void USART2_IRQHandler()   {       if(USART_GetITStatus(USART2,USART_IT_RXNE) != RESET) //中断产生            {          USART_ClearITPendingBit(USART2,USART_IT_RXNE); //清除中断标志                Uart2_Buffer[Uart2_Rx] = USART_ReceiveData(USART2); //把数据存储到缓冲数组                Uart2_Rx++;          Uart2_Rx &= 0xFF;            }       if(Uart2_Buffer[Uart2_Rx-1] == 0x5A) //如果收到的是 0x5A 则下面就是有效数据                  Uart2_Tx = Uart2_Rx-1;       if((Uart2_Buffer[Uart2_Tx] == 0x5A)&&(Uart2_Buffer[Uart2_Rx-1] == 0xA5)) //检测到头的情况下检测到尾         {              Uart2_Len = Uart2_Rx-1- Uart2_Tx; //长度                          Uart2_Sta=1; //标志位            }       if(USART_GetFlagStatus(USART2,USART_FLAG_ORE) == SET) //溢出            {              USART_ClearFlag(USART2,USART_FLAG_ORE); //读SR                          USART_ReceiveData(USART2); //读DR            }  } main.c###################################################################     if( Uart2_Sta )//数据帧接收完毕      {              for(tx2=0;tx2 <= Uart2_Len;tx2++,Uart2_Tx++)              USART2_SendByte(Uart2_Buffer[Uart2_Tx]); //发送数据                     Uart2_Rx = 0; //初始化                     Uart2_Tx = 0;                 Uart2_Sta = 0;       }	      比如数据帧为  5A 00 11 65 33 22 23 43 A5    此为一帧