STM32F103 AD问题

只看该作者 · 2013-7-29 09:41

请教大家stm32 ad 采样的问题:

采样的结果始终在2000左右波动，折合电压1.6左右，而且波动的比较明显。

我这个采样脚接的是2v的固定电平，所以结果明显不对，配置改了几次没有效果，有没有人遇到过这个问题？
ad采的值完全不对，式了DMA和定时采样都一样。

只看该作者 · 2013-7-29 10:04

void  ADC1_Init(u8 ADC_Channel)
{
ADC_InitTypeDef ADC_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_ADCCLKConfig(RCC_PCLK2_Div6); //六分频后作为AD时钟。 RCC_CFGR |= 0x00008000;

/* Enable DMA clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);//开启dma时钟。  RCC_AHBENR |= 0x00000001
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE); //RCC_APB2ENR |= 0x00000e00;
/* Enable ADC2 clock */
ADC_DeInit(ADC1);
/* ADC2 registers reset ----------------------------------------------------*/

/* Enable ADC1 */
ADC_Cmd(ADC1, ENABLE); //开启ADC1

ADC_InitStructure.ADC_Mode =  ADC_Mode_Independent;  //转换模式，为独立转换。转换模式太多了，以后深究
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right; //对齐方式，ADC 结果是 12 位的，显然有个对齐左边还是右边的问题。一般是右对齐
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;  //连续转换模式开启
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;  //ADC 外部出发开关，关闭
ADC_InitStructure.ADC_NbrOfChannel = 1;  //开启通道数，2 个
ADC_InitStructure.ADC_ScanConvMode = ENABLE;  //扫描转换模式开启
ADC_Init(ADC1, &ADC_InitStructure);
ADC_RegularChannelConfig(ADC1,  ADC_Channel,  1,  ADC_SampleTime_239Cycles5);  //规则组通道设置，关键函数  转换器 ADC1，选择哪个通道 channel，
//  ADC1 to DMA, Enable
// ADC_DMACmd(ADC1, ENABLE);  //ADC 命令，和 DMA 关联。
//ADC1 Enable
ADC_Cmd(ADC1,ENABLE); //开启 ADC1
//Reset the Calibration  of ADC1
ADC_ResetCalibration(ADC1);
//wait until the Calibration's  fini sh
while(ADC_GetResetCalibrationStatus(ADC1));

ADC_StartCalibration(ADC1);
while(ADC_GetCalibrationStatus(ADC1));

   /* Configure one bit for preemption priority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

//  NVIC_StructInit(&NVIC_InitStructure);
/* Enable the ADC Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = ADC1_2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ADC_PRE_EMPTION_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = ADC_SUB_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

/* Enable the Update Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = TIM1_UP_PRE_EMPTION_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = TIM1_UP_SUB_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

/* Enable the TIM1 BRK Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM1_BRK_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = BRK_PRE_EMPTION_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = BRK_SUB_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //没有打开紧急停车功能
NVIC_Init(&NVIC_InitStructure);

/* Enable the DMA_CHANEL1 Interrupt */
/* NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = DMA_CH1_PRE_EMPTION_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = DMA_CH1_SUB_PRIORITY;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);    */

ADC1->CR2 |= 0x00400000;
ADC1->CR1 |= 0x00000020;

// ADC_SoftwareStartConvCmd(ADC1, ENABLE);  //连续转换开始，从选择开始，MCU 可以不用管了，ADC 将通过 DMA 不断刷新制定 RAM 区
//  Attach them;
}