Copter: Add a switch option to enable/disable RC_Override

ArduCopter/Copter.h

@@ -288,6 +288,7 @@ private:
             uint8_t in_arming_delay         : 1; // 24      // true while we are armed but waiting to spin motors
             uint8_t initialised_params      : 1; // 25      // true when the all parameters have been initialised. we cannot send parameters to the GCS until this is done
             uint8_t compass_init_location   : 1; // 26      // true when the compass's initial location has been set
+            uint8_t rc_override_enable      : 1; // 27      // aux switch rc_override is allowed
         };
         uint32_t value;
     } ap_t;

ArduCopter/GCS_Mavlink.cpp

@@ -761,6 +761,13 @@ void GCS_MAVLINK_Copter::handleMessage(mavlink_message_t* msg)
         // or for complete GCS control of switch position
         // and RC PWM values.
         if(msg->sysid != copter.g.sysid_my_gcs) break;                         // Only accept control from our gcs
+        if (!copter.ap.rc_override_enable) {
+            if (copter.failsafe.rc_override_active) {  // if overrides were active previously, disable them
+                copter.failsafe.rc_override_active = false;
+                hal.rcin->clear_overrides();
+            }
+            break;
+        }
         mavlink_rc_channels_override_t packet;
         int16_t v[8];
         mavlink_msg_rc_channels_override_decode(msg, &packet);

ArduCopter/defines.h

@@ -74,6 +74,7 @@ enum aux_sw_func {
     AUXSW_INVERTED  =           43,  // enable inverted flight
     AUXSW_WINCH_ENABLE =        44, // winch enable/disable
     AUXSW_WINCH_CONTROL =       45, // winch control
+    AUXSW_RC_OVERRIDE_ENABLE =  46, // enable RC Override
     AUXSW_SWITCH_MAX,
 };
 

ArduCopter/switches.cpp

@@ -198,6 +198,7 @@ void Copter::init_aux_switch_function(int8_t ch_option, uint8_t ch_flag)
         case AUXSW_AVOID_PROXIMITY:
         case AUXSW_INVERTED:
         case AUXSW_WINCH_ENABLE:
+        case AUXSW_RC_OVERRIDE_ENABLE:
             do_aux_switch_function(ch_option, ch_flag);
             break;
     }
@@ -657,6 +658,20 @@ void Copter::do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
                     break;
                 }
             break;
+
+        case AUXSW_RC_OVERRIDE_ENABLE:
+            // Allow or disallow RC_Override
+            switch (ch_flag) {
+                case AUX_SWITCH_HIGH: {
+                    ap.rc_override_enable = true;
+                    break;
+                }
+                case AUX_SWITCH_LOW: {
+                    ap.rc_override_enable = false;
+                    break;
+                }
+            }
+            break;
     }
 }