使用两路PA.1 (ADC Channel 1) 和 PA.4 (ADC Channel 4),配置方式如代码所示。使用的芯片是STM32F030C8。
需定义两个变量
static __IO uint16_t RegularConvertedAdcValue[ADC_CHANNEL_NUM]; // ADC1转换的电压值通过MDA方式传到flash
static float AdcValueConvertToVoltage; // 局部变量,用于存从flash读到的电压值
然后上电初始化时调用
void ADCD_Init(void)
{
GPIO_Config();
DMA_Config();
ADC_Config();
}
通过以下方式可以打印看到AD值和电压转换值。
printf("ADC Value[0] = %d rn", RegularConvertedAdcValue[0]);
AdcValueConvertToVoltage = (((float)RegularConvertedAdcValue[0] / 4096) * 3.3); /* 2^12 = 4096, Vref = 3.3V */
printf(" Voltage[0] = %2.2f Vrn", AdcValueConvertToVoltage);
printf("ADC Value[1] = %d rn", RegularConvertedAdcValue[1]);
AdcValueConvertToVoltage = (((float)RegularConvertedAdcValue[1] / 4096) * 3.3); /* 2^12 = 4096, Vref = 3.3V */
printf(" Voltage[1] = %2.2f Vrn", AdcValueConvertToVoltage);
printf("ADC Value[2] = %d rn", RegularConvertedAdcValue[2]);
AdcValueConvertToVoltage = (((float)RegularConvertedAdcValue[2] / 4096) * 3.3); /* 2^12 = 4096, Vref = 3.3V */
printf(" Voltage[2] = %2.2f Vrn", AdcValueConvertToVoltage);
以下是初始化代码,供参考。
static void GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Enable the GPIOA Clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* Configure PA.1 (ADC Channel1) & PA.4 (ADC Channel4) in analog mode */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_Speed= GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
static void DMA_Config(void)
{
DMA_InitTypeDef DMA_InitStructure;
/* Enable DMA1 clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
//DMA1通道1配置
DMA_DeInit(DMA1_Channel1);
//外设地址
DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_ADDRESS;
//内存地址
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&RegularConvertedAdcValue;
//DMA传输方向单向
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
//设置DMA在传输时缓冲区的长度
DMA_InitStructure.DMA_BufferSize = 2;
//设置DMA的外设递增模式,一个外设
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
//设置DMA的内存递增模式
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
//外设数据字长
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
//内存数据字长
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
//设置DMA的传输模式:连续不断的循环模式
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
//设置DMA的优先级别
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
//设置DMA的2个memory中的变量互相访问
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel1, &DMA_InitStructure);
/* Enable DMA1 Channel1 */
DMA_Cmd(DMA1_Channel1, ENABLE);
}
static void ADC_Config(void)
{
ADC_InitTypeDef ADC_InitStructure;
/* ADC1 DeInit */
ADC_DeInit(ADC1);
/* Load ADC default value */
ADC_StructInit(&ADC_InitStructure);
/* Enable ADC1 clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
//转换分辨率
ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
//连续转换
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
//外部触发禁止
ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
//ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_TRGO;
//数据右对齐
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
//扫描方向
ADC_InitStructure.ADC_ScanDirection = ADC_ScanDirection_Upward;
ADC_Init(ADC1, &ADC_InitStructure);
/* ADC1 regular channel1 configuration */
ADC_ChannelConfig(ADC1, ADC_Channel_1, ADC_SampleTime_55_5Cycles);
ADC_ChannelConfig(ADC1, ADC_Channel_4, ADC_SampleTime_55_5Cycles);
/* ADC Calibration */
ADC_GetCalibrationFactor(ADC1);
/* ADC DMA request in Circular mode */
ADC_DMARequestModeConfig(ADC1, ADC_DMAMode_Circular);
/* Enable ADC DMA request */
ADC_DMACmd(ADC1, ENABLE);
/* Enable ADC1 */
ADC_Cmd(ADC1, ENABLE);
/* Wait until the ADC enable falg is set to start conversion */
while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_ADEN));
/* Start ADC1 Software Conversion */
ADC_StartOfConversion(ADC1);
}
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