC_WaitForLastTask();
   
      /* Enable the RTC Second */
     // RTC_ITConfig(RTC_IT_SEC, ENABLE);
   
      /* Wait until last write operation on RTC registers has finished */
     // RTC_WaitForLastTask();
   
      /* Set RTC prescaler: set RTC period to 1sec */
      RTC_SetPrescaler(32767); /* RTC period = RTCCLK/RTC_PR = (32.768 KHz)/(32767+1) */
   
      /* Wait until last write operation on RTC registers has finished */
      RTC_WaitForLastTask();

}

void RTC_Config(void)
{
     //lzf 2011.12.7 下面三句用来对BKP寄存器清0，缺一不可，只供实验用
      //RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
   
      //Allow access to BKP Domain
      //PWR_BackupAccessCmd(ENABLE);
      //BKP_WriteBackupRegister(BKP_DR1, 0x0);
      //BKP_WriteBackupRegister(BKP_DR1, 0x0);
      //Reset Backup Domain
      //2011.12.7 
 
     if (BKP_ReadBackupRegister(BKP_DR1) != 0xA5A5 )
      {
           //Backup data register value is not correct or not yet programmed (when the first time the program is executed)
       
          //  g_bNVRamBl=0;     //电池电压低
            //RTC Configuration
            RTC_Configuration();
           
            Os_InitTime();    //修改系统时间
                
            BKP_WriteBackupRegister(BKP_DR1, 0xA5A5);
      }
      else
      {
           // g_bNVRamBl=1;    //电池电压正常
            //Check if the Power On Reset flag is set
            if (RCC_GetFlagStatus(RCC_FLAG_PORRST) != RESET)
            {
            }
            //Check if the Pin Reset flag is set
            else if (RCC_GetFlagStatus(RCC_FLAG_PINRST) != RESET)
            {
            }
                  // Enable PWR and BKP clocks
            RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
         
            //Allow access to BKP Domain
            PWR_BackupAccessCmd(ENABLE);
           
            Os_InitTime();
           
            RTC_WaitForLastTask();
       }
     
#ifdef RTCClockOutput_Enable 
  //Enable PWR and BKP clocks
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
 
  //Allow access to BKP Domain
  PWR_BackupAccessCmd(ENABLE);
 
  //Disable the Tamper Pin
  BKP_TamperPinCmd(DISABLE); //To output RTCCLK/64 on Tamper pin, the tamper
                              //functionality must be disabled
                              
  //Enable RTC Clock Output on Tamper Pin
  BKP_RTCOutputConfig(BKP_RTCOutputSource_CalibClock);
#endif

  //Clear reset flags
  RCC_ClearFlag();

}

void Os_SetTime(TIME_S7* Time)
{
    #if OS_CRITICAL_METHOD == 3                                   /* Storage for CPU status register       */
    OS_CPU_SR  cpu_sr = 0;
    #endif

    u32  TimValue,IsLeap,i,DateNum=0;

    OS_ENTER_CRITICAL();

    sSysTime.Year = Time->Year;
    sSysTime.Month = Time->Month;
    sSysTime.Date = Time->Date;
    sSysTime.Hour = Time->Hour;
    sSysTime.Minute = Time->Minute;
    sSysTime.Second = Time->Second;
    sSysTime.MillSec = Time->MillSec;

    IsLeap = IsLeapYear(&sSysTime);

    if(IsLeap==0)
    {
        for(i=0;i<Time->Month;i++)
        {
      DateNum = DateNum + EachMonth[IsLeap];
        }
        TimValue=(sSysTime.Year-Ymark)*31536000+(DateNum+sSysTime.Date)*86400+sSysTime.Hour*3600
                                              + sSysTime.Minute*60 + sSysTime.Second+sSysTime.MillSec/1000;
    }
    else
    {

        for(i=0;i<Time->Month;i++)
        {
      DateNum = DateNum + EachMonth[IsLeap];
        }
         /*  the value to store in RTC counter register */
        TimValue=(sSysTime.Year-Ymark)*31622400+(DateNum+sSysTime.Date)*86400+sSysTime.Hour*3600
                                              + sSysTime.Minute*60 + sSysTime.Second+sSysTime.MillSec/1000;

    }

    /* Enable PWR and BKP clocks */
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);

    /* Allow access to BKP Domain */
    PWR_BackupAccessCmd(ENABLE);

    /* Change the current time */
    RTC_SetCounter(TimValue);

    /* Wait until last write operation on RTC registers has finished */
    RTC_WaitForLastTask();

 //   RTC_T_NUM = RTC_GetCounter();

 //   RTC_WaitForLastTask();

    OS_EXIT_CRITICAL();
}

正点原子

移植我们的代码看看。我的那个RTC代码。

玉珊瑚

我一会试试