Merged master into safelinksafelink

22 files changed, 481 insertions, 233 deletions

diff --git a/src/modules/systemlib/circuit_breaker.c b/src/modules/systemlib/circuit_breaker.c
new file mode 100644
index 000000000..8f697749e
--- /dev/null
+++ b/src/modules/systemlib/circuit_breaker.c
@@ -0,0 +1,93 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/*
+ * @file circuit_breaker.c
+ *
+ * Circuit breaker parameters.
+ * Analog to real aviation circuit breakers these parameters
+ * allow to disable subsystems. They are not supported as standard
+ * operation procedure and are only provided for development purposes.
+ * To ensure they are not activated accidentally, the associated
+ * parameter needs to set to the key (magic).
+ */
+
+#include <systemlib/param/param.h>
+#include <systemlib/circuit_breaker.h>
+
+/**
+ * Circuit breaker for power supply check
+ *
+ * Setting this parameter to 894281 will disable the power valid
+ * checks in the commander.
+ * WARNING: ENABLING THIS CIRCUIT BREAKER IS AT OWN RISK
+ *
+ * @min 0
+ * @max 894281
+ * @group Circuit Breaker
+ */
+PARAM_DEFINE_INT32(CBRK_SUPPLY_CHK, 0);
+
+/**
+ * Circuit breaker for rate controller output
+ *
+ * Setting this parameter to 140253 will disable the rate
+ * controller uORB publication.
+ * WARNING: ENABLING THIS CIRCUIT BREAKER IS AT OWN RISK
+ *
+ * @min 0
+ * @max 140253
+ * @group Circuit Breaker
+ */
+PARAM_DEFINE_INT32(CBRK_RATE_CTRL, 0);
+
+/**
+ * Circuit breaker for IO safety
+ *
+ * Setting this parameter to 894281 will disable IO safety.
+ * WARNING: ENABLING THIS CIRCUIT BREAKER IS AT OWN RISK
+ *
+ * @min 0
+ * @max 22027
+ * @group Circuit Breaker
+ */
+PARAM_DEFINE_INT32(CBRK_IO_SAFETY, 0);
+
+bool circuit_breaker_enabled(const char* breaker, int32_t magic)
+{
+	int32_t val;
+	(void)param_get(param_find(breaker), &val);
+
+	return (val == magic);
+}
+
diff --git a/src/modules/systemlib/circuit_breaker.h b/src/modules/systemlib/circuit_breaker.h
new file mode 100644
index 000000000..1175dbce8
--- /dev/null
+++ b/src/modules/systemlib/circuit_breaker.h
@@ -0,0 +1,64 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/*
+ * @file circuit_breaker.h
+ *
+ * Circuit breaker functionality.
+ */
+
+#ifndef CIRCUIT_BREAKER_H_
+#define CIRCUIT_BREAKER_H_
+
+/* SAFETY WARNING  --  SAFETY WARNING  --  SAFETY WARNING
+ *
+ * OBEY THE DOCUMENTATION FOR ALL CIRCUIT BREAKERS HERE,
+ * ENSURE TO READ CAREFULLY ALL SAFETY WARNINGS.
+ * http://pixhawk.org/dev/circuit_breakers
+ *
+ * CIRCUIT BREAKERS ARE NOT PART OF THE STANDARD OPERATION PROCEDURE
+ * AND MAY DISABLE CHECKS THAT ARE VITAL FOR SAFE FLIGHT.
+ */
+#define CBRK_SUPPLY_CHK_KEY	894281
+#define CBRK_RATE_CTRL_KEY	140253
+#define CBRK_IO_SAFETY_KEY	22027
+
+#include <stdbool.h>
+
+__BEGIN_DECLS
+
+__EXPORT bool circuit_breaker_enabled(const char* breaker, int32_t magic);
+
+__END_DECLS
+
+#endif /* CIRCUIT_BREAKER_H_ */
diff --git a/src/modules/systemlib/cpuload.c b/src/modules/systemlib/cpuload.c
index ccc516f39..7aa2f3a5f 100644
--- a/src/modules/systemlib/cpuload.c
+++ b/src/modules/systemlib/cpuload.c
@@ -67,7 +67,7 @@ __EXPORT void sched_note_switch(FAR struct tcb_s *pFromTcb, FAR struct tcb_s *pT
 
 __EXPORT struct system_load_s system_load;
 
-extern FAR struct _TCB *sched_gettcb(pid_t pid);
+extern FAR struct tcb_s *sched_gettcb(pid_t pid);
 
 void cpuload_initialize_once()
 {
diff --git a/src/modules/systemlib/err.c b/src/modules/systemlib/err.c
index 6c0e876d1..998b5ac7d 100644
--- a/src/modules/systemlib/err.c
+++ b/src/modules/systemlib/err.c
@@ -86,7 +86,7 @@ warnerr_core(int errcode, const char *fmt, va_list args)
 	fprintf(stderr, "\n");
 #elif CONFIG_ARCH_LOWPUTC
 	lowsyslog("%s: ", getprogname());
-	lowvyslog(fmt, args);
+	lowvsyslog(fmt, args);
 
