STM32 ADC DMA初始化

STM32的ADC DMA初始化步骤如下：

1. 配置ADC模块：选择采样时间、采样通道、转换模式等参数。
2. 配置DMA模块：选择传输方向、数据长度、传输模式等参数。
3. 配置NVIC中断：打开DMA中断并设置中断优先级。
4. 启动ADC和DMA模块：使能ADC和DMA模块。
5. 等待DMA传输完成：在DMA中断中等待DMA传输完成。

下面是一个简单的ADC DMA初始化的代码示例：

#include "stm32f4xx.h"

#define ADC_BUF_LEN 10

uint16_t adc_buf[ADC_BUF_LEN];

void ADC_DMA_Init(void)
{
    // 1. 配置ADC模块
    ADC_InitTypeDef  ADC_InitStruct;
    ADC_CommonInitTypeDef ADC_CommonInitStruct;

    ADC_CommonInitStruct.ADC_Mode = ADC_Mode_Independent;
    ADC_CommonInitStruct.ADC_Prescaler = ADC_Prescaler_Div2;
    ADC_CommonInitStruct.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;
    ADC_CommonInitStruct.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
    ADC_CommonInit(&ADC_CommonInitStruct);

    ADC_InitStruct.ADC_Resolution = ADC_Resolution_12b;
    ADC_InitStruct.ADC_ScanConvMode = DISABLE;
    ADC_InitStruct.ADC_ContinuousConvMode = ENABLE;
    ADC_InitStruct.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;
    ADC_InitStruct.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
    ADC_InitStruct.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStruct.ADC_NbrOfConversion = 1;
    ADC_Init(ADC1, &ADC_InitStruct);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_56Cycles);

    ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);
    ADC_DMACmd(ADC1, ENABLE);

    // 2. 配置DMA模块
    DMA_InitTypeDef DMA_InitStruct;

    DMA_InitStruct.DMA_Channel = DMA_Channel_0;
    DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)&ADC1->DR;
    DMA_InitStruct.DMA_Memory0BaseAddr = (uint32_t)adc_buf;
    DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStruct.DMA_BufferSize = ADC_BUF_LEN;
    DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    DMA_InitStruct.DMA_Mode = DMA_Mode_Circular;
    DMA_InitStruct.DMA_Priority = DMA_Priority_High;
    DMA_InitStruct.DMA_FIFOMode = DMA_FIFOMode_Disable;
    DMA_InitStruct.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
    DMA_InitStruct.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStruct.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA2_Stream0, &DMA_InitStruct);

    // 3. 配置NVIC中断
    NVIC_InitTypeDef NVIC_InitStruct;

    NVIC_InitStruct.NVIC_IRQChannel = DMA2_Stream0_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);

    // 4. 启动ADC和DMA模块
    ADC_Cmd(ADC1, ENABLE);
    DMA_Cmd(DMA2_Stream0, ENABLE);

    // 5. 等待DMA传输完成
    while(DMA_GetFlagStatus(DMA2_Stream0, DMA_FLAG_TCIF0) == RESET);
}