Merge branch 'master' into px4io-i2c

16 files changed, 815 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 85d846b98..8e9075ba4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -47,6 +47,7 @@ nsh_romfsimg.h
 cscope.out
 .configX-e
 nuttx-export.zip
+.~lock.*
 dot.gdbinit
 mavlink/include/mavlink/v0.9/
 .*.swp
diff --git a/Documentation/arming_state_machine.odg b/Documentation/arming_state_machine.odg
new file mode 100644
index 000000000..cfadbab7c
--- /dev/null
+++ b/Documentation/arming_state_machine.odg
diff --git a/Documentation/arming_state_machine.pdf b/Documentation/arming_state_machine.pdf
new file mode 100644
index 000000000..2c3e8be23
--- /dev/null
+++ b/Documentation/arming_state_machine.pdf
diff --git a/Documentation/flight_mode_state_machine.odg b/Documentation/flight_mode_state_machine.odg
new file mode 100644
index 000000000..b630ecb40
--- /dev/null
+++ b/Documentation/flight_mode_state_machine.odg
diff --git a/Documentation/flight_mode_state_machine.pdf b/Documentation/flight_mode_state_machine.pdf
new file mode 100644
index 000000000..cd234ada7
--- /dev/null
+++ b/Documentation/flight_mode_state_machine.pdf
diff --git a/Documentation/rc_mode_switch.odg b/Documentation/rc_mode_switch.odg
new file mode 100644
index 000000000..e35a83372
--- /dev/null
+++ b/Documentation/rc_mode_switch.odg
diff --git a/Documentation/rc_mode_switch.pdf b/Documentation/rc_mode_switch.pdf
new file mode 100644
index 000000000..823b1d868
--- /dev/null
+++ b/Documentation/rc_mode_switch.pdf
diff --git a/apps/hott_telemetry/Makefile b/apps/hott_telemetry/Makefile
new file mode 100644
index 000000000..8d5faa3b7
--- /dev/null
+++ b/apps/hott_telemetry/Makefile
@@ -0,0 +1,45 @@
+############################################################################
+#
+#   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.
+#
+############################################################################
+
+#
+# Graupner HoTT Telemetry application.
+#
+
+# The following line is required for accessing UARTs directly.
+INCLUDES	 = $(TOPDIR)/arch/arm/src/stm32 $(TOPDIR)/arch/arm/src/common
+
+APPNAME		 = hott_telemetry
+PRIORITY	 = SCHED_PRIORITY_DEFAULT
+STACKSIZE	 = 2048
+
+include $(APPDIR)/mk/app.mk
diff --git a/apps/hott_telemetry/hott_telemetry_main.c b/apps/hott_telemetry/hott_telemetry_main.c
new file mode 100644
index 000000000..d67ab06a9
--- /dev/null
+++ b/apps/hott_telemetry/hott_telemetry_main.c
@@ -0,0 +1,311 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Author: @author Simon Wilks <sjwilks@gmail.com>
+ *
+ * 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 hott_telemetry_main.c
+ *
+ * Graupner HoTT Telemetry implementation.
+ *
+ * The HoTT receiver polls each device at a regular interval at which point
+ * a data packet can be returned if necessary.
+ *
+ * TODO: Add support for at least the vario and GPS sensor data.
+ *
+ */
+
+#include <fcntl.h>
+#include <nuttx/config.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <systemlib/systemlib.h>
+
+#include "messages.h"
+
+/* The following are equired for UART direct manipulation. */
+#include <arch/board/board.h>
+#include "up_arch.h"
+#include "chip.h"
+#include "stm32_internal.h"
+
+static int thread_should_exit = false;		/**< Deamon exit flag */
+static int thread_running = false;		/**< Deamon status flag */
+static int deamon_task;				/**< Handle of deamon task / thread */
+static char *daemon_name = "hott_telemetry";
+static char *commandline_usage = "usage: hott_telemetry start|status|stop [-d <device>]";
+
+
+/* A little console messaging experiment - console helper macro */
+#define FATAL_MSG(_msg)		fprintf(stderr, "[%s] %s\n", daemon_name, _msg); exit(1);
+#define ERROR_MSG(_msg)		fprintf(stderr, "[%s] %s\n", daemon_name, _msg);
+#define INFO_MSG(_msg)		printf("[%s] %s\n", daemon_name, _msg);
+/**
+ * Deamon management function.
+ */
+__EXPORT int hott_telemetry_main(int argc, char *argv[]);
+
+/**
+ * Mainloop of deamon.
