crsf.cpp File Reference

#include <drivers/drv_hrt.h>
#include <termios.h>
#include <string.h>
#include <unistd.h>
#include "crsf.h"
#include "common_rc.h"

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Classes
struct	crsf_payload_RC_channels_packed_t

Macros
#define	CRSF_DEBUG(...)
#define	CRSF_VERBOSE(...)
#define	MIN(a, b)   (((a)<(b))?(a):(b))
#define	MAX(a, b)   (((a)>(b))?(a):(b))
#define	CRSF_BAUDRATE   420000
#define	CRSF_SYNC_BYTE   0xC8

Enumerations
enum	crsf_frame_type_t : uint8_t {   crsf_frame_type_t::gps = 0x02, crsf_frame_type_t::battery_sensor = 0x08, crsf_frame_type_t::link_statistics = 0x14, crsf_frame_type_t::rc_channels_packed = 0x16,   crsf_frame_type_t::attitude = 0x1E, crsf_frame_type_t::flight_mode = 0x21, crsf_frame_type_t::device_ping = 0x28, crsf_frame_type_t::device_info = 0x29,   crsf_frame_type_t::parameter_settings_entry = 0x2B, crsf_frame_type_t::parameter_read = 0x2C, crsf_frame_type_t::parameter_write = 0x2D, crsf_frame_type_t::command = 0x32 }
enum	crsf_payload_size_t : uint8_t {   crsf_payload_size_t::gps = 15, crsf_payload_size_t::battery_sensor = 8, crsf_payload_size_t::link_statistics = 10, crsf_payload_size_t::rc_channels = 22,   crsf_payload_size_t::attitude = 6 }
enum	crsf_address_t : uint8_t {   crsf_address_t::broadcast = 0x00, crsf_address_t::usb = 0x10, crsf_address_t::tbs_core_pnp_pro = 0x80, crsf_address_t::reserved1 = 0x8A,   crsf_address_t::current_sensor = 0xC0, crsf_address_t::gps = 0xC2, crsf_address_t::tbs_blackbox = 0xC4, crsf_address_t::flight_controller = 0xC8,   crsf_address_t::reserved2 = 0xCA, crsf_address_t::race_tag = 0xCC, crsf_address_t::radio_transmitter = 0xEA, crsf_address_t::crsf_receiver = 0xEC,   crsf_address_t::crsf_transmitter = 0xEE }
enum	crsf_parser_state_t : uint8_t { crsf_parser_state_t::unsynced = 0, crsf_parser_state_t::synced }

Functions
static bool	crsf_parse_buffer (uint16_t *values, uint16_t *num_values, uint16_t max_channels)
	parse the current crsf_frame buffer More...
static uint8_t	crc8_dvb_s2 (uint8_t crc, uint8_t a)
static uint8_t	crc8_dvb_s2_buf (uint8_t *buf, int len)
uint8_t	crsf_frame_CRC (const crsf_frame_t &frame)
int	crsf_config (int uart_fd)
	Configure an UART port to be used for CRSF. More...
static uint16_t	convert_channel_value (unsigned chan_value)
	Convert from RC to PWM value. More...
bool	crsf_parse (const uint64_t now, const uint8_t *frame, unsigned len, uint16_t *values, uint16_t *num_values, uint16_t max_channels)
	Parse the CRSF protocol and extract RC channel data. More...
static void	write_uint8_t (uint8_t *buf, int &offset, uint8_t value)
	write an uint8_t value to a buffer at a given offset and increment the offset More...
static void	write_uint16_t (uint8_t *buf, int &offset, uint16_t value)
	write an uint16_t value to a buffer at a given offset and increment the offset More...
static void	write_uint24_t (uint8_t *buf, int &offset, int value)
	write an uint24_t value to a buffer at a given offset and increment the offset More...
static void	write_int32_t (uint8_t *buf, int &offset, int32_t value)
	write an int32_t value to a buffer at a given offset and increment the offset More...
static void	write_frame_header (uint8_t *buf, int &offset, crsf_frame_type_t type, uint8_t payload_size)
static void	write_frame_crc (uint8_t *buf, int &offset, int buf_size)
bool	crsf_send_telemetry_battery (int uart_fd, uint16_t voltage, uint16_t current, int fuel, uint8_t remaining)
	Send telemetry battery information. More...
bool	crsf_send_telemetry_gps (int uart_fd, int32_t latitude, int32_t longitude, uint16_t groundspeed, uint16_t gps_heading, uint16_t altitude, uint8_t num_satellites)
	Send telemetry GPS information. More...
bool	crsf_send_telemetry_attitude (int uart_fd, int16_t pitch, int16_t roll, int16_t yaw)
	Send telemetry Attitude information. More...
bool	crsf_send_telemetry_flight_mode (int uart_fd, const char *flight_mode)
	Send telemetry Flight Mode information. More...

