ADC DMA得到的值是倒序的吗

142zjb · 发表于 2021-1-7 17:01:40

初始化关键的地方如下,

  DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&ADC->DR;
  DMA_InitStructure.DMA_Memory0BaseAddr =(u32)ADC_ConvertedValue;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;//
  DMA_InitStructure.DMA_BufferSize = 12;

在这里中，当DMA完成中断后，我将ADC_ConvertedValue这个数组的值存到另一个数组中，但是我发现ADC_ConvertedValue[11]反而才是对应ADC-DR的最一个值，倒序了。
这个有人遇到吗

142zjb · 发表于 2021-1-7 17:03:56

好像也不能确定是完全的倒序，算是乱序

正点原子 · 发表于 2021-1-8 01:47:13

继续检查设置

142zjb · 发表于 2021-1-8 08:12:11

正点原子发表于 2021-1-8 01:47
继续检查设置

DMA_InitTypeDef DMA_InitStructure;
ADC_CommonInitTypeDef ADC_CommonInitStructure;
ADC_InitTypeDef ADC_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);
DMA_DeInit(DMA2_Stream0);
DMA_InitStructure.DMA_Channel = DMA_Channel_0;
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&ADC1->DR;
DMA_InitStructure.DMA_Memory0BaseAddr = (u32)ADC_ConvertedValue;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_BufferSize = 12;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
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_ITConfig(DMA2_Stream0,DMA_IT_TC,ENABLE);

NVIC_InitStructure.NVIC_IRQChannel=DMA2_Stream0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0x00;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=0x00;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_Init(&NVIC_InitStructure);

DMA_Cmd(DMA2_Stream0 , ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 , ENABLE);
ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;// 60/2=30Mhz
ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_1;
ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
ADC_CommonInit(&ADC_CommonInitStructure);

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_CC2;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfConversion =1;
ADC_Init(ADC1, &ADC_InitStructure);

ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_3Cycles);

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

ADC_Cmd(ADC1, ENABLE);

ADC_SoftwareStartConv(ADC1);
// while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC ));

上述是初始化代码，中断代码会在中途修改DMA_BufferSize为100,
DMA_Cmd(DMA2_Stream0 , DISABLE);
DMA2_Stream0->NDTR = 100;
while(DMA_GetFIFOStatus(DMA2_Stream0) != DMA_FIFOStatus_Empty);
DMA_Cmd(DMA2_Stream0 , ENABLE);
不知道是哪一步可能会导致这样的原因

142zjb · 发表于 2021-1-8 15:40:39

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

ADC_Cmd(ADC1, ENABLE);
DMA_Cmd(DMA2_Stream0 , ENABLE);

ADC_SoftwareStartConv(ADC1);
排查出一个问题，改成DMA_Mode_Normald后，debug发现这里ADC_Cmd(ADC1, ENABLE);需要在DMA_Cmd(DMA2_Stream0 , ENABLE); 前面，否则在DMA还未获取到数据，我的ADC_ConvertedValue便开始自增。
尽管如此，但改回DMA_Mode_Circular模式，依旧有数据错乱，而且设置断点观察到每次进入DMA完成中断函数，DMA2_Stream0->NDTR这个值都不为0，但是DMA_Mode_Normald模式下，倒每次都是0。