diff --git a/include/etl/callback_timer_deferred_locked.h b/include/etl/callback_timer_deferred_locked.h
index e9679bc7..d0a46e89 100644
--- a/include/etl/callback_timer_deferred_locked.h
+++ b/include/etl/callback_timer_deferred_locked.h
@@ -97,7 +97,6 @@ namespace etl
               count -= timer.delta;
 
               active_list.remove(timer.id, true);
-              remove_callback.call_if(timer.id);
 
               if (timer.callback.is_valid())
               {
@@ -112,9 +111,10 @@ namespace etl
                 // Reinsert the timer.
                 timer.delta = timer.period;
                 active_list.insert(timer.id);
-                insert_callback.call_if(timer.id);
               }
 
+              time_to_next_callback.call_if(time_to_next());
+
               has_active = !active_list.empty();
             }
 
diff --git a/include/etl/callback_timer_locked.h b/include/etl/callback_timer_locked.h
index 5579ec0b..39f5bde0 100644
--- a/include/etl/callback_timer_locked.h
+++ b/include/etl/callback_timer_locked.h
@@ -53,7 +53,7 @@ namespace etl
     typedef etl::delegate<void(void)> lock_type;
     typedef etl::delegate<void(void)> unlock_type;
 
-    typedef etl::delegate<void(etl::timer::id::type)> event_callback_type;
+    typedef etl::delegate<void(uint32_t)> event_callback_type;
 
     //*******************************************
     /// Register a timer.
@@ -102,7 +102,7 @@ namespace etl
           {
             lock();
             active_list.remove(timer.id, false);
-            remove_callback.call_if(timer.id);
+            time_to_next_callback.call_if(time_to_next());
             unlock();
           }
 
@@ -180,12 +180,11 @@ namespace etl
             if (timer.is_active())
             {
               active_list.remove(timer.id, false);
-              remove_callback.call_if(timer.id);
             }
 
             timer.delta = immediate_ ? 0U : timer.period;
             active_list.insert(timer.id);
-            insert_callback.call_if(timer.id);
+            time_to_next_callback.call_if(time_to_next());
             unlock();
 
             result = true;
@@ -215,7 +214,7 @@ namespace etl
           {
             lock();
             active_list.remove(timer.id, false);
-            remove_callback.call_if(timer.id);
+            time_to_next_callback.call_if(time_to_next());
             unlock();
           }
 
@@ -324,31 +323,17 @@ namespace etl
     }
 
     //*******************************************
-    /// Set a callback when a timer is inserted on list
+    /// Set a callback when the time to the next timer changes
     //*******************************************
-    void set_insert_callback(event_callback_type insert_)
+    void set_time_to_next_callback(event_callback_type callback_)
     {
-      insert_callback = insert_;
+      time_to_next_callback = callback_;
     }
 
     //*******************************************
-    /// Set a callback when a timer is removed from list
-    //*******************************************
-    void set_remove_callback(event_callback_type remove_)
+    void clear_time_to_next_callback()
     {
-      remove_callback = remove_;
-    }
-
-    //*******************************************
-    void clear_insert_callback()
-    {
-      insert_callback.clear();
-    }
-
-    //*******************************************
-    void clear_remove_callback()
-    {
-      remove_callback.clear();
+      time_to_next_callback.clear();
     }
 
   protected:
@@ -641,8 +626,7 @@ namespace etl
     lock_type     lock;     ///< The callback that locks.
     unlock_type   unlock;   ///< The callback that unlocks.
 
-    event_callback_type insert_callback;
-    event_callback_type remove_callback;
+    event_callback_type time_to_next_callback;
 
   public:
 
@@ -714,7 +698,6 @@ namespace etl
               count -= timer.delta;
 
               active_list.remove(timer.id, true);
-              remove_callback.call_if(timer.id);
 
               if (timer.callback.is_valid())
               {
@@ -726,9 +709,10 @@ namespace etl
                 // Reinsert the timer.
                 timer.delta = timer.period;
                 active_list.insert(timer.id);
-                insert_callback.call_if(timer.id);
               }
 
