stm32F030C6单片机的一个有点扯淡的地方。

WorkerNotEngine

STM32F030单片机的ADC里面有个Vrefint，这个Vrefint的范围在1.16V-1.24V之间，比起标准的1.2V，其误差达0.04V，误差0.04/1.2=3.333%，感觉已经失去参考电压的意义了，TL431最差的等级误差也就2%。

xuande

参考源有两个重要的指标，准确度和温漂。后者更重要。

fanghuiopenedv

void ADC_DMA_Config(void)
{
        ADC_InitTypeDef     ADC_InitStructure;
        DMA_InitTypeDef     DMA_InitStructure;
        GPIO_InitTypeDef    GPIO_InitStructure;

        /* GPIOC Periph clock enable */
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA|RCC_AHBPeriph_GPIOB, ENABLE);
        /* ADC1 Periph clock enable */
        RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
       
        /* DMA1 clock enable */
        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1 , ENABLE);
       
       
    /* GPIO Config */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
//        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
//    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
//    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
//    GPIO_Init(GPIOB, &GPIO_InitStructure);       
       
               
        /* ADC1 DeInit */  
        ADC_DeInit(ADC1);
        /* Initialize ADC structure */
        ADC_StructInit(&ADC_InitStructure);
       

        /* Configure the ADC1 in continous mode withe a resolutuion equal to 12 bits  */
        ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
        ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
        ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
        //ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T3_TRGO;
        ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
        ADC_InitStructure.ADC_ScanDirection = ADC_ScanDirection_Upward;//ADC_ScanDirection_Backward;//ADC_ScanDirection_Upward
        ADC_Init(ADC1, &ADC_InitStructure);

        ADC_ChannelConfig(ADC1, ADC_Channel_8 , ADC_SampleTime_239_5Cycles);       
        ADC_ChannelConfig(ADC1, ADC_Channel_9 , ADC_SampleTime_239_5Cycles);       
        //ADC_ChannelConfig(ADC1, ADC_Channel_9 , ADC_SampleTime_239_5Cycles);
   

        /* DMA1 Channel1 Config */
        DMA_DeInit(DMA1_Channel1);
        DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_Address;
        DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)ADC_Data_Tab;
        DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
        DMA_InitStructure.DMA_BufferSize = 2;
        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_M2M = DMA_M2M_Disable;
        DMA_Init(DMA1_Channel1, &DMA_InitStructure);
       
        /* ADC Calibration */
        ADC_GetCalibrationFactor(ADC1);
       
        /* ADC DMA request in circular mode */
        ADC_DMARequestModeConfig(ADC1, ADC_DMAMode_Circular);       
       
        /* Enable ADC_DMA */
        ADC_DMACmd(ADC1, ENABLE);
       
        /* Enable ADC1 */
        ADC_Cmd(ADC1, ENABLE);
        /* Wait the ADRDY falg */
        while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_ADRDY));       
       
        /* DMA1 Channel1 enable */
        DMA_Cmd(DMA1_Channel1, ENABLE);


        /* ADC1 regular Software Start Conv */
        ADC_StartOfConversion(ADC1);
       
}

fanghuiopenedv

没感觉到有偏差。