c2.c

基于51的RS485的多机发送和接收的通信程序

#include <reg51.h>
#define uchar unsigned char
void open();
void delay();
void send();
void wai();
void closed();
sbit p35=P3^5;
sbit p10=P1^0;
uchar cort=0,result;


void main(){
          TMOD=0x20;
	  TL1=0xfd;
	  TH1=0xfd;
	  PCON=0x00;
	  TR1=1;
	  SCON=0xf8;
         EX0=1;
         IT0=1;
	  EA=1;
	  ES=1;
p35=0;
while(1){;}}


void wai() interrupt 0
{cort++;P2=cort;}


void chuan() interrupt 4
{
ES=0;
while(RI==0);RI=0;result=SBUF;
if(result!=0x02){ES=1;SM2=1;goto reti;}
  SM2=0;p35=1;SBUF=0X02;while(TI==0);TI=0;
p35=0;while(RI==0);RI=0;result=SBUF;
if((result&0x80)==0x80){ES=1;SM2=1;goto reti;}
a1:p35=0;while(RI==0);RI=0;result=SBUF;
p35=0;while(RI==0);RI=0;
if(SBUF!=result){p35=1;SBUF=0X80;while(TI==0);TI=0;goto a1;}
p35=1;SBUF=0X00;while(TI==0);TI=0;
switch(result){
              case 0x03:send();break;
              case 0x04:closed();break;
              case 0x05:open();break;
              default:;
              }
reti:ES=1;SM2=1;p35=0;
}


//发送函数
void send()
{a3:p35=1;SBUF=cort;while(TI==0);TI=0;
delay();
p35=1;SBUF=cort;while(TI==0);TI=0;
p35=0;while(RI==0);RI=0;result=SBUF;
if((result&0x80)==0x80)goto a3;
}
void closed()
{p10=1;}
void open()
{p10=0;}
void delay()
{uchar i;
for(i=5;i>0;i--);
}