+              time_to_next_callback.call_if(time_to_next());
+
               has_active = !active_list.empty();
             }
 
diff --git a/test/test_callback_timer_deferred_locked.cpp b/test/test_callback_timer_deferred_locked.cpp
index 9ab130ea..6c0508d3 100644
--- a/test/test_callback_timer_deferred_locked.cpp
+++ b/test/test_callback_timer_deferred_locked.cpp
@@ -156,38 +156,29 @@ namespace
   callback_type member_callback_inc2 = callback_type::create<Object, object, &Object::callback_inc2>();
   callback_type member_callback_inc3 = callback_type::create<Object, object, &Object::callback_inc3>();
 
-  class TimerInsertRemoveTest
+  class TimerTimeToNextTest
   {
   public:
 
-    uint32_t inserted;
-    uint32_t removed;
-    TimerInsertRemoveTest()
-      : inserted(0)
-      , removed(0)
+    uint32_t time_to_next;
+
+    TimerTimeToNextTest()
+      : time_to_next(0)
     {
     }
 
-    void insert_handler(etl::timer::id::type id_)
+    void time_to_next_handler(uint32_t time_to_next_)
     {
-      (void)id_;
-      inserted++;
-    }
-
-    void remove_handler(etl::timer::id::type id_)
-    {
-      (void)id_;
-      removed++;
+      time_to_next = time_to_next_;
     }
 
     void clear(void)
     {
-      inserted = 0;
-      removed  = 0;
+      time_to_next = 0;
     }
   };
 
-  TimerInsertRemoveTest timerInsertRemoveTest;
+  TimerTimeToNextTest timerTimeToNextTest;
 
   //***************************************************************************
   // Free function callback via etl::function
@@ -1013,9 +1004,49 @@ namespace
     }
 
     //*************************************************************************
-    TEST(callback_timer_is_active)
+    // Tick	ID1	ID2	ID3
+    //   0   .   .   .
+    //   1	 .   .   .
+    //   2	 .   .   .
+    //   3	 .   .   .
+    //   4	 .   .   .
+    //   5	 .   .   .
+    //   6	 .   .   .
+    //   7	 .   .   .
+    //   8	 .   .   .
+    //   9	 .   .   O
+    //  10	 .   .   .
+    //  11	 .   .   .
+    //  12	 .   .   .
+    //  13	 .   .   .
+    //  14	 .   .   .
+    //  15	 .   .   .
+    //  16	 .   .   .
+    //  17	 .   .   .
+    //  18	 .   .   O
+    //  19	 .   .   .
+    //  20	 .   .   .
+    //  21	 .   .   .
+    //  22	 .   .   .
+    //  23	 .   O   .
+    //  24	 .   .   .
+    //  25	 .   .   .
+    //  26	 .   .   .
+    //  27	 .   .   O
+    //  28	 .   .   .
+    //  29	 .   .   .
+    //  30	 .   .   .
+    //  31	 .   .   .
+    //  32	 .   .   .
+    //  33	 .   .   .
+    //  34	 .   .   .
+    //  35	 .   .   .
+    //  36	 .   .   O
+    //  37	 O   .   .
+    //
+    TEST(callback_timer_is_active_and_time_to_next)
     {
-      timerInsertRemoveTest.clear();
+      timerTimeToNextTest.clear();
       locks.clear();
       try_lock_type try_lock = try_lock_type::create<Locks, locks, &Locks::try_lock>();
       lock_type     lock     = lock_type::create<Locks, locks, &Locks::lock>();
@@ -1025,19 +1056,20 @@ namespace
 
       etl::timer::id::type id1 = timer_controller.register_timer(member_callback, 37, etl::timer::mode::Single_Shot);
       etl::timer::id::type id2 = timer_controller.register_timer(free_function_callback, 23, etl::timer::mode::Single_Shot);
-      etl::timer::id::type id3 = timer_controller.register_timer(free_function_callback2, 11, etl::timer::mode::Single_Shot);
+      etl::timer::id::type id3 = timer_controller.register_timer(free_function_callback2, 9, etl::timer::mode::Repeating);
 
