10 files changed, 294 insertions, 314 deletions

diff --git a/apps/drivers/px4io/px4io.cpp b/apps/drivers/px4io/px4io.cpp
index 11f2f6f68..80a61e303 100644
--- a/apps/drivers/px4io/px4io.cpp
+++ b/apps/drivers/px4io/px4io.cpp
@@ -87,15 +87,13 @@ public:
 
 	virtual int		ioctl(file *filp, int cmd, unsigned long arg);
 
-	void			set_rx_mode(unsigned mode);
-
 private:
 	static const unsigned	_max_actuators = PX4IO_OUTPUT_CHANNELS;
 
 	int			_serial_fd;	///< serial interface to PX4IO
 	hx_stream_t		_io_stream;	///< HX protocol stream
 
-	int			_task;		///< worker task
+	volatile int		_task;		///< worker task
 	volatile bool		_task_should_exit;
 	volatile bool		_connected;	///< true once we have received a valid frame
 
@@ -121,8 +119,6 @@ private:
 	bool			_send_needed;	///< If true, we need to send a packet to IO
 	bool			_config_needed;	///< if true, we need to set a config update to IO
 
-	uint8_t			_rx_mode;	///< the current RX mode on IO
-
 	/**
 	 * Trampoline to the worker task
 	 */
@@ -190,8 +186,7 @@ PX4IO::PX4IO() :
 	_primary_pwm_device(false),
 	_switch_armed(false),
 	_send_needed(false),
-	_config_needed(false),
-	_rx_mode(RX_MODE_PPM_ONLY)
+	_config_needed(false)
 {
 	/* we need this potentially before it could be set in task_main */
 	g_dev = this;
@@ -201,33 +196,17 @@ PX4IO::PX4IO() :
 
 PX4IO::~PX4IO()
 {
-	if (_task != -1) {
-		/* tell the task we want it to go away */
-		_task_should_exit = true;
-
-		/* spin waiting for the thread to stop */
-		unsigned i = 10;
-
-		do {
-			/* wait 50ms - it should wake every 100ms or so worst-case */
-			usleep(50000);
-
-			/* if we have given up, kill it */
-			if (--i == 0) {
-				task_delete(_task);
-				break;
-			}
+	/* tell the task we want it to go away */
+	_task_should_exit = true;
 
-		} while (_task != -1);
+	/* spin waiting for the task to stop */
+	for (unsigned i = 0; (i < 10) && (_task != -1); i++) {
+		/* give it another 100ms */
+		usleep(100000);
 	}
-
-	/* clean up the alternate device node */
-	if (_primary_pwm_device)
-		unregister_driver(PWM_OUTPUT_DEVICE_PATH);
-
-	/* kill the HX stream */
-	if (_io_stream != nullptr)
-		hx_stream_free(_io_stream);
+	/* well, kill it anyway, though this will probably crash */
+	if (_task != -1)
+		task_delete(_task);
 
 	g_dev = nullptr;
 }
@@ -295,6 +274,16 @@ PX4IO::task_main()
 		goto out;
 	}
 
+	/* 115200bps, no parity, one stop bit */
+	{
+		struct termios t;
+
+		tcgetattr(_serial_fd, &t);
+		cfsetspeed(&t, 115200);
+		t.c_cflag &= ~(CSTOPB | PARENB);
+		tcsetattr(_serial_fd, TCSANOW, &t);
+	}
+
 	/* protocol stream */
 	_io_stream = hx_stream_init(_serial_fd, &PX4IO::rx_callback_trampoline, this);
 	if (_io_stream == nullptr) {
@@ -402,8 +391,16 @@ PX4IO::task_main()
 	}
 
 out:
+	debug("exiting");
+
+	/* kill the HX stream */
 	if (_io_stream != nullptr)
 		hx_stream_free(_io_stream);
+	::close(_serial_fd);
+
+	/* clean up the alternate device node */
+	if (_primary_pwm_device)
+		unregister_driver(PWM_OUTPUT_DEVICE_PATH);
 
 	/* tell the dtor that we are exiting */
 	_task = -1;
@@ -514,7 +511,6 @@ PX4IO::config_send()
 	int		ret;
 
 	cfg.f2i_config_magic = F2I_CONFIG_MAGIC;
-	cfg.serial_rx_mode = _rx_mode;
 
 	ret = hx_stream_send(_io_stream, &cfg, sizeof(cfg));
 	if (ret)
@@ -634,17 +630,6 @@ PX4IO::ioctl(file *filep, int cmd, unsigned long arg)
 	return ret;
 }
 
