ADC-DMA代码

这是一个基于STM32的ADC-DMA代码示例，可以将ADC采集到的数据通过DMA传输到内存中：

#include "stm32f4xx.h"
#include "stm32f4xx_adc.h"
#include "stm32f4xx_dma.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_rcc.h"

#define ADC1_DR_ADDRESS     ((uint32_t)0x4001204C)

__IO uint16_t ADCConvertedValue;

void ADC_Config(void)
{
  GPIO_InitTypeDef       GPIO_InitStructure;
  ADC_InitTypeDef        ADC_InitStructure;
  DMA_InitTypeDef        DMA_InitStructure;

  /* Enable ADC3, DMA2 and GPIO clocks ****************************************/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOC, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

  /* DMA2 Stream0 channel0 configuration **************************************/
  DMA_InitStructure.DMA_Channel = DMA_Channel_0;
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADCConvertedValue;
  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 ADC1 Channel11 pin as analog input ******************************/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* ADC Common Init *********************************************************/
  ADC_CommonInitTypeDef ADC_CommonInitStructure;
  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);

  /* ADC1 Init ****************************************************************/
  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
  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(ADC1, &ADC_InitStructure);

  /* ADC1 regular channel11 configuration *************************************/
  ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 1, ADC_SampleTime_144Cycles);

  /* Enable DMA request after last transfer (Single-ADC mode) */
  ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);

  /* Enable ADC1 DMA */
  ADC_DMACmd(ADC1, ENABLE);

  /* Enable ADC1 **************************************************************/
  ADC_Cmd(ADC1, ENABLE);

  /* Start ADC1 Software Conversion */
  ADC_SoftwareStartConv(ADC1);
}

int main(void)
{
  ADC_Config();

  while (1)
  {
    /* Wait DMA interrupt */
  }
}

在这个示例中，我们使用了ADC1和DMA2，采集了PC1引脚的模拟信号。ADC1使用了单次转换模式，采样时间为144个时钟周期，并且启用了DMA传输。DMA传输是循环模式，一旦转换完成就会将结果存储到内存中。

在主循环中，我们可以插入需要执行的代码，或者直接等待DMA中断。当DMA传输完成时，可以在DMA中断处理函数中对数据进行处理。