Merged master

12 files changed, 113 insertions, 69 deletions

diff --git a/src/drivers/drv_rc_input.h b/src/drivers/drv_rc_input.h
index 6f773b82a..03f1dfbe5 100644
--- a/src/drivers/drv_rc_input.h
+++ b/src/drivers/drv_rc_input.h
@@ -89,7 +89,7 @@ struct rc_input_values {
 	/** number of channels actually being seen */
 	uint32_t		channel_count;
 
-	/** receive signal strength indicator (RSSI): < 0: Undefined, 0: no signal, 1000: full reception */
+	/** receive signal strength indicator (RSSI): < 0: Undefined, 0: no signal, 255: full reception */
 	int32_t			rssi;
 
 	/** Input source */
diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index 4e9daf910..9812ea497 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -1801,6 +1801,16 @@ PX4IO::print_status()
 		printf(" %u", io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_BASE + i));
 
 	printf("\n");
+
+	if (raw_inputs > 0) {
+		int frame_len = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_RC_DATA);
+		printf("RC data (PPM frame len) %u us\n", frame_len);
+
+		if ((frame_len - raw_inputs * 2000 - 3000) < 0) {
+			printf("WARNING  WARNING  WARNING! This RC receiver does not allow safe frame detection.\n");
+		}
+	}
+
 	uint16_t mapped_inputs = io_reg_get(PX4IO_PAGE_RC_INPUT, PX4IO_P_RC_VALID);
 	printf("mapped R/C inputs 0x%04x", mapped_inputs);
 
diff --git a/src/drivers/stm32/drv_hrt.c b/src/drivers/stm32/drv_hrt.c
index 36226c941..b7c9b89a4 100644
--- a/src/drivers/stm32/drv_hrt.c
+++ b/src/drivers/stm32/drv_hrt.c
@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Copyright (c) 2012, 2013 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
@@ -168,7 +168,7 @@
 # error HRT_TIMER_CLOCK must be greater than 1MHz
 #endif
 
-/*
+/**
  * Minimum/maximum deadlines.
  *
  * These are suitable for use with a 16-bit timer/counter clocked
@@ -276,12 +276,16 @@ static void		hrt_call_invoke(void);
  * Specific registers and bits used by PPM sub-functions
  */
 #ifdef HRT_PPM_CHANNEL
-/* 
+/*
  * If the timer hardware doesn't support GTIM_CCER_CCxNP, then we will work around it.
  *
  * Note that we assume that M3 means STM32F1 (since we don't really care about the F2).
  */
 # ifdef CONFIG_ARCH_CORTEXM3
+#  undef GTIM_CCER_CC1NP
+#  undef GTIM_CCER_CC2NP
+#  undef GTIM_CCER_CC3NP
+#  undef GTIM_CCER_CC4NP
 #  define GTIM_CCER_CC1NP 0
 #  define GTIM_CCER_CC2NP 0
 #  define GTIM_CCER_CC3NP 0
@@ -332,19 +336,21 @@ static void		hrt_call_invoke(void);
 /*
  * PPM decoder tuning parameters
  */
-# define PPM_MAX_PULSE_WIDTH	550		/* maximum width of a valid pulse */
-# define PPM_MIN_CHANNEL_VALUE	800		/* shortest valid channel signal */
-# define PPM_MAX_CHANNEL_VALUE	2200		/* longest valid channel signal */
-# define PPM_MIN_START		2500		/* shortest valid start gap */
+# define PPM_MIN_PULSE_WIDTH	200		/**< minimum width of a valid first pulse */
+# define PPM_MAX_PULSE_WIDTH	600		/**< maximum width of a valid first pulse */
+# define PPM_MIN_CHANNEL_VALUE	800		/**< shortest valid channel signal */
+# define PPM_MAX_CHANNEL_VALUE	2200		/**< longest valid channel signal */
+# define PPM_MIN_START		2300		/**< shortest valid start gap (only 2nd part of pulse) */
 