 	/* convenience as many parts of NuttX use negative errno */
 	if (errcode < 0)
diff --git a/src/modules/systemlib/hx_stream.c b/src/modules/systemlib/hx_stream.c
index 8e9c2bfcf..52ae77de5 100644
--- a/src/modules/systemlib/hx_stream.c
+++ b/src/modules/systemlib/hx_stream.c
@@ -63,7 +63,7 @@ struct hx_stream {
 	/* TX state */
 	int			fd;
 	bool			tx_error;
-	uint8_t			*tx_buf;
+	const uint8_t		*tx_buf;
 	unsigned		tx_resid;
 	uint32_t		tx_crc;
 	enum {
diff --git a/src/modules/systemlib/mixer/mixer.cpp b/src/modules/systemlib/mixer/mixer.cpp
index cce46bf5f..20b1f18ed 100644
--- a/src/modules/systemlib/mixer/mixer.cpp
+++ b/src/modules/systemlib/mixer/mixer.cpp
@@ -171,7 +171,6 @@ NullMixer *
 NullMixer::from_text(const char *buf, unsigned &buflen)
 {
 	NullMixer *nm = nullptr;
-	const char *end = buf + buflen;
 
 	/* enforce that the mixer ends with space or a new line */
 	for (int i = buflen - 1; i >= 0; i--) {
diff --git a/src/modules/systemlib/mixer/mixer.h b/src/modules/systemlib/mixer/mixer.h
index 1c889a811..225570fa4 100644
--- a/src/modules/systemlib/mixer/mixer.h
+++ b/src/modules/systemlib/mixer/mixer.h
@@ -447,6 +447,7 @@ public:
 		QUAD_WIDE,	/**< quad in wide configuration */
 		HEX_X,		/**< hex in X configuration */
 		HEX_PLUS,	/**< hex in + configuration */
+		HEX_COX,
 		OCTA_X,
 		OCTA_PLUS,
 		OCTA_COX,
@@ -516,7 +517,7 @@ private:
 	float				_roll_scale;
 	float				_pitch_scale;
 	float				_yaw_scale;
-	float				_deadband;
+	float				_idle_speed;
 
 	unsigned			_rotor_count;
 	const Rotor			*_rotors;
diff --git a/src/modules/systemlib/mixer/mixer_load.c b/src/modules/systemlib/mixer/mixer_load.c
index a55ddf8a3..bf3428a50 100644
--- a/src/modules/systemlib/mixer/mixer_load.c
+++ b/src/modules/systemlib/mixer/mixer_load.c
@@ -41,6 +41,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <ctype.h>
+#include <systemlib/err.h>
 
 #include "mixer_load.h"
 
@@ -52,7 +53,8 @@ int load_mixer_file(const char *fname, char *buf, unsigned maxlen)
 	/* open the mixer definition file */
 	fp = fopen(fname, "r");
 	if (fp == NULL) {
-		return 1;
+		warnx("file not found");
+		return -1;
 	}
 
 	/* read valid lines from the file into a buffer */
@@ -88,7 +90,8 @@ int load_mixer_file(const char *fname, char *buf, unsigned maxlen)
 
 		/* if the line is too long to fit in the buffer, bail */
 		if ((strlen(line) + strlen(buf) + 1) >= maxlen) {
-			return 1;
+			warnx("line too long");
+			return -1;
 		}
 
 		/* add the line to the buffer */
diff --git a/src/modules/systemlib/mixer/mixer_multirotor.cpp b/src/modules/systemlib/mixer/mixer_multirotor.cpp
index bf77795d5..4b22a46d0 100644
--- a/src/modules/systemlib/mixer/mixer_multirotor.cpp
+++ b/src/modules/systemlib/mixer/mixer_multirotor.cpp
@@ -67,6 +67,11 @@
 namespace
 {
 
+float constrain(float val, float min, float max)
+{
+	return (val < min) ? min : ((val > max) ? max : val);
+}
+
 /*
  * These tables automatically generated by multi_tables - do not edit.
  */
@@ -110,6 +115,14 @@ const MultirotorMixer::Rotor _config_hex_plus[] = {
 	{  0.866025,  0.500000,  1.00 },
 	{ -0.866025, -0.500000, -1.00 },
 };
+const MultirotorMixer::Rotor _config_hex_cox[] = {
+	{ -0.866025,  0.500000, -1.00 },
+	{ -0.866025,  0.500000,  1.00 },
+	{ -0.000000, -1.000000, -1.00 },
+	{ -0.000000, -1.000000,  1.00 },
+	{  0.866025,  0.500000, -1.00 },
+	{  0.866025,  0.500000,  1.00 },
+};
 const MultirotorMixer::Rotor _config_octa_x[] = {
 	{ -0.382683,  0.923880, -1.00 },
 	{  0.382683, -0.923880, -1.00 },
@@ -147,6 +160,7 @@ const MultirotorMixer::Rotor *_config_index[MultirotorMixer::MAX_GEOMETRY] = {
 	&_config_quad_wide[0],
 	&_config_hex_x[0],
 	&_config_hex_plus[0],
+	&_config_hex_cox[0],
 	&_config_octa_x[0],
 	&_config_octa_plus[0],
 	&_config_octa_cox[0],
@@ -158,6 +172,7 @@ const unsigned _config_rotor_count[MultirotorMixer::MAX_GEOMETRY] = {
 	4, /* quad_wide */
 	6, /* hex_x */
 	6, /* hex_plus */
+	6, /* hex_cox */
 	8, /* octa_x */
 	8, /* octa_plus */
 	8, /* octa_cox */
@@ -171,12 +186,12 @@ MultirotorMixer::MultirotorMixer(ControlCallback control_cb,
 				 float roll_scale,
 				 float pitch_scale,
 				 float yaw_scale,
-				 float deadband) :
+				 float idle_speed) :
 	Mixer(control_cb, cb_handle),
 	_roll_scale(roll_scale),
 	_pitch_scale(pitch_scale),
 	_yaw_scale(yaw_scale),
-	_deadband(-1.0f + deadband),	/* shift to output range here to avoid runtime calculation */
+	_idle_speed(-1.0f + idle_speed * 2.0f),	/* shift to output range here to avoid runtime calculation */
 	_rotor_count(_config_rotor_count[geometry]),
 	_rotors(_config_index[geometry])
 {
@@ -193,7 +208,6 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 	char geomname[8];
 	int s[4];
 	int used;
-	const char *end = buf + buflen;
 
