#include <reg51.h>
#include <stdio.h>
#include <math.h>
#define unit unsigned int

sbit P1_0=P1^0;
int a=500,b=200,c,d,c1,d1;


void init()
{
 TMOD=0X11;
 TH0=c1;
 TL0=d1;
 TH1=c;
 TL1=d;
 EA=1;
 ET0=1;TR0=1;
 ET1=1;TR1=1;
 }

void main()
{
c=(65536-b)/256;
d=(65536-b)%256;
c1=(65536-a)/256;
d1=(65536-a)%256;
init();
P1_0=0;
while(1);
  }

void timer0(void) interrupt 1
 {   TR0=0;
     P1_0=1;
   //P1_0=~P1_0;
   
   TH0=c1;
   TL0=d1;
   }

void timer1(void) interrupt 3
{ 
   P1_0=0;
 //P1_0=~P1_0;
 TH1=c;
 TL1=d;
  TR0=1;
  }