 /* decoded PPM buffer */
 #define PPM_MIN_CHANNELS	5
 #define PPM_MAX_CHANNELS	20
 
-/* Number of same-sized frames required to 'lock' */
-#define PPM_CHANNEL_LOCK	2		/* should be less than the input timeout */
+/** Number of same-sized frames required to 'lock' */
+#define PPM_CHANNEL_LOCK	4		/**< should be less than the input timeout */
 
 __EXPORT uint16_t ppm_buffer[PPM_MAX_CHANNELS];
+__EXPORT uint16_t ppm_frame_length = 0;
 __EXPORT unsigned ppm_decoded_channels = 0;
 __EXPORT uint64_t ppm_last_valid_decode = 0;
 
@@ -358,11 +364,12 @@ unsigned ppm_pulse_next;
 
 static uint16_t ppm_temp_buffer[PPM_MAX_CHANNELS];
 
-/* PPM decoder state machine */
+/** PPM decoder state machine */
 struct {
-	uint16_t	last_edge;	/* last capture time */
-	uint16_t	last_mark;	/* last significant edge */
-	unsigned	next_channel;
+	uint16_t	last_edge;	/**< last capture time */
+	uint16_t	last_mark;	/**< last significant edge */
+	uint16_t	frame_start;	/**< the frame width */
+	unsigned	next_channel;	/**< next channel index */
 	enum {
 		UNSYNCH = 0,
 		ARM,
@@ -384,7 +391,7 @@ static void	hrt_ppm_decode(uint32_t status);
 # define CCER_PPM	0
 #endif /* HRT_PPM_CHANNEL */
 
-/*
+/**
  * Initialise the timer we are going to use.
  *
  * We expect that we'll own one of the reduced-function STM32 general
@@ -430,7 +437,7 @@ hrt_tim_init(void)
 }
 
 #ifdef HRT_PPM_CHANNEL
-/*
+/**
  * Handle the PPM decoder state machine.
  */
 static void
@@ -447,7 +454,6 @@ hrt_ppm_decode(uint32_t status)
 
 	/* how long since the last edge? - this handles counter wrapping implicitely. */
 	width = count - ppm.last_edge;
-	ppm.last_edge = count;
 
 	ppm_edge_history[ppm_edge_next++] = width;
 
@@ -491,6 +497,7 @@ hrt_ppm_decode(uint32_t status)
 					ppm_buffer[i] = ppm_temp_buffer[i];
 
 				ppm_last_valid_decode = hrt_absolute_time();
+
 			}
 		}
 
@@ -500,29 +507,39 @@ hrt_ppm_decode(uint32_t status)
 		/* next edge is the reference for the first channel */
 		ppm.phase = ARM;
 
+		ppm.last_edge = count;
 		return;
 	}
 
 	switch (ppm.phase) {
 	case UNSYNCH:
 		/* we are waiting for a start pulse - nothing useful to do here */
-		return;
+		break;
 
 	case ARM:
 
 		/* we expect a pulse giving us the first mark */
-		if (width > PPM_MAX_PULSE_WIDTH)
-			goto error;		/* pulse was too long */
+		if (width < PPM_MIN_PULSE_WIDTH || width > PPM_MAX_PULSE_WIDTH)
+			goto error;		/* pulse was too short or too long */
 
 		/* record the mark timing, expect an inactive edge */
-		ppm.last_mark = count;
-		ppm.phase = INACTIVE;
-		return;
+		ppm.last_mark = ppm.last_edge;
+
+		/* frame length is everything including the start gap */
+		ppm_frame_length = (uint16_t)(ppm.last_edge - ppm.frame_start);
+		ppm.frame_start = ppm.last_edge;
+		ppm.phase = ACTIVE;
+		break;
 
 	case INACTIVE:
+
+		/* we expect a short pulse */
+		if (width < PPM_MIN_PULSE_WIDTH || width > PPM_MAX_PULSE_WIDTH)
+			goto error;		/* pulse was too short or too long */
+
 		/* this edge is not interesting, but now we are ready for the next mark */
 		ppm.phase = ACTIVE;
-		return;
+		break;
 
 	case ACTIVE:
 		/* determine the interval from the last mark */
@@ -543,10 +560,13 @@ hrt_ppm_decode(uint32_t status)
 			ppm_temp_buffer[ppm.next_channel++] = interval;
 
 		ppm.phase = INACTIVE;
-		return;
+		break;
 