 	/* enforce that the mixer ends with space or a new line */
 	for (int i = buflen - 1; i >= 0; i--) {
@@ -247,6 +261,9 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 	} else if (!strcmp(geomname, "6x")) {
 		geometry = MultirotorMixer::HEX_X;
 
+	} else if (!strcmp(geomname, "6c")) {
+		geometry = MultirotorMixer::HEX_COX;
+
 	} else if (!strcmp(geomname, "8+")) {
 		geometry = MultirotorMixer::OCTA_PLUS;
 
@@ -276,67 +293,66 @@ MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handl
 unsigned
 MultirotorMixer::mix(float *outputs, unsigned space)
 {
-	float		roll    = get_control(0, 0) * _roll_scale;
+	float		roll    = constrain(get_control(0, 0) * _roll_scale, -1.0f, 1.0f);
 	//lowsyslog("roll: %d, get_control0: %d, %d\n", (int)(roll), (int)(get_control(0, 0)), (int)(_roll_scale));
-	float		pitch   = get_control(0, 1) * _pitch_scale;
-	float		yaw     = get_control(0, 2) * _yaw_scale;
-	float		thrust  = get_control(0, 3);
+	float		pitch   = constrain(get_control(0, 1) * _pitch_scale, -1.0f, 1.0f);
+	float		yaw     = constrain(get_control(0, 2) * _yaw_scale, -1.0f, 1.0f);
+	float		thrust  = constrain(get_control(0, 3), 0.0f, 1.0f);
 	//lowsyslog("thrust: %d, get_control3: %d\n", (int)(thrust), (int)(get_control(0, 3)));
-	float		max     = 0.0f;
-	float		fixup_scale;
+	float		min_out = 0.0f;
+	float		max_out = 0.0f;
 
-	/* use an output factor to prevent too strong control signals at low throttle */
-	float min_thrust = 0.05f;
-	float max_thrust = 1.0f;
-	float startpoint_full_control = 0.40f;
-	float output_factor;
+	/* perform initial mix pass yielding unbounded outputs, ignore yaw */
+	for (unsigned i = 0; i < _rotor_count; i++) {
+		float out = roll * _rotors[i].roll_scale +
+			    pitch * _rotors[i].pitch_scale +
+			    thrust;
 
-	/* keep roll, pitch and yaw control to 0 below min thrust */
-	if (thrust <= min_thrust) {
-		output_factor = 0.0f;
-		/* linearly increase the output factor from 0 to 1 between min_thrust and startpoint_full_control */
+		/* limit yaw if it causes outputs clipping */
+		if (out >= 0.0f && out < -yaw * _rotors[i].yaw_scale) {
+			yaw = -out / _rotors[i].yaw_scale;
+		}
 
-	} else if (thrust < startpoint_full_control && thrust > min_thrust) {
-		output_factor = (thrust / max_thrust) / (startpoint_full_control - min_thrust);
-		/* and then stay at full control */
+		/* calculate min and max output values */
+		if (out < min_out) {
+			min_out = out;
+		}
+		if (out > max_out) {
+			max_out = out;
+		}
 
-	} else {
-		output_factor = max_thrust;
+		outputs[i] = out;
 	}
 
-	roll *= output_factor;
-	pitch *= output_factor;
-	yaw *= output_factor;
-
-
-	/* perform initial mix pass yielding un-bounded outputs */
-	for (unsigned i = 0; i < _rotor_count; i++) {
-		float tmp = roll  * _rotors[i].roll_scale +
-			    pitch * _rotors[i].pitch_scale +
-			    yaw   * _rotors[i].yaw_scale +
-			    thrust;
+	/* scale down roll/pitch controls if some outputs are negative, don't add yaw, keep total thrust */
+	if (min_out < 0.0f) {
+		float scale_in = thrust / (thrust - min_out);
 
-		if (tmp > max)
-			max = tmp;
+		/* mix again with adjusted controls */
+		for (unsigned i = 0; i < _rotor_count; i++) {
+			outputs[i] = scale_in * (roll * _rotors[i].roll_scale + pitch * _rotors[i].pitch_scale) + thrust;
+		}
 
-		outputs[i] = tmp;
+	} else {
+		/* roll/pitch mixed without limiting, add yaw control */
+		for (unsigned i = 0; i < _rotor_count; i++) {
+			outputs[i] += yaw * _rotors[i].yaw_scale;
+		}
 	}
 
-	/* scale values into the -1.0 - 1.0 range */
-	if (max > 1.0f) {
-		fixup_scale = 2.0f / max;
+	/* scale down all outputs if some outputs are too large, reduce total thrust */
+	float scale_out;
+	if (max_out > 1.0f) {
+		scale_out = 1.0f / max_out;
 
