STM32F1 芯片我用单次AD采样和 AD+DMA连续采样的结果有偏差

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JPJ1234 提问时间：2022-1-17 12:23 / 未解决

问答
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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，负载开启时： 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;

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); // }

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);

RCC_ADCCLKConfig(RCC_PCLK2_Div8);

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(); }