Variables
static crsf_frame_t &	crsf_frame = rc_decode_buf.crsf_frame
static unsigned	current_frame_position = 0
static crsf_parser_state_t	parser_state = crsf_parser_state_t::unsynced

Macro Definition Documentation

CRSF_BAUDRATE

#define CRSF_BAUDRATE   420000

Definition at line 58 of file crsf.cpp.

Referenced by crsf_config().

CRSF_DEBUG

#define CRSF_DEBUG

(

...

)

Definition at line 37 of file crsf.cpp.

Referenced by crsf_parse(), and crsf_parse_buffer().

CRSF_SYNC_BYTE

#define CRSF_SYNC_BYTE   0xC8

Definition at line 60 of file crsf.cpp.

Referenced by write_frame_header().

CRSF_VERBOSE

#define CRSF_VERBOSE

(

...

)

Definition at line 43 of file crsf.cpp.

Referenced by crsf_parse_buffer().

MAX

#define MAX	(		a,
			b
	)		(((a)>(b))?(a):(b))

Definition at line 55 of file crsf.cpp.

MIN

#define MIN	(		a,
			b
	)		(((a)<(b))?(a):(b))

Definition at line 54 of file crsf.cpp.

Referenced by crsf_parse(), and crsf_parse_buffer().

Enumeration Type Documentation

crsf_address_t

enum crsf_address_t : uint8_t

strong

Enumerator
broadcast
usb
tbs_core_pnp_pro
reserved1
current_sensor
gps
tbs_blackbox
flight_controller
reserved2
race_tag
radio_transmitter
crsf_receiver
crsf_transmitter

Definition at line 88 of file crsf.cpp.

crsf_frame_type_t

enum crsf_frame_type_t : uint8_t

strong

Enumerator
gps
battery_sensor
link_statistics
rc_channels_packed
attitude
flight_mode
device_ping
device_info
parameter_settings_entry
parameter_read
parameter_write
command

Definition at line 62 of file crsf.cpp.

crsf_parser_state_t

enum crsf_parser_state_t : uint8_t

strong

Enumerator
unsynced
synced

Definition at line 127 of file crsf.cpp.

crsf_payload_size_t

enum crsf_payload_size_t : uint8_t

strong

Enumerator
gps
battery_sensor
link_statistics
rc_channels	11 bits per channel * 16 channels = 22 bytes.
attitude

Definition at line 79 of file crsf.cpp.

Function Documentation

convert_channel_value()

static uint16_t convert_channel_value ( unsigned  chan_value )

static

Convert from RC to PWM value.

Parameters

chan_value

channel value in [172, 1811]

Returns

PWM channel value in [1000, 2000]

Definition at line 244 of file crsf.cpp.

References f().

Referenced by crsf_config(), and crsf_parse_buffer().

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crc8_dvb_s2()

static uint8_t crc8_dvb_s2 ( uint8_t  crc, uint8_t  a  )

static

Definition at line 205 of file crsf.cpp.

Referenced by crc8_dvb_s2_buf(), and crsf_frame_CRC().

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crc8_dvb_s2_buf()

static uint8_t crc8_dvb_s2_buf ( uint8_t *  buf, int  len  )

static

Definition at line 221 of file crsf.cpp.

References crc8_dvb_s2().

Referenced by write_frame_crc().

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crsf_config()

int crsf_config

(

int

uart_fd

)

Configure an UART port to be used for CRSF.

