#include <AT89X52.H>
unsigned char code dispbitcode[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};
unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x00};
unsigned char dispbuf[8]={10,10,10,10,10,0,0,0};	
unsigned char dispcount;

sbit ST=P3^0;
sbit OE=P3^1;
sbit EOC=P3^2;
unsigned char channel=0xbc;//IN3
unsigned char getdata;

void main(void)
{
  TMOD=0x01;
  TH0=(65536-4000)/256;
  TL0=(65536-4000)%256;
  TR0=1;
  ET0=1;
  EA=1;
  
  P3=channel;

  while(1)
    {
      ST=0;
      ST=1;
      ST=0;
      while(EOC==0);
      OE=1;
      getdata=P0;
      OE=0;
      dispbuf[2]=getdata/100;
      getdata=getdata%10;
      dispbuf[1]=getdata/10;
      dispbuf[0]=getdata%10;
    }
}

void t0(void) interrupt 1 using 0
{
  TH0=(65536-4000)/256;
  TL0=(65536-4000)%256;
  P1=dispcode[dispbuf[dispcount]];
  P2=dispbitcode[dispcount];
  dispcount++;
  if(dispcount==8)
    {
      dispcount=0;
    }
}