+ */
+int hott_telemetry_thread_main(int argc, char *argv[]);
+
+static int read_data(int uart, int *id);
+static int send_data(int uart, uint8_t *buffer, int size);
+
+static int open_uart(const char *device, struct termios *uart_config_original)
+{
+	/* baud rate */
+	int speed = B19200;
+	int uart;
+
+	/* open uart */
+	uart = open(device, O_RDWR | O_NOCTTY);
+
+	if (uart < 0) {
+		char msg[80];
+		sprintf(msg, "Error opening port: %s\n", device);
+		FATAL_MSG(msg);
+	}
+
+	/* Try to set baud rate */
+	struct termios uart_config;
+	int termios_state;
+
+	/* Back up the original uart configuration to restore it after exit */
+	char msg[80];
+
+	if ((termios_state = tcgetattr(uart, uart_config_original)) < 0) {
+		sprintf(msg, "Error getting baudrate / termios config for %s: %d\n", device, termios_state);
+		close(uart);
+		FATAL_MSG(msg);
+	}
+
+	/* Fill the struct for the new configuration */
+	tcgetattr(uart, &uart_config);
+
+	/* Clear ONLCR flag (which appends a CR for every LF) */
+	uart_config.c_oflag &= ~ONLCR;
+
+	/* Set baud rate */
+	if (cfsetispeed(&uart_config, speed) < 0 || cfsetospeed(&uart_config, speed) < 0) {
+		sprintf(msg, "Error setting baudrate / termios config for %s: %d (cfsetispeed, cfsetospeed)\n",
+			device, termios_state);
+		close(uart);
+		FATAL_MSG(msg);
+	}
+
+	if ((termios_state = tcsetattr(uart, TCSANOW, &uart_config)) < 0) {
+		sprintf(msg, "Error setting baudrate / termios config for %s (tcsetattr)\n", device);
+		close(uart);
+		FATAL_MSG(msg);
+	}
+
+	/* Activate single wire mode */
+	ioctl(uart, TIOCSSINGLEWIRE, SER_SINGLEWIRE_ENABLED);
+
+	return uart;
+}
+
+int read_data(int uart, int *id)
+{
+	const int timeout = 1000;
+	struct pollfd fds[] = { { .fd = uart, .events = POLLIN } };
+
+	char mode;
+
+	if (poll(fds, 1, timeout) > 0) {
+		/* Get the mode: binary or text  */
+		read(uart, &mode, 1);
+		/* Read the device ID being polled */
+		read(uart, id, 1);
+
+		/* if we have a binary mode request */
+		if (mode != BINARY_MODE_REQUEST_ID) {
+			return ERROR;
+		}
+
+	} else {
+		ERROR_MSG("UART timeout on TX/RX port");
+		return ERROR;
+	}
+
+	return OK;
+}
+
+int send_data(int uart, uint8_t *buffer, int size)
+{
+	usleep(POST_READ_DELAY_IN_USECS);
+
+	uint16_t checksum = 0;
+
+	for (int i = 0; i < size; i++) {
+		if (i == size - 1) {
+			/* Set the checksum: the first uint8_t is taken as the checksum. */
+			buffer[i] = checksum & 0xff;
+
+		} else {
+			checksum += buffer[i];
+		}
+
+		write(uart, &buffer[i], 1);
+
+		/* Sleep before sending the next byte. */
+		usleep(POST_WRITE_DELAY_IN_USECS);
+	}
+
+	/* A hack the reads out what was written so the next read from the receiver doesn't get it. */
+	/* TODO: Fix this!! */
+	uint8_t dummy[size];
+	read(uart, &dummy, size);
+
+	return OK;
+}
+
+int hott_telemetry_thread_main(int argc, char *argv[])
+{
+	INFO_MSG("starting");
+
+	thread_running = true;
+
+	char *device = "/dev/ttyS1";		/**< Default telemetry port: USART2 */
+
+	/* read commandline arguments */
+	for (int i = 0; i < argc && argv[i]; i++) {
+		if (strcmp(argv[i], "-d") == 0 || strcmp(argv[i], "--device") == 0) { //device set
+			if (argc > i + 1) {
+				device = argv[i + 1];
+
+			} else {
+				thread_running = false;
+				ERROR_MSG("missing parameter to -d");
+				ERROR_MSG(commandline_usage);
+				exit(1);
+			}
+		}
+	}
+
+	/* enable UART, writes potentially an empty buffer, but multiplexing is disabled */
+	struct termios uart_config_original;
+	int uart = open_uart(device, &uart_config_original);
+
+	if (uart < 0) {
+		ERROR_MSG("Failed opening HoTT UART, exiting.");
+		thread_running = false;
+		exit(ERROR);
+	}
+
+	messages_init();
+
+	uint8_t buffer[MESSAGE_BUFFER_SIZE];
+	int size = 0;
+	int id = 0;
+
+	while (!thread_should_exit) {
+		if (read_data(uart, &id) == OK) {
+			switch (id) {
+			case ELECTRIC_AIR_MODULE:
+				build_eam_response(buffer, &size);
+				break;
+
+			default:
+				continue;	// Not a module we support.
