 }
 
 //----------------------------------------
-// frequency of sinewave (datasheet page 12) will be <sys clock> * <frequency tuning word> / 2^32
+// Frequency of sinewave (datasheet page 12) will be "<sys clock> * <frequency tuning word> / 2^32".
+// Rearranging: FTW = (frequency * 2^32) / sys_clock .
 //
 // 'VfoClockOffset' is the value the 'Calibrate' menu tweaks, initially 0.
 //----------------------------------------

// Set the current 'doubleclick' time and save to EEPROM if 'actioned'.
//   menu      address of 'calling' menu
//   item_num  index of MenuItem we were actioned from
// This works differently from brightness/contrast.  We show menuitems
// of the time to use.
//----------------------------------------

void doubleclick_action(struct Menu *menu, int item_num)

  struct MenuItem **items;    // array of pointers to MenuItem data
};

//----------------------------------------
// dump a MenuItem to the console
// only called from dump_menu()
//----------------------------------------

void dump_menuitem(struct MenuItem *menuitem)
{
  Serial.printf(F("  menuitem address=%08x\n"), menuitem);
