__INLINE void ConfigureTIMxAsInputCapture(void)
{
  /* Configure NVIC for TIMx */
  /* (1) Enable Interrupt on TIMx */
  /* (2) Set priority for TIMx*/
  NVIC_EnableIRQ(TIMx_IRQn); /* (1) */
  NVIC_SetPriority(TIMx_IRQn,0); /* (2) */
 
  /* (1) Enable the peripheral clock of Timer x */
  /* (2) Set PCLK clock prescaler to /16 (111)
         set HCLK clock prescaler to /64 (1100) */
  /* (3) Enable the peripheral clock of GPIOA */
  /* (4) Select alternate function mode on GPIOA pin 8 */
  /* (5) Select AF2 on PA8 in AFRH for TIM1_CH1 */
 

  RCC->APB2ENR |= RCC_APB2ENR_TIM1EN; /* (1) */
  RCC->CFGR |= RCC_CFGR_PPRE | RCC_CFGR_HPRE_3 | RCC_CFGR_HPRE_2; /* (2) */
  RCC->AHBENR |= RCC_AHBENR_GPIOAEN; /* (3) */
  GPIOA->MODER = (GPIOA->MODER & ~(GPIO_MODER_MODER8)) | (GPIO_MODER_MODER8_1); /* (4) */
  GPIOA->AFR[1] |= 0x02; /* (5) */
 
  /* (1) Select the active input TI1 (CC1S = 01),
         program the input filter for 8 clock cycles (IC1F = 0011),
         select the rising edge on CC1 (CC1P = 0, reset value)
         and prescaler at each valid transition (IC1PS = 00, reset value) */
  /* (2) Enable capture by setting CC1E */
  /* (3) Enable interrupt on Capture/Compare */
  /* (4) Enable counter */ 
 
  TIMx->CCMR1 |= TIM_CCMR1_CC1S_0 \
               | TIM_CCMR1_IC1F_0 | TIM_CCMR1_IC1F_1; /* (1)*/
  TIMx->CCER |= TIM_CCER_CC1E; /* (2) */ 
  TIMx->DIER |= TIM_DIER_CC1IE; /* (3) */
  TIMx->CR1 |= TIM_CR1_CEN; /* (4) */
}
----------
/**
  * @brief  This function handles TIM1 interrupt request.
  *         This interrupt subroutine computes the laps between 2 rising edges
  *         on T1IC. This laps is stored in the "Counter" variable.
  * @param  None
  * @retval None
  */
void TIM1_CC_IRQHandler(void)
{
uint16_t counter1;
 
/*
 
*/
  if ((TIMx->SR & TIM_SR_CC1IF) != 0)
  {
    if ((TIMx->SR & TIM_SR_CC1OF) != 0)  /* Check the overflow */
    {
      error = 0xFF;
      gap = 0;  /* Reinitialize the laps computing */
      TIMx->SR &= ~(TIM_SR_CC1OF | TIM_SR_CC1IF); /* Clear the flags */
      return;
    }
    if (gap == 0) /* Test if it is the first rising edge */
    {
      counter0 = TIMx->CCR1; /* Read the capture counter which clears the CC1ICF */
      gap = 1; /* Indicate that the first rising edge has yet been detected */
    }
    else
    {
      counter1 = TIMx->CCR1; /* Read the capture counter which clears the CC1ICF */
      if (counter1 > counter0) /* Check capture counter overflow */
      {
        Counter = counter1 - counter0;
      }
      else
      {
        Counter = counter1 + 0xFFFF - counter0 + 1;
      }
      counter0 = counter1;
      error = 0;
    }   
  }
  else
  {
    error = ERROR_WRONG_IT; /* Report an error */
  }
}