diff --git a/master/datagram.h b/master/datagram.h
index b4519df1e5852d8b790acec56c3aea8413d849ec..35fec906220d0c0c6efe2355ce82141d9f3abbe5 100644
--- a/master/datagram.h
+++ b/master/datagram.h
@@ -89,12 +89,15 @@ ec_datagram_state_t;
 
 typedef union
 {
+    /**
+     * Physical address.
+     */
     struct
     {
         uint16_t slave; /**< configured or autoincrement address */
         uint16_t mem; /**< physical memory address */
     }
-    physical; /**< physical address */
+    physical;
 
     uint32_t logical; /**< logical address */
 }
diff --git a/master/master.c b/master/master.c
index 9c83e2358c51aa246a1f80551f0733b5d7186f7a..d558ae7832cf5e5ae6e035c81d1efca6b2833542 100644
--- a/master/master.c
+++ b/master/master.c
@@ -374,6 +374,7 @@ void ec_master_thread_stop(ec_master_t *master /**< EtherCAT master */)
 /*****************************************************************************/
 
 /**
+ * Transition function from ORPHANED to IDLE mode.
 */
 
 int ec_master_enter_idle_mode(ec_master_t *master /**< EtherCAT master */)
@@ -394,6 +395,7 @@ int ec_master_enter_idle_mode(ec_master_t *master /**< EtherCAT master */)
 /*****************************************************************************/
 
 /**
+ * Transition function from IDLE to ORPHANED mode.
 */
 
 void ec_master_leave_idle_mode(ec_master_t *master /**< EtherCAT master */)
@@ -408,6 +410,7 @@ void ec_master_leave_idle_mode(ec_master_t *master /**< EtherCAT master */)
 /*****************************************************************************/
 
 /**
+ * Transition function from IDLE to OPERATION mode.
 */
 
 int ec_master_enter_operation_mode(ec_master_t *master /**< EtherCAT master */)
@@ -467,6 +470,7 @@ int ec_master_enter_operation_mode(ec_master_t *master /**< EtherCAT master */)
 /*****************************************************************************/
 
 /**
+ * Transition function from OPERATION to IDLE mode.
 */
 
 void ec_master_leave_operation_mode(ec_master_t *master