STM32F1单片机我用单次AD采样和AD+DMA连接采样的结果有偏差 -

标题: STM32F1单片机我用单次AD采样和AD+DMA连接采样的结果有偏差 [打印本页]

作者: jpj1234 时间: 2022-1-17 11:35
标题: STM32F1单片机我用单次AD采样和AD+DMA连接采样的结果有偏差
      请教大家一个问题，硬件是一样的，采样电阻接地。       负载不工作：
      AD单次采样时，可以采样到0x 00;
      AD+DMA连续采样，采样到 0x 0F到0x 12
      抬高了采样值，
      负载开起时：
      AD单次采样时，可以采样到0x 67 左右波动;
      AD+DMA连续采样，采样到 0x89  左右波动;

      抬高了采样值，是我那里没有设置好吗，我就在例程上修改一个脚，从PC1改到PA1.

#include "adc.h"

#define ADC1_DR_Address ((u32)0x40012400+0x4c)

__IO uint16_t ADC_ConvertedValue;
//__IO u16 ADC_ConvertedValueLocal;

static void ADC1_GPIO_Config(void)
{
      GPIO_InitTypeDef GPIO_InitStructure;

      /* Enable DMA clock */
      RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

      /* Enable ADC1 and GPIOC clock */
      RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOA, ENABLE);

      /* Configure PC.01  as analog input */
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
      GPIO_Init(GPIOA, &GPIO_InitStructure);
}

/* oˉêyÃû￡oADC1_Mode_Config
* Ãèêö  ￡oÅäÖÃADC1μÄ1¤×÷Ä￡ê½ÎaMDAÄ￡ê½
* êäèë  : ÎT
* êä3ö  ￡oÎT
* μ÷óÃ  ￡oÄú2¿μ÷óÃ
*/
static void ADC1_Mode_Config(void)
{
      DMA_InitTypeDef DMA_InitStructure;
      ADC_InitTypeDef ADC_InitStructure;

      /* DMA channel1 configuration */
      DMA_DeInit(DMA1_Channel1);
      DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;
      DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&ADC_ConvertedValue;
      DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
      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_M2M = DMA_M2M_Disable;
      DMA_Init(DMA1_Channel1, &DMA_InitStructure);

      /* Enable DMA channel1 */
      DMA_Cmd(DMA1_Channel1, ENABLE);

      /* ADC1 configuration */

      ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
      ADC_InitStructure.ADC_ScanConvMode = DISABLE ;
      ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
      ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
      ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
      ADC_InitStructure.ADC_NbrOfChannel = 1;
      ADC_Init(ADC1, &ADC_InitStructure);


      ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 1, ADC_SampleTime_55Cycles5);

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

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


      ADC_ResetCalibration(ADC1);

      while(ADC_GetResetCalibrationStatus(ADC1));


      ADC_StartCalibration(ADC1);

      while(ADC_GetCalibrationStatus(ADC1));


      ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}

void ADC1_Init(void)
{
      ADC1_GPIO_Config();
      ADC1_Mode_Config();
}

作者: 人工置顶员 时间: 2022-1-18 03:06
顶一下

作者: jpj1234 时间: 2022-1-19 14:05
在没有开启负载时，已降低到0x 04H 不管了，只能这样了

作者: ljfljfljf123 时间: 2022-1-27 15:52
你是怎么降低到0x04H的

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