+			}
+
+			send_data(uart, buffer, size);
+		}
+	}
+
+	INFO_MSG("exiting");
+
+	close(uart);
+
+	thread_running = false;
+
+	return 0;
+}
+
+/**
+ * Process command line arguments and tart the daemon.
+ */
+int hott_telemetry_main(int argc, char *argv[])
+{
+	if (argc < 1) {
+		ERROR_MSG("missing command");
+		ERROR_MSG(commandline_usage);
+		exit(1);
+	}
+
+	if (!strcmp(argv[1], "start")) {
+
+		if (thread_running) {
+			INFO_MSG("deamon already running");
+			exit(0);
+		}
+
+		thread_should_exit = false;
+		deamon_task = task_spawn("hott_telemetry",
+					 SCHED_DEFAULT,
+					 SCHED_PRIORITY_MAX - 40,
+					 2048,
+					 hott_telemetry_thread_main,
+					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "stop")) {
+		thread_should_exit = true;
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "status")) {
+		if (thread_running) {
+			INFO_MSG("daemon is running");
+
+		} else {
+			INFO_MSG("daemon not started");
+		}
+
+		exit(0);
+	}
+
+	ERROR_MSG("unrecognized command");
+	ERROR_MSG(commandline_usage);
+	exit(1);
+}
+
+
+
diff --git a/apps/hott_telemetry/messages.c b/apps/hott_telemetry/messages.c
new file mode 100644
index 000000000..8bfb99773
--- /dev/null
+++ b/apps/hott_telemetry/messages.c
@@ -0,0 +1,87 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Author: @author Simon Wilks <sjwilks@gmail.com>
+ *
+ * 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 messages.c
+ *
+ */
+
+#include "messages.h"
+
+#include <string.h>
+#include <systemlib/systemlib.h>
+#include <unistd.h>
+#include <uORB/topics/battery_status.h>
+#include <uORB/topics/sensor_combined.h>
+
+static int battery_sub = -1;
+static int sensor_sub = -1;
+
+void messages_init(void)
+{
+	battery_sub = orb_subscribe(ORB_ID(battery_status));
+	sensor_sub = orb_subscribe(ORB_ID(sensor_combined));
+}
+
+void build_eam_response(uint8_t *buffer, int *size)
+{
+	/* get a local copy of the current sensor values */
+	struct sensor_combined_s raw;
+	memset(&raw, 0, sizeof(raw));
+	orb_copy(ORB_ID(sensor_combined), sensor_sub, &raw);
+
+	/* get a local copy of the battery data */
+	struct battery_status_s battery;
+	memset(&battery, 0, sizeof(battery));
+	orb_copy(ORB_ID(battery_status), battery_sub, &battery);
+
+	struct eam_module_msg msg;
+	*size = sizeof(msg);
+	memset(&msg, 0, *size);
+
+	msg.start = START_BYTE;
+	msg.eam_sensor_id = ELECTRIC_AIR_MODULE;
+	msg.sensor_id = EAM_SENSOR_ID;
+	msg.temperature1 = (uint8_t)(raw.baro_temp_celcius + 20);
+	msg.temperature2 = TEMP_ZERO_CELSIUS;
+	msg.main_voltage_L = (uint8_t)(battery.voltage_v * 10);
+
+	uint16_t alt = (uint16_t)(raw.baro_alt_meter + 500);
+	msg.altitude_L = (uint8_t)alt & 0xff;
+	msg.altitude_H = (uint8_t)(alt >> 8) & 0xff;
+
+	msg.stop = STOP_BYTE;
+
+	memcpy(buffer, &msg, *size);
+}
\ No newline at end of file
diff --git a/apps/hott_telemetry/messages.h b/apps/hott_telemetry/messages.h
new file mode 100644
index 000000000..44001e04f
--- /dev/null
+++ b/apps/hott_telemetry/messages.h
@@ -0,0 +1,123 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Author: @author Simon Wilks <sjwilks@gmail.com>
+ *
+ * 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 messages.h
+ *
+ * Graupner HoTT Telemetry message generation.
