extern FlagStatus RX_status;

void USART1_IRQHandler(void)

{

       GPIO_SetBits(GPIOB, GPIO_Pin_5);


       //确认是否接收到数据

       RX_status = USART_GetFlagStatus(USART1, USART_FLAG_RXNE);

       //接收到数据

       if(RX_status == SET)

       {

              //将数据回送至超级终端

              USART_SendData(USART1, USART_ReceiveData(USART1));

              //等待数据发送完毕

              while(USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);

              GPIO_ResetBits(GPIOB, GPIO_Pin_5);

       }

}