-void
-PX4IO::set_rx_mode(unsigned mode)
-{
-	/*
-	 * Always (re)set the rx mode; makes testing
-	 * easier after PX4IO has been restarted.
-	 */
-	_rx_mode = mode;
-	_config_needed = true;
-}
-
 extern "C" __EXPORT int px4io_main(int argc, char *argv[]);
 
 namespace
@@ -748,25 +733,10 @@ px4io_main(int argc, char *argv[])
 
 	if (!strcmp(argv[1], "rx_dsm") ||
 	    !strcmp(argv[1], "rx_dsm_10bit") ||
-	    !strcmp(argv[1], "rx_dsm_11bit")) {
-		if (g_dev == nullptr)
-			errx(1, "not started");
-		g_dev->set_rx_mode(RX_MODE_DSM);
-		exit(0);
-	}
-	if (!strcmp(argv[1], "rx_sbus")) {
-		if (g_dev == nullptr)
-			errx(1, "not started");
-		g_dev->set_rx_mode(RX_MODE_FUTABA_SBUS);
-		exit(0);
-	}
-	if (!strcmp(argv[1], "rx_ppm")) {
-		if (g_dev == nullptr)
-			errx(1, "not started");
-		g_dev->set_rx_mode(RX_MODE_PPM_ONLY);
-		exit(0);
-	}
-
+	    !strcmp(argv[1], "rx_dsm_11bit") ||
+	    !strcmp(argv[1], "rx_sbus") ||
+	    !strcmp(argv[1], "rx_ppm"))
+		errx(0, "receiver type is automatically detected, option '%s' is deprecated", argv[1]);
 	if (!strcmp(argv[1], "test"))
 		test();
 
diff --git a/apps/px4io/comms.c b/apps/px4io/comms.c
index c44b677d1..a93ef9cb8 100644
--- a/apps/px4io/comms.c
+++ b/apps/px4io/comms.c
@@ -32,10 +32,11 @@
  ****************************************************************************/
 
 /**
- * @file FMU communication for the PX4IO module.
+ * @file comms.c
+ *
+ * FMU communication for the PX4IO module.
  */
 
-
 #include <nuttx/config.h>
 #include <stdio.h>
 #include <stdbool.h>
@@ -44,7 +45,6 @@
 #include <debug.h>
 #include <stdlib.h>
 #include <errno.h>
-#include <termios.h>
 #include <string.h>
 #include <poll.h>
 
@@ -54,101 +54,50 @@
 #include <systemlib/hx_stream.h>
 #include <systemlib/perf_counter.h>
 
+#define DEBUG
 #include "px4io.h"
 
 #define FMU_MIN_REPORT_INTERVAL	  5000	/*  5ms */
 #define FMU_MAX_REPORT_INTERVAL	100000	/* 100ms */
 
+int frame_rx;
+int frame_bad;
+
 static int			fmu_fd;
 static hx_stream_t		stream;
-static int			rx_fd;
 static struct px4io_report	report;
 
 static void			comms_handle_frame(void *arg, const void *buffer, size_t length);
 
-static struct pollfd pollfds[2];
-static int pollcount;
-
 void
 comms_init(void)
 {
 	/* initialise the FMU interface */
 	fmu_fd = open("/dev/ttyS1", O_RDWR | O_NONBLOCK);
-	if (fmu_fd < 0)
-		lib_lowprintf("COMMS: fmu open failed %d\n", errno);
 	stream = hx_stream_init(fmu_fd, comms_handle_frame, NULL);
-	pollfds[0].fd = fmu_fd;
-	pollfds[0].events = POLLIN;
-	pollcount = 1;
 
