用stm32测频率

zdyz111

我打算用单片机的输入捕获功能来测量由信号发生器产生的方波的频率和高电平时间(我用的单片机是stm32f103zet6)，思路是这样的：
用TIM5的CH1通道来测它的高电平，TIM3的CH2通道测它的周期。
我编好代码后，发现高电平测量是对的，周期却是65536us,我认为是配置的问题，但我修改了半天，还是65536us。
以下是TIM3的代码：
void TIM3_Cap_Init(u16 arr,u16 psc)
{  
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);  
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;  
GPIO_Init(GPIOA,&GPIO_InitStructure);
   

//³õʼ»¯¶¨Ê±Æ÷5 TIM5  
TIM_TimeBaseStructure.TIM_Period = arr;  
TIM_TimeBaseStructure.TIM_Prescaler =psc;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
   TIM3_ICInitStructure.TIM_Channel= TIM_Channel_2;
   TIM3_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
   TIM3_ICInitStructure.TIM_ICSelection = TIM_ICSelection_IndirectTI;
   TIM3_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
   TIM3_ICInitStructure.TIM_ICFilter = 0x00;
   TIM_ICInit(TIM3, &TIM3_ICInitStructure);


NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;  
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;  
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

TIM_ITConfig(TIM3,TIM_IT_Update|TIM_IT_CC1,ENABLE);

    TIM_Cmd(TIM3,ENABLE );  //ʹÄܶ¨Ê±Æ÷5
   

}
u8  TIM3CH2_CAPTURE_STA=0; //ÊäÈ벶»ñ״̬         
u16 TIM3CH2_CAPTURE_VAL; //ÊäÈ벶»ñÖµ

//¶¨Ê±Æ÷5ÖжϷþÎñ³ÌÐò  
void TIM3_IRQHandler(void)
{
  if((TIM3CH2_CAPTURE_STA&0X80)==0)//»¹Î´³É¹¦²¶»ñ
{   
  if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
   
  {     
   if(TIM3CH2_CAPTURE_STA&0X40)//ÒѾ­²¶»ñµ½¸ßµçƽÁË
   {
    if((TIM3CH2_CAPTURE_STA&0X3F)==0X3F)//¸ßµçƽ̫³¤ÁË
    {
     TIM3CH2_CAPTURE_STA|=0X80;//±ê¼Ç³É¹¦²¶»ñÁËÒ»´Î
     TIM3CH2_CAPTURE_VAL=0XFFFF;
    }else TIM3CH2_CAPTURE_STA++;
   }  
  }
if (TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET)//²¶»ñ1·¢Éú²¶»ñʼþ
  {
   if(TIM3CH2_CAPTURE_STA&0X40)  //²¶»ñµ½Ò»¸öϽµÑØ   
   {      
    TIM3CH2_CAPTURE_STA|=0X80;  //±ê¼Ç³É¹¦²¶»ñµ½Ò»´ÎÉÏÉýÑØ
    TIM3CH2_CAPTURE_VAL=TIM_GetCapture1(TIM3);
      //TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Rising); //CC1P=0 ÉèÖÃΪÉÏÉýÑز¶»ñ
   }else          //»¹Î´¿ªÊ¼,µÚÒ»´Î²¶»ñÉÏÉýÑØ
   {
    TIM3CH2_CAPTURE_STA=0;   //Çå¿Õ
    TIM3CH2_CAPTURE_VAL=0;
     TIM_SetCounter(TIM3,0);
    TIM3CH2_CAPTURE_STA|=0X40;  //±ê¼Ç²¶»ñµ½ÁËÉÏÉýÑØ
       //TIM_OC1PolarityConfig(TIM3,TIM_ICPolarity_Falling);  //CC1P=1 ÉèÖÃΪϽµÑز¶»ñ
   }      
  }                     
  }
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC1|TIM_IT_Update);

}
请各位大佬帮我看看哪里错了，谢谢（注释是从软件直接复制过来的。。）