为什么用mini版USART1的例程改为 UART4后不能收发数据，串口调试助手也收不到printf里的字符

半寸时光 · 发表于 2016-4-28 14:14:20

//重定义fputc函数
int fputc(int ch, FILE *f)
{
while((UART4->SR&0X40)==0);//循环发送,直到发送完毕
UART4->DR = (u8) ch;
return ch;
}

void uart_init(u32 bound){
//GPIO端口设置
GPIO_InitTypeDef GPIO_InitStructure;
   USART_InitTypeDef USART_InitStructure;
   NVIC_InitTypeDef NVIC_InitStructure;

      RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4,ENABLE);
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
   USART_DeInit(UART4);  //复位串口1
   //UART4_TX PA.10
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //PA.10
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
GPIO_Init(GPIOC, &GPIO_InitStructure); //初始化PA9

//UART4_RX    PA.11
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
GPIO_Init(GPIOC, &GPIO_InitStructure);  //初始化PA10

//Usart1 NVIC 配置

NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn;
   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;
   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStructure);

//USART 初始化设置

   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(UART4, &USART_InitStructure); //初始化串口
USART_ITConfig(UART4, USART_IT_RXNE, ENABLE);//开启中断
USART_Cmd(UART4, ENABLE);                   //使能串口
}

void UART4_IRQHandler(void)
{
u8 Res;
if(USART_GetITStatus(UART4, USART_IT_RXNE) != RESET)  //接收中断(接收到的数据必须是0x0d 0x0a结尾)
      {
      Res =USART_ReceiveData(UART4);  //读取接收到的数据

      if((USART_RX_STA&0x8000)==0)//接收未完成
         {
         if(USART_RX_STA&0x4000)//接收到了0x0d
            {
            if(Res!=0x0a)USART_RX_STA=0;//接收错误,重新开始
            else USART_RX_STA|=0x8000; //接收完成了
            }
         else //还没收到0X0D
            {
            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-1)) USART_RX_STA=0;//接收数据错误,重新开始接收
                  }
            }
         }
   }
}

while(1)
{
      if(USART_RX_STA&0x8000)
      {
         len=USART_RX_STA&0x3fff;//得到此次接收到的数据长度
         printf("\r\n您发送的消息为:\r\n");
         for(t=0;t<len;t++)
         {
            UART4->DR=USART_RX_BUF[t];
            while((UART4->SR&0X40)==0);//等待发送结束
         }
         printf("\r\n\r\n");//插入换行
         USART_RX_STA=0;
      }else
      {
         times++;
         if(times%200==0)printf("请输入数据,以回车键结束\r\n");
         if(times%30==0)LED0=!LED0;//闪烁LED,提示系统正在运行.
         delay_ms(10);
      }
}