 	/* default state in the report to FMU */
 	report.i2f_magic = I2F_MAGIC;
-
 }
 
-static void
-serial_rx_init(unsigned serial_mode)
+void
+comms_main(void)
 {
-	if (serial_mode == system_state.serial_rx_mode)
-		return;
-	system_state.serial_rx_mode = serial_mode;
-
-	if (serial_mode == RX_MODE_PPM_ONLY) {
-		if (rx_fd != -1) {
-			pollcount = 1;
-			close(rx_fd);
-			rx_fd = -1;
-		}
-		return;
-	}
-
-	/* open the serial port used for DSM and S.bus communication */
-	rx_fd = open("/dev/ttyS0", O_RDONLY | O_NONBLOCK);
-	pollfds[1].fd = rx_fd;
-	pollfds[1].events = POLLIN;
-	pollcount = 2;
-
-	struct termios t;
-	tcgetattr(rx_fd, &t);
 
-	switch (serial_mode) {
-	case RX_MODE_DSM:
-		/* 115200, no parity, one stop bit */
-		cfsetspeed(&t, 115200);
-		t.c_cflag &= ~(CSTOPB | PARENB);
+	struct pollfd fds;
+	fds.fd = fmu_fd;
+	fds.events = POLLIN;
+	debug("FMU: ready");
 
-		dsm_init(serial_mode);
-		break;
+	for (;;) {
+		/* wait for serial data, but no more than 100ms */
+		poll(&fds, 1, 100);
 
-	case RX_MODE_FUTABA_SBUS:
-		/* 100000, even parity, two stop bits */
-		cfsetspeed(&t, 100000);
-		t.c_cflag |= (CSTOPB | PARENB);
-
-		sbus_init(serial_mode);
-		break;
-
-	default:
-		break;
-	}
-
-	tcsetattr(rx_fd, TCSANOW, &t);
-}
-
-void
-comms_check(void)
-{
-	/*
-	 * Check for serial data
-	 */
-	int ret = poll(pollfds, pollcount, 0);
-
-	if (ret > 0) {
 		/*
 		 * Pull bytes from FMU and feed them to the HX engine.
 		 * Limit the number of bytes we actually process on any one iteration.
 		 */
-		if (pollfds[0].revents & POLLIN) {
+		if (fds.revents & POLLIN) {
 			char buf[32];
 			ssize_t count = read(fmu_fd, buf, sizeof(buf));
 			for (int i = 0; i < count; i++)
@@ -156,54 +105,32 @@ comms_check(void)
 		}
 
 		/*
-		 * Pull bytes from the serial RX port and feed them to the decoder
-		 * if we care about serial RX data.
+		 * Decide if it's time to send an update to the FMU.
 		 */
-		if ((pollcount > 1) && (pollfds[1].revents & POLLIN)) {
-			switch (system_state.serial_rx_mode) {
-			case RX_MODE_DSM:
-				dsm_input(rx_fd);
-				break;
-
-			case RX_MODE_FUTABA_SBUS:
-				sbus_input(rx_fd);
-				break;
-
-			default:
-				break;
-			}
+		static hrt_abstime last_report_time;
+		hrt_abstime now, delta;
+
+		/* should we send a report to the FMU? */
+		now = hrt_absolute_time();
+		delta = now - last_report_time;
+		if ((delta > FMU_MIN_REPORT_INTERVAL) && 
+		    (system_state.fmu_report_due || (delta > FMU_MAX_REPORT_INTERVAL))) {
+
+			system_state.fmu_report_due = false;
+			last_report_time = now;
+
+			/* populate the report */
+			for (int i = 0; i < system_state.rc_channels; i++)
+				report.rc_channel[i] = system_state.rc_channel_data[i];
+			report.channel_count = system_state.rc_channels;
+			report.armed = system_state.armed;
+
+			/* and send it */
+			hx_stream_send(stream, &report, sizeof(report));
 		}
 	}
-
-	/*
-	 * Decide if it's time to send an update to the FMU.
-	 */
-	static hrt_abstime last_report_time;
-	hrt_abstime now, delta;
-
-	/* should we send a report to the FMU? */
-	now = hrt_absolute_time();
-	delta = now - last_report_time;
-	if ((delta > FMU_MIN_REPORT_INTERVAL) && 
-	    (system_state.fmu_report_due || (delta > FMU_MAX_REPORT_INTERVAL))) {
-
-		system_state.fmu_report_due = false;
-		last_report_time = now;
-
-		/* populate the report */
-		for (int i = 0; i < system_state.rc_channels; i++)
-			report.rc_channel[i] = system_state.rc_channel_data[i];
-		report.channel_count = system_state.rc_channels;
-		report.armed = system_state.armed;
-
-		/* and send it */
-		hx_stream_send(stream, &report, sizeof(report));
-	}
 }
 
