STM32 collects multi-channel AD through DMA

environment:

Host: XP

Development environment: MDK4.23

MCU:STM32F103CBT6

illustrate:

Collect AD through pins PA1 and PA2. Collect AD 10 times for each channel.

#include "ad_driver.h"  

//Global variables  

//AD sampling storage space  

__IO uint16_t ADCConvertedValue[20];  

//function  

//Initialize AD  

void init_ad(void)  

{  

    ADC_InitTypeDef ADC_InitStructure;  

    DMA_InitTypeDef DMA_InitStructure;  

    GPIO_InitTypeDef GPIO_InitStructure;  

    //---------------------Charge AD initialization--------------------  

    //Start DMA clock  

    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);  

    //Start ADC1 clock  

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);  

    //Sampling pin settings  

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);  

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2;  

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;  

    GPIO_Init(GPIOA, &GPIO_InitStructure);  

    //DMA1 channel 1 configuration  

    DMA_DeInit(DMA1_Channel1);  

    //Peripheral address  

    DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_ADDRESS;  

    //Memory address  

    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)ADCConvertedValue;  

    //dma transmission direction is one-way  

    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;  

    //Set the length of the DMA buffer during transmission  

    DMA_InitStructure.DMA_BufferSize = 20;  

    //Set the DMA peripheral increment mode, a peripheral  

    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;  

    //Set DMA memory increment mode  

    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;  

    //Peripheral data word length  

    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;  

    //Memory data word length  

    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;  

    //Set DMA transfer mode: continuous loop mode  

    DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;  

    //Set the DMA priority level  

    DMA_InitStructure.DMA_Priority = DMA_Priority_High;  

    //Set the variables in the two DMA memories to access each other  

    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;  

    DMA_Init(DMA1_Channel1, &DMA_InitStructure);  

    // Enable channel 1  

    DMA_Cmd(DMA1_Channel1, ENABLE);  

    //ADC1 configuration  

    //Independent working mode  

    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;  

    //scanning method  

    ADC_InitStructure.ADC_ScanConvMode = ENABLE;  

    //Continuous conversion  

    ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;  

    //External trigger disabled  

    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;  

    //Right align the data  

    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;  

    //Number of channels to convert  

    ADC_InitStructure.ADC_NbrOfChannel = 2;  

    ADC_Init(ADC1, &ADC_InitStructure);  

    //Rule mode channel configuration  

    ADC_RegularChannelConfig(ADC1, ADC_Channel_1 , 1, ADC_SampleTime_239Cycles5);  

    ADC_RegularChannelConfig(ADC1, ADC_Channel_2 , 2, ADC_SampleTime_239Cycles5);  

    // Enable DMA of ADC1  

    ADC_DMACmd(ADC1, ENABLE);  

    // Enable ADC1  

    ADC_Cmd(ADC1, ENABLE);  

    // Enable ADC1 reset calibration register    

    ADC_ResetCalibration(ADC1);  

    // Check if the calibration register is reset  

    while(ADC_GetResetCalibrationStatus(ADC1));  

    //Start calibration  

    ADC_StartCalibration(ADC1);  

    //Check if calibration is complete  

    while(ADC_GetCalibrationStatus(ADC1));  

    //Start software conversion of ADC1  

    ADC_SoftwareStartConvCmd(ADC1, ENABLE);  

}  

//Get charging voltage  

float voltage_charge(void)  

{  

    uint8_t i = 0;  

    uint16_t sum = 0;  

    float v = 0;  

    //Get the average value of charging voltage for 10 times  

    for (i = 0;i < 10;i++)  

    {  

        sum += ADCConvertedValue[i * 2];   

    }  

    sum /= 10;  

    //Convert to voltage value  

    v = 0.002991 * sum;  

    return v;  

}  

//Get the discharge voltage  

float voltage_discharge(void)  

{  

    uint8_t i = 0;  

    uint16_t sum = 0;  

    float v = 0;  

    //Get the average value of charging voltage for 10 times  

    for (i = 0;i < 10;i++)  

    {  

        sum += ADCConvertedValue[i * 2 + 1];   

    }  

    sum /= 10;  

    //Convert to voltage value  

    v = 0.002991 * sum;  

    return v;  

}