STM32标准库中DMA配置详解 （标准库版）

  写博客Mark下自己对STM32中DMA功能的一些分析： 

DMA_ISR:
0x4002 0000
DMA_IFCR
0x4002 0004
DMA_CCR1:
0x4002 0008
DMA_CNDTR1: 0x4002 000C
DMA_CPAR1:
0x4002 0010
DMA_CMAR1:
0x4002 0014

void DMA_Configuration(void)
{
DMA_InitTypeDef DMA_InitStructure;
/* DMA channel1 configuration */
DMA_DeInit(DMA1_Channel1);//重置DMA的寄存器的值，配置为缺省值
DMA_InitStructure.DMA_PeripheralBaseAddr =(u32)&ADC1->DR;	/*设置 DMA 外设基地址，即为转换结果的寄存器*/
DMA_InitStructure.DMA_MemoryBaseAddr =(u32)&AD_Value;/*定义内存基地址*/
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;	/*定义AD外设作为数据传输的来源*/
DMA_InitStructure.DMA_BufferSize = N*M;/*指定DMA通道DMA缓存的大小，即需要开辟几个内存空间*/
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;	/*寄存器地址国定*/
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;	/*设定内存地址递增，即每次DMA都是将*/
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;/* 定义外设和内存的数据宽度*/
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;/*设定DMA工作再循环缓存模式*/
DMA_InitStructure.DMA_Priority = DMA_Priority_High;/*设定DMA选定的通道的软件优先级*/
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//关闭内存到内存的传输
DMA_Init(DMA1_Channel1, &DMA_InitStructure);
DMA_Cmd(DMA1_Channel1, ENABLE);/* Enable DMA channel1 */
}

void DMA_Init(DMA_Channel_TypeDef* DMAy_Channelx, DMA_InitTypeDef* DMA_InitStruct)
{
uint32_t tmpreg = 0;
/*--------------------------- DMAy Channelx CCR Configuration -----------------*/
/* Get the DMAy_Channelx CCR value */
tmpreg = DMAy_Channelx->CCR;
/* Clear MEM2MEM, PL, MSIZE, PSIZE, MINC, PINC, CIRC and DIR bits */
tmpreg &= CCR_CLEAR_Mask;
/* Configure DMAy Channelx: data transfer, data size, priority level and mode */
/* Set DIR bit according to DMA_DIR value */
/* Set CIRC bit according to DMA_Mode value */
/* Set PINC bit according to DMA_PeripheralInc value */
/* Set MINC bit according to DMA_MemoryInc value */
/* Set PSIZE bits according to DMA_PeripheralDataSize value */
/* Set MSIZE bits according to DMA_MemoryDataSize value */
/* Set PL bits according to DMA_Priority value */
/* Set the MEM2MEM bit according to DMA_M2M value */
tmpreg |= DMA_InitStruct->DMA_DIR | DMA_InitStruct->DMA_Mode |
DMA_InitStruct->DMA_PeripheralInc | DMA_InitStruct->DMA_MemoryInc |
DMA_InitStruct->DMA_PeripheralDataSize | DMA_InitStruct->DMA_MemoryDataSize |
DMA_InitStruct->DMA_Priority | DMA_InitStruct->DMA_M2M;
/* Write to DMAy Channelx CCR */
DMAy_Channelx->CCR = tmpreg;
/*--------------------------- DMAy Channelx CNDTR Configuration ---------------*/
/* Write to DMAy Channelx CNDTR */
DMAy_Channelx->CNDTR = DMA_InitStruct->DMA_BufferSize;
/*--------------------------- DMAy Channelx CPAR Configuration ----------------*/
/* Write to DMAy Channelx CPAR */
DMAy_Channelx->CPAR = DMA_InitStruct->DMA_PeripheralBaseAddr;
/*--------------------------- DMAy Channelx CMAR Configuration ----------------*/
/* Write to DMAy Channelx CMAR */
DMAy_Channelx->CMAR = DMA_InitStruct->DMA_MemoryBaseAddr;
}

  将上面两个函数比较一下就可以知道，前者函数对于后者来说就相当于是一个中间量的过程，暂时的将需要的配置参数写入一个结构体DMA_InitTypeDef中，后面调用DMA_Init这个函数之后，重新配置物理地址中DMA的寄存器相应的位。下面附录上两个函数中的结构体参数组成。

typedef struct
{
__IO uint32_t CCR;
__IO uint32_t CNDTR;
__IO uint32_t CPAR;
__IO uint32_t CMAR;
} DMA_Channel_TypeDef;

DMA_InitTypeDef
DMA_InitStructure;
typedef struct
{
uint32_t DMA_PeripheralBaseAddr;
uint32_t DMA_MemoryBaseAddr;
uint32_t DMA_DIR;
uint32_t DMA_BufferSize;
uint32_t DMA_PeripheralInc;
uint32_t DMA_MemoryInc;
uint32_t DMA_PeripheralDataSize;
uint32_t DMA_MemoryDataSize;
uint32_t DMA_Mode;
uint32_t DMA_Priority;
uint32_t DMA_M2M;
}DMA_InitTypeDef;

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