-int frame_rx;
-int frame_bad;
-
 static void
 comms_handle_config(const void *buffer, size_t length)
 {
@@ -215,8 +142,6 @@ comms_handle_config(const void *buffer, size_t length)
 	}
 
 	frame_rx++;
-
-	serial_rx_init(cfg->serial_rx_mode);
 }
 
 static void
@@ -274,9 +199,9 @@ comms_handle_frame(void *arg, const void *buffer, size_t length)
 			comms_handle_config(buffer, length);
 			break;
 		default:
+		    	frame_bad++;
 			break;
 		}
 	}
-    	frame_bad++;
 }
 
diff --git a/apps/px4io/controls.c b/apps/px4io/controls.c
new file mode 100644
index 000000000..d4eace3df
--- /dev/null
+++ b/apps/px4io/controls.c
@@ -0,0 +1,88 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 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 controls.c
+ *
+ * R/C inputs and servo outputs.
+ */
+
+
+#include <nuttx/config.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <debug.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <termios.h>
+#include <string.h>
+#include <poll.h>
+
+#include <nuttx/clock.h>
+
+#include <drivers/drv_hrt.h>
+#include <systemlib/hx_stream.h>
+#include <systemlib/perf_counter.h>
+
+#define DEBUG
+#include "px4io.h"
+
+void
+controls_main(void)
+{
+	struct pollfd fds[2];
+
+	fds[0].fd = dsm_init("/dev/ttyS0");
+	fds[0].events = POLLIN;
+
+
+	fds[1].fd = sbus_init("/dev/ttyS2");
+	fds[1].events = POLLIN;
+
+	for (;;) {
+		/* run this loop at ~100Hz */
+		poll(fds, 2, 10);
+
+		if (fds[0].revents & POLLIN)
+			dsm_input();
+		if (fds[1].revents & POLLIN)
+			sbus_input();
+
+		/* XXX do ppm processing, bypass mode, etc. here */
+
+		/* do PWM output updates */
+		mixer_tick();
+	}
+}
diff --git a/apps/px4io/dsm.c b/apps/px4io/dsm.c
index 0e9fd25f1..da7d1a361 100644
--- a/apps/px4io/dsm.c
+++ b/apps/px4io/dsm.c
@@ -44,6 +44,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <string.h>
+#include <termios.h>
 
 #include <systemlib/ppm_decode.h>
  
@@ -57,6 +58,8 @@
 #define DSM_FRAME_SIZE		16
 #define DSM_FRAME_CHANNELS	7
 
+static int dsm_fd = -1;
+
 static hrt_abstime last_rx_time;
 static hrt_abstime last_frame_time;
 
@@ -66,27 +69,46 @@ static unsigned partial_frame_count;
 static bool	insync;
 static unsigned	channel_shift;
 
+unsigned dsm_frame_drops;
+
 static bool dsm_decode_channel(uint16_t raw, unsigned shift, unsigned *channel, unsigned *value);
 static void dsm_guess_format(bool reset);
 static void dsm_decode(hrt_abstime now);
 
-void
-dsm_init(unsigned mode)
+int
+dsm_init(const char *device)
 {
-	insync = false;
-	partial_frame_count = 0;
-	last_rx_time = hrt_absolute_time();
+	if (dsm_fd < 0)
+		dsm_fd = open(device, O_RDONLY);
 
-	/* reset the format detector */
-	dsm_guess_format(true);
+	if (dsm_fd >= 0) {
+		struct termios t;
+
+		/* 115200bps, no parity, one stop bit */
+		tcgetattr(dsm_fd, &t);
+		cfsetspeed(&t, 115200);
+		t.c_cflag &= ~(CSTOPB | PARENB);
+		tcsetattr(dsm_fd, TCSANOW, &t);
+
+		/* initialise the decoder */
+		insync = false;
+		partial_frame_count = 0;
+		last_rx_time = hrt_absolute_time();
+
+		/* reset the format detector */
+		dsm_guess_format(true);
 
-	debug("DSM: enabled and waiting\n");
+		debug("DSM: ready");
+	} else {
+		debug("DSM: open failed");
+	}
+
+	return dsm_fd;
 }
 
 void
-dsm_input(int fd)
+dsm_input(void)
 {
-	uint8_t		buf[DSM_FRAME_SIZE];
 	ssize_t		ret;
 	hrt_abstime	now;
 
