stm32 同时 adc 读取

Question

I have been using STM32 IDE which incorporates the CUBE MX.

Using the HAL code I am able to read on three pins using a separate ADC for each pin. I have started all the ADC's at the same time and then I poll for completion. I am I correct in thinking these ADC reads should be practically simultaneous (ie they all read in at a very similar time)?

Code fragment below. Using a NUCLEO-STM32 F446RE btw.

  MX_ADC1_Init();
  MX_ADC2_Init();
  MX_ADC3_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
      static int flip,sysclk=0,old_sysclk=0,adc1,adc2,adc3;//adc3_0,adc3_1,adc3_2, adc_pstat0,
      int adc_pstat1, adc_pstat2, adc_pstat3;

      flip ^= 1;

          HAL_GPIO_WritePin(GPIOC,GPIO_PIN_0/*|GPIO_PIN_2|GPIO_PIN_6*/, flip);


           HAL_ADC_Start(&hadc3);
           HAL_ADC_Start(&hadc2);
           HAL_ADC_Start(&hadc1);
           adc_pstat1 = HAL_ADC_PollForConversion(&hadc1, 10);
          adc_pstat3 = HAL_ADC_PollForConversion(&hadc3, 10); // should already be done!
          adc_pstat2 = HAL_ADC_PollForConversion(&hadc2, 10); // should already be done!
          adc3 = HAL_ADC_GetValue(&hadc3);
          adc2 = HAL_ADC_GetValue(&hadc2);
          adc1 = HAL_ADC_GetValue(&hadc1);

                  if (adc_pstat2 ||adc_pstat3)
                     asm("\t nop");
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
          sysclk = HAL_GetTick();

          if ( (sysclk - 1000) > old_sysclk ){
              //printf("nucleo F446 0x%X adc3_0 0x%X adc3_1 0x%X adc3_2 0x%X\n",sysclk,adc3_0,adc3_1,adc3_2);
              printf("|->nucleo F446 sysclk=0x%X adc1=0x%X adc2=0x%X adc3=0x%X\n",sysclk,adc1,adc2,adc3);
              old_sysclk = sysclk;
          }
      }
      /* USER CODE END 3 */
    }

Answer 1

Your code does not read it simultaneously as you do not start the ADCs at the sime moment.

You need to use the same external trigger for all of them or use ADCs in the double or tripple mode.

Answer 2

I found a way to do this easily. I set up a timer and used to to update a trigger event. The ADC's then triggered off this event (TIM8_TRGO). Using this trigger I can get two or three ADCs to read simultaneously. The Dual Simultaneous mode seems to support ADCs reading at the same time