Parameters

uart_fd

UART file descriptor

Returns

0 on success, -errno otherwise

Definition at line 147 of file crsf.cpp.

References convert_channel_value(), and CRSF_BAUDRATE.

Referenced by RCInput::cycle().

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crsf_frame_CRC()

uint8_t crsf_frame_CRC

(

const crsf_frame_t &

frame

)

Definition at line 232 of file crsf.cpp.

References crc8_dvb_s2(), crsf_frame_t::header, crsf_frame_header_t::length, crsf_frame_t::payload, and crsf_frame_t::type.

Referenced by crsf_parse_buffer().

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crsf_parse()

bool crsf_parse	(	const uint64_t	now,
		const uint8_t *	frame,
		unsigned	len,
		uint16_t *	values,
		uint16_t *	num_values,
		uint16_t	max_channels
	)

Parse the CRSF protocol and extract RC channel data.

Parameters

now	current time
frame	data to parse
len	length of frame
values	output channel values, each in range [1000, 2000]
num_values	set to the number of parsed channels in values
max_channels	maximum length of values

Returns

true if channels successfully decoded

Definition at line 166 of file crsf.cpp.

References CRSF_DEBUG, crsf_parse_buffer(), current_frame_position, MIN, and unsynced.

Referenced by RCTest::crsfTest(), and RCInput::cycle().

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crsf_parse_buffer()

static bool crsf_parse_buffer ( uint16_t *  values, uint16_t *  num_values, uint16_t  max_channels  )

static

parse the current crsf_frame buffer

Definition at line 257 of file crsf.cpp.

References crsf_payload_RC_channels_packed_t::chan0, crsf_payload_RC_channels_packed_t::chan1, crsf_payload_RC_channels_packed_t::chan10, crsf_payload_RC_channels_packed_t::chan11, crsf_payload_RC_channels_packed_t::chan12, crsf_payload_RC_channels_packed_t::chan13, crsf_payload_RC_channels_packed_t::chan14, crsf_payload_RC_channels_packed_t::chan15, crsf_payload_RC_channels_packed_t::chan2, crsf_payload_RC_channels_packed_t::chan3, crsf_payload_RC_channels_packed_t::chan4, crsf_payload_RC_channels_packed_t::chan5, crsf_payload_RC_channels_packed_t::chan6, crsf_payload_RC_channels_packed_t::chan7, crsf_payload_RC_channels_packed_t::chan8, crsf_payload_RC_channels_packed_t::chan9, convert_channel_value(), CRSF_DEBUG, crsf_frame_CRC(), CRSF_VERBOSE, current_frame_position, crsf_frame_t::header, crsf_frame_header_t::length, MIN, crsf_frame_t::payload, rc_channels, rc_channels_packed, synced, crsf_frame_t::type, and unsynced.

Referenced by crsf_parse().

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crsf_send_telemetry_attitude()

bool crsf_send_telemetry_attitude	(	int	uart_fd,
		int16_t	pitch,
		int16_t	roll,
		int16_t	yaw
	)

Send telemetry Attitude information.

Parameters

uart_fd	UART file descriptor
pitch	Pitch angle [rad * 1e4]
roll	Roll angle [rad * 1e4]
yaw	Yaw angle [rad * 1e4]

Returns

true on success

Definition at line 478 of file crsf.cpp.

References attitude, write(), write_frame_crc(), write_frame_header(), and write_uint16_t().

Referenced by CRSFTelemetry::send_attitude().

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crsf_send_telemetry_battery()

bool crsf_send_telemetry_battery	(	int	uart_fd,
		uint16_t	voltage,
		uint16_t	current,
		int	fuel,
		uint8_t	remaining
	)

Send telemetry battery information.

Parameters

uart_fd	UART file descriptor
voltage	Voltage [0.1V]
current	Current [0.1A]
fuel	drawn mAh
remaining	battery remaining [%]

Returns

true on success

Definition at line 449 of file crsf.cpp.

References battery_sensor, write(), write_frame_crc(), write_frame_header(), write_uint16_t(), write_uint24_t(), and write_uint8_t().

Referenced by CRSFTelemetry::send_battery().

