Merge remote-tracking branch 'px4/beta' into fix_mission_dive

Conflicts:
	src/modules/navigator/navigator_main.cpp

8 files changed, 86 insertions, 79 deletions

diff --git a/src/drivers/drv_pwm_output.h b/src/drivers/drv_pwm_output.h
index c3eea310f..7a93e513e 100644
--- a/src/drivers/drv_pwm_output.h
+++ b/src/drivers/drv_pwm_output.h
@@ -160,7 +160,7 @@ ORB_DECLARE(output_pwm);
 
 #define DSM2_BIND_PULSES 3	/* DSM_BIND_START ioctl parameter, pulses required to start dsm2 pairing */
 #define DSMX_BIND_PULSES 7	/* DSM_BIND_START ioctl parameter, pulses required to start dsmx pairing */
-#define DSMX8_BIND_PULSES 10	/* DSM_BIND_START ioctl parameter, pulses required to start 8 or more channel dsmx pairing */
+#define DSMX8_BIND_PULSES 10 	/* DSM_BIND_START ioctl parameter, pulses required to start 8 or more channel dsmx pairing */
 
 /** power up DSM receiver */
 #define DSM_BIND_POWER_UP _IOC(_PWM_SERVO_BASE, 11)
diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index efcf4d12b..7c7b3dcb7 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -244,8 +244,7 @@ private:
 	volatile int		_task;			///< worker task id
 	volatile bool		_task_should_exit;	///< worker terminate flag
 
-	int			_mavlink_fd;		///< mavlink file descriptor. This is opened by class instantiation and Doesn't appear to be usable in main thread.
-	int			_thread_mavlink_fd;	///< mavlink file descriptor for thread.
+	int			_mavlink_fd;		///< mavlink file descriptor.
 
 	perf_counter_t		_perf_update;		///<local performance counter for status updates
 	perf_counter_t		_perf_write;		///<local performance counter for PWM control writes
@@ -474,7 +473,6 @@ PX4IO::PX4IO(device::Device *interface) :
 	_task(-1),
 	_task_should_exit(false),
 	_mavlink_fd(-1),
-	_thread_mavlink_fd(-1),
 	_perf_update(perf_alloc(PC_ELAPSED, "io update")),
 	_perf_write(perf_alloc(PC_ELAPSED, "io write")),
 	_perf_chan_count(perf_alloc(PC_COUNT, "io rc #")),
@@ -507,9 +505,6 @@ PX4IO::PX4IO(device::Device *interface) :
 	/* we need this potentially before it could be set in task_main */
 	g_dev = this;
 
-	/* open MAVLink text channel */
-	_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
-
 	_debug_enabled = false;
 	_servorail_status.rssi_v = 0;
 }
@@ -785,7 +780,7 @@ PX4IO::task_main()
 	hrt_abstime poll_last = 0;
 	hrt_abstime orb_check_last = 0;
 
-	_thread_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
+	_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
 
 	/*
 	 * Subscribe to the appropriate PWM output topic based on whether we are the
@@ -880,6 +875,10 @@ PX4IO::task_main()
 			/* run at 5Hz */
 			orb_check_last = now;
 
+			/* try to claim the MAVLink log FD */
+			if (_mavlink_fd < 0)
+				_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);
+
 			/* check updates on uORB topics and handle it */
 			bool updated = false;
 
@@ -1275,16 +1274,14 @@ void
 PX4IO::dsm_bind_ioctl(int dsmMode)
 {
 	if (!(_status & PX4IO_P_STATUS_FLAGS_SAFETY_OFF)) {
-		/* 0: dsm2, 1:dsmx */
-		if ((dsmMode == 0) || (dsmMode == 1)) {
-			mavlink_log_info(_thread_mavlink_fd, "[IO] binding dsm%s rx", (dsmMode == 0) ? "2" : ((dsmMode == 1) ? "x" : "x8"));
-			ioctl(nullptr, DSM_BIND_START, (dsmMode == 0) ? DSM2_BIND_PULSES : ((dsmMode == 1) ? DSMX_BIND_PULSES : DSMX8_BIND_PULSES));
-		} else {
-			mavlink_log_info(_thread_mavlink_fd, "[IO] invalid dsm bind mode, bind request rejected");
-		}
+		mavlink_log_info(_mavlink_fd, "[IO] binding DSM%s RX", (dsmMode == 0) ? "2" : ((dsmMode == 1) ? "-X" : "-X8"));
+		int ret = ioctl(nullptr, DSM_BIND_START, (dsmMode == 0) ? DSM2_BIND_PULSES : ((dsmMode == 1) ? DSMX_BIND_PULSES : DSMX8_BIND_PULSES));
+
+		if (ret)
+			mavlink_log_critical(_mavlink_fd, "binding failed.");
 
