STM32F4四路ADC采样问题探讨

╰+哭是因爲堅強的太久メ 2022-06-03 03:21 370阅读 0赞

# 1.ADC配置 #

## 1.1模式确定 ##

主从模式，选择主ADC1模式带动从ADC2模式  
![ADC模式][ADC]  
![交替模式][SouthEast]  
对应代码段：

/* Enable DMA request after last transfer (Multi-ADC mode)  */
    ADC_MultiModeDMARequestAfterLastTransferCmd(ENABLE);

## 1.2 时钟初始化ADC ##

ADC时钟挂在APB2上，这里程序配置为168MHz

RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,DISABLE);
    
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC2,ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC2,DISABLE);

## 1.3 引脚选择和初始化 ##

### 1.3.1 引脚 ###

这里的ADC是加DMA的，需要根据DMA和ADC相关默认引脚来选择  
简化来说 PC0–ADC通道10，PC1–ADC通道11…  
![选定相应引脚][SouthEast 1]

### 1.3.2 初始化配置 ###

ADC_Init(ADC2, &ADC_InitStructure);
    /* ADC2 regular channel5 configuration ****************/
    ADC_RegularChannelConfig(ADC2,ADC_Channel_13,1,
    ADC_SampleTime_15Cycles);		//PC3
    /* ADC1 regular channel5 configuration ************/
    ADC_RegularChannelConfig(ADC2, ADC_Channel_11, 2, ADC_SampleTime_15Cycles);		//PA3
    
    ADC_Init(ADC1, &ADC_InitStructure); 
    
    /* ADC1 regular channel5 configuration ****************/
    ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 1, ADC_SampleTime_15Cycles);		//PC2
    /* ADC1 regular channel5 configuration ******************/
    ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 2, ADC_SampleTime_15Cycles);		//PA5
    ...
    ADC_Cmd(ADC1, ENABLE)
    ADC_Cmd(ADC2, ENABLE);

# 2.DMA配置 #

## 2.1初始化 ##

确定数据流，这里F4系列的开发板有3个ADC  
![DMA2][]

## 2.2程序配置 ##

/* DMA2 Stream0 channel2 configuration */
    DMA_InitStructure.DMA_Channel = DMA_Channel_0;  
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC_DR_ADDRESS;
    DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)aADCConvertedValue;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
    DMA_InitStructure.DMA_BufferSize = ADC_BUF_SIZE;
    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_Enable;         
    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_Cmd(DMA2_Stream0, ENABLE);

# 3.滤波平均 #

## 3.1一般滤波方法 ##

这里尝试过其他一些滤波方法，加权滤波，中值滤波，滑动滤波方法，在大数据量下，排序消耗时间和占用资源都比较不好，经测试，一般滤波方法比较好。

u32 adc_filter(u32 cnt,u32 adc_num_value){
    	u8 i;
    	u32 adc_min=0,adc_max=0;
    	u32 adc_sum=0,adc_ave=0;
    	for(i=0;i<cnt;i++){
    		adc_sum += adc_num_value;
    		adc_min=adc_num_value;
    		adc_max=adc_num_value;
    		
    		if(adc_num_value<=adc_min)
    			adc_min=adc_num_value;
    		if(adc_num_value>=adc_max)
    			adc_max=adc_num_value;
    	}
    	adc_sum -= (adc_max+adc_min);	
    	adc_ave=adc_sum/(cnt-2);
    	adc_sum=0;
    	return adc_ave;
    }

## 3.2 采样计算求值 ##

根据之前规定的组合依次可计算出各采样值，这里优化了浮点计算方法

u8 j,k;
    u32 adc_getvalue[4];
    memset(&adc_getvalue,0,sizeof(adc_getvalue));
    for(j=0;j<40;j++)
    {
    	for(k=0;k<4;k++)
    	adc_getvalue[k] += adc_filter(8,aADCConvertedValue[k]);
    }//PC3--[1] PC1--[3] PC2--[0] PA5--[2]
    voltage1_calculate=	(float)adc_getvalue[0]*33/(400*4096);
    voltage2_calculate=	(float)adc_getvalue[1]*33/(400*4096);
    current1_calculate=	(float)adc_getvalue[2]*33/(400*4096);
    current2_calculate=	(float)adc_getvalue[3]*33/(400*4096);
    	
    memset(&adc_getvalue,0,sizeof(adc_getvalue));
    	
    //减少线差
    adc_voltage1=voltage1_calculate;
    adc_voltage2=voltage2_calculate;
    adc_current1=current1_calculate;
    adc_current2=current2_calculate;

这里相关配置就可以结束了，需注意的是，计算采样时需要定义数组，数组类型也有明确要求。这里附上程序配置[相关文件][Link 1]。

[ADC]: /images/20220603/55621a09ac824b4d9677317a5b7a5e32.png
[SouthEast]: /images/20220603/30c93863895149ff944dc45cf0a38fa5.png
[SouthEast 1]: /images/20220603/351ccec8708f45b7a51fbc307419666a.png
[DMA2]: /images/20220603/9ee9a562ff414ce3a0924b90719db60c.png
[Link 1]: http://download.csdn.net/download/klaus_x/10164703