stm32 ADC模数转换 ADC多通道 ADC DMA

通过调节电位器，改变AD转换值和电压值

STM32F1 ADC 配置步骤

1.使能GPIO时钟和ADC时钟

2.配置引脚模式为模拟输入

3.配置ADC的分频因子

4.初始化ADC参数，ADC_InitTypeDef

5.使能ADC

6.执行ADC校准

7.设置ADC软件启动

8.读取ADC转换值

9.设置ADC规则，采样时间等

10.使能ADC的软件转换

11.读取ADC转换结果

举例

u16 ADC_value(u8 time)

{

    u8 i = 0;

    u16 value;

    for(i = 0; i < time; i++)

    {

        ADC_SoftwareStartConvCmd(ADC1, ENABLE); //使能ADC的软件转换

        while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) != SET);

        value += ADC_GetConversionValue(ADC1); //读取ADC转换结果

    }

    return value/time;

}

typedef struct

{

    uint32_t ADC_Mode; //双模式选择

    FunctionalState ADC_ScanConvMode; //扫描模式

    FunctionalState ADC_ContinuousConvMode; //连续转换

    uint32_t ADC_ExternalTrigConv;  //注入通道的外部触发转换模式

    uint32_t ADC_DataAlign; //数据对齐

    uint8_t ADC_NbrOfChannel; //规则通道序列长度

}ADC_InitTypeDef;

void ADC_init()

{

    GPIO_InitTypeDef gpio =

    {

        GPIO_Pin_1,

        GPIO_Speed_50MHz,

        GPIO_Mode_AIN //模拟输入

    };

    ADC_InitTypeDef adc =

    {

        ADC_Mode_Independent, //独立模式

        DISABLE, //关闭扫描模式

        DISABLE, //单次转换模式

        ADC_ExternalTrigConv_None, //不用外部事件启动转换

        ADC_DataAlign_Right, //右对齐

        1, //通道数目1

    };

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_ADC1, ENABLE); //使能GPIO时钟和ADC时钟

    GPIO_Init(GPIOA, &gpio); //配置引脚模式

    RCC_ADCCLKConfig(RCC_PCLK2_Div6); //配置ADC的分频因子 72/6=12（通常）

    ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 1, ADC_SampleTime_55Cycles5); //设置ADC规则，采样周期

    ADC_Init(ADC1, &adc); //初始化ADC参数

    ADC_Cmd(ADC1, ENABLE); //使能ADC

    ADC_ResetCalibration(ADC1); //执行ADC复位校准

    while(ADC_GetResetCalibrationStatus(ADC1) == SET); //等待校准完成

    ADC_StartCalibration(ADC1); //执行ADC校准

    while(ADC_GetCalibrationStatus(ADC1) == SET);

    ADC_SoftwareStartConvCmd(ADC1, ENABLE); //ADC软件启动

}

int main(void)

{

    ADC_init();

    while(1)

    {

        adc = ADC_value(15); //15次平均值

        printf("ADC_value is %d.\n", adc);

        printf("vol is %.3fV.\n", adc * (3.3 / 4096)); //电压值

        delay_ms(500);

        led1 = ~led1;

    }

}

电压计算

vol = ADC * (3.3 / 4096);

ADC的参考电压VREF+为3.3V。ADC为12位转换精度， 2^12为4096

DMA方式

ADC_DMACmd开启DMA，在ADC初始化之后

ADC_RegularChannelConfig通道配置，在ADC初始化之后

DMA_MemoryInc要设置为DMA_MemoryInc_Enable，存储器地址递增

DMA_BufferSize大小，是定义DMA_MemoryBaseAddr内存的大小。根据DMA_MemoryDataSize存储器数据宽度，HalfWord占16bit

#define CHANNEL_NUM 4

volatile u16 AD_Bufer[4];

volatile u8 adc1_ok;

//多通道配置。4路输入

void ADC_init()

{

    ...

    ADC_InitTypeDef adc =

    {

        ADC_Mode_Independent, //独立模式

        ENABLE, //开启扫描模式

        ENABLE, //开启连续转换模式

        ADC_ExternalTrigConv_None, //不用外部事件启动转换

        ADC_DataAlign_Right, //右对齐

        CHANNEL_NUM, //通道数目4

    };

    ADC_Init(ADC1, &adc);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 1, ADC_SampleTime_55Cycles5);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_2, 2, ADC_SampleTime_55Cycles5);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_3, 3, ADC_SampleTime_55Cycles5);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_4, 4, ADC_SampleTime_55Cycles5);

    DMA_adc_init(ADC1, (u32)AD_Bufer, CHANNEL_NUM);

    ...

}

void DMA_adc_init(ADC_TypeDef *ADCx, u32 mem_addr, u32 size)

{

   DMA_InitTypeDef DMA_InitStructure;

   NVIC_InitTypeDef NVIC_InitStructure;

   RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //使能DMA控制器时钟

   NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

   NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel1_IRQn;

   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

   NVIC_Init(&NVIC_InitStructure);

   DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&ADCx->DR; //外设地址

   DMA_InitStructure.DMA_MemoryBaseAddr = mem_addr; //内存地址

   DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;

   DMA_InitStructure.DMA_BufferSize = size; //4个缓存大小

   DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

   DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

   DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;

   DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;

   DMA_InitStructure.DMA_Mode = DMA_Mode_Circular; //循环模式

   DMA_InitStructure.DMA_Priority = DMA_Priority_High;

   DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

   DMA_Init(DMA1_Channel1, &DMA_InitStructure);

   DMA_ITConfig(DMA1_Channel1, DMA1_IT_TC1, ENABLE); //开启中断

   DMA_Cmd(DMA1_Channel1, ENABLE);

   ADC_DMACmd(ADCx, ENABLE); //开启ADC1 DMA采集

}

void DMA1_Channel1_IRQHandler(void)

{

    if(DMA_GetITStatus(DMA1_IT_TC1) != RESET)

    {

        DMA_ClearITPendingBit(DMA1_IT_TC1);

        adc1_ok = 1;

    }

}

int main(void)

{

    ADC_init();

    while(1)

    {

        if(adc1_ok == 1)

        {

            v0 = AD_Bufer[0];

            v1 = AD_Bufer[1];

            v2 = AD_Bufer[2];

            v3 = AD_Bufer[3];

            printf("v0 is %.3fV.\n", v0 * (3.3 / 4096)); //电压值

            printf("v1 is %.3fV.\n", v1 * (3.3 / 4096));

            printf("v2 is %.3fV.\n", v2 * (3.3 / 4096));

            printf("v3 is %.3fV.\n", v3 * (3.3 / 4096));

            led1 = ~led1;

            adc1_ok = 0;

        }

        delay_ms(500);

    }

}

stm32 ADC模数转换 ADC多通道 ADC DMA的相关教程结束。