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crsf_send_telemetry_flight_mode()

bool crsf_send_telemetry_flight_mode	(	int	uart_fd,
		const char *	flight_mode
	)

Send telemetry Flight Mode information.

Parameters

uart_fd	UART file descriptor
flight_mode	Flight Mode string (max length = 15)

Returns

true on success

Definition at line 490 of file crsf.cpp.

References flight_mode, write(), write_frame_crc(), and write_frame_header().

Referenced by CRSFTelemetry::send_flight_mode().

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crsf_send_telemetry_gps()

bool crsf_send_telemetry_gps	(	int	uart_fd,
		int32_t	latitude,
		int32_t	longitude,
		uint16_t	groundspeed,
		uint16_t	gps_heading,
		uint16_t	altitude,
		uint8_t	num_satellites
	)

Send telemetry GPS information.

Parameters

uart_fd	UART file descriptor
latitude	latitude [degree * 1e7]
longitude	longitude [degree * 1e7]
groundspeed	Ground speed [km/h * 10]
gps_heading	GPS heading [degree * 100]
altitude	Altitude [meters + 1000m offset]
num_satellites	number of satellites used

Returns

true on success

Definition at line 462 of file crsf.cpp.

References gps, write(), write_frame_crc(), write_frame_header(), write_int32_t(), write_uint16_t(), and write_uint8_t().

Referenced by CRSFTelemetry::send_gps().

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write_frame_crc()

static void write_frame_crc ( uint8_t *  buf, int &  offset, int  buf_size  )

inlinestatic

Definition at line 440 of file crsf.cpp.

References crc8_dvb_s2_buf(), and write_uint8_t().

Referenced by crsf_send_telemetry_attitude(), crsf_send_telemetry_battery(), crsf_send_telemetry_flight_mode(), and crsf_send_telemetry_gps().

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write_frame_header()

static void write_frame_header ( uint8_t *  buf, int &  offset, crsf_frame_type_t  type, uint8_t  payload_size  )

inlinestatic

Definition at line 434 of file crsf.cpp.

References CRSF_SYNC_BYTE, and write_uint8_t().

Referenced by crsf_send_telemetry_attitude(), crsf_send_telemetry_battery(), crsf_send_telemetry_flight_mode(), and crsf_send_telemetry_gps().

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write_int32_t()

static void write_int32_t ( uint8_t *  buf, int &  offset, int32_t  value  )

inlinestatic

write an int32_t value to a buffer at a given offset and increment the offset

Definition at line 424 of file crsf.cpp.

Referenced by crsf_send_telemetry_gps().

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write_uint16_t()

static void write_uint16_t ( uint8_t *  buf, int &  offset, uint16_t  value  )

inlinestatic

write an uint16_t value to a buffer at a given offset and increment the offset

Definition at line 402 of file crsf.cpp.

Referenced by crsf_send_telemetry_attitude(), crsf_send_telemetry_battery(), and crsf_send_telemetry_gps().

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write_uint24_t()

static void write_uint24_t ( uint8_t *  buf, int &  offset, int  value  )

inlinestatic

write an uint24_t value to a buffer at a given offset and increment the offset

Definition at line 412 of file crsf.cpp.

Referenced by crsf_send_telemetry_battery().

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write_uint8_t()

static void write_uint8_t ( uint8_t *  buf, int &  offset, uint8_t  value  )

inlinestatic

write an uint8_t value to a buffer at a given offset and increment the offset

Definition at line 395 of file crsf.cpp.

Referenced by crsf_send_telemetry_battery(), crsf_send_telemetry_gps(), write_frame_crc(), and write_frame_header().

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Variable Documentation

crsf_frame

crsf_frame_t& crsf_frame = rc_decode_buf.crsf_frame

static

Definition at line 132 of file crsf.cpp.

current_frame_position

unsigned current_frame_position = 0

static

Definition at line 133 of file crsf.cpp.

Referenced by crsf_parse(), and crsf_parse_buffer().

parser_state

crsf_parser_state_t parser_state = crsf_parser_state_t::unsynced

static

Definition at line 134 of file crsf.cpp.

Referenced by sf0x_parser(), and tfmini_parse().