From 094d571196f2daaba2446e0d8934d09992d71849 Mon Sep 17 00:00:00 2001
From: Grant Morphett <grant@gmorph.com>
Date: Wed, 1 Jun 2016 10:12:02 +1000
Subject: [PATCH] Rover: Skid steering disarming fixes

I have disabled steering disarming for skid steering rovers.  Its
perfectly reasonable for a skid steering rover to go hard left on the
spot without any throttle and the user wouldn't want the rover to
disarm during this procedure.
If you disarm from the GCS for a skid steering rover we also ensure
the steering channel is disabled.
---
 APMrover2/radio.cpp  | 13 ++++++++++++-
 APMrover2/system.cpp |  3 +++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/APMrover2/radio.cpp b/APMrover2/radio.cpp
index cf7df427b6..5c5f36b3e1 100644
--- a/APMrover2/radio.cpp
+++ b/APMrover2/radio.cpp
@@ -18,6 +18,9 @@ void Rover::set_control_channels(void)
     // For a rover safety is TRIM throttle
     if (!arming.is_armed() && arming.arming_required() == AP_Arming::YES_MIN_PWM) {
         hal.rcout->set_safety_pwm(1UL<<(rcmap.throttle()-1), channel_throttle->get_radio_trim());
+        if (g.skid_steer_out) {
+            hal.rcout->set_safety_pwm(1UL<<(rcmap.roll()-1),  channel_steer->get_radio_trim());
+        }
     }
 
     // setup correct scaling for ESCs like the UAVCAN PX4ESC which
@@ -42,6 +45,9 @@ void Rover::init_rc_out()
 
     if (arming.arming_required() != AP_Arming::YES_ZERO_PWM) {
         channel_throttle->enable_out();
+        if (g.skid_steer_out) {
+            channel_steer->enable_out();
+        }
     }
 
     RC_Channel::output_trim_all();    
@@ -55,6 +61,9 @@ void Rover::init_rc_out()
     // full speed backward.
     if (arming.arming_required() == AP_Arming::YES_MIN_PWM) {
         hal.rcout->set_safety_pwm(1UL<<(rcmap.throttle()-1),  channel_throttle->get_radio_trim());
+        if (g.skid_steer_out) {
+            hal.rcout->set_safety_pwm(1UL<<(rcmap.roll()-1),  channel_steer->get_radio_trim());
+        }
     }
 }
 
@@ -96,8 +105,10 @@ void Rover::rudder_arm_disarm_check()
 			// not at full right rudder
 			rudder_arm_timer = 0;
 		}
-	} else if (!motor_active()) {
+	} else if (!motor_active() & !g.skid_steer_out) {
 		// when armed and motor not active (not moving), full left rudder starts disarming counter
+        // This is disabled for skid steering otherwise when tring to turn a skid steering rover around
+        // the rover would disarm
 		if (channel_steer->get_control_in() < -4000) {
 			uint32_t now = millis();
 
diff --git a/APMrover2/system.cpp b/APMrover2/system.cpp
index 1361492bc6..fec3cae615 100644
--- a/APMrover2/system.cpp
+++ b/APMrover2/system.cpp
@@ -528,6 +528,9 @@ bool Rover::disarm_motors(void)
     }
     if (arming.arming_required() == AP_Arming::YES_ZERO_PWM) {
         channel_throttle->disable_out();
+        if (g.skid_steer_out) {
+            channel_steer->disable_out();
+        }
     }
     if (control_mode != AUTO) {
         // reset the mission on disarm if we are not in auto