TIM2定时闪灯程序。。。

void TIM2_Configuration(void)
{
 TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
 NVIC_InitTypeDef NVIC_InitStructure; 

     //配置TIM2中断
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

  NVIC_InitStructure.NVIC_IRQChannel =TIM2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure); 
 
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);     //打开TIM2定时器的时钟
   
  TIM_DeInit(TIM2);                                      //TIMx寄存器重设为缺省值
 
  TIM_TimeBaseStructure.TIM_Period = 20000;              //自动重装载寄存器周期的值
  //TIM_Period 设置了在下一个更新事件装入活动的自动重装载寄存器周期的值。它的取值必须在0x0000和0xFFFF之间。
  TIM_TimeBaseStructure.TIM_Prescaler=360 - 1;               //TIMx时钟频率除数的预分频值
  //TIM_Prescaler 设置了用来作为TIMx时钟频率除数的预分频值。它的取值必须在 0x0000 和0xFFFF之间。
  TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;     //采样分频
  TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式
  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
 
  TIM_ARRPreloadConfig(TIM2, ENABLE);                       //允许自动重装载寄存器（ARR）
  TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);                 //允许TIM2溢出中断
 
  TIM_Cmd(TIM2, ENABLE);                                 //TIM2开启时钟

}

bool bFlag=FALSE;
void TIM2_IRQHandler(void)
{
// GPIOC->ODR ^= (1<<4);                         //闪灯
 if(bFlag){
  GPIO_SetBits(GPIOA,GPIO_Pin_8);
  bFlag=FALSE;
  }
    else {
  GPIO_ResetBits(GPIOA,GPIO_Pin_8);
  bFlag=TRUE;
  }
 
 TIM_ClearITPendingBit(TIM2, TIM_FLAG_Update); //清中断
}