#define USART_REC_LEN ??? ??? ??? ?16 ??? ?//定义最大接收字节数 ?16
extern u8 USART2_RX_BUF[USART_REC_LEN];
u8 USART2_RX_BUF[USART_REC_LEN];?
void uart2_init(u32 bound)
{
?? ?//GPIO端口设置
?? ?GPIO_InitTypeDef GPIO_InitStructure;
?? ?USART_InitTypeDef USART_InitStructure;
?? ?//NVIC_InitTypeDef NVIC_InitStructure;
?? ?DMA_InitTypeDef ?DMA_InitStructure;
?? ?RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2|RCC_APB2Periph_GPIOA, ENABLE);?? ?//使能USART2，GPIOA时钟
? RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
?? ?//USART2_TX ? GPIOA.2
?? ?GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; //PA.2
?? ?GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
?? ?GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;?? ?//复用推挽输出
?? ?GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA.2
?? ?//USART2_RX?? ? ?GPIOA.3初始化
?? ?GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;//PA3
?? ?GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
?? ?GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA.3 ?
?? ?//Usart2 NVIC 配置
//?? ?NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
//?? ?NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2 ;//抢占优先级3
//?? ?NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;?? ??? ?//子优先级3
//?? ?NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;?? ??? ??? ?//IRQ通道使能
//?? ?NVIC_Init(&NVIC_InitStructure);?? ?//根据指定的参数初始化VIC寄存器
?? ?//USART 初始化设置
?? ?USART_InitStructure.USART_BaudRate = bound;//串口波特率
?? ?USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式
?? ?USART_InitStructure.USART_StopBits = USART_StopBits_1;//一个停止位
?? ?USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位
?? ?USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制
?? ?USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;?? ?//收发模式
? USART_Init(USART2, &USART_InitStructure); //初始化串口2
?// USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);//开启串口接受中断
??
?? ?
?? ?/* DMA1 channel1 configuration */
? ?DMA_DeInit(DMA1_Channel6);
? ?DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(USART2->DR);//外设站点起始的地址
? ?DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)USART2_RX_BUF;//存储器的地址
? ?DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;//传输方向 从外设站点搬到存储器站点
? ?DMA_InitStructure.DMA_BufferSize = 16;//数据量（字节数小于65535)
? ?DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设地址不需要自增
? ?DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//地址需要自增
? ?DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//宽度 字节
? ?DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Byte;
? ?DMA_InitStructure.DMA_Mode = DMA_Mode_Circular ; //单次 ?循环
? ?DMA_InitStructure.DMA_Priority = DMA_Priority_High;//优先级设置高级
? ?DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//使能 存储器到存储器的搬运
? ?DMA_Init(DMA1_Channel6, &DMA_InitStructure);
?? ? /* Enable DMA1 Channel6 Transfer Complete interrupt */
? // DMA_ITConfig(DMA1_Channel5, DMA_IT_TC, ENABLE);//传输结束的的中断
? ?DMA_Cmd(DMA1_Channel6,ENABLE);
?? ? USART_DMACmd(USART2,USART_DMAReq_Rx,ENABLE);
? ?USART_Cmd(USART2, ENABLE); ? ? ? ? ? ? ? ? ? ?//使能串口2
}