stm32的DMA串口應用（以串口1為例）

stm32的DMA串口應用（以串口1為例）

1.定義宏常量

#define BuffSize 12

#define DATA_HEAD0xAA

#define DATA_END 0x55

#define USART1_DR_Address (u32)0x40013804

2.聲明DMA初始化函數

void DMA_Configuration(void);

3.打開DMA1時鐘

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

4.調用初始化函數

DMA_Configuration();

5.DMA初始化函數

void DMA_Configuration(void)

{

DMA_InitTypeDef DMA_InitStructure;

DMA_DeInit(DMA1_Channel4);

DMA_InitStructure.DMA_PeripheralBaseAddr = USART1_DR_Address;

DMA_InitStructure.DMA_MemoryBaseAddr = (u32)TxBuffer;

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;

DMA_InitStructure.DMA_BufferSize =BuffSize;

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;

DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;

DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;

DMA_InitStructure.DMA_Priority = DMA_Priority_High;

DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

DMA_Init(DMA1_Channel4, &DMA_InitStructure);

// DMA_ITConfig(DMA1_Channel4, DMA_IT_TC, ENABLE);

//USART_DMACmd(USART1, USART_DMAReq_Tx, ENABLE);

DMA_Cmd(DMA1_Channel4, ENABLE);

}

6.為要發送的數據賦值

TxBuffer[0]=DATA_HEAD;

TxBuffer[1]=DATA_HEAD;

TxBuffer[2]=PH;

TxBuffer[3]=PL;

TxBuffer[4]=pressureh;

TxBuffer[5]=pressurem;

TxBuffer[6]=pressurel;

TxBuffer[7]=TH;

TxBuffer[8]=TL;

TxBuffer[9]=rh;

TxBuffer[10]=DATA_END;

TxBuffer[11]=DATA_END;

7.在適當的地方調用DMA發送命令

// USART_Cmd(USART1, ENABLE);

USART_DMACmd(USART1, USART_DMAReq_Tx, ENABLE);

DMA_Cmd(DMA1_Channel4, ENABLE);

while(DMA_GetFlagStatus(DMA1_FLAG_TC4) == RESET){}

while(USART_GetFlagStatus(USART1, USART_FLAG_TC)==RESET){}

// USART_Cmd(USART1, DISABLE);

DMA_Cmd(DMA1_Channel4, DISABLE);

DMA_ClearFlag(DMA1_FLAG_TC4);

USART_DMACmd(USART1, USART_DMAReq_Tx, DISABLE);

DMA1_Channel4->CNDTR = BuffSize;

DMA1_Channel4->CMAR = (u32)TxBuffer;