原创 STM32 怎样在程序运行中改写RTC计数器寄存器的值

STM32 怎样在程序运行中改写RTC计数器寄存器的值呢？我用以下方法总是清0，请高手指点。

        RCC->APB1ENR |= RCC_APB1ENR_PWREN;              // enable clock for Power interface
     PWR->CR      |= PWR_CR_DBP;  // enable access to RTC, BDC registers

     if ((0x00000100 & RCC_BDCR_RTCSEL) == 0x00000100) {   
       RCC->BDCR |= RCC_BDCR_LSEON;                                // enable LSE
       while ((RCC->BDCR & RCC_BDCR_LSERDY) == 0);  
     }
     
        RTC->CRL  |=  RTC_CRL_CNF;                                    // set configuration mode
     RTC->CNTH  = (((17 *3600UL)+(31 *60UL)+(1))>>16) & 0xFFFF;  
     RTC->CNTL  = (((17 *3600UL)+(31 *60UL)+(1))>>16) & 0xFFFF; 
     RTC->ALRH  = (((17 *3600UL)+(30 *60UL)+(1))>>16) & 0xFFFF; 
     RTC->ALRL  = (((17 *3600UL)+(30 *60UL)+(1))>>16) & 0xFFFF; 
     RTC->CRL  &= ~RTC_CRL_CNF;                                    // reset configuration mode
     
     RTC->CRH = 0x00000003;       // enable RTC interrupts
       NVIC->Enable[0] |= (1 << (RTC_IRQChannel & 0x1F));   // enable interrupt
       
     while ((RTC->CRL & RTC_CRL_RTOFF) == 0);   // wait until write is finished

     PWR->CR   &= ~PWR_CR_DBP;                       // disable access to RTC registers

/*------------------------------------------------------------------------------
* 函数: void RTC_Config(void) 这个是修改好的例程
* 功能: RTC配置（修改的数值在RTCTime里面）
* 参数: 无
* 返回: 无
 *------------------------------------------------------------------------------*/
void RTC_Config(void)
{   
   RCC->APB1ENR |= RCC_APB1ENR_PWREN;              // enable clock for Power interface 打开电源管理
   PWR->CR      |= PWR_CR_DBP;                                   // enable access to RTC, BDC registers 使能RTC和备份寄存器的访问

   RCC->BDCR |= RCC_BDCR_LSEON;                                // enable LSE外部低速振荡器使能
   while ((RCC->BDCR & RCC_BDCR_LSERDY) == 0);       // Wait for LSERDY = 1 (LSE is ready)
 
   RCC->BDCR |= (0x00000100 | RCC_BDCR_RTCEN);    // set RTC clock source, enable RTC clock选择LSE位RTC时钟,使能RTC时钟
 
   RTC->CRL &= (u16)~RTC_CRL_RSF;//Clear RSF flag [清RSF标志]   
   while ((RTC->CRL & RTC_CRL_RSF) == (u16)RESET);//Loop until RSF flag is set [循环到RSF标志置位]
   while ((RTC->CRL & RTC_CRL_RTOFF) == 0);                      // wait until write is finished
 
   RTC->CRH = 0x00000003;       // enable RTC interrupts
   NVIC->Enable[0] |= (1 << (RTC_IRQChannel & 0x1F));          // enable interrupt
 while ((RTC->CRL & RTC_CRL_RTOFF) == 0);                      // wait until write is finished
 
   RTC->CRL  |=  RTC_CRL_CNF;                                    // set configuration mode
   RTC->PRLH  = ((0x000003E8*32768/1000-1)>>16) & 0x00FF;   // set prescaler load register high
   RTC->PRLL  = ((0x000003E8*32768/1000-1)) & 0xFFFF;   // set prescaler load register low
   while ((RTC->CRL & RTC_CRL_RTOFF) == 0);                      // wait until write is finished
 
   RTC->CNTH = RTCTime >> 16;/* Set RTC COUNTER MSB word [设置RTC计数器高半字节]*/
   RTC->CNTL = (RTCTime & 0xFFFF);/* Set RTC COUNTER LSB word [设置RTC计数器低半字节]*/
   RTC->CRL  &= ~RTC_CRL_CNF;                                    // reset configuration mode       
   while ((RTC->CRL & RTC_CRL_RTOFF) == 0);                      // wait until write is finished
}