comparing-adc-performance-on-stm32-through-pll-it-dma

#include "main.h"

/* USER CODE BEGIN PV */
uint16_t ADC_VAL = 0 ;
/* USER CODE END PV */

/* USER CODE BEGIN 0 */
 void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc)
{
   //callBacK IT
   if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_1)==GPIO_PIN_SET)
       {
       //Read and update the ADC Result
     ADC_VAL = HAL_ADC_GetValue(&hadc1);
       }
   //CallBack DMA
   else if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_2)==GPIO_PIN_SET)
       {
         // Conversion complete and DMA Transfer as well
        //=> Update the PWM Duty Cycle whit the last ADC Conversion Result
     TIM2->CCR2 = (ADC_VAL<<4);
       }

}
/* USER CODE END 0 */

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_ADC1_Init();
  MX_TIM2_Init();

  /* USER CODE BEGIN 2 */
HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_2);
//Calibrate the ADC on Power-up for better Accuracy
HAL_ADCEx_Calibration_Start(&hadc1);
  /* USER CODE END 2 */
 
while (1)
{
//Polling Mode
if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_0)==GPIO_PIN_SET)
{
 HAL_ADC_Start(&hadc1);                   //Start ADC Conversion
 HAL_ADC_PollForConversion(&hadc1, 1);//Poll ADC1  and Timeout =1mSec
 ADC_VAL = HAL_ADC_GetValue(&hadc1);      // Read the ADC Conversion Result
      TIM2->CCR2 = (ADC_VAL<<4);
      HAL_Delay(1);
}
 //IT Mode
 else if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_1)==GPIO_PIN_SET)
 {
 HAL_ADC_Start_IT(&hadc1);  //Start ADC Conversion IT
 TIM2->CCR2 = (ADC_VAL<<4);//update PWM Duty Cycle whit the latest Conversion 
 HAL_Delay(1);
 }
//DMA Mode
else if(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_2)==GPIO_PIN_SET)
{
HAL_ADC_Start_DMA(&hadc1, (uint32_t*)&ADC_VAL, 1); //Start ADC Conversion DMA
HAL_Delay(1);
}
else{
 HAL_ADC_Stop(&hadc1);
 HAL_ADC_Start_IT(&hadc1);
 HAL_ADC_Stop_DMA(&hadc1);
 }
}
  /* USER CODE END 3 */
}