APM:Libraries
Macros | Functions | Variables
srxl.cpp File Reference
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include "srxl.h"
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Macros

#define SRXL_MIN_FRAMESPACE_US   8000U /* Minumum space between srxl frames in us (applies to all variants) */
 
#define SRXL_MAX_CHANNELS   20U /* Maximum number of channels from srxl datastream */
 
#define STATE_IDLE   0x00U /* do nothing */
 
#define STATE_NEW   0x01U /* get header of frame + prepare for frame reception + begin new crc cycle */
 
#define STATE_COLLECT   0x02U /* collect RC channel data from frame + concurrently calc crc over payload data + extract channel information */
 
#define SRXL_FRAMELEN_V1   27U /* Framelength with header in byte for: Mpx SRXLv1 or XBUS Mode B */
 
#define SRXL_FRAMELEN_V2   35U /* Framelength with header in byte for: Mpx SRXLv2 */
 
#define SRXL_FRAMELEN_V5   18U /* Framelength with header in byte for Spk AR7700 etc. */
 
#define SRXL_FRAMELEN_MAX   35U /* maximum possible framelengh */
 
#define SRXL_HEADER_V1   0xA1U /* Headerbyte for: Mpx SRXLv1 or XBUS Mode B */
 
#define SRXL_HEADER_V2   0xA2U /* Headerbyte for: Mpx SRXLv2 */
 
#define SRXL_HEADER_V5   0xA5U /* Headerbyte for: Spk AR7700 etc. */
 
#define SRXL_HEADER_NOT_IMPL   0xFFU /* Headerbyte for non impemented srxl header*/
 

Functions

static uint16_t srxl_crc16 (uint16_t crc, uint8_t new_byte)
 
static int srxl_channels_get_v1v2 (uint16_t max_values, uint8_t *num_values, uint16_t *values, bool *failsafe_state)
 
static int srxl_channels_get_v5 (uint16_t max_values, uint8_t *num_values, uint16_t *values, bool *failsafe_state)
 
int srxl_decode (uint64_t timestamp_us, uint8_t byte, uint8_t *num_values, uint16_t *values, uint16_t max_values, bool *failsafe_state)
 

Variables

static uint8_t buffer [SRXL_FRAMELEN_MAX]
 
static uint8_t buflen
 
static uint64_t last_data_us
 
static uint16_t channels [SRXL_MAX_CHANNELS]
 
static uint8_t frame_header = 0U
 
static uint8_t frame_len_full = 0U
 
static uint8_t decode_state = STATE_IDLE
 
static uint8_t decode_state_next = STATE_IDLE
 
static uint16_t crc_fmu = 0U
 
static uint16_t crc_receiver = 0U
 
static uint16_t max_channels
 

Macro Definition Documentation

◆ SRXL_FRAMELEN_MAX

#define SRXL_FRAMELEN_MAX   35U /* maximum possible framelengh */

Definition at line 45 of file srxl.cpp.

◆ SRXL_FRAMELEN_V1

#define SRXL_FRAMELEN_V1   27U /* Framelength with header in byte for: Mpx SRXLv1 or XBUS Mode B */

Definition at line 42 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_FRAMELEN_V2

#define SRXL_FRAMELEN_V2   35U /* Framelength with header in byte for: Mpx SRXLv2 */

Definition at line 43 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_FRAMELEN_V5

#define SRXL_FRAMELEN_V5   18U /* Framelength with header in byte for Spk AR7700 etc. */

Definition at line 44 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_HEADER_NOT_IMPL

#define SRXL_HEADER_NOT_IMPL   0xFFU /* Headerbyte for non impemented srxl header*/

Definition at line 51 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_HEADER_V1

#define SRXL_HEADER_V1   0xA1U /* Headerbyte for: Mpx SRXLv1 or XBUS Mode B */

Definition at line 48 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_HEADER_V2

#define SRXL_HEADER_V2   0xA2U /* Headerbyte for: Mpx SRXLv2 */

Definition at line 49 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_HEADER_V5

#define SRXL_HEADER_V5   0xA5U /* Headerbyte for: Spk AR7700 etc. */

Definition at line 50 of file srxl.cpp.

Referenced by srxl_decode().

◆ SRXL_MAX_CHANNELS

#define SRXL_MAX_CHANNELS   20U /* Maximum number of channels from srxl datastream */

Definition at line 32 of file srxl.cpp.

Referenced by srxl_channels_get_v5().

◆ SRXL_MIN_FRAMESPACE_US

#define SRXL_MIN_FRAMESPACE_US   8000U /* Minumum space between srxl frames in us (applies to all variants) */

Definition at line 31 of file srxl.cpp.

Referenced by srxl_decode().

◆ STATE_COLLECT

#define STATE_COLLECT   0x02U /* collect RC channel data from frame + concurrently calc crc over payload data + extract channel information */

Definition at line 37 of file srxl.cpp.

Referenced by srxl_decode().

◆ STATE_IDLE

#define STATE_IDLE   0x00U /* do nothing */

Definition at line 35 of file srxl.cpp.

Referenced by srxl_decode().

◆ STATE_NEW

#define STATE_NEW   0x01U /* get header of frame + prepare for frame reception + begin new crc cycle */

Definition at line 36 of file srxl.cpp.

