NUCLEO_G431RB测评 (3）过采样16位ADC

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NUCLEO_G431RB测评 (3）过采样16位ADC [复制链接]

NUCLEO_G431RB测评 (3）过采样16位ADC

 

NUCLEO_G431的一个亮点是通过硬件过采样技术使得ADC转换位数达到16位，值得进行评测。

 

 

硬件外接1只电位器，将AVDD分压送ADC通道0，OLED以毫伏为单位显示采样的电压值。

 

OLED驱动请参考上一贴《NUCLEO_G431RB测评 (2)驱动OLED》

 

软件设定ADC过采样128次，右移3位，得到16位分辨率。相关代码如下：

 

#include "adc.h"
ADC_HandleTypeDef hadc1;
void MX_ADC1_Init(void)
{
  ADC_MultiModeTypeDef multimode = {0};
  ADC_ChannelConfTypeDef sConfig = {0};
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.GainCompensation = 0;
  hadc1.Init.ScanConvMode = ADC_SCAN_DISABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc1.Init.LowPowerAutoWait = DISABLE;
  hadc1.Init.ContinuousConvMode = ENABLE;
  hadc1.Init.NbrOfConversion = 1;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.DMAContinuousRequests = DISABLE;
  hadc1.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
  hadc1.Init.OversamplingMode = ENABLE;
  hadc1.Init.Oversampling.Ratio = ADC_OVERSAMPLING_RATIO_128;
  hadc1.Init.Oversampling.RightBitShift = ADC_RIGHTBITSHIFT_3;
  hadc1.Init.Oversampling.TriggeredMode = ADC_TRIGGEREDMODE_SINGLE_TRIGGER;
  hadc1.Init.Oversampling.OversamplingStopReset = ADC_REGOVERSAMPLING_CONTINUED_MODE;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }
  multimode.Mode = ADC_MODE_INDEPENDENT;
  if (HAL_ADCEx_MultiModeConfigChannel(&hadc1, &multimode) != HAL_OK)
  {
    Error_Handler();
  }
	  if (HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED) != HAL_OK)
  {
    Error_Handler();
  }
	
  sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = ADC_REGULAR_RANK_1;
  sConfig.SamplingTime = ADC_SAMPLETIME_92CYCLES_5;
  sConfig.SingleDiff = ADC_SINGLE_ENDED;
  sConfig.OffsetNumber = ADC_OFFSET_NONE;
  sConfig.Offset = 0;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_ADC_Start(&hadc1) != HAL_OK)
  {
    Error_Handler();
  }

}

void HAL_ADC_MspInit(ADC_HandleTypeDef* adcHandle)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(adcHandle->Instance==ADC1)
  {
    __HAL_RCC_ADC12_CLK_ENABLE();
     __HAL_RCC_GPIOA_CLK_ENABLE();
    GPIO_InitStruct.Pin = GPIO_PIN_0;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  }
}

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_ADC1_Init();
  Disp_buf[4]='m';
  Disp_buf[5]='V';
  LCD_Init();
  LCD_Print(24, 8,"STM32G431RB",TYPE16X16,TYPE8X16);
  LCD_Print(36, 24, "Nucleo64",TYPE16X16,TYPE8X16);

  while (1)
  {
     if (HAL_ADC_PollForConversion(&hadc1, 1) != HAL_OK)
    {
      Error_Handler();
    }
    uwConvertedValue = HAL_ADC_GetValue(&hadc1);
    uwInputVoltage =uwConvertedValue * 3300;  
    uwInputVoltage = uwInputVoltage / 0xFFF0; 

   Disp_buf[0]=uwInputVoltage%10000/1000+0x30;
   Disp_buf[1]=uwInputVoltage%1000/100+0x30;
   Disp_buf[2]=uwInputVoltage%100/10+0x30;
   Disp_buf[3]=uwInputVoltage%10+0x30;
   LCD_Print(40, 48,Disp_buf,TYPE16X16,TYPE8X16);
  }
}

 

运行结果如图。

 

    评测过程发现NUCLEO_G431的硬件16位过采样ADC转换结果非常稳定，转换后未经任何软件滤波处理，显示的读数只在最后1位偶尔跳动1个数字。可见NUCLEO_G431确实是一款性能优异的STM32芯片。

 

感谢社区，感谢ST提供本次评测机会。

 

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littleshrimp

分压电阻多大的 SAR ADC内部用放大器缓冲了吗

wenyangzeng

littleshrimp 发表于 2019-9-20 19:18 分压电阻多大的 SAR ADC内部用放大器缓冲了吗

10K电位器，未使用ADC内部放大器缓冲。ADC初始化在贴出的代码中

lin2983265615

学习一下

ohahaha

看楼主的测评感觉这块板子确实性能挺好。