论坛 › 问答 › ADC_DMA模式只采样一次是什么原因呢？

woshilee 发表于 2015-7-27 10:32:03

ADC_DMA模式只采样一次是什么原因呢？

int main(void)
{

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);
       
       
       
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource2,GPIO_AF_1);
        GPIO_PinAFConfig(GPIOA, GPIO_PinSource3,GPIO_AF_1);

       
        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
       
       
ADC_InitStructure.ADC_Resolution=ADC_Resolution_12b;
        ADC_InitStructure.ADC_ContinuousConvMode=ENABLE;
        ADC_InitStructure.ADC_ExternalTrigConvEdge=ADC_ExternalTrigConvEdge_None;
        ADC_InitStructure.ADC_ExternalTrigConv=DISABLE;
        ADC_InitStructure.ADC_DataAlign=ADC_DataAlign_Right;
        ADC_InitStructure.ADC_ScanDirection=ADC_ScanDirection_Upward;
        ADC_Init(ADC1, &ADC_InitStructure);               
        ADC_DMACmd(ADC1, ENABLE);
ADC_Cmd(ADC1, ENABLE);
ADC_ChannelConfig(ADC1, ADC_Channel_0, ADC_SampleTime_239_5Cycles);
       
        ADC_StartOfConversion(ADC1);
       
       
       
        USART_InitStructure.USART_BaudRate=9600;
        USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
        USART_InitStructure.USART_Mode=USART_Mode_Tx|USART_Mode_Rx;
        USART_InitStructure.USART_Parity=USART_Parity_No;
        USART_InitStructure.USART_StopBits=USART_StopBits_1;
        USART_InitStructure.USART_WordLength=USART_WordLength_8b;
        USART_Init(USART2, &USART_InitStructure);


DMA_InitStructure.DMA_PeripheralBaseAddr=0x40012440;
        DMA_InitStructure.DMA_MemoryBaseAddr=(uint32_t)&adcdata;
        DMA_InitStructure.DMA_DIR=DMA_DIR_PeripheralSRC;
        DMA_InitStructure.DMA_BufferSize=DMA_PeripheralDataSize_HalfWord;
        DMA_InitStructure.DMA_PeripheralInc=DMA_PeripheralInc_Disable;
        DMA_InitStructure.DMA_MemoryInc=DMA_MemoryInc_Disable;
        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);
DMA_ITConfig(DMA1_Channel1, DMA_IT_TC, ENABLE);
        DMA_Cmd(DMA1_Channel1, ENABLE);
       

        USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
        USART_ClearITPendingBit(USART2, USART_IT_RXNE);
        USART_ClearFlag(USART2,USART_FLAG_TC);
USART_Cmd(USART2, ENABLE);
       
        NVIC_InitStructure.NVIC_IRQChannel=USART2_IRQn;
        NVIC_InitStructure.NVIC_IRQChannelPriority=0;
        NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
        NVIC_Init(&NVIC_InitStructure);
       
       
        NVIC_InitStructure.NVIC_IRQChannel=DMA1_Channel1_IRQn;
        NVIC_InitStructure.NVIC_IRQChannelPriority=1;
        NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
        NVIC_Init(&NVIC_InitStructure);
       
       

while (1)
{
                  voltage=adcdata*3.3/4096;

                  printf("\r\nV=%f\r\n",voltage);

                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();
                  delay();delay();delay();delay();delay();delay();delay();


               
}
}

creep 发表于 2015-7-27 11:44:47

DMA传送完成中断函数是不是没有清除中断标志导致一直在响应中断了。

woshilee 发表于 2015-7-27 11:46:27

找到原因了，没有配置 ADC_DMAMode_Circular:
ADC_DMARequestModeConfig(ADC1, ADC_DMAMode_Circular);
这个函数配置的是ADCx的CFGR1寄存器。


而DMA初始化中的连续模式配置的是配置的是DMA的CCR寄存器，DMA_CCR_CIRC                        ((uint32_t)0x00000020)

woshilee 发表于 2015-7-27 11:47:27

creep 发表于 2015-7-27 11:44
DMA传送完成中断函数是不是没有清除中断标志导致一直在响应中断了。

没贴出来中断函数，中断中清理标志位了。
void DMA1_Channel1_IRQHandler(void)
{
       
        if(DMA_GetFlagStatus(DMA1_FLAG_TC1)==1)
        {
                DMA_ClearFlag(DMA1_FLAG_TC1);
                ADC_ClearFlag(ADC1, ADC_FLAG_EOC);
        }
               
}

stary666 发表于 2015-7-27 12:13:30

看看，，，，，，

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