 	}
 
+	ppm.last_edge = count;
+	return;
+
 	/* the state machine is corrupted; reset it */
 
 error:
@@ -557,7 +577,7 @@ error:
 }
 #endif /* HRT_PPM_CHANNEL */
 
-/*
+/**
  * Handle the compare interupt by calling the callout dispatcher
  * and then re-scheduling the next deadline.
  */
@@ -586,6 +606,7 @@ hrt_tim_isr(int irq, void *context)
 
 		hrt_ppm_decode(status);
 	}
+
 #endif
 
 	/* was this a timer tick? */
@@ -604,7 +625,7 @@ hrt_tim_isr(int irq, void *context)
 	return OK;
 }
 
-/*
+/**
  * Fetch a never-wrapping absolute time value in microseconds from
  * some arbitrary epoch shortly after system start.
  */
@@ -651,7 +672,7 @@ hrt_absolute_time(void)
 	return abstime;
 }
 
-/*
+/**
  * Convert a timespec to absolute time
  */
 hrt_abstime
@@ -665,7 +686,7 @@ ts_to_abstime(struct timespec *ts)
 	return result;
 }
 
-/*
+/**
  * Convert absolute time to a timespec.
  */
 void
@@ -676,7 +697,7 @@ abstime_to_ts(struct timespec *ts, hrt_abstime abstime)
 	ts->tv_nsec = abstime * 1000;
 }
 
-/*
+/**
  * Compare a time value with the current time.
  */
 hrt_abstime
@@ -691,7 +712,7 @@ hrt_elapsed_time(const volatile hrt_abstime *then)
 	return delta;
 }
 
-/*
+/**
  * Store the absolute time in an interrupt-safe fashion
  */
 hrt_abstime
@@ -706,7 +727,7 @@ hrt_store_absolute_time(volatile hrt_abstime *now)
 	return ts;
 }
 
-/*
+/**
  * Initalise the high-resolution timing module.
  */
 void
@@ -721,7 +742,7 @@ hrt_init(void)
 #endif
 }
 
-/*
+/**
  * Call callout(arg) after interval has elapsed.
  */
 void
@@ -734,7 +755,7 @@ hrt_call_after(struct hrt_call *entry, hrt_abstime delay, hrt_callout callout, v
 			  arg);
 }
 
-/*
+/**
  * Call callout(arg) at calltime.
  */
 void
@@ -743,7 +764,7 @@ hrt_call_at(struct hrt_call *entry, hrt_abstime calltime, hrt_callout callout, v
 	hrt_call_internal(entry, calltime, 0, callout, arg);
 }
 
-/*
+/**
  * Call callout(arg) every period.
  */
 void
@@ -762,13 +783,13 @@ hrt_call_internal(struct hrt_call *entry, hrt_abstime deadline, hrt_abstime inte
 	irqstate_t flags = irqsave();
 
 	/* if the entry is currently queued, remove it */
-        /* note that we are using a potentially uninitialised
-           entry->link here, but it is safe as sq_rem() doesn't
-           dereference the passed node unless it is found in the
-           list. So we potentially waste a bit of time searching the
-           queue for the uninitialised entry->link but we don't do
-           anything actually unsafe.
-        */
+	/* note that we are using a potentially uninitialised
+	   entry->link here, but it is safe as sq_rem() doesn't
+	   dereference the passed node unless it is found in the
+	   list. So we potentially waste a bit of time searching the
+	   queue for the uninitialised entry->link but we don't do
+	   anything actually unsafe.
+	*/
 	if (entry->deadline != 0)
 		sq_rem(&entry->link, &callout_queue);
 
