exploring-the-different-modes-of-timer-operation-in-stm32

#include "main.h"

/* USER CODE BEGIN PFP */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if(htim == &htim3)
  {
    pulseEND = 1 ;
  }

}
/* USER CODE END PFP */

/* USER CODE BEGIN 0 */

#define TIMCLOCK   60000000
#define PRESCALAR  60
#define ERRUR  416 // ERRUR Simulation is not running in real time

uint32_t IC_Val1 = 0;
uint32_t IC_Val2 = 0;
uint32_t Difference = 0;
uint8_t MSG[50];

int Is_First_Captured = 0;
float frequency = 0;

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
  if (htim->Channel == HAL_TIM_ACTIVE_CHANNEL_4)
   {
    if (Is_First_Captured==0) // if the first rising edge is not captured
      {
     IC_Val1 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_4); // read the first value
     Is_First_Captured = 1;  // set the first captured as true
      }
   else   // If the first rising edge is captured, now we will capture the second edge
      {
       IC_Val2 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_4);  // read second value
        if (IC_Val2 > IC_Val1)
        {
          Difference = IC_Val2-IC_Val1;
        }

        else if (IC_Val1 > IC_Val2)
        {
          Difference = (0xffffffff - IC_Val1) + IC_Val2;
        }

        float refClock = TIMCLOCK/(PRESCALAR);

        frequency = refClock/Difference;
        int x = frequency;
        x-=ERRUR;
        sprintf(MSG,"result = %d \n\r",x);
        HAL_UART_Transmit(&huart1,MSG, sizeof(MSG), 100);
          __HAL_TIM_SET_COUNTER(htim, 0);  // reset the counter
        Is_First_Captured = 0; // set it back to false
      }
    }
}
/* USER CODE END 0 */

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_TIM1_Init();
  MX_TIM2_Init();
  MX_TIM3_Init();
  MX_USART1_UART_Init();

  while (1)
  {
    if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_13)==GPIO_PIN_SET)
    {
      HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_3); //start the TIMER 3 in PWM MODE
      HAL_Delay(1000);                          //1 second delay
      TIM3->ARR = 1 ;                           // signal period of the PWM
      __HAL_TIM_ENABLE(&htim3);                 //ENable TIM3
      while(!pulseEND){};
      pulseEND=0;
    }
    else if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_14)==GPIO_PIN_SET)
    {
      HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_2); //start the TIMER 2 in PWM MODE
      uint32_t CH1;
      while (CH1 < 99 )
      {
        TIM2->CCR2 = CH1;
        CH1+= 1 ;
        HAL_Delay(1);
      }
      while (CH1 > 0 )
      {
       TIM2->CCR2 = CH1;
       CH1-= 1 ;
       HAL_Delay(1);
      }
   }
    else if (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_15)==GPIO_PIN_SET)
    {
      TIM2->CCR3 = 50; //set the PWM duty cycle of TIMER2 to 50%
      HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_3); //start the PWM signal on TIM2
      HAL_TIM_IC_Start_IT(&htim1, TIM_CHANNEL_4);//starts an interrupt input capture 
    }
    else
    {
      HAL_TIM_PWM_Stop(&htim2, TIM_CHANNEL_2);
      HAL_TIM_PWM_Stop(&htim2, TIM_CHANNEL_3);
      HAL_TIM_PWM_Stop(&htim3, TIM_CHANNEL_2);
      HAL_TIM_IC_Stop_IT(&htim1, TIM_CHANNEL_4);
    }

  }
  /* USER CODE END 3 */
}