Copter: support inverted flight CH7 option

ArduCopter/Copter.h

@@ -631,6 +631,7 @@ private:
     struct {
         uint8_t dynamic_flight          : 1;    // 0   // true if we are moving at a significant speed (used to turn on/off leaky I terms)
         uint8_t init_targets_on_arming  : 1;    // 1   // true if we have been disarmed, and need to reset rate controller targets when we arm
+        uint8_t inverted_flight         : 1;    // 2   // true for inverted flight mode
     } heli_flags;
 
     int16_t hover_roll_trim_scalar_slew;

ArduCopter/defines.h

@@ -71,6 +71,7 @@ enum aux_sw_func {
     AUXSW_AVOID_PROXIMITY =     40,  // enable object avoidance using proximity sensors (ie. horizontal lidar)
     AUXSW_ARMDISARM =           41,  // arm or disarm vehicle
     AUXSW_SMART_RTL =           42, // change to SmartRTL flight mode
+    AUXSW_INVERTED  =           43,  // enable inverted flight
     AUXSW_SWITCH_MAX,
 };
 

ArduCopter/switches.cpp

@@ -196,6 +196,7 @@ void Copter::init_aux_switch_function(int8_t ch_option, uint8_t ch_flag)
         case AUXSW_AVOID_ADSB:
         case AUXSW_PRECISION_LOITER:
         case AUXSW_AVOID_PROXIMITY:
+        case AUXSW_INVERTED:
             do_aux_switch_function(ch_option, ch_flag);
             break;
     }
@@ -606,6 +607,23 @@ void Copter::do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
                 }
             }
             break;
+            
+        case AUXSW_INVERTED:
+#if FRAME_CONFIG == HELI_FRAME
+            switch (ch_flag) {
+            case AUX_SWITCH_HIGH:
+                motors->set_inverted_flight(true);
+                attitude_control->set_inverted_flight(true);
+                heli_flags.inverted_flight = true;
+                break;
+            case AUX_SWITCH_LOW:
+                motors->set_inverted_flight(false);
+                attitude_control->set_inverted_flight(false);
+                heli_flags.inverted_flight = false;
+                break;
+            }
+#endif
+            break;
     }
 }