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

//--------------------------------------------------------------------------
//函數(shù)名稱(chēng):      UART_Init()
//函數(shù)功能:      串口初始化函數(shù),在系統(tǒng)時(shí)鐘為11.059MHZ時(shí)，設(shè)定串口波特率為9600bit/s
//其他說(shuō)明:      串口接收中斷允許，發(fā)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(shù)名稱(chēng):      main(void)
//函數(shù)功能:      主函數(shù)
//其他說(shuō)明:      無(wú)
//--------------------------------------------------------------------------

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


//--------------------------------------------------------------------------
//函數(shù)名稱(chēng):      Uart_SendData()
//函數(shù)功能:      串口發(fā)送一個(gè)字節(jié)的數(shù)據(jù)
//其他說(shuō)明:      此程序供中斷調(diào)用
//--------------------------------------------------------------------------

void Uart_SendData(uchar dat)
{
SBUF=dat; //寫(xiě)SBUF，開(kāi)始發(fā)送
while(TI==0); //等待發(fā)送
TI="0";   //清發(fā)送標(biāo)志位 
}


//--------------------------------------------------------------------------
//函數(shù)名稱(chēng):      INT_UartRcv()
//函數(shù)功能:      串口接收中斷函數(shù)
//其他說(shuō)明:      無(wú)
//--------------------------------------------------------------------------

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

NO。2

＃i nclude<reg52.h>
＃i nclude <string.h>
#define INBUF_LEN 4 //數(shù)據(jù)長(zhǎng)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(fā)送一個(gè)字符 
void send_char_com( unsigned char ch) 
{ 
 SBUF=ch; 
 while (TI== 0 ); 
 TI= 0 ; 
}

//向串口發(fā)送一個(gè)字符串，strlen為該字符串長(zhǎng)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(shù) 
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(shù)據(jù)達(dá)到INBUF_LEN個(gè)，且校驗(yàn)沒(méi)錯(cuò)， 
  //就置位取數(shù)標(biāo)志 
  } 
 } 
} 
}

main() 
{ 
 init_serialcomm(); //初始化串口 
 while ( 1 ) 
 { 
  if (read_flag) //如果取數(shù)標(biāo)志已置位，就將讀到的數(shù)從串口發(fā)出 
  { 
  read_flag= 0 ; //取數(shù)標(biāo)志清0 
  send_string_com(inbuf1,INBUF_LEN); 
  }        
 }

}