@@ -782,7 +803,7 @@ hrt_call_internal(struct hrt_call *entry, hrt_abstime deadline, hrt_abstime inte
 	irqrestore(flags);
 }
 
-/*
+/**
  * If this returns true, the call has been invoked and removed from the callout list.
  *
  * Always returns false for repeating callouts.
@@ -793,7 +814,7 @@ hrt_called(struct hrt_call *entry)
 	return (entry->deadline == 0);
 }
 
-/*
+/**
  * Remove the entry from the callout list.
  */
 void
@@ -876,17 +897,18 @@ hrt_call_invoke(void)
 		/* if the callout has a non-zero period, it has to be re-entered */
 		if (call->period != 0) {
 			// re-check call->deadline to allow for
-			// callouts to re-schedule themselves 
+			// callouts to re-schedule themselves
 			// using hrt_call_delay()
 			if (call->deadline <= now) {
 				call->deadline = deadline + call->period;
 			}
+
 			hrt_call_enter(call);
 		}
 	}
 }
 
-/*
+/**
  * Reschedule the next timer interrupt.
  *
  * This routine must be called with interrupts disabled.
diff --git a/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c b/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c
index 52dac652b..e1280445b 100755
--- a/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c
+++ b/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c
@@ -52,11 +52,13 @@ PARAM_DEFINE_FLOAT(EKF_ATT_V3_Q3, 0.005f);
 PARAM_DEFINE_FLOAT(EKF_ATT_V3_Q4, 0.0f);
 
 /* gyro measurement noise */
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R0, 0.0008f);
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R1, 10000.0f);
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R2, 1.0f);
-/* accelerometer measurement noise */
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R3, 0.0f);
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R0, 0.0008f);
+/* accel measurement noise */
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R1, 10000.0f);
+/* mag measurement noise */
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R2, 100.0f);
+/* offset estimation - UNUSED */
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R3, 0.0f);
 
 /* offsets in roll, pitch and yaw of sensor plane and body */
 PARAM_DEFINE_FLOAT(ATT_ROLL_OFF3, 0.0f);
diff --git a/src/modules/px4iofirmware/controls.c b/src/modules/px4iofirmware/controls.c
index f630b6f2a..541eed0e1 100644
--- a/src/modules/px4iofirmware/controls.c
+++ b/src/modules/px4iofirmware/controls.c
@@ -50,7 +50,7 @@
 #define RC_CHANNEL_HIGH_THRESH		5000
 #define RC_CHANNEL_LOW_THRESH		-5000
 
-static bool	ppm_input(uint16_t *values, uint16_t *num_values);
+static bool	ppm_input(uint16_t *values, uint16_t *num_values, uint16_t *frame_len);
 
 static perf_counter_t c_gather_dsm;
 static perf_counter_t c_gather_sbus;
@@ -94,7 +94,7 @@ controls_tick() {
 	 * other.  Don't do that.
 	 */
 
-	/* receive signal strenght indicator (RSSI). 0 = no connection, 1000: perfect connection */
+	/* receive signal strenght indicator (RSSI). 0 = no connection, 255: perfect connection */
 	uint16_t rssi = 0;
 
 	perf_begin(c_gather_dsm);
@@ -108,7 +108,7 @@ controls_tick() {
 		else
 			r_status_flags &= ~PX4IO_P_STATUS_FLAGS_RC_DSM11;
 
-		rssi = 1000;
+		rssi = 255;
 	}
 	perf_end(c_gather_dsm);
 
@@ -125,11 +125,11 @@ controls_tick() {
 	 * disable the PPM decoder completely if we have S.bus signal.
 	 */
 	perf_begin(c_gather_ppm);
-	bool ppm_updated = ppm_input(r_raw_rc_values, &r_raw_rc_count);
+	bool ppm_updated = ppm_input(r_raw_rc_values, &r_raw_rc_count, &r_page_status[PX4IO_P_STATUS_RC_DATA]);
 	if (ppm_updated) {
 