@@ -107,16 +129,17 @@ dsm_input(int fd)
 	 */
 	now = hrt_absolute_time();
 	if ((now - last_rx_time) > 5000) {
-		if (partial_frame_count > 0)
-			debug("DSM: reset @ %d", partial_frame_count);
-		partial_frame_count = 0;
+		if (partial_frame_count > 0) {
+			dsm_frame_drops++;
+			partial_frame_count = 0;
+		}
 	}
 
 	/*
 	 * Fetch bytes, but no more than we would need to complete
 	 * the current frame.
 	 */
-	ret = read(fd, buf, DSM_FRAME_SIZE - partial_frame_count);
+	ret = read(dsm_fd, &frame[partial_frame_count], DSM_FRAME_SIZE - partial_frame_count);
 
 	/* if the read failed for any reason, just give up here */
 	if (ret < 1)
@@ -126,7 +149,6 @@ dsm_input(int fd)
 	/*
 	 * Add bytes to the current frame
 	 */
-	memcpy(&frame[partial_frame_count], buf, ret);
 	partial_frame_count += ret;
 
 	/*
@@ -292,8 +314,12 @@ dsm_decode(hrt_abstime frame_time)
 		/* convert 0-1024 / 0-2048 values to 1000-2000 ppm encoding in a very sloppy fashion */
 		if (channel_shift == 11)
 			value /= 2;
+
+		/* stuff the decoded channel into the PPM input buffer */
 		ppm_buffer[channel] = 988 + value;
 	}
 
+	/* and note that we have received data from the R/C controller */
+	/* XXX failsafe will cause problems here - need a strategy for detecting it */
 	ppm_last_valid_decode = hrt_absolute_time();
 }
diff --git a/apps/px4io/mixer.c b/apps/px4io/mixer.c
index 572344d00..61e716474 100644
--- a/apps/px4io/mixer.c
+++ b/apps/px4io/mixer.c
@@ -60,17 +60,6 @@
  */
 static unsigned fmu_input_drops;
 #define FMU_INPUT_DROP_LIMIT	20
-
-/*
- * HRT periodic call used to check for control input data.
- */
-static struct hrt_call mixer_input_call;
-
-/*
- * Mixer periodic tick.
- */
-static void	mixer_tick(void *arg);
-
 /*
  * Collect RC input data from the controller source(s).
  */
@@ -92,20 +81,8 @@ struct mixer {
 	/* XXX more config here */
 } mixers[IO_SERVO_COUNT];
 
-int
-mixer_init(void)
-{
-
-
-	/* look for control data at 50Hz */
-	hrt_call_every(&mixer_input_call, 1000, 20000, mixer_tick, NULL);
-
-	return 0;
-}
-
-
-static void
-mixer_tick(void *arg)
+void
+mixer_tick(void)
 {
 	uint16_t *control_values;
 	int control_count;
diff --git a/apps/px4io/protocol.h b/apps/px4io/protocol.h
index 8d051d385..c704b1201 100644
--- a/apps/px4io/protocol.h
+++ b/apps/px4io/protocol.h
@@ -62,10 +62,7 @@ struct px4io_config {
 	uint16_t f2i_config_magic;
 #define F2I_CONFIG_MAGIC 0x6366
 
-	uint8_t		serial_rx_mode;
-#define RX_MODE_PPM_ONLY	0
-#define RX_MODE_DSM		1
-#define RX_MODE_FUTABA_SBUS	2
+	/* XXX currently nothing here */
 };
 
 /* report from IO to FMU */
diff --git a/apps/px4io/px4io.c b/apps/px4io/px4io.c
index 197bad7c6..ba16ce247 100644
--- a/apps/px4io/px4io.c
+++ b/apps/px4io/px4io.c
@@ -55,37 +55,15 @@
 __EXPORT int user_start(int argc, char *argv[]);
 
 struct sys_state_s 	system_state;
-int			gpio_fd;
-
-static const char cursor[] = {'|', '/', '-', '\\'};
-
-static struct hrt_call timer_tick_call;
-volatile int timers[TIMER_NUM_TIMERS];
-static void timer_tick(void *arg);
 
 int user_start(int argc, char *argv[])
 {
-	int     cycle = 0;
-	bool	heartbeat = false;
-	bool	failsafe = false;
 
