STM32F407ZG ADC+DMA单通道采样数据不对

juway · 发表于 2022-3-9 15:36:34

用信号发生器产生的单一频率正弦波，采样后要么有10%内的偏差，要么完全不对，求助看一下初始化代码有没有问题
adc初始化：
void  ADC1_Init(void)
{
  GPIO_InitTypeDef  GPIO_InitStructure;
ADC_CommonInitTypeDef ADC_CommonInitStructure;
ADC_InitTypeDef    ADC_InitStructure;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);//使能GPIOA时钟
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE); //使能ADC1时钟

  //先初始化ADC1通道6 IO口
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;//PA6
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;//模拟输入
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;//不带上下拉
  GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化

RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,ENABLE);    //ADC1复位
RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,DISABLE); //复位结束

  ADC_DeInit();
  ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;//独立模式
  ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;//两个采样阶段之间的延迟5个时钟
  ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_1; //DMA使能
  ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div4;//预分频4分频。ADCCLK=PCLK2/4=84/4=21Mhz,ADC时钟最好不要超过36Mhz
  ADC_CommonInit(&ADC_CommonInitStructure);//初始化

  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;//12位模式
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;//关闭扫描模式
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;//开启连续转换
  ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;//禁止触发检测，使用软件触发
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;//右对齐
  ADC_InitStructure.ADC_NbrOfConversion = 1;//通道数
  ADC_Init(ADC1, &ADC_InitStructure);//ADC初始化

ADC_RegularChannelConfig(ADC1, ADC_Channel_6, 1, ADC_SampleTime_112Cycles);
//单次ad转换时间，频率 (112+12)/21 =5.9us

  ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);

  ADC_DMACmd(ADC1, ENABLE);
  ADC_Cmd(ADC1, ENABLE);//开启AD转换器

  ADC_SoftwareStartConv(ADC1);    //使能指定的ADC1的软件转换启动功能
}

DMA初始化:
void DMA_Config(DMA_Stream_TypeDef *DMA_Streamx, u32 chx, u32 par, u32 mar, u16 ndtr)
{
   //初始化结构体
DMA_InitTypeDef DMA_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
   //开启DMA时钟
   if((u32)DMA_Streamx>(u32)DMA2)
{
      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);
}
else
{
      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
}

DMA_DeInit(DMA_Streamx);
   while (DMA_GetCmdStatus(DMA_Streamx)!=DISABLE){}

DMA_InitStructure.DMA_BufferSize = ndtr;
DMA_InitStructure.DMA_Channel = chx;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_Memory0BaseAddr = mar; //存储器0地址
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular; //正常/循环
DMA_InitStructure.DMA_PeripheralBaseAddr = par;  //ADC->DR地址
DMA_InitStructure.DMA_PeripheralBurst =DMA_PeripheralBurst_Single;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_Init(DMA_Streamx,&DMA_InitStructure);

DMA_ClearFlag(DMA2_Stream0,DMA_IT_TC);
   DMA_ITConfig(DMA2_Stream0,DMA_IT_TC,ENABLE);

NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0X01;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0X01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

while (DMA_GetCmdStatus(DMA2_Stream0) != DISABLE){}
DMA_Cmd(DMA2_Stream0,ENABLE);
}

数据我是用dma存1024个点到数组中，然后串口展示出来。
关于adc初始化中这句
ADC_RegularChannelConfig(ADC1, ADC_Channel_6, 1, ADC_SampleTime_112Cycles);
我设置为480的时候采的误差很小，但这个采样率不是很高。所以我想把这个值调小，但是144的误差就大了，112及以下就完全不对了，求大佬看一下是什么方面的原因