 	} else {
-		fixup_scale = 2.0f;
+		scale_out = 1.0f;
 	}
 
-	for (unsigned i = 0; i < _rotor_count; i++)
-		outputs[i] = -1.0f + (outputs[i] * fixup_scale);
-
-	/* ensure outputs are out of the deadband */
-	for (unsigned i = 0; i < _rotor_count; i++)
-		if (outputs[i] < _deadband)
-			outputs[i] = _deadband;
+	/* scale outputs to range _idle_speed..1, and do final limiting */
+	for (unsigned i = 0; i < _rotor_count; i++) {
+		outputs[i] = constrain(_idle_speed + (outputs[i] * (1.0f - _idle_speed) * scale_out), _idle_speed, 1.0f);
+	}
 
 	return _rotor_count;
 }
diff --git a/src/modules/systemlib/mixer/multi_tables b/src/modules/systemlib/mixer/multi_tables
index 050bf2f47..b5698036e 100755
--- a/src/modules/systemlib/mixer/multi_tables
+++ b/src/modules/systemlib/mixer/multi_tables
@@ -52,6 +52,15 @@ set hex_plus {
 	 120 CW
 }
 
+set hex_cox {
+	  60 CW
+	  60 CCW
+	 180 CW
+	 180 CCW
+	 -60 CW
+	 -60 CCW
+}
+
 set octa_x {
 	  22.5 CW
 	-157.5 CW
@@ -85,7 +94,7 @@ set octa_cox {
 	-135 CW
 }
 
-set tables {quad_x quad_plus quad_v quad_wide hex_x hex_plus octa_x octa_plus octa_cox}
+set tables {quad_x quad_plus quad_v quad_wide hex_x hex_plus hex_cox octa_x octa_plus octa_cox}
 
 proc factors {a d} { puts [format "\t{ %9.6f, %9.6f, %5.2f }," [rcos [expr $a + 90]] [rcos $a] [expr -$d]]}
 
@@ -104,13 +113,13 @@ foreach table $tables {
 	puts "};"
 }
 
-puts "const MultirotorMixer::Rotor *_config_index\[MultirotorMixer::Geometry::MAX_GEOMETRY\] = {"
+puts "const MultirotorMixer::Rotor *_config_index\[MultirotorMixer::MAX_GEOMETRY\] = {"
 foreach table $tables {
 	puts [format "\t&_config_%s\[0\]," $table]
 }
 puts "};"
 
-puts "const unsigned _config_rotor_count\[MultirotorMixer::Geometry::MAX_GEOMETRY\] = {"
+puts "const unsigned _config_rotor_count\[MultirotorMixer::MAX_GEOMETRY\] = {"
 foreach table $tables {
 	upvar #0 $table angles
 	puts [format "\t%u, /* %s */" [expr [llength $angles] / 2] $table]
diff --git a/src/modules/systemlib/module.mk b/src/modules/systemlib/module.mk
index 3953b757d..147903aa0 100644
--- a/src/modules/systemlib/module.mk
+++ b/src/modules/systemlib/module.mk
@@ -1,6 +1,6 @@
 ############################################################################
 #
-#   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+#   Copyright (c) 2012-2014 PX4 Development Team. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -52,5 +52,6 @@ SRCS		 = err.c \
 		   rc_check.c \
 		   otp.c \
 		   board_serial.c \
-		   pwm_limit/pwm_limit.c
+		   pwm_limit/pwm_limit.c \
+		   circuit_breaker.c
 
diff --git a/src/modules/systemlib/otp.c b/src/modules/systemlib/otp.c
index 695574fdc..0548a9f7d 100644
--- a/src/modules/systemlib/otp.c
+++ b/src/modules/systemlib/otp.c
@@ -133,7 +133,7 @@ int lock_otp(void)
 
 
 // COMPLETE, BUSY, or other flash error?
-int F_GetStatus(void)
+static int F_GetStatus(void)
 {
 	int fs = F_COMPLETE;
 
diff --git a/src/modules/systemlib/param/param.c b/src/modules/systemlib/param/param.c
index 2d773fd25..e44e6cdb0 100644
--- a/src/modules/systemlib/param/param.c
+++ b/src/modules/systemlib/param/param.c
@@ -96,8 +96,6 @@ ORB_DEFINE(parameter_update, struct parameter_update_s);
 /** parameter update topic handle */
 static orb_advert_t param_topic = -1;
 
-static sem_t param_sem = { .semcount = 1 };
-
 /** lock the parameter store */
 static void
 param_lock(void)
@@ -521,73 +519,15 @@ param_save_default(void)
 		return ERROR;
 	}
 
-	if (res == OK) {
-		res = param_export(fd, false);
+	res = param_export(fd, false);
 
-	        if (res != OK) {
-	            warnx("failed to write parameters to file: %s", filename);
-	        }
+	if (res != OK) {
+		warnx("failed to write parameters to file: %s", filename);
 	}
 
 	close(fd);
 
 	return res;
-
-#if 0
-	const char *filename_tmp = malloc(strlen(filename) + 5);
-	sprintf(filename_tmp, "%s.tmp", filename);
-
-	/* delete temp file if exist */
-	res = unlink(filename_tmp);
-
-	if (res != OK && errno == ENOENT)
-		res = OK;
-
-	if (res != OK)
-		warn("failed to delete temp file: %s", filename_tmp);
-
-	if (res == OK) {
-		/* write parameters to temp file */
-		fd = open(filename_tmp, O_WRONLY | O_CREAT | O_EXCL);
-
-		if (fd < 0) {
-			warn("failed to open temp file: %s", filename_tmp);
-			res = ERROR;
-		}
-
-		if (res == OK) {
-			res = param_export(fd, false);
-
-			if (res != OK)
-				warnx("failed to write parameters to file: %s", filename_tmp);
-		}
-
-		close(fd);
-	}
-
-	if (res == OK) {
-		/* delete parameters file */
-		res = unlink(filename);
-
-		if (res != OK && errno == ENOENT)
-			res = OK;
-
-		if (res != OK)
-			warn("failed to delete parameters file: %s", filename);
-	}
-
-	if (res == OK) {
-		/* rename temp file to parameters */
-		res = rename(filename_tmp, filename);
-
-		if (res != OK)
-			warn("failed to rename %s to %s", filename_tmp, filename);
-	}
-
-	free(filename_tmp);
-
-	return res;
-#endif
 }
 