 	/* configure the high-resolution time/callout interface */
 	hrt_init();
 
-	/* init the FMU and receiver links */
-	comms_init();
-
-	/* configure the first 8 PWM outputs (i.e. all of them) */
-	/* note, must do this after comms init to steal back PA0, which is CTS otherwise */
-	up_pwm_servo_init(0xff);
-
 	/* print some startup info */
 	lib_lowprintf("\nPX4IO: starting\n");
-	struct mallinfo minfo = mallinfo();
-	lib_lowprintf("free %u largest %u\n", minfo.mxordblk, minfo.fordblks);
-
-	/* start the software timer service */
-	hrt_call_every(&timer_tick_call, 1000, 1000, timer_tick, NULL);
 
 	/* default all the LEDs to off while we start */
 	LED_AMBER(false);
@@ -95,66 +73,27 @@ int user_start(int argc, char *argv[])
 	/* turn on servo power */
 	POWER_SERVO(true);
 
-	/* start the mixer */
-	mixer_init();
-
 	/* start the safety switch handler */
 	safety_init();
 
-	/* set up some timers for the main loop */
-	timers[TIMER_BLINK_BLUE] = 250;		/* heartbeat blink @ 2Hz */
-	timers[TIMER_STATUS_PRINT] = 1000;	/* print status message @ 1Hz */
-
-	/*
-	 * Main loop servicing communication with FMU
-	 */
-	while(true) {
-
-		/* check for communication from FMU, send updates */
-		comms_check();
-
-		/* blink the heartbeat LED */
-		if (timers[TIMER_BLINK_BLUE] == 0) {
-			timers[TIMER_BLINK_BLUE] = 250;
-			LED_BLUE(heartbeat = !heartbeat);
-		}
-
-		/* blink the failsafe LED if we don't have FMU input */
-		if (!system_state.mixer_use_fmu) {
-			if (timers[TIMER_BLINK_AMBER] == 0) {
-				timers[TIMER_BLINK_AMBER] = 125;
-				failsafe = !failsafe;
-			}
-		} else {
-			failsafe = false;
-		}
-		LED_AMBER(failsafe);
-		
-		/* print some simple status */
-#if 0
-		if (timers[TIMER_STATUS_PRINT] == 0) {
-			timers[TIMER_STATUS_PRINT] = 1000;
-			lib_lowprintf("%c %s | %s | %s | %s | C=%d F=%d B=%d   \r",
-				cursor[cycle++ & 3],
-				(system_state.arm_ok        ? "FMU_ARMED"  : "FMU_SAFE"),
-				(system_state.armed         ? "ARMED"  : "SAFE"),
-				(system_state.rc_channels   ? "RC OK"  : "NO RC"),
-				(system_state.mixer_use_fmu ? "FMU OK" : "NO FMU"),
-				system_state.rc_channels,
-				frame_rx, frame_bad
-			);
-		}
-#endif
-	}
-
-	/* Should never reach here */
-	return ERROR;
-}
-
-static void
-timer_tick(void *arg)
-{
-	for (unsigned i = 0; i < TIMER_NUM_TIMERS; i++)
-		if (timers[i] > 0)
-			timers[i]--;
-}
+	/* start the flight control signal handler */
+	task_create("FCon", 
+		    SCHED_PRIORITY_DEFAULT,
+		    1024,
+		    (main_t)controls_main,
+		    NULL);
+
+
+	/* initialise the FMU communications interface */
+	comms_init();
+
+	/* configure the first 8 PWM outputs (i.e. all of them) */
+	/* note, must do this after comms init to steal back PA0, which is CTS otherwise */
+	up_pwm_servo_init(0xff);
+
+	struct mallinfo minfo = mallinfo();
+	lib_lowprintf("free %u largest %u\n", minfo.mxordblk, minfo.fordblks);
+
+	/* we're done here, go run the communications loop */
+	comms_main();
+}
\ No newline at end of file
diff --git a/apps/px4io/px4io.h b/apps/px4io/px4io.h
index 0a3a4448c..2ecab966d 100644
--- a/apps/px4io/px4io.h
+++ b/apps/px4io/px4io.h
@@ -147,7 +147,7 @@ extern volatile int	timers[TIMER_NUM_TIMERS];
 /*
  * Mixer
  */
-extern int	mixer_init(void);
+extern void	mixer_tick(void);
 
