STM8 PWM输入捕捉完整程序

大家好，最近在做一个项目关于PWM输入捕捉的，使用的单片机为STM8S105，我在用STM8的输入捕捉功能 利用库函数TIME1 CH1 捕捉PE0的频率 很准，但是我在此程序基础上将PE0口的频率 改为由 TIME2 产生，同样使用TIME1 CH1 捕捉，捕捉到的频率不对是怎么回事? TIME2 产生的PWM 用示波器测试很准的 望高手指点，谢谢！
库函数捕捉程序如下：
void main(void)
{
  TIM1_Channel = TIM1_CHANNEL_1
  TIM1_ICPolarity = TIM1_ICPOLARITY_FALLING
  TIM1_ICSelection = TIM1_ICSELECTION_DIRECTTI
  TIM1_ICPrescaler = TIM1_ICPSC_div8
  TIM1_ICFilter = 0x0
  TIM1_ICInit( TIM1_CHANNEL_1, TIM1_ICPOLARITY_FALLING, TIM1_ICSELECTION_DIRECTTI,  TIM1_ICPSC_div8, 0x0);
  TIM1_ITConfig(TIM1_IT_CC1, ENABLE);
   /* Enable TIM1 */
  TIM1_Cmd(ENABLE);
   /* Clear CC1 Flag*/
  TIM1_ClearFlag(TIM1_FLAG_CC1);
   /* Connect LSI to COO pin*/
  GPIO_Init(GPIOE, GPIO_PIN_0, GPIO_MODE_OUT_PP_LOW_FAST);
  CLK_CCOConfig(CLK_OUTPUT_LSI);
  CLK_CCOCmd(ENABLE);
  /* wait a capture on CC1 */
  while((TIM1->SR1 & TIM1_FLAG_CC1) ！= TIM1_FLAG_CC1);
  /* Get CCR1 value*/
        ICValue1 = TIM1_GetCapture1();
        TIM1_ClearFlag(TIM1_FLAG_CC1);
        /* wait a capture on cc1 */
  while((TIM1->SR1 & TIM1_FLAG_CC1) ！= TIM1_FLAG_CC1);
  /* Get CCR1 value*/
        ICValue2 = TIM1_GetCapture1();
        TIM1_ClearFlag(TIM1_FLAG_CC1);
  /* Compute LSI clock frequency */
  LSIClockFreq = (8 * TIM1ClockFreq) / (ICValue2 - ICValue1);
/* Insert a break point here */
        while (1);
}

在此库函数基础上，改为TIME2产生PWM程序如下，
void init_hsiclk(void)
{
CLK_DeInit(); //寄存器复位
CLK_HSICmd(ENABLE); //内部高速时钟使能
CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIdiv1); //内部分频 2M
}

void TIM2_init(void)
{
  TIM2_TimeBaseInit(TIM2_PRESCALER_16, 6665);
  TIM2_OC3Init(TIM2_OCMODE_PWM1, TIM2_OUTPUTSTATE_ENABLE,CCR3_Val, TIM2_OCPOLARITY_HIGH);
  TIM2_OC3PreloadConfig(ENABLE);
  TIM2_ARRPreloadConfig(ENABLE);
  TIM2_Cmd(ENABLE);
}
void main(void)
{
  //CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIdiv1);//主时钟16/16=1MHZ   4分频
        init_hsiclk();
        GPIO_Init(TIME2PWMOUT_PORT, TIME2PWMOUT_PIN , GPIO_MODE_OUT_PP_LOW_FAST);     //设置PA3端口为推挽输出模式
        GPIO_Init(TIME1PWMIN_PORT , TIME1PWMIN_PIN, GPIO_MODE_IN_FL_NO_IT);
  TIM2_init();
        TIM1_ICInit( TIM1_CHANNEL_1, TIM1_ICPOLARITY_FALLING, TIM1_ICSELECTION_DIRECTTI,  TIM1_ICPSC_div8, 0x0);
        /* Enable CC1 interrupt */
        TIM1_ITConfig(TIM1_IT_CC1, ENABLE);
        /* Enable TIM1 */
  TIM1_Cmd(ENABLE);
        /* Clear CC1 Flag*/
  TIM1_ClearFlag(TIM1_FLAG_CC1);
        /* Connect LSI to COO pin*/
//GPIO_Init(GPIOE, GPIO_PIN_0, GPIO_MODE_OUT_PP_LOW_FAST);    //不使用
        //CLK_CCOConfig(CLK_OUTPUT_LSI);
        //CLK_CCOCmd(ENABLE);
        
        /* wait a capture on CC1 */
  while((TIM1->SR1 & TIM1_FLAG_CC1) ！= TIM1_FLAG_CC1);
  /* Get CCR1 value*/
        ICValue1 = TIM1_GetCapture1();
        TIM1_ClearFlag(TIM1_FLAG_CC1);
        /* wait a capture on cc1 */
  while((TIM1->SR1 & TIM1_FLAG_CC1) ！= TIM1_FLAG_CC1);
  /* Get CCR1 value*/
        ICValue2 = TIM1_GetCapture1();
        TIM1_ClearFlag(TIM1_FLAG_CC1);
  /* Compute LSI clock frequency */
  LSIClockFreq = (8 * TIM1ClockFreq) / (ICValue2 - ICValue1);
        
        /* Insert a break point here */
        while (1);
}

谢谢分享学习一下

DSP  ecap
捕获比较容易

小编有何高见没?

回一个看看，哈哈哈哈哈

有时候捕获的两个值相减 求得的频率会有一点点偏差