text4.c

分两个程序：接收端和发送端都有程序

#include<reg52.h>
#include<math.h>
#include<stdio.h>
#define uchar unsigned char;
uchar freq;
main()
{ TMOD=0x21;
  EA=1;
  ET0=1;
  PT0=1;
  ET1=1;
  //T2CON=0x08;

  TH0=-1000/256;
  TL0=-1000%256;
  TH1=0xfd;
  TL0=0xfd;
  SCON=0x50;
  PCON=0x80;

  TR0=1;
  TR1=1;
  TI=1;
  while(1)
  {}

}


void send(void) interrupt 1
{ TH0=-1000/256;
  TL0=-1000%256;
  freq++;
  if(freq==1000)
  { freq=0;
   printf("*");
  }


}