最近公司又做了一款407的樣板，正好需要用到407的ADC功能，需要用PC.2來檢測RFID芯片的射頻電源功率，首先看了下407的數(shù)據(jù)手冊
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可以配置到ADC1/2/3任何一個控制器的信道12上面.我打算將PC.2映射到ADC3上面和使用DMA功能，又看了下DMA的請求映射表，ADC3使用的DMA2的流0信道2
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編程思路：
首先將DMA和IO以及ADC的時鐘使能，其次將相應(yīng)的IO配置成輸入模式，最后配置DMA和ADC
注意
/*定義ADC3的數(shù)據(jù)寄存器地址，DMA功能要用到外設(shè)的數(shù)據(jù)地址
*ADC3的數(shù)據(jù)地址為外設(shè)基地址+偏移地址，基地址在RM0090 Reference
*manual（參考手冊）的地址映射表里，為0x40012200，ADC_DR
*偏移地址為0x4C，故實際地址為0x40012200+0x4C = 0x4001224C */
#defineADC3_DR_Address ((uint32_t)0x4001224C)
代碼詳見:
void Adc3_Init(void)
{
/* Enable peripheral clocks ------------------------------------------------*/
/* Enable DMA1 clock */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC3, ENABLE);
GPIO_Configuration();
DMA_Configuration();
}
void DMA_Configuration(void)
{
ADC_InitTypeDef ADC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
ADC_CommonInitTypeDef ADC_CommonInitStructure;
/* DMA2 Stream0 channel0 configuration **************************************/
DMA_InitStructure.DMA_Channel = DMA_Channel_2;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC3_DR_Address;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADCConvertedValue;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_BufferSize = 1;
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_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA2_Stream0, &DMA_InitStructure);
DMA_Cmd(DMA2_Stream0, ENABLE);
/* ADC Common Init **********************************************************/
ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;
ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
ADC_CommonInit(&ADC_CommonInitStructure);
/* ADC3 Init ****************************************************************/
ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
ADC_InitStructure.ADC_ScanConvMode = DISABLE; // PS ： 在多通道 2個通道以上 該選項應(yīng)該使能
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfConversion = 1;
ADC_Init(ADC3, &ADC_InitStructure);
/* ADC3 regular channel12 configuration *************************************/
ADC_RegularChannelConfig(ADC3, ADC_Channel_12, 1, ADC_SampleTime_3Cycles);
/* Enable DMA request after last transfer (Single-ADC mode) */
ADC_DMARequestAfterLastTransferCmd(ADC3, ENABLE);
/* Enable ADC3 DMA */
ADC_DMACmd(ADC3, ENABLE);
/* Enable ADC3 */
ADC_Cmd(ADC3, ENABLE);
/* Start ADC3 Software Conversion */
ADC_SoftwareStartConv(ADC3); //如果不是外部觸發(fā)則必須軟件開始轉(zhuǎn)換
}
/**
* @brief Configures the different GPIO ports.
* @param None
* @retval None
*/
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure PC.2 (ADC Channel2) PC.1 (ADC Channel1) as analog input -------------------------*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
GPIO_Init(GPIOC, &GPIO_InitStructure);
}
PS： 以上程序有錯誤: 在配置DMA的時候需要先使能DMA時鐘
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