STM32 ADC 測電壓

1. STM32F103 ADC

本例使用STM32F103芯片的PA1引腳測試模擬輸入的電壓值。

查看文檔《STM32F103X.pdf》第31頁，引腳定義圖：

得知PA1使用ADC1的通道1。

查看文檔《STM32F103X.pdf》第13頁，時鍾樹圖：

得知ADC1可2,4,6,8分頻,又ADC輸入時鍾不得超過14MHZ(參見STM32參考手冊RM0008第11章ADC)。

//初始化ADC
//這里我們僅以規則通道為例
//我們默認將開啟通道0~3                                                   
void  Adc_Init(void)
{     
    ADC_InitTypeDef ADC_InitStructure; 
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |RCC_APB2Periph_ADC1, ENABLE );      //使能ADC1通道時鍾
 

    RCC_ADCCLKConfig(RCC_PCLK2_Div6);   //設置ADC分頻因子6 72M/6=12,ADC最大時間不能超過14M

    //PA1 作為模擬通道輸入引腳                         
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;        //模擬輸入引腳
    GPIO_Init(GPIOA, &GPIO_InitStructure);    

    ADC_DeInit(ADC1);  //復位ADC1,將外設 ADC1 的全部寄存器重設為缺省值

    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;    //ADC工作模式:ADC1和ADC2工作在獨立模式
    ADC_InitStructure.ADC_ScanConvMode = DISABLE;    //模數轉換工作在單通道模式
    ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;    //模數轉換工作在單次轉換模式
    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;    //轉換由軟件而不是外部觸發啟動
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;    //ADC數據右對齊
    ADC_InitStructure.ADC_NbrOfChannel = 1;    //順序進行規則轉換的ADC通道的數目
    ADC_Init(ADC1, &ADC_InitStructure);    //根據ADC_InitStruct中指定的參數初始化外設ADCx的寄存器

      ADC_Cmd(ADC1, ENABLE);    //使能指定的ADC1
    ADC_ResetCalibration(ADC1);    //使能復位校准  
    while(ADC_GetResetCalibrationStatus(ADC1));    //等待復位校准結束
    ADC_StartCalibration(ADC1);     //開啟AD校准
     while(ADC_GetCalibrationStatus(ADC1));     //等待校准結束
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);        //使能指定的ADC1的軟件轉換啟動功能
}

//獲得ADC值
//ch:通道值 0~3
u16 Get_Adc(u8 ch)   
{
      //設置指定ADC的規則組通道，一個序列，采樣時間
    ADC_RegularChannelConfig(ADC1, ch, 1, ADC_SampleTime_239Cycles5 );    //ADC1,ADC通道,采樣時間為239.5周期                      
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);        //使能指定的ADC1的軟件轉換啟動功能    
    while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC ));//等待轉換結束
    return ADC_GetConversionValue(ADC1);           //返回最近一次ADC1規則組的轉換結果
}

u16 Get_Adc_Average(u8 ch,u8 times)
{
    u32 temp_val=0;
    u8 t;
    for(t=0;t<times;t++)
    {
        temp_val+=Get_Adc(ch);
        delay_ms(5);
    }
    return temp_val/times;
}

void ADCTask(void)
{
    float vol, adcx;
    while(1)
    {
        adcx=Get_Adc_Average(ADC_Channel_1,10);    //ADC的值
         vol=(float)adcx*(3300/4096);               //電壓值(mv)
        delay_ms(200);
    }
}

2、 STM32F407 ADC

本例使用STM32F407芯片的PF9引腳測試模擬輸入的電壓值。

查看文檔《STM32F4x7-Datasheet.pdf》第43頁，引腳定義圖：

查看文檔《STM32F4x7-Reference manual.pdf》第51頁，內存映射：

點擊鏈接查看ADC寄存器映射：

又查看數據寄存器偏移量：

得知數據寄存器地址：#define ADC3_DR_ADDRESS ((uint32_t)0x4001224C)

查看《STM32F4x7-Reference manual.pdf》第165頁DMA2 request mapping:

得知使用DMA2 Stream0 通道2映射ADC3。

#define ADC3_DR_ADDRESS    ((uint32_t)0x4001224C)

__IO uint16_t ADC3ConvertedValue = 0;
__IO uint32_t ADC3ConvertedVoltage = 0;

//ADC3 channel07 with DMA configuration
void ADC3_CH7_DMA_Config(void)
{
  ADC_InitTypeDef       ADC_InitStructure;
  ADC_CommonInitTypeDef ADC_CommonInitStructure;
  DMA_InitTypeDef       DMA_InitStructure;
  GPIO_InitTypeDef      GPIO_InitStructure;

  /* Enable ADC3, DMA2 and GPIO clocks ****************************************/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOF, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC3, ENABLE);

  /* DMA2 Stream0 channel2 configuration **************************************/
  DMA_InitStructure.DMA_Channel = DMA_Channel_2;  
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC3_DR_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADC3ConvertedValue;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize = 1;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Disable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
  DMA_Init(DMA2_Stream0, &DMA_InitStructure);
  DMA_Cmd(DMA2_Stream0, ENABLE);

  /* Configure ADC3 Channel7 pin as analog input ******************************/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
  GPIO_Init(GPIOF, &GPIO_InitStructure);

  /* ADC Common Init **********************************************************/
  ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
  ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;
  ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
  ADC_CommonInit(&ADC_CommonInitStructure);

  /* ADC3 Init ****************************************************************/
  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfConversion = 1;
  ADC_Init(ADC3, &ADC_InitStructure);

  /* ADC3 regular channel7 configuration *************************************/
  ADC_RegularChannelConfig(ADC3, ADC_Channel_7, 1, ADC_SampleTime_3Cycles);

 /* Enable DMA request after last transfer (Single-ADC mode) */
  ADC_DMARequestAfterLastTransferCmd(ADC3, ENABLE);

  /* Enable ADC3 DMA */
  ADC_DMACmd(ADC3, ENABLE);

  /* Enable ADC3 */
  ADC_Cmd(ADC3, ENABLE);
}

int main(void)
{
  /* ADC3 configuration *******************************************************/
  /*  - Enable peripheral clocks                                              */
  /*  - DMA2_Stream0 channel2 configuration                                   */
  /*  - Configure ADC Channel7 pin as analog input                             */
  /*  - Configure ADC3 Channel7                                               */
  ADC3_CH7_DMA_Config();

  /* Start ADC3 Software Conversion */ 
  ADC_SoftwareStartConv(ADC3);

  while (1)
  {
    ADC3ConvertedVoltage = ADC3ConvertedValue *3300/0xFFF;

    delay_ms(200);
  }
}