if (!GCtgOsc)
  { // reload 60Hz timer
    GCtgOsc = 10;
    GBtgLvl = !GBtgLvl;
    SB_P1_SQWOUT = GBtgLvl; // change 60Hz state P1.0  
  }
  
  if (GBtgLvl)
  {
    if  (GCtgOsc == 1)
    { // output is positive
      switch (GCmeasureState) ////// THIS IS THE ALARM LINE