-      timer_controller.set_insert_callback(
-        event_callback_type::create<TimerInsertRemoveTest, timerInsertRemoveTest, &TimerInsertRemoveTest::insert_handler>());
-      timer_controller.set_remove_callback(
-        event_callback_type::create<TimerInsertRemoveTest, timerInsertRemoveTest, &TimerInsertRemoveTest::remove_handler>());
+      timer_controller.set_time_to_next_callback(
+        event_callback_type::create<TimerTimeToNextTest, timerTimeToNextTest, &TimerTimeToNextTest::time_to_next_handler>());
 
       timer_controller.start(id1);
       timer_controller.start(id3);
       timer_controller.start(id2);
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(0, timerInsertRemoveTest.removed);
+      timer_controller.start(id1);
+      timer_controller.start(id3);
+      timer_controller.start(id2);
+
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next); // The time to next should be the interval for id3.
 
       timer_controller.enable(true);
 
@@ -1045,81 +1077,77 @@ namespace
       CHECK_TRUE(timer_controller.is_active(id2));
       CHECK_TRUE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(0, timerInsertRemoveTest.removed);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next); // The time to next should be the interval for id3.
 
-      timer_controller.tick(11);
+      // Tick the time for id3 to expire.
+      timer_controller.tick(9);
       timer_controller.handle_deferred();
       CHECK_TRUE(timer_controller.is_active(id1));
       CHECK_TRUE(timer_controller.is_active(id2));
-      CHECK_FALSE(timer_controller.is_active(id3));
+      CHECK_TRUE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(1, timerInsertRemoveTest.removed);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next); // The time to next should be the what's left of the interval for id3.
 
-      timer_controller.tick(23 - 11);
+      // Stop the timer and check that the time to next is updated to that of id2.
+      timer_controller.stop(id3);
+      CHECK_EQUAL(14, timerTimeToNextTest.time_to_next); // The time to next should be the what's left of the interval for id2.
+
+      // Start the timer again and check that the time to next is updated to the interval for id3.
+      timer_controller.start(id3);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next);
+
+      // Tick the time for id3 to expire.
+      timer_controller.tick(9);
+      timer_controller.handle_deferred();
+      CHECK_TRUE(timer_controller.is_active(id1));
+      CHECK_TRUE(timer_controller.is_active(id2));
+      CHECK_TRUE(timer_controller.is_active(id3));
+
+      // The time to next should be the what's left of the interval for id2.
+      CHECK_EQUAL(5, timerTimeToNextTest.time_to_next);
+
+      // Tick the remaining time for id2 to expire.
+      timer_controller.tick(5);
       timer_controller.handle_deferred();
       CHECK_TRUE(timer_controller.is_active(id1));
       CHECK_FALSE(timer_controller.is_active(id2));
-      CHECK_FALSE(timer_controller.is_active(id3));
+      CHECK_TRUE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(2, timerInsertRemoveTest.removed);
+      // The time to next should be the what's left of the interval for id3.
+      CHECK_EQUAL(4, timerTimeToNextTest.time_to_next);
 
