STM32 ADC 测电压

1. STM32F103 ADC

本例使用STM32F103芯片的PA1引脚测试模拟输入的电压值。

查看文档《STM32F103X.pdf》第31页，引脚定义图：

得知PA1使用ADC1的通道1。

查看文档《STM32F103X.pdf》第13页，时钟树图：

得知ADC1可2,4,6,8分频,又ADC输入时钟不得超过14MHZ(参见STM32参考手册RM0008第11章ADC)。

//初始化ADC

//这里我们仅以规则通道为例

//我们默认将开启通道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通道时钟

    RCC_ADCCLKConfig(RCC_PCLK2_Div6);   //设置ADC分频因子6 72M/6=12,ADC最大时间不能超过14M

    //PA1 作为模拟通道输入引脚

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;        //模拟输入引脚

    GPIO_Init(GPIOA, &GPIO_InitStructure);    

    ADC_DeInit(ADC1);  //复位ADC1,将外设 ADC1 的全部寄存器重设为缺省值

    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;    //ADC工作模式:ADC1和ADC2工作在独立模式

    ADC_InitStructure.ADC_ScanConvMode = DISABLE;    //模数转换工作在单通道模式

    ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;    //模数转换工作在单次转换模式

    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;    //转换由软件而不是外部触发启动

    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;    //ADC数据右对齐

    ADC_InitStructure.ADC_NbrOfChannel = 1;    //顺序进行规则转换的ADC通道的数目

    ADC_Init(ADC1, &ADC_InitStructure);    //根据ADC_InitStruct中指定的参数初始化外设ADCx的寄存器

      ADC_Cmd(ADC1, ENABLE);    //使能指定的ADC1

    ADC_ResetCalibration(ADC1);    //使能复位校准

    while(ADC_GetResetCalibrationStatus(ADC1));    //等待复位校准结束

    ADC_StartCalibration(ADC1);     //开启AD校准

     while(ADC_GetCalibrationStatus(ADC1));     //等待校准结束

    ADC_SoftwareStartConvCmd(ADC1, ENABLE);        //使能指定的ADC1的软件转换启动功能

}

//获得ADC值

//ch:通道值 0~3

u16 Get_Adc(u8 ch)

{

      //设置指定ADC的规则组通道，一个序列，采样时间

    ADC_RegularChannelConfig(ADC1, ch, 1, ADC_SampleTime_239Cycles5 );    //ADC1,ADC通道,采样时间为239.5周期

    ADC_SoftwareStartConvCmd(ADC1, ENABLE);        //使能指定的ADC1的软件转换启动功能

    while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC ));//等待转换结束

    return ADC_GetConversionValue(ADC1);           //返回最近一次ADC1规则组的转换结果

}

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);               //电压值(mv)

        delay_ms(200);

    }

}

2、 STM32F407 ADC

本例使用STM32F407芯片的PF9引脚测试模拟输入的电压值。

查看文档《STM32F4x7-Datasheet.pdf》第43页，引脚定义图：

查看文档《STM32F4x7-Reference manual.pdf》第51页，内存映射：

点击链接查看ADC寄存器映射：

又查看数据寄存器偏移量：

得知数据寄存器地址：#define ADC3_DR_ADDRESS ((uint32_t)0x4001224C)

查看《STM32F4x7-Reference manual.pdf》第165页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);

  }

}

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STM32 ADC 测电压

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