使用 DMA 使用 stm32f4-discovery 板从多个 ADC 通道读取数据时出现问题答案

【问题标题】：Problem reading data from multiple ADC channels with stm32f4-discovery board using DMA使用 DMA 使用 stm32f4-discovery 板从多个 ADC 通道读取数据时出现问题
【发布时间】：2021-01-05 06:52:18
【问题描述】：

我正在尝试从 ADC1 的通道 0、1、2 和 3 读取数据。问题是，当我从通道 1 和通道 2 读取并在调试模式下运行代码时，它显示正确的值enter image description heres 但是当我修改它以对通道 3 和 4 执行相同操作时，它没有显示任何value.以下是内存映射的代码和截图：

#include "stm32f4xx.h"
#include "stm32f4_discovery.h"

uint16_t ADC1ConvertedValue[4] = {0,0,0,0};//Stores converted vals [2] = {0,0}
void DMA_config()
{
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 ,ENABLE);
    DMA_InitTypeDef       DMA_InitStruct;
    
    DMA_InitStruct.DMA_Channel = DMA_Channel_0;
    DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t) 0x4001204C;//ADC1's data register
    DMA_InitStruct.DMA_Memory0BaseAddr = (uint32_t)&ADC1ConvertedValue;
    DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStruct.DMA_BufferSize = 4;//2
    DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;//Reads 16 bit values _HalfWord
    DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;//Stores 16 bit values _Halfword
    DMA_InitStruct.DMA_Mode = DMA_Mode_Circular;
    DMA_InitStruct.DMA_Priority = DMA_Priority_High;
    DMA_InitStruct.DMA_FIFOMode = DMA_FIFOMode_Enable;
    DMA_InitStruct.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;//_HalfFull
    DMA_InitStruct.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStruct.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    DMA_Init(DMA2_Stream0, &DMA_InitStruct);
    DMA_Cmd(DMA2_Stream0, ENABLE);


}

void ADC_config()
{
        /* Configure GPIO pins ******************************************************/
    ADC_InitTypeDef       ADC_InitStruct;
    ADC_CommonInitTypeDef ADC_CommonInitStruct;
    GPIO_InitTypeDef      GPIO_InitStruct;
    RCC_AHB1PeriphClockCmd( RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);//ADC1 is connected to the APB2 peripheral bus
    
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;// PA0,PA1,PA3,PA3
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AN;//The pins are configured in analog mode
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL ;//We don't need any pull up or pull down
    GPIO_Init(GPIOA, &GPIO_InitStruct);//Initialize GPIOA pins with the configuration


    /* ADC Common Init **********************************************************/
    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);

    /* ADC1 Init ****************************************************************/
    
    ADC_InitStruct.ADC_Resolution = ADC_Resolution_12b;//Input voltage is converted into a 12bit int (max 4095)
    ADC_InitStruct.ADC_ScanConvMode = ENABLE;//The scan is configured in multiple channels
    ADC_InitStruct.ADC_ContinuousConvMode = ENABLE;//Continuous conversion: input signal is sampled more than once
    ADC_InitStruct.ADC_ExternalTrigConv = DISABLE;
    ADC_InitStruct.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
    ADC_InitStruct.ADC_DataAlign = ADC_DataAlign_Right;//Data converted will be shifted to right
    ADC_InitStruct.ADC_NbrOfConversion = 4;
    ADC_Init(ADC1, &ADC_InitStruct);//Initialize ADC with the configuration

    /* Select the channels to be read from **************************************/
    ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_144Cycles);//PA0
    ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 2, ADC_SampleTime_144Cycles);//PA1
    ADC_RegularChannelConfig(ADC1, ADC_Channel_2, 3, ADC_SampleTime_144Cycles);//PA2
    ADC_RegularChannelConfig(ADC1, ADC_Channel_3, 4, ADC_SampleTime_144Cycles);//PA3

    /* 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);

}

int main(void)
{
    
    DMA_config();
    ADC_config();

    while(1)
    {
        ADC_SoftwareStartConv(ADC1);
        //value=ADC_Read();
    }

    return 0;
}

【问题讨论】：

标签： dma adc stm32f4

【解决方案1】：

您不应多次启动 ADC 转换（在您的 while(1) 循环中）。

由于您已经使用.ADC_ContinuousConvMode = ENABLE 配置了 ADC，因此在循环之前启动它并且在其中不执行任何操作就足够了。

【讨论】：