From 7e672628ea70422f131215ba8156a982b8972b79 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Tue, 11 Sep 2012 13:37:25 +1000
Subject: [PATCH] APM: removed the GPS_enabled flag

this fixes using GPS_PROTOCOL to specify a specific GPS with a GPS
that takes a few updates before it works (eg. needing baud rate
changes).

This makes it easier to use an APM1-1280 with more features enabled
---
 ArduPlane/ArduPlane.pde      |  9 ++-------
 ArduPlane/commands_logic.pde |  2 +-
 ArduPlane/navigation.pde     |  7 +++++--
 ArduPlane/system.pde         | 17 -----------------
 4 files changed, 8 insertions(+), 27 deletions(-)

diff --git a/ArduPlane/ArduPlane.pde b/ArduPlane/ArduPlane.pde
index 26a03be474..ae867cffaa 100644
--- a/ArduPlane/ArduPlane.pde
+++ b/ArduPlane/ArduPlane.pde
@@ -399,9 +399,6 @@ static byte ground_start_count      = 5;
 // on the ground or in the air.  Used to decide if a ground start is appropriate if we
 // booted with an air start.
 static int16_t ground_start_avg;
-// Tracks if GPS is enabled based on statup routine
-// If we do not detect GPS at startup, we stop trying and assume GPS is not connected
-static bool GPS_enabled     = false;
 
 // true if we have a position estimate from AHRS
 static bool have_position;
@@ -844,10 +841,8 @@ static void medium_loop()
     //-------------------------------
     case 0:
         medium_loopCounter++;
-        if(GPS_enabled) {
-            update_GPS();
-            calc_gndspeed_undershoot();
-        }
+        update_GPS();
+        calc_gndspeed_undershoot();
 
 #if HIL_MODE != HIL_MODE_ATTITUDE
         if (g.compass_enabled && compass.read()) {
diff --git a/ArduPlane/commands_logic.pde b/ArduPlane/commands_logic.pde
index aee57bb671..ad1013ee08 100644
--- a/ArduPlane/commands_logic.pde
+++ b/ArduPlane/commands_logic.pde
@@ -560,7 +560,7 @@ static void do_change_speed()
 
 static void do_set_home()
 {
-    if(next_nonnav_command.p1 == 1 && GPS_enabled) {
+    if (next_nonnav_command.p1 == 1 && g_gps->status() == GPS::GPS_OK) {
         init_home();
     } else {
         home.id         = MAV_CMD_NAV_WAYPOINT;
diff --git a/ArduPlane/navigation.pde b/ArduPlane/navigation.pde
index d039d5e8f9..00a0577944 100644
--- a/ArduPlane/navigation.pde
+++ b/ArduPlane/navigation.pde
@@ -99,8 +99,11 @@ static void calc_airspeed_errors()
 
 static void calc_gndspeed_undershoot()
 {
-    // Function is overkill, but here in case we want to add filtering later
-    groundspeed_undershoot = (g.min_gndspeed_cm > 0) ? (g.min_gndspeed_cm - g_gps->ground_speed) : 0;
+    // Function is overkill, but here in case we want to add filtering
+    // later
+    if (g_gps && g_gps->status() == GPS::GPS_OK) {
+        groundspeed_undershoot = (g.min_gndspeed_cm > 0) ? (g.min_gndspeed_cm - g_gps->ground_speed) : 0;
+    }
 }
 
 static void calc_bearing_error()
diff --git a/ArduPlane/system.pde b/ArduPlane/system.pde
index e13f38348b..c7d54d92ca 100644
--- a/ArduPlane/system.pde
+++ b/ArduPlane/system.pde
@@ -249,9 +249,7 @@ static void init_ardupilot()
             old_pulse = APM_RC.InputCh(g.flight_mode_channel);
             delay(25);
         }
-        GPS_enabled = false;
         g_gps->update();
-        if (g_gps->status() != 0 || HIL_MODE != HIL_MODE_DISABLED) GPS_enabled = true;
 
         if (g.log_bitmask & MASK_LOG_CMD)
             Log_Write_Startup(TYPE_AIRSTART_MSG);
@@ -306,21 +304,6 @@ static void startup_ground(void)
     // -------------------
     init_commands();
 
-    // Read in the GPS - see if one is connected
-    GPS_enabled = false;
-    for (byte counter = 0;; counter++) {
-        g_gps->update();
-        if (g_gps->status() != 0 || HIL_MODE != HIL_MODE_DISABLED) {
-            GPS_enabled = true;
-            break;
-        }
-
-        if (counter >= 2) {
-            GPS_enabled = false;
-            break;
-        }
-    }
-
     // Makes the servos wiggle - 3 times signals ready to fly
     // -----------------------
     demo_servos(3);