Copter: initialise ch7 and ch8 aux switches

This ensures that if you have simple mode or sonar attached to an
auxiliary switch it will be enabled or disabled according to the switch
immediately after start-up

ArduCopter/control_modes.pde

@@ -74,6 +74,39 @@ static void read_aux_switches()
     }
 }
 
+// init_aux_switches - invoke configured actions at start-up for aux function where it is safe to do so
+static void init_aux_switches()
+{
+    // set channel 7 and 8 flags according to switch position
+    ap_system.CH7_flag = (g.rc_7.radio_in >= AUX_SWITCH_PWM_TRIGGER);
+    ap_system.CH8_flag = (g.rc_8.radio_in >= AUX_SWITCH_PWM_TRIGGER);
+
+    // init channel 7 options
+    switch(g.ch7_option) {
+        case AUX_SWITCH_SIMPLE_MODE:
+        case AUX_SWITCH_SONAR:
+        case AUX_SWITCH_FENCE:
+        case AUX_SWITCH_RESETTOARMEDYAW:
+            do_aux_switch_function(g.ch7_option, ap_system.CH7_flag);
+            break;
+    }
+
+    // safety check to ensure we ch7 and ch8 have different functions
+    if (g.ch7_option == g.ch8_option) {
+        return;
+    }
+
+    // init channel 8 option
+    switch(g.ch8_option) {
+        case AUX_SWITCH_SIMPLE_MODE:
+        case AUX_SWITCH_SONAR:
+        case AUX_SWITCH_FENCE:
+        case AUX_SWITCH_RESETTOARMEDYAW:
+            do_aux_switch_function(g.ch8_option, ap_system.CH8_flag);
+            break;
+    }
+}
+
 // do_aux_switch_function - implement the function invoked by the ch7 or ch8 switch
 static void do_aux_switch_function(int8_t ch_function, bool ch_flag)
 {

ArduCopter/system.pde

@@ -260,10 +260,10 @@ static void init_ardupilot()
     // -------------------
     init_commands();
 
-    // set the correct flight mode
+    // initialise the flight mode and aux switch
     // ---------------------------
     reset_control_switch();
-
+    init_aux_switches();
 
     startup_ground();