 /**
diff --git a/src/modules/systemlib/perf_counter.c b/src/modules/systemlib/perf_counter.c
index b4ca0ed3e..d6d8284d2 100644
--- a/src/modules/systemlib/perf_counter.c
+++ b/src/modules/systemlib/perf_counter.c
@@ -282,12 +282,18 @@ perf_reset(perf_counter_t handle)
 void
 perf_print_counter(perf_counter_t handle)
 {
+	perf_print_counter_fd(0, handle);
+}
+
+void
+perf_print_counter_fd(int fd, perf_counter_t handle)
+{
 	if (handle == NULL)
 		return;
 
 	switch (handle->type) {
 	case PC_COUNT:
-		printf("%s: %llu events\n",
+		dprintf(fd, "%s: %llu events\n",
 		       handle->name,
 		       ((struct perf_ctr_count *)handle)->event_count);
 		break;
@@ -295,7 +301,7 @@ perf_print_counter(perf_counter_t handle)
 	case PC_ELAPSED: {
 		struct perf_ctr_elapsed *pce = (struct perf_ctr_elapsed *)handle;
 
-		printf("%s: %llu events, %lluus elapsed, %llu avg, min %lluus max %lluus\n",
+		dprintf(fd, "%s: %llu events, %lluus elapsed, %lluus avg, min %lluus max %lluus\n",
 		       handle->name,
 		       pce->event_count,
 		       pce->time_total,
@@ -308,7 +314,7 @@ perf_print_counter(perf_counter_t handle)
 	case PC_INTERVAL: {
 		struct perf_ctr_interval *pci = (struct perf_ctr_interval *)handle;
 
-		printf("%s: %llu events, %llu avg, min %lluus max %lluus\n",
+		dprintf(fd, "%s: %llu events, %lluus avg, min %lluus max %lluus\n",
 		       handle->name,
 		       pci->event_count,
 		       (pci->time_last - pci->time_first) / pci->event_count,
@@ -349,12 +355,12 @@ perf_event_count(perf_counter_t handle)
 }
 
 void
-perf_print_all(void)
+perf_print_all(int fd)
 {
 	perf_counter_t handle = (perf_counter_t)sq_peek(&perf_counters);
 
 	while (handle != NULL) {
-		perf_print_counter(handle);
+		perf_print_counter_fd(fd, handle);
 		handle = (perf_counter_t)sq_next(&handle->link);
 	}
 }
diff --git a/src/modules/systemlib/perf_counter.h b/src/modules/systemlib/perf_counter.h
index e1e3cbe95..668d9dfdf 100644
--- a/src/modules/systemlib/perf_counter.h
+++ b/src/modules/systemlib/perf_counter.h
@@ -39,6 +39,8 @@
 #ifndef _SYSTEMLIB_PERF_COUNTER_H
 #define _SYSTEMLIB_PERF_COUNTER_H value
 
+#include <stdint.h>
+
 /**
  * Counter types.
  */
@@ -73,7 +75,7 @@ __EXPORT extern void		perf_free(perf_counter_t handle);
 /**
  * Count a performance event.
  *
- * This call only affects counters that take single events; PC_COUNT etc.
+ * This call only affects counters that take single events; PC_COUNT, PC_INTERVAL etc.
  *
  * @param handle		The handle returned from perf_alloc.
  */
@@ -119,16 +121,26 @@ __EXPORT extern void		perf_cancel(perf_counter_t handle);
 __EXPORT extern void		perf_reset(perf_counter_t handle);
 
 /**
- * Print one performance counter.
+ * Print one performance counter to stdout
  *
  * @param handle		The counter to print.
  */
 __EXPORT extern void		perf_print_counter(perf_counter_t handle);
 
 /**
+ * Print one performance counter to a fd.
+ *
+ * @param fd			File descriptor to print to - e.g. 0 for stdout
+ * @param handle		The counter to print.
+ */
+__EXPORT extern void		perf_print_counter_fd(int fd, perf_counter_t handle);
+
+/**
  * Print all of the performance counters.
+ *
+ * @param fd			File descriptor to print to - e.g. 0 for stdout
  */
-__EXPORT extern void		perf_print_all(void);
+__EXPORT extern void		perf_print_all(int fd);
 
 /**
  * Reset all of the performance counters.
diff --git a/src/modules/systemlib/pid/pid.c b/src/modules/systemlib/pid/pid.c
index 77c952f52..45f218a5b 100644
--- a/src/modules/systemlib/pid/pid.c
+++ b/src/modules/systemlib/pid/pid.c
@@ -39,7 +39,7 @@
 /**
  * @file pid.c
  *
- * Implementation of generic PID control interface.
+ * Implementation of generic PID controller.
  *
  * @author Laurens Mackay <mackayl@student.ethz.ch>
  * @author Tobias Naegeli <naegelit@student.ethz.ch>
@@ -53,24 +53,21 @@
 
