#include<reg51.h>

#include<string.h>

#defineINBUF_LEN4//数据长度

unsignedcharinbuf1[INBUF_LEN];

unsignedcharchecksum,count3;

bit read_flag=0;

voidinit_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;

}

//向串口发送一个字符

voidsend_char_com(unsignedcharch)

{

SBUF=ch;

while(TI==0);

TI=0;

}

//向串口发送一个字符串，strlen为该字符串长度

voidsend_string_com(unsignedchar*str,unsignedintstrlen)

{

unsignedintk=0;

do

{

send_char_com(*(str + k));

k++;

}while(k < strlen);

}

//串口接收中断函数

voidserial () interrupt4using3

{

if(RI)

{

unsignedcharch;

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，

//就置位取数标志

}

}

}

}

main()

{

init_serialcomm();//初始化串口

while(1)

{

if(read_flag)//如果取数标志已置位，就将读到的数从串口发出

{

read_flag=0;//取数标志清0

send_string_com(inbuf1,INBUF_LEN);

}

}

}