+ *
+ */
+#ifndef MESSAGES_H_
+#define MESSAGES_H
+
+#include <stdlib.h>
+
+/* The buffer size used to store messages. This must be at least as big as the number of
+ * fields in the largest message struct.
+ */
+#define MESSAGE_BUFFER_SIZE 50
+
+/* The HoTT receiver demands a minimum 5ms period of silence after delivering its request.
+ * Note that the value specified here is lower than 5000 (5ms) as time is lost constucting
+ * the message after the read which takes some milliseconds.
+ */
+#define POST_READ_DELAY_IN_USECS	4000
+/* A pause of 3ms is required between each uint8_t sent back to the HoTT receiver. Much lower
+ * values can be used in practise though.
+ */
+#define POST_WRITE_DELAY_IN_USECS	2000
+
+// Protocol constants.
+#define BINARY_MODE_REQUEST_ID	0x80	// Binary mode request.
+#define START_BYTE		0x7c
+#define STOP_BYTE		0x7d
+#define TEMP_ZERO_CELSIUS	0x14
+
+/* Electric Air Module (EAM) constants. */
+#define ELECTRIC_AIR_MODULE	0x8e
+#define EAM_SENSOR_ID		0xe0
+
+/* The Electric Air Module message. */
+struct eam_module_msg {
+	uint8_t start;			/**< Start byte   				*/
+	uint8_t eam_sensor_id;		/**< EAM sensor ID 				*/
+	uint8_t warning;
+	uint8_t sensor_id;		/**< Sensor ID, why different? 			*/
+	uint8_t alarm_inverse1;
+	uint8_t alarm_inverse2;
+	uint8_t cell1_L;		/**< Lipo cell voltages. Not supported. 	*/
+	uint8_t cell2_L;
+	uint8_t cell3_L;
+	uint8_t cell4_L;
+	uint8_t cell5_L;
+	uint8_t cell6_L;
+	uint8_t cell7_L;
+	uint8_t cell1_H;
+	uint8_t cell2_H;
+	uint8_t cell3_H;
+	uint8_t cell4_H;
+	uint8_t cell5_H;
+	uint8_t cell6_H;
+	uint8_t cell7_H;
+	uint8_t batt1_voltage_L;	/**< Battery 1 voltage, lower 8-bits in steps of 0.02V 	*/
+	uint8_t batt1_voltage_H;
+	uint8_t batt2_voltage_L;	/**< Battery 2 voltage, lower 8-bits in steps of 0.02V 	*/
+	uint8_t batt2_voltage_H;
+	uint8_t temperature1;		/**< Temperature sensor 1. 20 = 0 degrees 		*/
+	uint8_t temperature2;
+	uint8_t altitude_L;		/**< Attitude (meters) lower 8-bits. 500 = 0 meters 	*/
+	uint8_t altitude_H;
+	uint8_t current_L;		/**< Current (mAh) lower 8-bits in steps of 0.1V 	*/
+	uint8_t current_H;
+	uint8_t main_voltage_L;		/**< Main power voltage lower 8-bits in steps of 0.1V 	*/
+	uint8_t main_voltage_H;
+	uint8_t battery_capacity_L;	/**< Used battery capacity in steps of 10mAh 		*/
+	uint8_t battery_capacity_H;
+	uint8_t climbrate_L;		/**< Climb rate in 0.01m/s. 0m/s = 30000 		*/
+	uint8_t climbrate_H;
+	uint8_t climbrate_3s;		/**< Climb rate in m/3sec. 0m/3sec = 120 		*/
+	uint8_t rpm_L;			/**< RPM Lower 8-bits In steps of 10 U/min 		*/
+	uint8_t rpm_H;
+	uint8_t electric_min;		/**< Flight time in minutes. 				*/
+	uint8_t electric_sec;		/**< Flight time in seconds. 				*/
+	uint8_t speed_L;		/**< Airspeed in km/h in steps of 1 km/h 		*/
+	uint8_t speed_H;
+	uint8_t stop;			/**< Stop byte 						*/
+	uint8_t checksum;		/**< Lower 8-bits of all bytes summed. 			*/
+};
+
+void messages_init(void);
+void build_eam_response(uint8_t *buffer, int *size);
+
+#endif /* MESSAGES_H_ */
diff --git a/apps/px4/tests/test_hott_telemetry.c b/apps/px4/tests/test_hott_telemetry.c
new file mode 100644
index 000000000..74aa0e614
--- /dev/null
+++ b/apps/px4/tests/test_hott_telemetry.c
@@ -0,0 +1,239 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Author: @author Simon Wilks <sjwilks@gmail.com>
+ *
+ * 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 test_hott_telemetry.c
+ *
+ * Tests the Graupner HoTT telemetry support.