 	} else {
-		mavlink_log_info(_thread_mavlink_fd, "[IO] system armed, bind request rejected");
+		mavlink_log_info(_mavlink_fd, "[IO] system armed, bind request rejected");
 	}
 }
 
@@ -2115,14 +2112,24 @@ PX4IO::ioctl(file * /*filep*/, int cmd, unsigned long arg)
 		break;
 
 	case DSM_BIND_START:
-		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_down);
-		usleep(500000);
-		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_set_rx_out);
-		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_up);
-		usleep(72000);
-		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_send_pulses | (arg << 4));
-		usleep(50000);
-		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_reinit_uart);
+
+		/* only allow DSM2, DSM-X and DSM-X with more than 7 channels */
+		if (arg == DSM2_BIND_PULSES ||
+		    arg == DSMX_BIND_PULSES ||
+		    arg == DSMX8_BIND_PULSES) {
+			io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_down);
+			usleep(500000);
+			io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_set_rx_out);
+			io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_up);
+			usleep(72000);
+			io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_send_pulses | (arg << 4));
+			usleep(50000);
+			io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_reinit_uart);
+
+			ret = OK;
+		} else {
+			ret = -EINVAL;
+		}
 		break;
 
 	case DSM_BIND_POWER_UP:
@@ -2615,7 +2622,7 @@ bind(int argc, char *argv[])
 #endif
 
 	if (argc < 3)
-		errx(0, "needs argument, use dsm2 or dsmx");
+		errx(0, "needs argument, use dsm2, dsmx or dsmx8");
 
 	if (!strcmp(argv[2], "dsm2"))
 		pulses = DSM2_BIND_PULSES;
@@ -2624,7 +2631,7 @@ bind(int argc, char *argv[])
 	else if (!strcmp(argv[2], "dsmx8"))
 		pulses = DSMX8_BIND_PULSES;
 	else 
-		errx(1, "unknown parameter %s, use dsm2 or dsmx", argv[2]);
+		errx(1, "unknown parameter %s, use dsm2, dsmx or dsmx8", argv[2]);
 	// Test for custom pulse parameter
 	if (argc > 3)
 		pulses = atoi(argv[3]);
diff --git a/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp b/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
index 1feb539b9..ed57e0d34 100644
--- a/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
+++ b/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
@@ -233,7 +233,6 @@ private:
 		float speedrate_p;
 
 		float land_slope_angle;
-		float land_slope_length;
 		float land_H1_virt;
 		float land_flare_alt_relative;
 		float land_thrust_lim_alt_relative;
@@ -278,7 +277,6 @@ private:
 		param_t speedrate_p;
 
 		param_t land_slope_angle;
-		param_t land_slope_length;
 		param_t land_H1_virt;
 		param_t land_flare_alt_relative;
 		param_t land_thrust_lim_alt_relative;
@@ -427,7 +425,6 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_parameter_handles.throttle_land_max = param_find("FW_THR_LND_MAX");
 
 	_parameter_handles.land_slope_angle = param_find("FW_LND_ANG");
-	_parameter_handles.land_slope_length = param_find("FW_LND_SLLR");
 	_parameter_handles.land_H1_virt = param_find("FW_LND_HVIRT");
 	_parameter_handles.land_flare_alt_relative = param_find("FW_LND_FLALT");
 	_parameter_handles.land_thrust_lim_alt_relative = param_find("FW_LND_TLALT");
@@ -516,7 +513,6 @@ FixedwingPositionControl::parameters_update()
 	param_get(_parameter_handles.speedrate_p, &(_parameters.speedrate_p));
 
 	param_get(_parameter_handles.land_slope_angle, &(_parameters.land_slope_angle));
-	param_get(_parameter_handles.land_slope_length, &(_parameters.land_slope_length));
 	param_get(_parameter_handles.land_H1_virt, &(_parameters.land_H1_virt));
 	param_get(_parameter_handles.land_flare_alt_relative, &(_parameters.land_flare_alt_relative));
 	param_get(_parameter_handles.land_thrust_lim_alt_relative, &(_parameters.land_thrust_lim_alt_relative));
@@ -885,8 +881,10 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 			float airspeed_land = 1.3f * _parameters.airspeed_min;
 			float airspeed_approach = 1.3f * _parameters.airspeed_min;
 
