Copter: use scheduler ticks in place of mainloop_count

ArduCopter/ArduCopter.cpp

@@ -226,9 +226,6 @@ void Copter::loop()
     G_Dt                    = (float)(timer - fast_loopTimer) / 1000000.0f;
     fast_loopTimer          = timer;
 
-    // for mainloop failure monitoring
-    mainLoop_count++;
-
     // Execute the fast loop
     // ---------------------
     fast_loop();

ArduCopter/Copter.cpp

@@ -48,7 +48,6 @@ Copter::Copter(void)
     inertial_nav(ahrs),
     pmTest1(0),
     fast_loopTimer(0),
-    mainLoop_count(0),
     auto_trim_counter(0),
     in_mavlink_delay(false),
     param_loader(var_info),

ArduCopter/Copter.h

@@ -479,8 +479,6 @@ private:
     // --------------
     // Time in microseconds of main control loop
     uint32_t fast_loopTimer;
-    // Counter of main loop executions.  Used for performance monitoring and failsafe processing
-    uint16_t mainLoop_count;
     // arm_time_ms - Records when vehicle was armed. Will be Zero if we are disarmed.
     uint32_t arm_time_ms;
 

ArduCopter/failsafe.cpp

@@ -8,7 +8,7 @@
 //
 
 static bool failsafe_enabled = false;
-static uint16_t failsafe_last_mainLoop_count;
+static uint16_t failsafe_last_ticks;
 static uint32_t failsafe_last_timestamp;
 static bool in_failsafe;
 
@@ -36,9 +36,10 @@ void Copter::failsafe_check()
 {
     uint32_t tnow = AP_HAL::micros();
 
-    if (mainLoop_count != failsafe_last_mainLoop_count) {
+    const uint16_t ticks = scheduler.ticks();
+    if (ticks != failsafe_last_ticks) {
         // the main loop is running, all is OK
-        failsafe_last_mainLoop_count = mainLoop_count;
+        failsafe_last_ticks = ticks;
         failsafe_last_timestamp = tnow;
         if (in_failsafe) {
             in_failsafe = false;