From ba2b9f3d4721d894bacdab65d086816b521832c9 Mon Sep 17 00:00:00 2001
From: Randy Mackay <rmackay9@yahoo.com>
Date: Sat, 8 Sep 2018 12:30:21 +0900
Subject: [PATCH] AP_Arming: add RUDDER parameter

---
 libraries/AP_Arming/AP_Arming.cpp | 16 ++++++++++++++++
 libraries/AP_Arming/AP_Arming.h   |  9 +++++++++
 2 files changed, 25 insertions(+)

diff --git a/libraries/AP_Arming/AP_Arming.cpp b/libraries/AP_Arming/AP_Arming.cpp
index 74e1a8916b..7023bd7388 100644
--- a/libraries/AP_Arming/AP_Arming.cpp
+++ b/libraries/AP_Arming/AP_Arming.cpp
@@ -26,6 +26,12 @@
 #define AP_ARMING_ACCEL_ERROR_THRESHOLD 0.75f
 #define AP_ARMING_AHRS_GPS_ERROR_MAX    10      // accept up to 10m difference between AHRS and GPS
 
+#if APM_BUILD_TYPE(APM_BUILD_ArduPlane)
+  #define ARMING_RUDDER_DEFAULT         ARMING_RUDDER_ARMONLY
+#else
+  #define ARMING_RUDDER_DEFAULT         ARMING_RUDDER_ARMDISARM
+#endif
+
 extern const AP_HAL::HAL& hal;
 
 const AP_Param::GroupInfo AP_Arming::var_info[] = {
@@ -73,6 +79,16 @@ const AP_Param::GroupInfo AP_Arming::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("VOLT2_MIN",     5,     AP_Arming,  _min_voltage[1],  0),
 
+    // @Param: RUDDER
+    // @DisplayName: Arming with Rudder enable/disable
+    // @Description: Allow arm/disarm by rudder input. When enabled arming can be done with right rudder, disarming with left rudder. Rudder arming only works in manual throttle modes with throttle at zero +- deadzone (RCx_DZ)
+    // @Values: 0:Disabled,1:ArmingOnly,2:ArmOrDisarm
+    // @User: Advanced
+    AP_GROUPINFO_FRAME("RUDDER",  6,     AP_Arming, _rudder_arming, ARMING_RUDDER_DEFAULT, AP_PARAM_FRAME_PLANE |
+                                                                                           AP_PARAM_FRAME_ROVER |
+                                                                                           AP_PARAM_FRAME_COPTER |
+                                                                                           AP_PARAM_FRAME_TRICOPTER |
+                                                                                           AP_PARAM_FRAME_HELI),
     AP_GROUPEND
 };
 
diff --git a/libraries/AP_Arming/AP_Arming.h b/libraries/AP_Arming/AP_Arming.h
index 95514d0e12..4bd82851f8 100644
--- a/libraries/AP_Arming/AP_Arming.h
+++ b/libraries/AP_Arming/AP_Arming.h
@@ -68,6 +68,14 @@ public:
     // get expected magnetic field strength
     uint16_t compass_magfield_expected() const;
 
+    // rudder arming support
+    enum ArmingRudder {
+        ARMING_RUDDER_DISABLED  = 0,
+        ARMING_RUDDER_ARMONLY   = 1,
+        ARMING_RUDDER_ARMDISARM = 2
+    };
+    ArmingRudder rudder_arming() const { return (ArmingRudder)_rudder_arming.get(); }
+
     static const struct AP_Param::GroupInfo        var_info[];
 
 protected:
@@ -77,6 +85,7 @@ protected:
     AP_Int16                checks_to_perform;      // bitmask for which checks are required
     AP_Float                accel_error_threshold;
     AP_Float                _min_voltage[AP_BATT_MONITOR_MAX_INSTANCES];
+    AP_Int8                 _rudder_arming;
 
     // internal members
     bool                    armed:1;