-			float L_wp_distance = get_distance_to_next_waypoint(prev_wp(0), prev_wp(1), curr_wp(0), curr_wp(1)) * _parameters.land_slope_length;
+			/* Calculate distance (to landing waypoint) and altitude of last ordinary waypoint L */
+			float L_wp_distance = get_distance_to_next_waypoint(prev_wp(0), prev_wp(1), curr_wp(0), curr_wp(1));
 			float L_altitude = landingslope.getLandingSlopeAbsoluteAltitude(L_wp_distance, _pos_sp_triplet.current.alt);
+
 			float bearing_airplane_currwp = get_bearing_to_next_waypoint(current_position(0), current_position(1), curr_wp(0), curr_wp(1));
 			float landing_slope_alt_desired = landingslope.getLandingSlopeAbsoluteAltitudeSave(wp_distance, bearing_lastwp_currwp, bearing_airplane_currwp, _pos_sp_triplet.current.alt);
 
@@ -931,38 +929,24 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 				//warnx("Landing:  flare, _global_pos.alt  %.1f, flare_curve_alt %.1f, flare_curve_alt_last %.1f, flare_length %.1f, wp_distance %.1f", _global_pos.alt, flare_curve_alt, flare_curve_alt_last, flare_length, wp_distance);
 
 				flare_curve_alt_last = flare_curve_alt;
-
-			} else if (wp_distance < L_wp_distance) {
-
-				/* minimize speed to approach speed, stay on landing slope */
-				_tecs.update_pitch_throttle(_R_nb, _att.pitch, _global_pos.alt, landing_slope_alt_desired, calculate_target_airspeed(airspeed_approach),
-							    _airspeed.indicated_airspeed_m_s, eas2tas,
-							    false, flare_pitch_angle_rad,
-							    _parameters.throttle_min, _parameters.throttle_max, _parameters.throttle_cruise,
-							    math::radians(_parameters.pitch_limit_min), math::radians(_parameters.pitch_limit_max));
-				//warnx("Landing: stay on slope, alt_desired: %.1f (wp_distance: %.1f), calculate_target_airspeed(airspeed_land) %.1f, horizontal_slope_displacement %.1f, d1 %.1f, flare_length %.1f", landing_slope_alt_desired, wp_distance, calculate_target_airspeed(airspeed_land), horizontal_slope_displacement, d1, flare_length);
-
-				if (!land_onslope) {
-
-					mavlink_log_info(_mavlink_fd, "#audio: Landing, on slope");
-					land_onslope = true;
-				}
-
 			} else {
 
 				 /* intersect glide slope:
-				 * if current position is higher or within 10m of slope follow the glide slope
-				 * if current position is below slope -10m continue on maximum of previous wp altitude or L_altitude until the intersection with the slope
-				 * */
+				  * minimize speed to approach speed
+				  * if current position is higher or within 10m of slope follow the glide slope
+				  * if current position is below slope -10m continue on maximum of previous wp altitude or L_altitude until the intersection with the slope
+				  * */
 				float altitude_desired = _global_pos.alt;
 				if (_global_pos.alt > landing_slope_alt_desired - 10.0f) {
 					/* stay on slope */
 					altitude_desired = landing_slope_alt_desired;
-					//warnx("Landing: before L, stay on landing slope, alt_desired: %.1f (wp_distance: %.1f, L_wp_distance %.1f), calculate_target_airspeed(airspeed_land) %.1f, horizontal_slope_displacement %.1f", altitude_desired, wp_distance, L_wp_distance, calculate_target_airspeed(airspeed_land), horizontal_slope_displacement);
+					if (!land_onslope) {
+						mavlink_log_info(_mavlink_fd, "#audio: Landing, on slope");
+						land_onslope = true;
+					}
 				} else {
 					/* continue horizontally */
 					altitude_desired =  math::max(_global_pos.alt, L_altitude);
-					//warnx("Landing: before L,continue at: %.4f, (landing_slope_alt_desired %.4f, wp_distance: %.4f, L_altitude: %.4f L_wp_distance: %.4f)", altitude_desired, landing_slope_alt_desired, wp_distance, L_altitude, L_wp_distance);
 				}
 
 				_tecs.update_pitch_throttle(_R_nb, _att.pitch, _global_pos.alt, altitude_desired, calculate_target_airspeed(airspeed_approach),
diff --git a/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c b/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c
index 62a340e90..0909135e1 100644
--- a/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c
+++ b/src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c
@@ -349,13 +349,6 @@ PARAM_DEFINE_FLOAT(FW_T_SRATE_P, 0.05f);
 PARAM_DEFINE_FLOAT(FW_LND_ANG, 5.0f);
 
