unsigned char keyState(keyID)
 {
 switch(keyID) {
  case 0:
   return key0;
   break;
  #if MaxKey>1
  case 1:
   retrun key1;
   break;
  #endif
  // for each key, enclose case statement in #if
  #if MaxKey>N
  case N:
   return keyN;
   break;
  } // end switch
}