STM32F10x 学习笔记8（USART实现串口通讯 DMA 方式）

时间：11-20 来源：互联网点击：

T2,ENABLE);
USART_InitStructure.USART_BaudRate=9600;
USART_InitStructure.USART_WordLength=USART_WordLength_8b;
USART_InitStructure.USART_StopBits=USART_StopBits_1;
USART_InitStructure.USART_Parity=USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
USART_Init(USART2,&USART_InitStructure);
USART_Cmd(USART2,ENABLE);
NVIC_InitStructure.NVIC_IRQChannel=USART2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
voidUART2_TX_DMA_Init(uint8_t*p_str,uint16_tcnt)
{
//DMA_InitTypeDefDMA_InitStructure;
//DMA_InitStructure.DMA_PeripheralBaseAddr=(uint32_t)&(USART2->DR);
//DMA_InitStructure.DMA_MemoryBaseAddr=(uint32_t)str;
//DMA_InitStructure.DMA_DIR=DMA_DIR_PeripheralDST;
//DMA_InitStructure.DMA_BufferSize=14;
//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_Low;
//DMA_InitStructure.DMA_M2M=DMA_M2M_Disable;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);
//DMA_Init(DMA1_Channel7,&DMA_InitStructure);
DMA1_Channel7->CPAR=(uint32_t)&(USART2->DR);
DMA1_Channel7->CMAR=(uint32_t)p_str;
DMA1_Channel7->CNDTR=cnt;
DMA1_Channel7->CCR=DMA_DIR_PeripheralDST|DMA_Priority_Low|
DMA_Mode_Normal|DMA_PeripheralInc_Disable|
DMA_MemoryInc_Enable|DMA_PeripheralDataSize_Byte|
DMA_MemoryDataSize_Byte|DMA_M2M_Disable;
}
OS_EVENT*UART2_DMA_TX_Sem;
uint8_tstr[]="HelloWorld!!!";
voidTaskStart(void*pdata)
{
unsignedcharerr;
SysTick_Config(SystemCoreClock/10);
USART2_Init();
USART_DMACmd(USART2,USART_DMAReq_Tx,ENABLE);
UART2_TX_DMA_Init(str);
UART2_DMA_TX_Sem=OSSemCreate(1);
for(;;)
{
LED_Spark();
OSSemPend(UART2_DMA_TX_Sem,0,&err);
//DMA_Cmd(DMA1_Channel7,DISABLE);
DMA1_Channel7->CCR&=(uint16_t)(~DMA_CCR1_EN);
//DMA_Init(DMA1_Channel7,&DMA_InitStructure);
DMA1_Channel7->CNDTR=14;
//DMA_Cmd(DMA1_Channel7,ENABLE);
DMA1_Channel7->CCR|=DMA_CCR1_EN;
//USART_DMACmd(USART2,USART_DMAReq_Tx,ENABLE);
OSTimeDly(10);
}
}
intmain(void)
{
SystemInit();
LED_Init();
OSInit();
OSTaskCreate(TaskStart,(void*)0,&(TaskStartStk[TASK_STK_SIZE-1]),1);
OSStart();
for(;;)
{
}
}
voidDMA1_Channel7_IRQHandler(void)
{
OS_CPU_SRcpu_sr;
OS_ENTER_CRITICAL();/*TelluC/OS-IIthatwearestartinganISR*/
OSIntNesting++;
OS_EXIT_CRITICAL();
OSSemPost(UART2_DMA_TX_Sem);
//UART_PutChar(USART2,+);
DMA1->IFCR=DMA1_FLAG_TC7;
OSIntExit();
}

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