-      timer_controller.tick(37 - 23);
+      // Tick the remaining time for id3 to expire.
+      timer_controller.tick(4);
+      timer_controller.handle_deferred();
+      CHECK_TRUE(timer_controller.is_active(id1));
+      CHECK_FALSE(timer_controller.is_active(id2));
+      CHECK_TRUE(timer_controller.is_active(id3));
+
+      // The time to next should be the what's left of the interval for id3.
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next);
+
+      // Tick the remaining time for id3 to expire.
+      timer_controller.tick(9);
+      timer_controller.handle_deferred();
+      CHECK_TRUE(timer_controller.is_active(id1));
+      CHECK_FALSE(timer_controller.is_active(id2));
+      CHECK_TRUE(timer_controller.is_active(id3));
+
+      // The time to next should be the what's left of the interval for id1.
+      CHECK_EQUAL(1, timerTimeToNextTest.time_to_next);
+
+      // Stop timer id3 so that id1 is the last timeout.
+      timer_controller.stop(id3);
+
+      // Tick the remaining time for id1 to expire.
+      timer_controller.tick(1);
       timer_controller.handle_deferred();
       CHECK_FALSE(timer_controller.is_active(id1));
       CHECK_FALSE(timer_controller.is_active(id2));
       CHECK_FALSE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(3, timerInsertRemoveTest.removed);
-    }
-
-    //*************************************************************************
-    TEST(message_timer_time_to_next_with_has_active_timer)
-    {
-      locks.clear();
-      try_lock_type try_lock = try_lock_type::create<Locks, locks, &Locks::try_lock>();
-      lock_type     lock     = lock_type::create<Locks, locks, &Locks::lock>();
-      unlock_type   unlock   = unlock_type::create<Locks, locks, &Locks::unlock>();
-
-      etl::callback_timer_deferred_locked<3, 3> timer_controller(try_lock, lock, unlock);
-
-      etl::timer::id::type id1 = timer_controller.register_timer(member_callback, 37, etl::timer::mode::Single_Shot);
-      etl::timer::id::type id2 = timer_controller.register_timer(free_function_callback, 23, etl::timer::mode::Single_Shot);
-      etl::timer::id::type id3 = timer_controller.register_timer(free_function_callback2, 11, etl::timer::mode::Single_Shot);
-
-      timer_controller.set_insert_callback(
-        event_callback_type::create<TimerInsertRemoveTest, timerInsertRemoveTest, &TimerInsertRemoveTest::insert_handler>());
-      timer_controller.set_remove_callback(
-        event_callback_type::create<TimerInsertRemoveTest, timerInsertRemoveTest, &TimerInsertRemoveTest::remove_handler>());
-
-      timer_controller.start(id1);
-      timer_controller.start(id3);
-      timer_controller.start(id2);
-
-      timer_controller.enable(true);
-
-      timer_controller.tick(11);
-      timer_controller.handle_deferred();
-      CHECK_EQUAL(23 - 11, timer_controller.time_to_next());
-      CHECK_TRUE(timer_controller.has_active_timer());
-
-      timer_controller.tick(23);
-      timer_controller.handle_deferred();
-      CHECK_EQUAL(3, timer_controller.time_to_next());
-      CHECK_TRUE(timer_controller.has_active_timer());
-
-      timer_controller.tick(2);
-      timer_controller.handle_deferred();
-      CHECK_EQUAL(1, timer_controller.time_to_next());
-      CHECK_TRUE(timer_controller.has_active_timer());
-
-      timer_controller.tick(1);
-      timer_controller.handle_deferred();
-      CHECK_EQUAL(static_cast<etl::timer::interval::type>(etl::timer::interval::No_Active_Interval), timer_controller.time_to_next());
-      CHECK_FALSE(timer_controller.has_active_timer());
+      // There are no active timers so the time to next should be No_Active_Interval.
+      CHECK_EQUAL(etl::timer::interval::No_Active_Interval, timerTimeToNextTest.time_to_next);
     }
 
     //*************************************************************************
diff --git a/test/test_callback_timer_locked.cpp b/test/test_callback_timer_locked.cpp
index b87c4b8c..9ec3c6a1 100644
--- a/test/test_callback_timer_locked.cpp
+++ b/test/test_callback_timer_locked.cpp
@@ -127,38 +127,29 @@ namespace
   callback_type member_callback  = callback_type::create<Object, object, &Object::callback>();
   callback_type member_callback2 = callback_type::create<Object, object, &Object::callback2>();
 
-  class TimerInsertRemoveTest
+  class TimerTimeToNextTest
   {
   public:
 
-    uint32_t inserted;
-    uint32_t removed;
-    TimerInsertRemoveTest()
-      : inserted(0)
-      , removed(0)
+    uint32_t time_to_next;
+
+    TimerTimeToNextTest()
+      : time_to_next(0)
     {
     }
 
-    void insert_handler(etl::timer::id::type id_)
+    void time_to_next_handler(uint32_t time_to_next_)
     {
-      (void)id_;
-      inserted++;
-    }
-
-    void remove_handler(etl::timer::id::type id_)
-    {
-      (void)id_;
-      removed++;
+      time_to_next = time_to_next_;
     }
 
     void clear(void)
     {
-      inserted = 0;
-      removed  = 0;
+      time_to_next = 0;
     }
   };
 
-  TimerInsertRemoveTest timerInsertRemoveTest;
+  TimerTimeToNextTest timerTimeToNextTest;
 
   //***************************************************************************
   // Free function callback via etl::function
@@ -907,9 +898,49 @@ namespace
     }
 
