//这是一个单片机C51串口接收（中断）和发送例程，可以用来测试51单片机的中断接收 
//和查询发送，另外我觉得发送没有必要用中断，因为程序的开销是一样的

＃i nclude <reg51.h> 
＃i nclude <string.h>

#define INBUF_LEN 4 //数据长度
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 
// TI=1; 
}

//向串口发送一个字笿
void send_char_com( unsigned char ch) 
{ 
SBUF=ch; 
while (TI== 0 ); 
TI= 0 ; 
}

//向串口发送一个字符串，strlen为该字符串长庿
void send_string_com( unsigned char *str, unsigned int strlen) 
{ 
unsigned int k= 0 ; 
do 
{ 
send_char_com(*(str + k)); 
k++; 
} while (k < strlen); 
}


//串口接收中断函数 
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 ; //如果串口接收的数据达到INBUF_LEN个，且校验没错， 
//就置位取数标忿
} 
} 
} 
}


main() 
{ 
init_serialcomm(); //初始化串叿
while ( 1 ) 
{ 
if (read_flag) //如果取数标志已置位，就将读到的数从串口发凿
{ 
read_flag= 0 ; //取数标志渿 
send_string_com(inbuf1,INBUF_LEN); 
} 
}

}