#define MAX_CNT 50000
float pw_s,frq_Hz;

volatile uint16_t overflow_cnt,cntUpdate, temp_overflow_cnt;
volatile int32_t inputCapture_A,inputCapture_B;

volatile uint8_t update;
int32_t zw_Erg;
volatile int32_t capture_us;

void MX_TIM4_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig;
  TIM_MasterConfigTypeDef sMasterConfig;
  TIM_IC_InitTypeDef sConfigIC;

  htim4.Instance = TIM4;
  htim4.Init.Prescaler = 71;
  htim4.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim4.Init.Period = 49999;
  htim4.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim4.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim4) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim4, &sClockSourceConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  if (HAL_TIM_IC_Init(&htim4) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim4, &sMasterConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_FALLING;
  sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
  sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
  sConfigIC.ICFilter = 15;
  if (HAL_TIM_IC_ConfigChannel(&htim4, &sConfigIC, TIM_CHANNEL_1) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

}




void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
	if (htim == &htim4)
	{
		overflow_cnt++;
	}
}


void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
	static uint16_t captureState=1;

	if(update==0)
	{
		switch (captureState)
		{

			case 0: //inputCapture_B
				temp_overflow_cnt = overflow_cnt;
				inputCapture_B = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_1); //1)
				update = 1; //2)
				captureState = 1;
				cntUpdate=0;
				break;
			case 1:      // inputCapture_A
				inputCapture_A = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_1); //1)
				overflow_cnt = 0;
				update = 0;
				captureState = 0;
				cntUpdate=0;
				break;
			default:
				break;
		}

	}
}

int main(void)
{
	MX_TIM4_Init();
	while(1)
	{
	  if (update == 1)
	  {

		zw_Erg = inputCapture_B - inputCapture_A;
		if (zw_Erg >= 0) // Überlauf erkennung
		{
			capture_us = zw_Erg; // erg = (B-A)
		}
		else
		{
			capture_us = zw_Erg + MAX_CNT; // erg=(max-A)+B = (B-A)+max
			temp_overflow_cnt--;
		}
		capture_us = capture_us + (temp_overflow_cnt * MAX_CNT);
		if (capture_us >= 1)
		{
			pw_s = (double)capture_us / 1E6;
			frq_Hz = 1 / pw_s; // Frequenz in Hz
			frequenz_= (uint16_t)frq_Hz;
			if (frequenz_<20)
			{
				printf("\n\rpw_us= %li, Frequenz = %04.2f Hz OV=%i b=%li a=%li \r\n", capture_us,frq_Hz,temp_overflow_cnt,inputCapture_B,inputCapture_A);
			}
			//printf("\n\rpw_us= %li, Frequenz = %04.2f Hz OV=%i\r\n", pw_us,frq_Hz,overflow_cnt );
		}
		else
		{
			printf("\n Alles scheiße");
		}
		update = 0;
	  }
	}
}