int main(void)
{uint32 regval;
 RCCcfg();
 
  /*enable gpio port A clock*/
                                                        regval     =RCC_APB2ENR&0x0000FFFB;
                                                        RCC_APB2ENR=regval|PORT_A_CLK_ENA;
  /*enable AFIO clock */
                                                        regval     =RCC_APB2ENR&0x0000FFFE;
                                                        RCC_APB2ENR=regval|AFIO_CLK_ENA;
           
  /*set portA.0 as GPIO to drive LED */
                                                       PORT_A_CRL =0x01; //set port_a.0 as out put

  /*set portA.8 as Clock out */
                                                      PORT_A_CRH =0x03     //set port_a.8 as out put,and set max speed at 50Mhz
                                                                                 |(0x02

我有点看不懂你的程序，或许是个人习惯所致，我给你一个我在做RTC时钟用到的中断，你看一下，是如何配置的。
void RTC_It(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
    NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQChannel;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority =6;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}
可以根据你的需求将RTC_IRQChannel换成自己所需要开通的通道。