AP_Param: added a flag for hidden parameters

libraries/AP_Param/AP_Param.cpp

@@ -1682,6 +1682,9 @@ AP_Param *AP_Param::next_group(const uint16_t vindex, const struct GroupInfo *gr
                     ((AP_Int8 *)ret)->get() == 0) {
                     token->last_disabled = 1;
                 }
+                if (group_info[i].flags & AP_PARAM_FLAG_HIDDEN) {
+                    continue;
+                }
                 return ret;
             }
             if (group_id(group_info, group_base, i, group_shift) == token->group_element) {

libraries/AP_Param/AP_Param.h

@@ -72,13 +72,16 @@
 // use.
 #define AP_PARAM_FLAG_INTERNAL_USE_ONLY (1<<5)
 
+// hide parameter from param download
+#define AP_PARAM_FLAG_HIDDEN (1<<6)
+
 // keep all flags before the FRAME tags
 
 // vehicle and frame type flags, used to hide parameters when not
 // relevent to a vehicle type. Use AP_Param::set_frame_type_flags() to
 // enable parameters flagged in this way. frame type flags are stored
 // in flags field, shifted by AP_PARAM_FRAME_TYPE_SHIFT.
-#define AP_PARAM_FRAME_TYPE_SHIFT   6
+#define AP_PARAM_FRAME_TYPE_SHIFT   7
 
 // supported frame types for parameters
 #define AP_PARAM_FRAME_COPTER       (1<<0)