     //*************************************************************************
-    TEST(callback_timer_is_active)
+    // Tick	ID1	ID2	ID3
+    //   0   .   .   .
+    //   1	 .   .   .
+    //   2	 .   .   .
+    //   3	 .   .   .
+    //   4	 .   .   .
+    //   5	 .   .   .
+    //   6	 .   .   .
+    //   7	 .   .   .
+    //   8	 .   .   .
+    //   9	 .   .   O
+    //  10	 .   .   .
+    //  11	 .   .   .
+    //  12	 .   .   .
+    //  13	 .   .   .
+    //  14	 .   .   .
+    //  15	 .   .   .
+    //  16	 .   .   .
+    //  17	 .   .   .
+    //  18	 .   .   O
+    //  19	 .   .   .
+    //  20	 .   .   .
+    //  21	 .   .   .
+    //  22	 .   .   .
+    //  23	 .   O   .
+    //  24	 .   .   .
+    //  25	 .   .   .
+    //  26	 .   .   .
+    //  27	 .   .   O
+    //  28	 .   .   .
+    //  29	 .   .   .
+    //  30	 .   .   .
+    //  31	 .   .   .
+    //  32	 .   .   .
+    //  33	 .   .   .
+    //  34	 .   .   .
+    //  35	 .   .   .
+    //  36	 .   .   O
+    //  37	 O   .   .
+    //
+    TEST(callback_timer_is_active_and_time_to_next)
     {
-      timerInsertRemoveTest.clear();
+      timerTimeToNextTest.clear();
       locks.clear();
       try_lock_type try_lock = try_lock_type::create<Locks, locks, &Locks::try_lock>();
       lock_type     lock     = lock_type::create<Locks, locks, &Locks::lock>();
@@ -919,19 +950,16 @@ namespace
 
       etl::timer::id::type id1 = timer_controller.register_timer(member_callback, 37, etl::timer::mode::Single_Shot);
       etl::timer::id::type id2 = timer_controller.register_timer(free_function_callback, 23, etl::timer::mode::Single_Shot);
-      etl::timer::id::type id3 = timer_controller.register_timer(free_function_callback2, 11, etl::timer::mode::Single_Shot);
+      etl::timer::id::type id3 = timer_controller.register_timer(free_function_callback2, 9, etl::timer::mode::Repeating);
 
-      timer_controller.set_insert_callback(
-        event_callback_type::create<TimerInsertRemoveTest, timerInsertRemoveTest, &TimerInsertRemoveTest::insert_handler>());
-      timer_controller.set_remove_callback(
-        event_callback_type::create<TimerInsertRemoveTest, timerInsertRemoveTest, &TimerInsertRemoveTest::remove_handler>());
+      timer_controller.set_time_to_next_callback(
+        event_callback_type::create<TimerTimeToNextTest, timerTimeToNextTest, &TimerTimeToNextTest::time_to_next_handler>());
 
       timer_controller.start(id1);
       timer_controller.start(id3);
       timer_controller.start(id2);
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(0, timerInsertRemoveTest.removed);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next); // The time to next should be the interval for id3.
 
       timer_controller.enable(true);
 
@@ -939,69 +967,71 @@ namespace
       CHECK_TRUE(timer_controller.is_active(id2));
       CHECK_TRUE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(0, timerInsertRemoveTest.removed);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next); // The time to next should be the interval for id3.
 
-      timer_controller.tick(11);
+      // Tick the time for id3 to expire.
+      timer_controller.tick(9);
       CHECK_TRUE(timer_controller.is_active(id1));
       CHECK_TRUE(timer_controller.is_active(id2));
-      CHECK_FALSE(timer_controller.is_active(id3));
+      CHECK_TRUE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(1, timerInsertRemoveTest.removed);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next); // The time to next should be the what's left of the interval for id3.
 