 /**
- * Landing slope length
- *
- * @group L1 Control
- */
-PARAM_DEFINE_FLOAT(FW_LND_SLLR, 0.9f);
-
-/**
  *
  *
  * @group L1 Control
diff --git a/src/modules/mc_pos_control/mc_pos_control_main.cpp b/src/modules/mc_pos_control/mc_pos_control_main.cpp
index b06655385..b4bac53d6 100644
--- a/src/modules/mc_pos_control/mc_pos_control_main.cpp
+++ b/src/modules/mc_pos_control/mc_pos_control_main.cpp
@@ -730,7 +730,6 @@ MulticopterPositionControl::task_main()
 			} else {
 				/* run position & altitude controllers, calculate velocity setpoint */
 				math::Vector<3> pos_err;
-				float err_x, err_y;
 				get_vector_to_next_waypoint_fast(_global_pos.lat, _global_pos.lon, _lat_sp, _lon_sp, &pos_err.data[0], &pos_err.data[1]);
 				pos_err(2) = -(_alt_sp - alt);
 
diff --git a/src/modules/navigator/navigator_main.cpp b/src/modules/navigator/navigator_main.cpp
index f59663ca0..7d122c26d 100644
--- a/src/modules/navigator/navigator_main.cpp
+++ b/src/modules/navigator/navigator_main.cpp
@@ -853,7 +853,7 @@ Navigator::task_main()
 
 		/* notify user about state changes */
 		if (myState != prevState) {
-			mavlink_log_info(_mavlink_fd, "[navigator] nav state: %s", nav_states_str[myState]);
+			mavlink_log_info(_mavlink_fd, "#audio: navigation state: %s", nav_states_str[myState]);
 			prevState = myState;
 
 			/* reset time counter on state changes */
@@ -1061,11 +1061,11 @@ Navigator::start_loiter()
 		/* use current altitude if above min altitude set by parameter */
 		if (_global_pos.alt < min_alt_amsl && !_vstatus.is_rotary_wing) {
 			_pos_sp_triplet.current.alt = min_alt_amsl;
-			mavlink_log_info(_mavlink_fd, "[navigator] loiter %.1fm higher", (double)(min_alt_amsl - _global_pos.alt));
+			mavlink_log_info(_mavlink_fd, "#audio: loiter %.1fm higher", (double)(min_alt_amsl - _global_pos.alt));
 
 		} else {
 			_pos_sp_triplet.current.alt = _global_pos.alt;
-			mavlink_log_info(_mavlink_fd, "[navigator] loiter at current altitude");
+			mavlink_log_info(_mavlink_fd, "#audio: loiter at current altitude");
 		}
 
 	}
@@ -1162,14 +1162,14 @@ Navigator::set_mission_item()
 		}
 
 		if (_do_takeoff) {
-			mavlink_log_info(_mavlink_fd, "[navigator] takeoff to %.1fm above home", (double)(_pos_sp_triplet.current.alt - _home_pos.alt));
+			mavlink_log_info(_mavlink_fd, "#audio: takeoff to %.1fm above home", (double)(_pos_sp_triplet.current.alt - _home_pos.alt));
 
 		} else {
 			if (onboard) {
-				mavlink_log_info(_mavlink_fd, "[navigator] heading to onboard WP %d", index);
+				mavlink_log_info(_mavlink_fd, "#audio: heading to onboard WP %d", index);
 
 			} else {
-				mavlink_log_info(_mavlink_fd, "[navigator] heading to offboard WP %d", index);
+				mavlink_log_info(_mavlink_fd, "#audio: heading to offboard WP %d", index);
 			}
 		}
 
@@ -1318,7 +1318,7 @@ Navigator::set_rtl_item()
 
 			_pos_sp_triplet.next.valid = false;
 
-			mavlink_log_info(_mavlink_fd, "[navigator] RTL: climb to %.1fm above home", (double)(climb_alt - _home_pos.alt));
+			mavlink_log_info(_mavlink_fd, "#audio: RTL: climb to %.1fm above home", (double)(climb_alt - _home_pos.alt));
 			break;
 		}
 
@@ -1344,7 +1344,7 @@ Navigator::set_rtl_item()
 
 			_pos_sp_triplet.next.valid = false;
 
-			mavlink_log_info(_mavlink_fd, "[navigator] RTL: return at %.1fm above home", (double)(_mission_item.altitude - _home_pos.alt));
+			mavlink_log_info(_mavlink_fd, "#audio: RTL: return at %.1fm above home", (double)(_mission_item.altitude - _home_pos.alt));
 			break;
 		}
 
