#include <REGX52.H>

void Delay(unsigned int xms)    //@12.000MHz
{
  unsigned char i, j;
    while(xms)
    {
      i = 2;
      j = 239;
      do
      {
        while (--j);
      } while (--i);
      xms--;
    }
  
}

void main()
{
  while(1)
  {
    if(P3_1==0)
    {
        Delay(20);
        while(P3_1==0);
        Delay(20);
        P2_0=~P2_0;
        
    }
  
  }
}