 		/* XXX sample RSSI properly here */
-		rssi = 1000;
+		rssi = 255;
 
 		r_status_flags |= PX4IO_P_STATUS_FLAGS_RC_PPM;
 	}
@@ -321,7 +321,7 @@ controls_tick() {
 }
 
 static bool
-ppm_input(uint16_t *values, uint16_t *num_values)
+ppm_input(uint16_t *values, uint16_t *num_values, uint16_t *frame_len)
 {
 	bool result = false;
 
@@ -345,6 +345,10 @@ ppm_input(uint16_t *values, uint16_t *num_values)
 		/* clear validity */
 		ppm_last_valid_decode = 0;
 
+		/* store PPM frame length */
+		if (num_values)
+			*frame_len = ppm_frame_length;
+
 		/* good if we got any channels */
 		result = (*num_values > 0);
 	}
diff --git a/src/modules/px4iofirmware/protocol.h b/src/modules/px4iofirmware/protocol.h
index c10f0167c..e5bef6eb3 100644
--- a/src/modules/px4iofirmware/protocol.h
+++ b/src/modules/px4iofirmware/protocol.h
@@ -128,7 +128,8 @@
 #define PX4IO_P_STATUS_VSERVO			6	/* [2] servo rail voltage in mV */
 #define PX4IO_P_STATUS_VRSSI			7	/* [2] RSSI voltage */
 #define PX4IO_P_STATUS_PRSSI			8	/* [2] RSSI PWM value */
-#define PX4IO_P_STATUS_NRSSI			9	/* [2] Normalized RSSI value, 0: no reception, 1000: perfect reception */
+#define PX4IO_P_STATUS_NRSSI			9	/* [2] Normalized RSSI value, 0: no reception, 255: perfect reception */
+#define PX4IO_P_STATUS_RC_DATA			10	/* [1] + [2] Details about the RC source (PPM frame length, Spektrum protocol type) */
 
 /* array of post-mix actuator outputs, -10000..10000 */
 #define PX4IO_PAGE_ACTUATORS		2		/* 0..CONFIG_ACTUATOR_COUNT-1 */
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index 916b893c4..7ef1aa309 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -89,7 +89,9 @@ uint16_t		r_page_status[] = {
 	[PX4IO_P_STATUS_IBATT]			= 0,
 	[PX4IO_P_STATUS_VSERVO]			= 0,
 	[PX4IO_P_STATUS_VRSSI]			= 0,
-	[PX4IO_P_STATUS_PRSSI]			= 0
+	[PX4IO_P_STATUS_PRSSI]			= 0,
+	[PX4IO_P_STATUS_NRSSI]			= 0,
+	[PX4IO_P_STATUS_RC_DATA]		= 0
 };
 
 /**
diff --git a/src/modules/px4iofirmware/sbus.c b/src/modules/px4iofirmware/sbus.c
index 6aca2bd11..11ccd7356 100644
--- a/src/modules/px4iofirmware/sbus.c
+++ b/src/modules/px4iofirmware/sbus.c
@@ -280,7 +280,7 @@ sbus_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values, uint
 		*rssi = 100; // XXX magic number indicating bad signal, but not a signal loss (yet)
 	}
 
-	*rssi = 1000;
+	*rssi = 255;
 
 	return true;
 }
diff --git a/src/modules/sdlog2/sdlog2.c b/src/modules/sdlog2/sdlog2.c
index 2adb13f5c..e94b1e13c 100644
--- a/src/modules/sdlog2/sdlog2.c
+++ b/src/modules/sdlog2/sdlog2.c
@@ -1193,6 +1193,7 @@ int sdlog2_thread_main(int argc, char *argv[])
 				log_msg.msg_type = LOG_RC_MSG;
 				/* Copy only the first 8 channels of 14 */
 				memcpy(log_msg.body.log_RC.channel, buf.rc.chan, sizeof(log_msg.body.log_RC.channel));
+				log_msg.body.log_RC.channel_count = buf.rc.chan_count;
 				LOGBUFFER_WRITE_AND_COUNT(RC);
 			}
 
diff --git a/src/modules/sdlog2/sdlog2_messages.h b/src/modules/sdlog2/sdlog2_messages.h
index 90093a407..ab4dc9b00 100644
--- a/src/modules/sdlog2/sdlog2_messages.h
+++ b/src/modules/sdlog2/sdlog2_messages.h
@@ -159,6 +159,7 @@ struct log_STAT_s {
 #define LOG_RC_MSG 11
 struct log_RC_s {
 	float channel[8];
+	uint8_t channel_count;
 };
 