 #define SIGMA 0.000001f
 
-__EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax,
-		       float limit, uint8_t mode, float dt_min)
+__EXPORT void pid_init(PID_t *pid, pid_mode_t mode, float dt_min)
 {
-	pid->kp = kp;
-	pid->ki = ki;
-	pid->kd = kd;
-	pid->intmax = intmax;
-	pid->limit = limit;
 	pid->mode = mode;
 	pid->dt_min = dt_min;
-	pid->count = 0.0f;
-	pid->saturated = 0.0f;
-	pid->last_output = 0.0f;
-	pid->sp = 0.0f;
-	pid->error_previous = 0.0f;
+	pid->kp = 0.0f;
+	pid->ki = 0.0f;
+	pid->kd = 0.0f;
 	pid->integral = 0.0f;
+	pid->integral_limit = 0.0f;
+	pid->output_limit = 0.0f;
+	pid->error_previous = 0.0f;
+	pid->last_output = 0.0f;
 }
-__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float intmax, float limit)
+
+__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float integral_limit, float output_limit)
 {
 	int ret = 0;
 
@@ -95,15 +92,15 @@ __EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float
 		ret = 1;
 	}
 
-	if (isfinite(intmax)) {
-		pid->intmax = intmax;
+	if (isfinite(integral_limit)) {
+		pid->integral_limit = integral_limit;
 
 	}  else {
 		ret = 1;
 	}
 
-	if (isfinite(limit)) {
-		pid->limit = limit;
+	if (isfinite(output_limit)) {
+		pid->output_limit = output_limit;
 
 	}  else {
 		ret = 1;
@@ -112,42 +109,18 @@ __EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float
 	return ret;
 }
 
-//void pid_set(PID_t *pid, float sp)
-//{
-//	pid->sp = sp;
-//	pid->error_previous = 0;
-//	pid->integral = 0;
-//}
-
-/**
- *
- * @param pid
- * @param val
- * @param dt
- * @return
- */
 __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, float dt)
 {
-	/*  error = setpoint - actual_position
-	 integral = integral + (error*dt)
-	 derivative = (error - previous_error)/dt
-	 output = (Kp*error) + (Ki*integral) + (Kd*derivative)
-	 previous_error = error
-	 wait(dt)
-	 goto start
-	 */
-
 	if (!isfinite(sp) || !isfinite(val) || !isfinite(val_dot) || !isfinite(dt)) {
 		return pid->last_output;
 	}
 
 	float i, d;
-	pid->sp = sp;
 
-	// Calculated current error value
-	float error = pid->sp - val;
+	/* current error value */
+	float error = sp - val;
 
-	// Calculate or measured current error derivative
+	/* current error derivative */
 	if (pid->mode == PID_MODE_DERIVATIV_CALC) {
 		d = (error - pid->error_previous) / fmaxf(dt, pid->dt_min);
 		pid->error_previous = error;
@@ -167,39 +140,34 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo
 		d = 0.0f;
 	}
 
-	if (pid->ki > 0.0f) {
+	/* calculate PD output */
+	float output = (error * pid->kp) + (d * pid->kd);
+
+	if (pid->ki > SIGMA) {
 		// Calculate the error integral and check for saturation
 		i = pid->integral + (error * dt);
 
-		if ((pid->limit > SIGMA && (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit)) ||
-		    fabsf(i) > pid->intmax) {
-			i = pid->integral;		// If saturated then do not update integral value
-			pid->saturated = 1;
-
-		} else {
-			if (!isfinite(i)) {
-				i = 0.0f;
+		/* check for saturation */
+		if (isfinite(i)) {
+			if ((pid->output_limit < SIGMA || (fabsf(output + (i * pid->ki)) <= pid->output_limit)) &&
+			    fabsf(i) <= pid->integral_limit) {
+				/* not saturated, use new integral value */
+				pid->integral = i;
 			}
-
-			pid->integral = i;
-			pid->saturated = 0;
 		}
 
-	} else {
-		i = 0.0f;
-		pid->saturated = 0;
+		/* add I component to output */
+		output += pid->integral * pid->ki;
 	}
 
-	// Calculate the output.  Limit output magnitude to pid->limit
-	float output = (error * pid->kp) + (i * pid->ki) + (d * pid->kd);
-
+	/* limit output */
 	if (isfinite(output)) {
-		if (pid->limit > SIGMA) {
-			if (output > pid->limit) {
-				output = pid->limit;
+		if (pid->output_limit > SIGMA) {
+			if (output > pid->output_limit) {
+				output = pid->output_limit;
 
-			} else if (output < -pid->limit) {
-				output = -pid->limit;
+			} else if (output < -pid->output_limit) {
+				output = -pid->output_limit;
 			}
 		}
 
@@ -212,5 +180,5 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo
 
 __EXPORT void pid_reset_integral(PID_t *pid)
 {
-	pid->integral = 0;
+	pid->integral = 0.0f;
 }
diff --git a/src/modules/systemlib/pid/pid.h b/src/modules/systemlib/pid/pid.h
index eca228464..e8b1aac4f 100644
--- a/src/modules/systemlib/pid/pid.h
+++ b/src/modules/systemlib/pid/pid.h
@@ -39,7 +39,7 @@
 /**
  * @file pid.h
  *
- * Definition of generic PID control interface.
+ * Definition of generic PID controller.
  *
  * @author Laurens Mackay <mackayl@student.ethz.ch>
  * @author Tobias Naegeli <naegelit@student.ethz.ch>
@@ -55,38 +55,35 @@
 