+ *
+ */
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <drivers/drv_gpio.h>
+#include <nuttx/config.h>
+#include <sys/types.h>
+
+#include <debug.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <termios.h>
+#include <unistd.h>
+
+#include "tests.h"
+
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+static int open_uart(const char *device)
+{
+	/* baud rate */
+	int speed = B19200;
+
+	/* open uart */
+	int uart = open(device, O_RDWR | O_NOCTTY);
+
+	if (uart < 0) {
+		errx(1, "FAIL: Error opening port");
+		return ERROR;
+	}
+
+	/* Try to set baud rate */
+	struct termios uart_config;
+
+	/* Fill the struct for the new configuration */
+	tcgetattr(uart, &uart_config);
+
+	/* Clear ONLCR flag (which appends a CR for every LF) */
+	uart_config.c_oflag &= ~ONLCR;
+
+	/* Set baud rate */
+	if (cfsetispeed(&uart_config, speed) < 0 || cfsetospeed(&uart_config, speed) < 0) {
+		errx(1, "FAIL: Error setting baudrate / termios config for cfsetispeed, cfsetospeed");
+		return ERROR;
+	}
+
+	if (tcsetattr(uart, TCSANOW, &uart_config) < 0) {
+		errx(1, "FAIL: Error setting baudrate / termios config for tcsetattr");
+		return ERROR;
+	}
+
+	return uart;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: test_hott_telemetry
+ ****************************************************************************/
+
+int test_hott_telemetry(int argc, char *argv[])
+{
+	warnx("HoTT Telemetry Test Requirements:");
+	warnx("- Radio on and Electric Air. Mod on (telemetry -> sensor select).");
+	warnx("- Receiver telemetry port must be in telemetry mode.");
+	warnx("- Connect telemetry wire to /dev/ttyS1 (USART2).");
+	warnx("Testing...");
+
+	const char device[] = "/dev/ttyS1";
+	int fd = open_uart(device);
+
+	if (fd < 0) {
+		close(fd);
+		return ERROR;
+	}
+
+	/* Activate single wire mode */
+	ioctl(fd, TIOCSSINGLEWIRE, SER_SINGLEWIRE_ENABLED);
+
+	char send = 'a';
+	write(fd, &send, 1);
+
+	/* Since TX and RX are now connected we should be able to read in what we wrote */
+	const int timeout = 1000;
+	struct pollfd fds[] = { { .fd = fd, .events = POLLIN } };
+
+	if (poll(fds, 1, timeout) == 0) {
+		errx(1, "FAIL: Could not read sent data.");
+	}
+
+	char receive;
+	read(fd, &receive, 1);
+	warnx("PASS: Single wire enabled. Sent %x and received %x", send, receive);
+
+
+	/* Attempt to read HoTT poll messages from the HoTT receiver */
+	int received_count = 0;
+	int valid_count = 0;
+	const int max_polls = 5;
+	uint8_t byte;
+
+	for (; received_count < 5; received_count++) {
+		if (poll(fds, 1, timeout) == 0) {
+			errx(1, "FAIL: Could not read sent data. Is your HoTT receiver plugged in on %s?", device);
+			break;
+
+		} else {
+			read(fd, &byte, 1);
+
+			if (byte == 0x80) {
+				valid_count++;
+			}
+
+			/* Read the device ID being polled */
+			read(fd, &byte, 1);
+		}
+	}
+
+	if (received_count > 0 && valid_count > 0) {
+		if (received_count == max_polls && valid_count == max_polls) {
+			warnx("PASS: Received %d out of %d valid byte pairs from the HoTT receiver device.", received_count, max_polls);
+
+		} else {
+			warnx("WARN: Received %d out of %d byte pairs of which %d were valid from the HoTT receiver device.", received_count, max_polls, valid_count);
+		}
+
+	} else {
+		/* Let's work out what went wrong */
+		if (received_count == 0) {
