STM32 single channel and multi-channel sampling of non DMA polling ADC based on Hal Library

Catalog

single channel （ Continuous conversion mode ）

single channel （ Single conversion mode ） 

Not DMA Multi channel sampling

single channel （ Continuous conversion mode ）

Scan mode disabled , Intermittent mode deactivation , Continuous conversion mode enable

Rule mode enable

about F1 Series of chips

HAL_ADCEx_Calibration_Start(&hadc1);    //AD calibration 

F4 You don't need to , It has been calibrated automatically

stay while Only need to start once before ADC

 HAL_ADC_Start(&hadc1);     // start-up ADC transformation 

Timed read adc

  if(adct>1000){ 
        adct=0;
 
       HAL_ADC_PollForConversion(&hadc1, 50);   // Wait for the conversion to complete ,50 For maximum waiting time , Unit is ms
        if(HAL_IS_BIT_SET(HAL_ADC_GetState(&hadc1), HAL_ADC_STATE_REG_EOC))
        {
          adcval[0] = HAL_ADC_GetValue(&hadc1);   // obtain AD value 
          printf("ADC1 Reading : %d \r\n",adcval[0]);
          printf("PA1 True Voltage value : %.4f \r\n",adcval[0]*3.3f/4096);
        
        }
       
  }
 

  Serial port read

[2022-07-20_18:10:59:740]ADC1 Reading : 2017 
[2022-07-20_18:10:59:740]PA1 True Voltage value : 1.6250 

single channel （ Single conversion mode ） 

And a single conversion, each conversion must start adc

      HAL_ADC_Start(&hadc1);     // start-up ADC transformation 
       HAL_ADC_PollForConversion(&hadc1, 50);   // Wait for the conversion to complete ,50 For maximum waiting time , Unit is ms

Not DMA Multi channel sampling

This question has puzzled me for a long time , Polling mode （ Single plus intermittent ） I've tried , The data is inaccurate during multi-channel testing , For example, the pins of two channels are externally connected 0 or 3.3v The voltage of , Or both 0 Or both 3.3

But after testing, it is read that the voltage values of the two channels are different

Reference resources

stm32cubeMX To configure ADC Multi channel acquisition （ Not dma And interrupt mode ）_Error-500 The blog of -CSDN Blog _stm32 Scan multi-channel acquisition

contrast cubeMX basis hal Library generated adc Initialization code

As long as cubeMX Configure multi-channel , So many channels will enable you .

There are also these two sentences

 sConfig.Channel = ADC_CHANNEL_5;
  sConfig.Rank = ADC_REGULAR_RANK_1;
  sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /** Configure Regular Channel
  */
  sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = ADC_REGULAR_RANK_2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

In this way, it is obvious that the channel set by the latter covers the former , It belongs to redundant code .

This is the structure parameter of the channel configuration , That is to say sConfig 

  Enter again HAL_ADC_ConfigChannel（ Assign values to registers ）

#define MODIFY_REG(REG, CLEARMASK, SETMASK)  WRITE_REG((REG), (((READ_REG(REG)) & (~(CLEARMASK))) | (SETMASK)))

Or I didn't look at the configuration process carefully before , Use the library simply for the sake of using the Library , So follow many tutorials （ Not DMA Many channels of sampling failed .）

Finally, I see the code on the punctual atomic document .（ It uses hal library , But it continues the style of the standard library , So it's all about writing by yourself , of no avail cubeMX To automatically generate code ）

The final solution ： To put it simply, we need to turn multi-channel into single channel , Just change the configuration , The changed configuration is the channel ！ because cubeMX Only generated once , So we define a configuration ....

  rewrite adc The initialization ： That is, it becomes a single channel

void MX_ADC1_Init(void)
{
  ADC_ChannelConfTypeDef sConfig = {0};

  /** Common config
  */
  hadc1.Instance = ADC1;
  hadc1.Init.ScanConvMode = DISABLE;
  hadc1.Init.ContinuousConvMode = DISABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 1;

}

Other pin GPIO Initialize to analog input with cubeMX Generated can .

Every time according to what you want to read adc Channel to read , That is to change adc Handle configuration , With adc1 Two examples

u16 get_adc(u32 ch){ 

ADC_ChannelConfTypeDef _adc;
_adc.Channel=ch;
_adc.Rank=1;
_adc.SamplingTime=ADC_SAMPLETIME_239CYCLES_5;
HAL_ADC_ConfigChannel(&hadc1,&_adc);
HAL_ADC_Start(&hadc1);
HAL_ADC_PollForConversion(&hadc1,10);
return (u16)HAL_ADC_GetValue(&hadc1);
}

effect （ The pin test voltage is correct ）

Conclusion ： Multi channel is configured as single channel . When I test, both single conversion and continuous conversion are ok .