 /*
  * Safety switch/LED.
@@ -158,15 +158,16 @@ extern void	safety_init(void);
  * FMU communications
  */
 extern void	comms_init(void);
-extern void	comms_check(void);
+extern void	comms_main(void) __attribute__((noreturn));
 
 /*
- * Serial receiver decoders.
+ * R/C receiver handling.
  */
-extern void	dsm_init(unsigned mode);
-extern void	dsm_input(int fd);
-extern void	sbus_init(unsigned mode);
-extern void	sbus_input(int fd);
+extern void	controls_main(void);
+extern int	dsm_init(const char *device);
+extern void	dsm_input(void);
+extern int	sbus_init(const char *device);
+extern void	sbus_input(void);
 
 /*
  * Assertion codes
diff --git a/apps/px4io/safety.c b/apps/px4io/safety.c
index 24fc9951a..d5bd103c1 100644
--- a/apps/px4io/safety.c
+++ b/apps/px4io/safety.c
@@ -51,6 +51,8 @@
 #include "px4io.h"
 
 static struct hrt_call arming_call;
+static struct hrt_call heartbeat_call;
+static struct hrt_call failsafe_call;
 
 /*
  * Count the number of times in a row that we see the arming button
@@ -63,13 +65,22 @@ static unsigned counter;
 
 static bool safety_led_state;
 static bool safety_button_pressed;
+
 static void safety_check_button(void *arg);
+static void heartbeat_blink(void *arg);
+static void failsafe_blink(void *arg);
 
 void
 safety_init(void)
 {
 	/* arrange for the button handler to be called at 10Hz */
 	hrt_call_every(&arming_call, 1000, 100000, safety_check_button, NULL);
+
+	/* arrange for the heartbeat handler to be called at 4Hz */
+	hrt_call_every(&heartbeat_call, 1000, 250000, heartbeat_blink, NULL);
+
+	/* arrange for the failsafe blinker to be called at 8Hz */
+	hrt_call_every(&failsafe_call, 1000, 125000, failsafe_blink, NULL);
 }
 
 static void
@@ -117,3 +128,28 @@ safety_check_button(void *arg)
 	}
 	LED_SAFETY(safety_led_state);
 }
+
+
+static void
+heartbeat_blink(void *arg)
+{
+	static bool heartbeat = false;
+
+	/* XXX add flags here that need to be frobbed by various loops */
+
+	LED_BLUE(heartbeat = !heartbeat);
+}
+
+static void
+failsafe_blink(void *arg)
+{
+	static bool failsafe = false;
+
+	/* blink the failsafe LED if we don't have FMU input */
+	if (!system_state.mixer_use_fmu) {
+		failsafe = !failsafe;
+	} else {
+		failsafe = false;
+	}
+	LED_AMBER(failsafe);
+}
\ No newline at end of file
diff --git a/apps/px4io/sbus.c b/apps/px4io/sbus.c
index e363a0a78..a91e37b5c 100644
--- a/apps/px4io/sbus.c
+++ b/apps/px4io/sbus.c
@@ -41,18 +41,39 @@
 
 #include <fcntl.h>
 #include <unistd.h>
+#include <termios.h>
 
 #include <drivers/drv_hrt.h>
 
+#define DEBUG
 #include "px4io.h"
-#include "protocol.h"
 
-void
-sbus_init(unsigned mode)
+static int sbus_fd = -1;
+
+int
+sbus_init(const char *device)
 {
+	if (sbus_fd < 0)
+		sbus_fd = open(device, O_RDONLY);
+
+	if (sbus_fd >= 0) {
+		struct termios t;
+
+		/* 100000bps, even parity, two stop bits */
+		tcgetattr(sbus_fd, &t);
+		cfsetspeed(&t, 100000);
+		t.c_cflag |= (CSTOPB | PARENB);
+		tcsetattr(sbus_fd, TCSANOW, &t);
+
+		debug("Sbus: ready");
+	} else {
+		debug("Sbus: open failed");
+	}
+
+	return sbus_fd;
 }
 
 void
-sbus_input(int fd)
+sbus_input(void)
 {
 }