+			errx(1, "FAIL: Could not read any polls from HoTT receiver device.");
+		}
+
+		if (valid_count == 0) {
+			errx(1, "FAIL: Received unexpected values from the HoTT receiver device.");
+		}
+	}
+
+
+	/* Attempt to send a HoTT response messages */
+	uint8_t response[] = {0x7c, 0x8e, 0x00, 0xe0, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, \
+			      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+			      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf4, 0x01, 0x00, 0x00, \
+			      0x19, 0x00, 0x00, 0x00, 0x30, 0x75, 0x78, 0x00, 0x00, 0x00, \
+			      0x00, 0x00, 0x00, 0x7d, 0x12
+			     };
+
+	usleep(5000);
+
+	for (unsigned int i = 0; i < sizeof(response); i++) {
+		write(fd, &response[i], 1);
+		usleep(1000);
+	}
+
+	warnx("PASS: Response sent to the HoTT receiver device. Voltage should now show 2.5V.");
+
+
+	/* Disable single wire */
+	ioctl(fd, TIOCSSINGLEWIRE, ~SER_SINGLEWIRE_ENABLED);
+
+	write(fd, &send, 1);
+
+	/* We should timeout as there will be nothing to read (TX and RX no longer connected) */
+	if (poll(fds, 1, timeout) == 0) {
+		errx(1, "FAIL: timeout expected.");
+	}
+
+	warnx("PASS: Single wire disabled.");
+
+	close(fd);
+	exit(0);
+}
diff --git a/apps/px4/tests/tests.h b/apps/px4/tests/tests.h
index 46450d10b..cc3f5493a 100644
--- a/apps/px4/tests/tests.h
+++ b/apps/px4/tests/tests.h
@@ -93,6 +93,7 @@ extern int	test_uart_send(int argc, char *argv[]);
 extern int	test_sleep(int argc, char *argv[]);
 extern int	test_time(int argc, char *argv[]);
 extern int	test_uart_console(int argc, char *argv[]);
+extern int	test_hott_telemetry(int argc, char *argv[]);
 extern int	test_jig_voltages(int argc, char *argv[]);
 extern int	test_param(int argc, char *argv[]);
 extern int	test_bson(int argc, char *argv[]);
diff --git a/apps/px4/tests/tests_main.c b/apps/px4/tests/tests_main.c
index 5bedd257b..ad6828f20 100644
--- a/apps/px4/tests/tests_main.c
+++ b/apps/px4/tests/tests_main.c
@@ -100,6 +100,7 @@ const struct {
 	{"uart_baudchange",	test_uart_baudchange,	OPT_NOJIGTEST | OPT_NOALLTEST},
 	{"uart_send",		test_uart_send,	OPT_NOJIGTEST | OPT_NOALLTEST},
 	{"uart_console",	test_uart_console,	OPT_NOJIGTEST | OPT_NOALLTEST},
+	{"hott_telemetry",	test_hott_telemetry,	OPT_NOJIGTEST | OPT_NOALLTEST},
 	{"tone",		test_tone,	0},
 	{"sleep",		test_sleep,	OPT_NOJIGTEST},
 	{"time",		test_time,	OPT_NOJIGTEST},
diff --git a/nuttx/configs/px4fmu/nsh/appconfig b/nuttx/configs/px4fmu/nsh/appconfig
index 5a85a8877..a03d1d3dc 100644
--- a/nuttx/configs/px4fmu/nsh/appconfig
+++ b/nuttx/configs/px4fmu/nsh/appconfig
@@ -92,6 +92,7 @@ CONFIGURED_APPS += fixedwing_att_control
 CONFIGURED_APPS += fixedwing_pos_control
 CONFIGURED_APPS += position_estimator
 CONFIGURED_APPS += attitude_estimator_ekf
+CONFIGURED_APPS += hott_telemetry
 
 # Hacking tools
 #CONFIGURED_APPS += system/i2c
diff --git a/nuttx/configs/px4fmu/nsh/defconfig b/nuttx/configs/px4fmu/nsh/defconfig
index 696d19a6c..fd783dec5 100755
--- a/nuttx/configs/px4fmu/nsh/defconfig
+++ b/nuttx/configs/px4fmu/nsh/defconfig
@@ -201,6 +201,12 @@ CONFIG_STM32_TIM10=y
 CONFIG_STM32_TIM11=y
 
 #
+# Enable single wire support.  If this is not defined, then this mode cannot
+# be enabled.
+#
+CONFIG_STM32_USART_SINGLEWIRE=y
+
+#
 # We want the flash prefetch on for max performance.
 #
 STM32_FLASH_PREFETCH=y