#include <reg51.h>
sbit P1_0=P1^0;
void timer0(void) interrupt 1 using 1{
  P1_0=!P1_0;
  TH0=(65536-1000)/256;
  TL0=(65536-1000)%256;
} 
void main(void) {
  TMOD=0x01;
  P1_0=0; 
  TH0=(65536-1000)/256;
  TL0=(65536-1000)%256;
  EA=1;
  ET0=1;
  TR0=1;
  do { }  while (1);
}