-      timer_controller.tick(23 - 11);
+      // Stop the timer and check that the time to next is updated to that of id2.
+      timer_controller.stop(id3);
+      CHECK_EQUAL(14, timerTimeToNextTest.time_to_next); // The time to next should be the what's left of the interval for id2.
+
+      // Start the timer again and check that the time to next is updated to the interval for id3.
+      timer_controller.start(id3);
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next);
+
+      // Tick the time for id3 to expire.
+      timer_controller.tick(9);
+      CHECK_TRUE(timer_controller.is_active(id1));
+      CHECK_TRUE(timer_controller.is_active(id2));
+      CHECK_TRUE(timer_controller.is_active(id3));
+
+      // The time to next should be the what's left of the interval for id2.
+      CHECK_EQUAL(5, timerTimeToNextTest.time_to_next);
+
+      // Tick the remaining time for id2 to expire.
+      timer_controller.tick(5);
       CHECK_TRUE(timer_controller.is_active(id1));
       CHECK_FALSE(timer_controller.is_active(id2));
-      CHECK_FALSE(timer_controller.is_active(id3));
+      CHECK_TRUE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(2, timerInsertRemoveTest.removed);
+      // The time to next should be the what's left of the interval for id3.
+      CHECK_EQUAL(4, timerTimeToNextTest.time_to_next);
 
-      timer_controller.tick(37 - 23);
+      // Tick the remaining time for id3 to expire.
+      timer_controller.tick(4);
+      CHECK_TRUE(timer_controller.is_active(id1));
+      CHECK_FALSE(timer_controller.is_active(id2));
+      CHECK_TRUE(timer_controller.is_active(id3));
+
+      // The time to next should be the what's left of the interval for id3.
+      CHECK_EQUAL(9, timerTimeToNextTest.time_to_next);
+
+      // Tick the remaining time for id3 to expire.
+      timer_controller.tick(9);
+      CHECK_TRUE(timer_controller.is_active(id1));
+      CHECK_FALSE(timer_controller.is_active(id2));
+      CHECK_TRUE(timer_controller.is_active(id3));
+
+      // The time to next should be the what's left of the interval for id1.
+      CHECK_EQUAL(1, timerTimeToNextTest.time_to_next);
+
+      // Stop timer id3 so that id1 is the last timeout.
+      timer_controller.stop(id3);
+
+      // Tick the remaining time for id1 to expire.
+      timer_controller.tick(1);
       CHECK_FALSE(timer_controller.is_active(id1));
       CHECK_FALSE(timer_controller.is_active(id2));
       CHECK_FALSE(timer_controller.is_active(id3));
 
-      CHECK_EQUAL(3, timerInsertRemoveTest.inserted);
-      CHECK_EQUAL(3, timerInsertRemoveTest.removed);
-    }
-
-    //*************************************************************************
-    TEST(message_timer_time_to_next_with_has_active_timer)
-    {
-      locks.clear();
-      try_lock_type try_lock = try_lock_type::create<Locks, locks, &Locks::try_lock>();
-      lock_type     lock     = lock_type::create<Locks, locks, &Locks::lock>();
-      unlock_type   unlock   = unlock_type::create<Locks, locks, &Locks::unlock>();
-
-      etl::callback_timer_locked<3> timer_controller(try_lock, lock, unlock);
-
-      etl::timer::id::type id1 = timer_controller.register_timer(member_callback, 37, etl::timer::mode::Single_Shot);
-      etl::timer::id::type id2 = timer_controller.register_timer(free_function_callback, 23, etl::timer::mode::Single_Shot);
-      etl::timer::id::type id3 = timer_controller.register_timer(free_function_callback2, 11, etl::timer::mode::Single_Shot);
-
-      timer_controller.start(id1);
-      timer_controller.start(id3);
-      timer_controller.start(id2);
-
-      timer_controller.enable(true);
-
-      timer_controller.tick(11);
-      CHECK_EQUAL(12, timer_controller.time_to_next());
-      CHECK_TRUE(timer_controller.has_active_timer());
-
-      timer_controller.tick(23);
-      CHECK_EQUAL(3, timer_controller.time_to_next());
-      CHECK_TRUE(timer_controller.has_active_timer());
-
-      timer_controller.tick(2);
-      CHECK_EQUAL(1, timer_controller.time_to_next());
-      CHECK_TRUE(timer_controller.has_active_timer());
-
-      timer_controller.tick(1);
-      CHECK_EQUAL(static_cast<etl::timer::interval::type>(etl::timer::interval::No_Active_Interval), timer_controller.time_to_next());
-      CHECK_FALSE(timer_controller.has_active_timer());
+      // There are no active timers so the time to next should be No_Active_Interval.
+      CHECK_EQUAL(etl::timer::interval::No_Active_Interval, timerTimeToNextTest.time_to_next);
     }
 
     //*************************************************************************