 __BEGIN_DECLS
 
-/* PID_MODE_DERIVATIV_CALC calculates discrete derivative from previous error
- * val_dot in pid_calculate() will be ignored */
-#define PID_MODE_DERIVATIV_CALC	0
-/* PID_MODE_DERIVATIV_CALC_NO_SP calculates discrete derivative from previous value, setpoint derivative is ignored
- * val_dot in pid_calculate() will be ignored */
-#define PID_MODE_DERIVATIV_CALC_NO_SP	1
-/* Use PID_MODE_DERIVATIV_SET if you have the derivative already (Gyros, Kalman) */
-#define PID_MODE_DERIVATIV_SET	2
-// Use PID_MODE_DERIVATIV_NONE for a PI controller (vs PID)
-#define PID_MODE_DERIVATIV_NONE 9
+typedef enum PID_MODE {
+	/* Use PID_MODE_DERIVATIV_NONE for a PI controller (vs PID) */
+	PID_MODE_DERIVATIV_NONE = 0,
+	/* PID_MODE_DERIVATIV_CALC calculates discrete derivative from previous error,
+	 * val_dot in pid_calculate() will be ignored */
+	PID_MODE_DERIVATIV_CALC,
+	/* PID_MODE_DERIVATIV_CALC_NO_SP calculates discrete derivative from previous value,
+	 * setpoint derivative will be ignored, val_dot in pid_calculate() will be ignored */
+	PID_MODE_DERIVATIV_CALC_NO_SP,
+	/* Use PID_MODE_DERIVATIV_SET if you have the derivative already (Gyros, Kalman) */
+	PID_MODE_DERIVATIV_SET
+} pid_mode_t;
 
 typedef struct {
+	pid_mode_t mode;
+	float dt_min;
 	float kp;
 	float ki;
 	float kd;
-	float intmax;
-	float sp;
 	float integral;
+	float integral_limit;
+	float output_limit;
 	float error_previous;
 	float last_output;
-	float limit;
-	float dt_min;
-	uint8_t mode;
-	uint8_t count;
-	uint8_t saturated;
 } PID_t;
 
-__EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax, float limit, uint8_t mode, float dt_min);
-__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float intmax, float limit);
-//void pid_set(PID_t *pid, float sp);
+__EXPORT void pid_init(PID_t *pid, pid_mode_t mode, float dt_min);
+__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float integral_limit, float output_limit);
 __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, float dt);
-
 __EXPORT void pid_reset_integral(PID_t *pid);
 
 __END_DECLS
diff --git a/src/modules/systemlib/pwm_limit/pwm_limit.c b/src/modules/systemlib/pwm_limit/pwm_limit.c
index 190b315f1..c733a53d7 100644
--- a/src/modules/systemlib/pwm_limit/pwm_limit.c
+++ b/src/modules/systemlib/pwm_limit/pwm_limit.c
@@ -97,7 +97,6 @@ void pwm_limit_calc(const bool armed, const unsigned num_channels, const uint16_
 	}
 
 	unsigned progress;
-	uint16_t temp_pwm;
 
 	/* then set effective_pwm based on state */
 	switch (limit->state) {
@@ -136,12 +135,26 @@ void pwm_limit_calc(const bool armed, const unsigned num_channels, const uint16_
 					}
 
 					effective_pwm[i] = output[i] * (max_pwm[i] - ramp_min_pwm)/2 + (max_pwm[i] + ramp_min_pwm)/2;
+
+					/* last line of defense against invalid inputs */
+					if (effective_pwm[i] < ramp_min_pwm) {
+						effective_pwm[i] = ramp_min_pwm;
+					} else if (effective_pwm[i] > max_pwm[i]) {
+						effective_pwm[i] = max_pwm[i];
+					}
 				}
 			}
 			break;
 		case PWM_LIMIT_STATE_ON:
 			for (unsigned i=0; i<num_channels; i++) {
 				effective_pwm[i] = output[i] * (max_pwm[i] - min_pwm[i])/2 + (max_pwm[i] + min_pwm[i])/2;
+
+				/* last line of defense against invalid inputs */
+				if (effective_pwm[i] < min_pwm[i]) {
+					effective_pwm[i] = min_pwm[i];
+				} else if (effective_pwm[i] > max_pwm[i]) {
+					effective_pwm[i] = max_pwm[i];
+				}
 			}
 			break;
 		default:
diff --git a/src/modules/systemlib/rc_check.c b/src/modules/systemlib/rc_check.c
index 21e15ec56..b35b333af 100644
--- a/src/modules/systemlib/rc_check.c
+++ b/src/modules/systemlib/rc_check.c
@@ -42,6 +42,7 @@
 #include <stdio.h>
 #include <fcntl.h>
 
+#include <systemlib/err.h>
 #include <systemlib/rc_check.h>
 #include <systemlib/param/param.h>
 #include <mavlink/mavlink_log.h>
@@ -98,32 +99,32 @@ int rc_calibration_check(int mavlink_fd) {
 		/* assert min..center..max ordering */
 		if (param_min < 500) {
 			count++;
-			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_MIN < 500", i+1);
+			mavlink_log_critical(mavlink_fd, "#audio ERR: RC_%d_MIN < 500", i+1);
 			/* give system time to flush error message in case there are more */
 			usleep(100000);
 		}
 		if (param_max > 2500) {
 			count++;
-			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_MAX > 2500", i+1);
+			mavlink_log_critical(mavlink_fd, "#audio ERR: RC_%d_MAX > 2500", i+1);
 			/* give system time to flush error message in case there are more */
 			usleep(100000);
 		}
 		if (param_trim < param_min) {
 			count++;
-			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_TRIM < MIN (%d/%d)", i+1, (int)param_trim, (int)param_min);
+			mavlink_log_critical(mavlink_fd, "#audio ERR: RC_%d_TRIM < MIN (%d/%d)", i+1, (int)param_trim, (int)param_min);
 			/* give system time to flush error message in case there are more */
 			usleep(100000);
 		}
 		if (param_trim > param_max) {
 			count++;
-			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_TRIM > MAX (%d/%d)", i+1, (int)param_trim, (int)param_max);
+			mavlink_log_critical(mavlink_fd, "#audio ERR: RC_%d_TRIM > MAX (%d/%d)", i+1, (int)param_trim, (int)param_max);
 			/* give system time to flush error message in case there are more */
 			usleep(100000);
 		}
 
