[STM32F103]串口UART配置

l 串口时钟使能，GPIO时钟使能:

　　RCC_APB2PeriphClockCmd();

l 串口复位:

　　USART_DeInit(); 这一步不是必须的

l GPIO端口模式设置:

　　GPIO_Init();

l 串口参数初始化：

　　USART_Init();

l 开启中断并且初始化NVIC（如果需要开启中断才需要这个步骤）

NVIC_Init();

USART_ITConfig();

l 使能串口:

　　USART_Cmd();

l 编写中断处理函数：

　　USARTx_IRQHandler();

l 串口数据收发：

　　void USART_SendData();//发送数据到串口，DR

　　uint16_t USART_ReceiveData();//接受数据，从DR读取接受到的数据

l 串口传输状态获取：

　　FlagStatus USART_GetFlagStatus(USART_TypeDef* USARTx, uint16_t USART_FLAG);

　　void USART_ClearITPendingBit(USART_TypeDef* USARTx, uint16_t USART_IT);

l 源代码：

 #pragma import(__use_no_semihosting)
 struct __FILE
 {
     int handle;
 }; 

 FILE __stdout;
 void _sys_exit(int x)
 {
     x = x;
 }
 int fputc(int ch, FILE *f)
 {
 while((USART1->SR&0X40)==);
     USART1->DR = (u8) ch;
     return ch;
 } 

 void uart_init(u32 bound){
   //GPIO¶Ë¿ÚÉèÖÃ
   GPIO_InitTypeDef GPIO_InitStructure;
 USART_InitTypeDef USART_InitStructure;
     NVIC_InitTypeDef NVIC_InitStructure;

     RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);    //ʹÄÜUSART1£¬GPIOAʱÖÓ

     //USART1_TX   GPIOA.9
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    //¸´ÓÃÍÆÍìÊä³ö
   GPIO_Init(GPIOA, &GPIO_InitStructure);//³õʼ»¯GPIOA.9

   //USART1_RX      GPIOA.10³õʼ»¯
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;//PA10
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//¸¡¿ÕÊäÈë
   GPIO_Init(GPIOA, &GPIO_InitStructure);//³õʼ»¯GPIOA.10  

   //Usart1 NVIC ÅäÖÃ
   NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority= ;//ÇÀÕ¼ÓÅÏȼ¶3
     NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;        //×ÓÓÅÏȼ¶3
     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;            //IRQͨµÀʹÄÜ
     NVIC_Init(&NVIC_InitStructure);    //¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õʼ»¯VIC¼Ä´æÆ÷

    //USART ³õʼ»¯ÉèÖÃ
     USART_InitStructure.USART_BaudRate = bound;//´®¿Ú²¨ÌØÂÊ
     USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8λÊý¾Ý¸ñʽ
     USART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öֹͣλ
     USART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæżУÑéλ
     USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆ
     USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;    //ÊÕ·¢Ä£Ê½

   USART_Init(USART1, &USART_InitStructure); //³õʼ»¯´®¿Ú1
   USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//¿ªÆô´®¿Ú½ÓÊÜÖжÏ
   USART_Cmd(USART1, ENABLE);                    //ʹÄÜ´®¿Ú1 

 }

 void USART1_IRQHandler(void)                    //´®¿Ú1ÖжϷþÎñ³ÌÐò
     {
     u8 Res;
     if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)  //½ÓÊÕÖжÏ(½ÓÊÕµ½µÄÊý¾Ý±ØÐëÊÇ0x0d 0x0a½áβ)
         {
         Res =USART_ReceiveData(USART1);    //¶ÁÈ¡½ÓÊÕµ½µÄÊý¾Ý

         if((USART_RX_STA&0x8000)==)//½ÓÊÕδÍê³É
             {
             if(USART_RX_STA&0x4000)//½ÓÊÕµ½ÁË0x0d
                 {
                 if(Res!=0x0a)USART_RX_STA=;//½ÓÊÕ´íÎó,ÖØпªÊ¼
                 else USART_RX_STA|=0x8000;    //½ÓÊÕÍê³ÉÁË
                 }
             else //»¹Ã»ÊÕµ½0X0D
                 {
                 if(Res==0x0d)USART_RX_STA|=0x4000;
                 else
                     {
                     USART_RX_BUF[USART_RX_STA&0X3FFF]=Res ;
                     USART_RX_STA++;
                     if(USART_RX_STA>(USART_REC_LEN-))USART_RX_STA=;//½ÓÊÕÊý¾Ý´íÎó,ÖØпªÊ¼½ÓÊÕ
                     }
                 }
             }
      }