?

＃i nclude "reg51_STC.H"
#define uchar unsigned char
#define uint unsigned int

//--------------------------------------------------------------------------
//函數名稱:????? UART_Init()
//函數功能:????? 串口初始化函數,在系統時鐘為11.059MHZ時，設定串口波特率為9600bit/s
//其他說明:????? 串口接收中斷允許，發送中斷禁止
//--------------------------------------------------------------------------

void UART_Init(void)
{
SCON = 0x50 ; //SCON: serail mode 1, 8-bit UART, enable ucvr?
TMOD |= 0x20 ; //TMOD: timer 1, mode 2, 8-bit reload?
PCON |= 0x80 ; //SMOD=1;?
TH1 = 0xFA ; //Baud:9600 fosc="11".0592MHz?
ES=1;
TR1 = 1 ;??? // timer 1 run?
EA=1;
}


//--------------------------------------------------------------------------
//函數名稱:????? main(void)
//函數功能:????? 主函數
//其他說明:????? 無
//--------------------------------------------------------------------------

void main(void)
{
UART_Init();
while(1);
}


//--------------------------------------------------------------------------
//函數名稱:????? Uart_SendData()
//函數功能:????? 串口發送一個字節的數據
//其他說明:????? 此程序供中斷調用
//--------------------------------------------------------------------------

void Uart_SendData(uchar dat)
{
SBUF=dat; //寫SBUF，開始發送
while(TI==0); //等待發送
TI="0";?? //清發送標志位?
}


//--------------------------------------------------------------------------
//函數名稱:????? INT_UartRcv()
//函數功能:????? 串口接收中斷函數
//其他說明:????? 無
//--------------------------------------------------------------------------

void INT_UartRcv(void) interrupt 4
{
uchar Rcv;
if(RI)
{
RI=0;???? //
Rcv=SBUF;
Uart_SendData(Rcv); //返回接收數據,可以改為其他函數?
}
}

NO。2

＃i nclude
＃i nclude
#define INBUF_LEN 4 //數據長度?
unsigned char inbuf1[INBUF_LEN];?
unsigned char checksum,count3;?
bit read_flag= 0 ;?
void init_serialcomm( void )?
{?
?SCON = 0x50 ; //SCON: serail mode 1, 8-bit UART, enable ucvr?
?TMOD |= 0x20 ; //TMOD: timer 1, mode 2, 8-bit reload?
?PCON |= 0x80 ; //SMOD=1;?
?TH1 = 0xF4 ; //Baud:4800 fosc=11.0592MHz?
?IE |= 0x90 ; //Enable Serial Interrupt?
?TR1 = 1 ; // timer 1 run?
??EA=1;
}

//向串口發送一個字符?
void send_char_com( unsigned char ch)?
{?
?SBUF=ch;?
?while (TI== 0 );?
?TI= 0 ;?
}

//向串口發送一個字符串，strlen為該字符串長度?
void send_string_com( unsigned char *str, unsigned int strlen)?
{?
?unsigned int k= 0 ;?
?do?
?{?
??send_char_com(*(str + k));?
??k++;?
?} while (k < strlen);?
}

//串口接收中斷函數?
void serial () interrupt 4 using 3?
{?
?if (RI)?
?{?
??unsigned char ch;?
??RI = 0 ;?
??ch=SBUF;?
??if (ch> 127 )?
?{?
??count3= 0 ;?
??inbuf1[count3]=ch;?
??checksum= ch- 128 ;?
?}?
??else?
??{?
??count3++;?
??inbuf1[count3]=ch;?
??checksum ^= ch;?
??if ( (count3==(INBUF_LEN- 1 )) && (!checksum) )?
??{?
??read_flag= 1 ; //如果串口接收的數據達到INBUF_LEN個，且校驗沒錯，?
??//就置位取數標志?
??}?
?}?
}?
}

main()?
{?
?init_serialcomm(); //初始化串口?
?while ( 1 )?
?{?
??if (read_flag) //如果取數標志已置位，就將讀到的數從串口發出?
??{?
??read_flag= 0 ; //取數標志清0?
??send_string_com(inbuf1,INBUF_LEN);?
??} ???????
?}

}