Sub: initialize pwm input on control channels to 1500 instead of 0

ArduSub/radio.cpp

@@ -61,6 +61,15 @@ void Sub::init_rc_in()
     // set default dead zones
     default_dead_zones();
 
+    // initialize rc input to 1500 on control channels (rather than 0)
+    for(int i = 0; i < 7; i++) {
+    	if(i == 4) {
+    		hal.rcin->set_override(i, 1100); // Channel 5 mode selection
+    	} else {
+    		hal.rcin->set_override(i, 1500);
+    	}
+    }
+
     // initialise throttle_zero flag
     ap.throttle_zero = true;
 }