 		/* assert deadzone is sane */
 		if (param_dz > 500) {
-			mavlink_log_critical(mavlink_fd, "ERR: RC_%d_DZ > 500", i+1);
+			mavlink_log_critical(mavlink_fd, "#audio ERR: RC_%d_DZ > 500", i+1);
 			/* give system time to flush error message in case there are more */
 			usleep(100000);
 			count++;
@@ -139,8 +140,8 @@ int rc_calibration_check(int mavlink_fd) {
 
 		/* sanity checks pass, enable channel */
 		if (count) {
-			mavlink_log_critical(mavlink_fd, "ERROR: %d config error(s) for RC channel %d.", count, (i + 1));
-			warnx(mavlink_fd, "ERROR: %d config error(s) for RC channel %d.", count, (i + 1));
+			mavlink_log_critical(mavlink_fd, "#audio ERROR: %d config error(s) for RC channel %d.", count, (i + 1));
+			warnx("ERROR: %d config error(s) for RC channel %d.", count, (i + 1));
 			usleep(100000);
 		}
 
diff --git a/src/modules/systemlib/state_table.h b/src/modules/systemlib/state_table.h
new file mode 100644
index 000000000..e6011fdef
--- /dev/null
+++ b/src/modules/systemlib/state_table.h
@@ -0,0 +1,82 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013-2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file state_table.h
+ *
+ * Finite-State-Machine helper class for state table
+ * @author: Julian Oes <julian@oes.ch>
+ */
+
+#ifndef __SYSTEMLIB_STATE_TABLE_H
+#define __SYSTEMLIB_STATE_TABLE_H
+
+class StateTable
+{
+public:
+	typedef void (StateTable::*Action)();
+	struct Tran {
+		Action action;
+		unsigned nextState;
+	};
+
+	StateTable(Tran const *table, unsigned nStates, unsigned nSignals)
+	: myTable(table), myNsignals(nSignals), myNstates(nStates) {}
+
+	#define NO_ACTION &StateTable::doNothing
+	#define ACTION(_target) StateTable::Action(_target)
+
+	virtual ~StateTable() {}
+
+	void dispatch(unsigned const sig) {
+		/* get transition using state table */
+		Tran const *t = myTable + myState*myNsignals + sig;
+
+		/* accept new state */
+		myState = t->nextState;
+
+		/*  */
+		(this->*(t->action))();
+	}
+	void doNothing() {
+		return;
+	}
+protected:
+	unsigned myState;
+private:
+	Tran const *myTable;
+	unsigned myNsignals;
+	unsigned myNstates;
+};
+
+#endif
diff --git a/src/modules/systemlib/system_params.c b/src/modules/systemlib/system_params.c
index 75be090f8..702e435ac 100644
--- a/src/modules/systemlib/system_params.c
+++ b/src/modules/systemlib/system_params.c
@@ -40,8 +40,45 @@
 #include <nuttx/config.h>
 #include <systemlib/param/param.h>
 
-// Auto-start script with index #n
+/**
+ * Auto-start script index.
+ *
+ * Defines the auto-start script used to bootstrap the system.
+ *
+ * @group System
+ */
 PARAM_DEFINE_INT32(SYS_AUTOSTART, 0);
 
-// Automatically configure default values
+/**
+ * Automatically configure default values.
+ *
+ * Set to 1 to set platform-specific parameters to their default
+ * values on next system startup. 
+ *
+ * @min 0
+ * @max 1
+ * @group System
+ */
 PARAM_DEFINE_INT32(SYS_AUTOCONFIG, 0);
+
+/**
+* Set usage of IO board
+*
+* Can be used to use a standard startup script but with a FMU only set-up. Set to 0 to force the FMU only set-up.
+*
+* @min 0
+* @max 1
+* @group System
+*/
+PARAM_DEFINE_INT32(SYS_USE_IO, 1);
+
+/**
+* Set restart type
+*
+* Set by px4io to indicate type of restart
+*
+* @min 0
+* @max 2
+* @group System
+*/
+PARAM_DEFINE_INT32(SYS_RESTART_TYPE, 2);
diff --git a/src/modules/systemlib/systemlib.c b/src/modules/systemlib/systemlib.c
index 57a751e1c..90d8dd77c 100644
--- a/src/modules/systemlib/systemlib.c
+++ b/src/modules/systemlib/systemlib.c
@@ -54,6 +54,9 @@
 
 #include "systemlib.h"
 
+// Didn't seem right to include up_internal.h, so direct extern instead.
+extern void up_systemreset(void) noreturn_function;
+
 void
 systemreset(bool to_bootloader)
 {
@@ -64,6 +67,9 @@ systemreset(bool to_bootloader)
 		*(uint32_t *)0x40002850 = 0xb007b007;
 	}
 	up_systemreset();
+
+	/* lock up here */
+	while(true);
 }
 
 static void kill_task(FAR struct tcb_s *tcb, FAR void *arg);