@@ -1371,12 +1371,12 @@ Navigator::set_rtl_item()
 
 			_pos_sp_triplet.next.valid = false;
 
-			mavlink_log_info(_mavlink_fd, "[navigator] RTL: descend to %.1fm above home", (double)(_mission_item.altitude - _home_pos.alt));
+			mavlink_log_info(_mavlink_fd, "#audio: RTL: descend to %.1fm above home", (double)(_mission_item.altitude - _home_pos.alt));
 			break;
 		}
 
 	default: {
-			mavlink_log_critical(_mavlink_fd, "[navigator] error: unknown RTL state: %d", _rtl_state);
+			mavlink_log_critical(_mavlink_fd, "#audio: [navigator] error: unknown RTL state: %d", _rtl_state);
 			start_loiter();
 			break;
 		}
@@ -1525,7 +1525,7 @@ Navigator::check_mission_item_reached()
 			_time_first_inside_orbit = now;
 
 			if (_mission_item.time_inside > 0.01f) {
-				mavlink_log_info(_mavlink_fd, "[navigator] waypoint reached, wait for %.1fs", (double)_mission_item.time_inside);
+				mavlink_log_info(_mavlink_fd, "#audio: waypoint reached, wait for %.1fs", (double)_mission_item.time_inside);
 			}
 		}
 
@@ -1550,7 +1550,7 @@ Navigator::on_mission_item_reached()
 		if (_do_takeoff) {
 			/* takeoff completed */
 			_do_takeoff = false;
-			mavlink_log_info(_mavlink_fd, "[navigator] takeoff completed");
+			mavlink_log_info(_mavlink_fd, "#audio: takeoff completed");
 
 		} else {
 			/* advance by one mission item */
diff --git a/src/modules/px4iofirmware/dsm.c b/src/modules/px4iofirmware/dsm.c
index 60eda2319..d3f365822 100644
--- a/src/modules/px4iofirmware/dsm.c
+++ b/src/modules/px4iofirmware/dsm.c
@@ -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
@@ -162,6 +162,7 @@ dsm_guess_format(bool reset)
 		0xff,	/* 8 channels (DX8) */
 		0x1ff,	/* 9 channels (DX9, etc.) */
 		0x3ff,	/* 10 channels (DX10) */
+		0x1fff,	/* 13 channels (DX10t) */
 		0x3fff	/* 18 channels (DX10) */
 	};
 	unsigned votes10 = 0;
@@ -368,11 +369,25 @@ dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values)
 		if (channel >= *num_values)
 			*num_values = channel + 1;
 
-		/* convert 0-1024 / 0-2048 values to 1000-2000 ppm encoding in a very sloppy fashion */
-		if (dsm_channel_shift == 11)
-			value /= 2;
+		/* convert 0-1024 / 0-2048 values to 1000-2000 ppm encoding. */
+		if (dsm_channel_shift == 10)
+			value *= 2;
 
-		value += 998;
+		/*
+		 * Spektrum scaling is special. There are these basic considerations
+		 *
+		 *   * Midpoint is 1520 us
+		 *   * 100% travel channels are +- 400 us
+		 *
+		 * We obey the original Spektrum scaling (so a default setup will scale from
+		 * 1100 - 1900 us), but we do not obey the weird 1520 us center point
+		 * and instead (correctly) center the center around 1500 us. This is in order
+		 * to get something useful without requiring the user to calibrate on a digital
+		 * link for no reason.
+		 */
+
+		/* scaled integer for decent accuracy while staying efficient */
+		value = ((((int)value - 1024) * 1000) / 1700) + 1500;
 
 		/*
 		 * Store the decoded channel into the R/C input buffer, taking into
@@ -400,6 +415,15 @@ dsm_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values)
 		values[channel] = value;
 	}
 
+	/*
+	 * Spektrum likes to send junk in higher channel numbers to fill
+	 * their packets. We don't know about a 13 channel model in their TX
+	 * lines, so if we get a channel count of 13, we'll return 12 (the last
+	 * data index that is stable).
+	 */
+	if (*num_values == 13)
+		*num_values = 12;
+
 	if (dsm_channel_shift == 11) {
 		/* Set the 11-bit data indicator */
 		*num_values |= 0x8000;
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index 1335f52e1..97d25bbfa 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -566,7 +566,7 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 			break;
 
 		case PX4IO_P_SETUP_DSM:
-			dsm_bind(value & 0x0f, (value >> 4) & 7);
+			dsm_bind(value & 0x0f, (value >> 4) & 0xF);
 			break;
 
 		default: