diff --git a/include/etl/fsm.h b/include/etl/fsm.h
index d06e2f6e..bb4d21f9 100644
--- a/include/etl/fsm.h
+++ b/include/etl/fsm.h
@@ -504,17 +504,17 @@ namespace etl
     bool have_changed_state(etl::fsm_state_id_t next_state_id) const
     {
       return (next_state_id != p_state->get_state_id()) &&
-        (next_state_id != ifsm_state::No_State_Change);
+             (next_state_id != ifsm_state::No_State_Change);
     }
 
-    etl::ifsm_state* p_state;          ///< A pointer to the current state.
-    etl::ifsm_state** state_list;       ///< The list of added states.
+    etl::ifsm_state*    p_state;          ///< A pointer to the current state.
+    etl::ifsm_state**   state_list;       ///< The list of added states.
     etl::fsm_state_id_t number_of_states; ///< The number of states.
   };
 
-//*************************************************************************************************
-// For C++17 and above.
-//*************************************************************************************************
+  //*************************************************************************************************
+  // For C++17 and above.
+  //*************************************************************************************************
 #if ETL_USING_CPP17 && !defined(ETL_FSM_FORCE_CPP03_IMPLEMENTATION) // For C++17 and above
   //***************************************************************************
   // The definition for all types.
@@ -524,12 +524,7 @@ namespace etl
   {
   public:
 
-  public:
-
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -586,6 +581,11 @@ namespace etl
       }
     }
   };
+
+  /// Definition of STATE_ID
+  template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, typename... TMessageTypes>
+  ETL_CONSTANT etl::fsm_state_id_t fsm_state<TContext, TDerived, STATE_ID_, TMessageTypes...>::STATE_ID;
+
 #else
 //*************************************************************************************************
 // For C++14 and below.
@@ -602,10 +602,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -667,10 +664,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -731,10 +725,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -794,10 +785,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -855,10 +843,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -915,10 +900,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -974,10 +956,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1032,10 +1011,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1088,10 +1064,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1143,10 +1116,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1197,10 +1167,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1250,10 +1217,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1301,10 +1265,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1351,10 +1312,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1400,10 +1358,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1448,10 +1403,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1494,10 +1446,7 @@ namespace etl
   {
   public:
 
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -1521,6 +1470,13 @@ namespace etl
       return p_parent ? p_parent->process_event(message) : static_cast<TDerived*>(this)->on_event_unknown(message);
     }
   };
+
+  template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, 
+            typename T1, typename T2, typename T3, typename T4, 
+            typename T5, typename T6, typename T7, typename T8, 
+            typename T9, typename T10, typename T11, typename T12, 
+            typename T13, typename T14, typename T15, typename T16>
+  ETL_CONSTANT etl::fsm_state_id_t fsm_state<TContext, TDerived, STATE_ID_, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16>::STATE_ID;
 #endif
 }
 
diff --git a/include/etl/generators/fsm_generator.h b/include/etl/generators/fsm_generator.h
index 6d5e945a..7a8f054a 100644
--- a/include/etl/generators/fsm_generator.h
+++ b/include/etl/generators/fsm_generator.h
@@ -93,12 +93,12 @@ namespace etl
   typedef typename etl::larger_type<etl::message_id_t>::type fsm_internal_id_t;
 
 #if ETL_USING_CPP17 && !defined(ETL_FSM_FORCE_CPP03_IMPLEMENTATION) // For C++17 and above
-  template <typename, typename, const etl::fsm_state_id_t, typename...>
+  template <typename, typename, etl::fsm_state_id_t, typename...>
   class fsm_state;
 #else
   /*[[[cog
   import cog
-  cog.outl("template <typename, typename, const etl::fsm_state_id_t,")
+  cog.outl("template <typename, typename, etl::fsm_state_id_t,")
   cog.out("          ")
   for n in range(1, int(Handlers)):
     cog.out("typename, ")
@@ -221,13 +221,16 @@ namespace etl
     friend class etl::fsm;
     friend class etl::hfsm;
 
+    using private_fsm::ifsm_state_helper<>::No_State_Change;
+    using private_fsm::ifsm_state_helper<>::Pass_To_Parent;
+
 #if ETL_USING_CPP17 && !defined(ETL_FSM_FORCE_CPP03_IMPLEMENTATION) // For C++17 and above
-    template <typename, typename, const etl::fsm_state_id_t, typename...>
+    template <typename, typename, etl::fsm_state_id_t, typename...>
     friend class fsm_state;
 #else
     /*[[[cog
     import cog
-    cog.outl("  template <typename, typename, const etl::fsm_state_id_t,")
+    cog.outl("  template <typename, typename, etl::fsm_state_id_t,")
     cog.out("            ")
     for n in range(1, int(Handlers)):
       cog.out("typename, ")
@@ -341,9 +344,6 @@ namespace etl
     ifsm_state& operator =(const ifsm_state&);
   };
 
-  ETL_CONSTANT fsm_state_id_t ifsm_state::No_State_Change;
-  ETL_CONSTANT fsm_state_id_t ifsm_state::Pass_To_Parent;
-
   //***************************************************************************
   /// The FSM class.
   //***************************************************************************
@@ -530,32 +530,27 @@ namespace etl
     bool have_changed_state(etl::fsm_state_id_t next_state_id) const
     {
       return (next_state_id != p_state->get_state_id()) &&
-        (next_state_id != ifsm_state::No_State_Change);
+             (next_state_id != ifsm_state::No_State_Change);
     }
 
-    etl::ifsm_state* p_state;          ///< A pointer to the current state.
-    etl::ifsm_state** state_list;       ///< The list of added states.
+    etl::ifsm_state*    p_state;          ///< A pointer to the current state.
+    etl::ifsm_state**   state_list;       ///< The list of added states.
     etl::fsm_state_id_t number_of_states; ///< The number of states.
   };
 
-//*************************************************************************************************
-// For C++17 and above.
-//*************************************************************************************************
+  //*************************************************************************************************
+  // For C++17 and above.
+  //*************************************************************************************************
 #if ETL_USING_CPP17 && !defined(ETL_FSM_FORCE_CPP03_IMPLEMENTATION) // For C++17 and above
   //***************************************************************************
   // The definition for all types.
   //***************************************************************************
-  template <typename TContext, typename TDerived, const etl::fsm_state_id_t STATE_ID_, typename... TMessageTypes>
+  template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, typename... TMessageTypes>
   class fsm_state : public ifsm_state
   {
   public:
 
-  public:
-
-    enum
-    {
-      STATE_ID = STATE_ID_
-    };
+    static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;
 
     fsm_state()
       : ifsm_state(STATE_ID)
@@ -612,6 +607,11 @@ namespace etl
       }
     }
   };
+
+  /// Definition of STATE_ID
+  template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, typename... TMessageTypes>
+  ETL_CONSTANT etl::fsm_state_id_t fsm_state<TContext, TDerived, STATE_ID_, TMessageTypes...>::STATE_ID;
+
 #else
 //*************************************************************************************************
 // For C++14 and below.
@@ -624,7 +624,7 @@ namespace etl
   cog.outl("//***************************************************************************")
   cog.outl("// The definition for all %s message types." % Handlers)
   cog.outl("//***************************************************************************")
-  cog.outl("template <typename TContext, typename TDerived, const etl::fsm_state_id_t STATE_ID_, ")
+  cog.outl("template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, ")
   cog.out("          ")
   for n in range(1, int(Handlers)):
       cog.out("typename T%s = void, " % n)
@@ -636,10 +636,7 @@ namespace etl
   cog.outl("{")
   cog.outl("public:")
   cog.outl("")
-  cog.outl("  enum")
-  cog.outl("  {")
-  cog.outl("    STATE_ID = STATE_ID_")
-  cog.outl("  };")
+  cog.outl("  static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;")
   cog.outl("")
   cog.outl("  fsm_state()")
   cog.outl("    : ifsm_state(STATE_ID)")
@@ -690,7 +687,7 @@ namespace etl
       else:
           cog.outl("// Specialisation for %d message types." % n)
       cog.outl("//***************************************************************************")
-      cog.outl("template <typename TContext, typename TDerived, const etl::fsm_state_id_t STATE_ID_, ")
+      cog.outl("template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, ")
       cog.out("          ")
       for t in range(1, n):
           cog.out("typename T%d, " % t)
@@ -713,10 +710,7 @@ namespace etl
       cog.outl("{")
       cog.outl("public:")
       cog.outl("")
-      cog.outl("  enum")
-      cog.outl("  {")
-      cog.outl("    STATE_ID = STATE_ID_")
-      cog.outl("  };")
+      cog.outl("  static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;")
       cog.outl("")
       cog.outl("  fsm_state()")
       cog.outl("    : ifsm_state(STATE_ID)")
@@ -762,7 +756,7 @@ namespace etl
   cog.outl("//***************************************************************************")
   cog.outl("// Specialisation for 0 message types.")
   cog.outl("//***************************************************************************")
-  cog.outl("template <typename TContext, typename TDerived, const etl::fsm_state_id_t STATE_ID_>")
+  cog.outl("template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_>")
   cog.out("class fsm_state<TContext, TDerived, STATE_ID_, ")
   for t in range(1, int(Handlers)):
       cog.out("void, ")
@@ -773,10 +767,7 @@ namespace etl
   cog.outl("{")
   cog.outl("public:")
   cog.outl("")
-  cog.outl("  enum")
-  cog.outl("  {")
-  cog.outl("    STATE_ID = STATE_ID_")
-  cog.outl("  };")
+  cog.outl("  static ETL_CONSTANT etl::fsm_state_id_t STATE_ID = STATE_ID_;")
   cog.outl("")
   cog.outl("  fsm_state()")
   cog.outl("    : ifsm_state(STATE_ID)")
@@ -800,6 +791,20 @@ namespace etl
   cog.outl("    return p_parent ? p_parent->process_event(message) : static_cast<TDerived*>(this)->on_event_unknown(message);")
   cog.outl("  }")
   cog.outl("};")
+
+  cog.outl("")
+  cog.outl("template <typename TContext, typename TDerived, etl::fsm_state_id_t STATE_ID_, ")
+  cog.out("          ")
+  for n in range(1, int(Handlers)):
+      cog.out("typename T%s, " % n)
+      if n % 4 == 0:
+          cog.outl("")
+          cog.out("          ")
+  cog.outl("typename T%s>" % Handlers)
+  cog.out("ETL_CONSTANT etl::fsm_state_id_t fsm_state<TContext, TDerived, STATE_ID_, ")
+  for n in range(1, int(Handlers)):
+      cog.out("T%s, " % n)
+  cog.outl("T%s>::STATE_ID;" % Handlers)
   ]]]*/
   /*[[[end]]]*/
 #endif