void buzzer_timer(void) interrupt 3 
{
  T1_Start();  // start timer again
  if (++ticks10 == 250)
  { 
    if (++ticks == 40)
    {
    P2 &= ~0x0C;
    ticks = 0;
    SCON &= 0x50;
    LCD_Flag = 1;
    TR1 = 0;
    }
    ticks10 = 0;
  }
  return;
}