 /* --- OUT0 - ACTUATOR_0 OUTPUT --- */
@@ -281,7 +282,7 @@ static const struct log_format_s log_formats[] = {
 	LOG_FORMAT(GPS, "QBffLLfffff", "GPSTime,FixType,EPH,EPV,Lat,Lon,Alt,VelN,VelE,VelD,Cog"),
 	LOG_FORMAT(ATTC, "ffff", "Roll,Pitch,Yaw,Thrust"),
 	LOG_FORMAT(STAT, "BBBfffBB", "MainState,NavState,ArmState,BatV,BatC,BatRem,BatWarn,Landed"),
-	LOG_FORMAT(RC, "ffffffff", "Ch0,Ch1,Ch2,Ch3,Ch4,Ch5,Ch6,Ch7"),
+	LOG_FORMAT(RC, "ffffffffB", "Ch0,Ch1,Ch2,Ch3,Ch4,Ch5,Ch6,Ch7,Count"),
 	LOG_FORMAT(OUT0, "ffffffff", "Out0,Out1,Out2,Out3,Out4,Out5,Out6,Out7"),
 	LOG_FORMAT(AIRS, "ff", "IndSpeed,TrueSpeed"),
 	LOG_FORMAT(ARSP, "fff", "RollRateSP,PitchRateSP,YawRateSP"),
diff --git a/src/modules/sensors/sensor_params.c b/src/modules/sensors/sensor_params.c
index c54128cb5..763723554 100644
--- a/src/modules/sensors/sensor_params.c
+++ b/src/modules/sensors/sensor_params.c
@@ -104,49 +104,49 @@ PARAM_DEFINE_FLOAT(RC1_MIN, 1000.0f);
 PARAM_DEFINE_FLOAT(RC1_TRIM, 1500.0f);
 PARAM_DEFINE_FLOAT(RC1_MAX, 2000.0f);
 PARAM_DEFINE_FLOAT(RC1_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC1_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC1_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC2_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC2_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC2_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC2_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC2_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC2_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC3_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC3_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC3_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC3_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC3_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC3_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC4_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC4_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC4_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC4_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC4_DZ, 30.0f);
+PARAM_DEFINE_FLOAT(RC4_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC5_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC5_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC5_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC5_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC5_DZ,  0.0f);
+PARAM_DEFINE_FLOAT(RC5_DZ,  10.0f);
 
 PARAM_DEFINE_FLOAT(RC6_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC6_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC6_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC6_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC6_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC6_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC7_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC7_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC7_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC7_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC7_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC7_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC8_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC8_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC8_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC8_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC8_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC8_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC9_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC9_TRIM, 1500);
diff --git a/src/modules/systemlib/ppm_decode.h b/src/modules/systemlib/ppm_decode.h
index 6c5e15345..5a1ad84da 100644
--- a/src/modules/systemlib/ppm_decode.h
+++ b/src/modules/systemlib/ppm_decode.h
@@ -57,6 +57,7 @@ __BEGIN_DECLS
  * PPM decoder state
  */
 __EXPORT extern uint16_t	ppm_buffer[PPM_MAX_CHANNELS];	/**< decoded PPM channel values */
+__EXPORT extern uint16_t	ppm_frame_length;				/**< length of the decoded PPM frame (includes gap) */
 __EXPORT extern unsigned	ppm_decoded_channels;	/**< count of decoded channels */
 __EXPORT extern hrt_abstime	ppm_last_valid_decode;	/**< timestamp of the last valid decode */