Referenced by srxl_decode().

Function Documentation

◆ srxl_channels_get_v1v2()

static int srxl_channels_get_v1v2 ( uint16_t  max_values,
uint8_t *  num_values,
uint16_t *  values,
bool *  failsafe_state 
)
static

Get RC channel information as microsecond pulsewidth representation from srxl version 1 and 2

This function extracts RC channel information from srxl dataframe. The function expects the whole dataframe in correct order in static array "buffer[SRXL_FRAMELEN_MAX]". After extracting all RC channel information, the data is transferred to "values" array from parameter list. If the pixhawk does not support all channels from srxl datastream, only supported number of channels will be refreshed.

IMPORTANT SAFETY NOTICE: This function shall only be used after CRC has been successful.

Structure of SRXL v1 dataframe –> 12 channels, 12 Bit per channel Byte0: Header 0xA1 Byte1: Bits7-4:Empty Bits3-0:Channel1 MSB Byte2: Bits7-0: Channel1 LSB (....) Byte23: Bits7-4:Empty Bits3-0:Channel12 MSB Byte24: Bits7-0: Channel12 LSB Byte25: CRC16 MSB Byte26: CRC16 LSB

Structure of SRXL v2 dataframe –> 16 channels, 12 Bit per channel Byte0: Header 0xA2 Byte1: Bits7-4:Empty Bits3-0:Channel1 MSB Byte2: Bits7-0: Channel1 LSB (....) Byte31: Bits7-4:Empty Bits3-0:Channel16 MSB Byte32: Bits7-0: Channel16 LSB Byte33: CRC16 MSB Byte34: CRC16 LSB

Parameters
[in]max_values- maximum number of values supported by the pixhawk
[out]num_values- number of RC channels extracted from srxl frame
[out]values- array of RC channels with refreshed information as pulsewidth in microseconds Range: 800us - 2200us
[out]failsafe_state- true: RC-receiver is in failsafe state, false: RC-receiver is not in failsafe state
Return values
0success

Definition at line 133 of file srxl.cpp.

Referenced by srxl_decode().

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◆ srxl_channels_get_v5()

static int srxl_channels_get_v5 ( uint16_t  max_values,
uint8_t *  num_values,
uint16_t *  values,
bool *  failsafe_state 
)
static

Get RC channel information as microsecond pulsewidth representation from srxl version 5

This function extracts RC channel information from srxl dataframe. The function expects the whole dataframe in correct order in static array "buffer[SRXL_FRAMELEN_MAX]". After extracting all RC channel information, the data is transferred to "values" array from parameter list. If the pixhawk does not support all channels from srxl datastream, only supported number of channels will be refreshed.

IMPORTANT SAFETY NOTICE: This function shall only be used after CRC has been successful.

Structure of SRXL v5 dataframe Byte0: Header 0xA5 Byte1 - Byte16: Payload Byte17: CRC16 MSB Byte18: CRC16 LSB

Parameters
[in]max_values- maximum number of values supported by the pixhawk
[out]num_values- number of RC channels extracted from srxl frame
[out]values- array of RC channels with refreshed information as pulsewidth in microseconds Range: 800us - 2200us
[out]failsafe_state- true: RC-receiver is in failsafe state, false: RC-receiver is not in failsafe state
Return values
0success

Definition at line 179 of file srxl.cpp.

Referenced by srxl_decode().

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◆ srxl_crc16()

static uint16_t srxl_crc16 ( uint16_t  crc,
uint8_t  new_byte 
)
static

This function calculates the 16bit crc as used throughout the srxl protocol variants

This function is intended to be called whenever a new byte shall be added to the crc. Simply provide the old crc and the new data byte and the function return the new crc value.

To start a new crc calculation for a new srxl frame, provide parameter crc=0 and the first byte of the frame.

Parameters
[in]crc- start value for crc
[in]new_byte- byte that shall be included in crc calculation
Returns
calculated crc

Definition at line 86 of file srxl.cpp.

Referenced by srxl_decode().

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◆ srxl_decode()

int srxl_decode ( uint64_t  timestamp_us,
uint8_t  byte,
uint8_t *  num_values,
uint16_t *  values,
uint16_t  max_values,
bool *  failsafe_state 
)

Decode SRXL frames

Structure of all SRXL frames Byte[0]: Header 0xA<VARIANT> –> Variant specific header. Variant is encoded in bits 3-0 of header byte. Byte[1] - Byte[N-2]: SRXL variant specific payload Byte[N-1] - Byte[N]: CRC16 over payload and header

Parameters
[in]timestamp_us- timestamp in microseconds
[in]receivedbyte in microseconds
[out]num_values- number of RC channels extracted from srxl frame
[out]values- array of RC channels with refreshed information as pulsewidth in microseconds Range: 800us - 2200us
[in]maximumnumber of values supported by pixhawk
[out]failsafe_state- true: RC-receiver is in failsafe state, false: RC-receiver is not in failsafe state
Return values
0success (a decoded packet)
1no packet yet (accumulating)
2unknown packet
4checksum error

Definition at line 262 of file srxl.cpp.

Referenced by Linux::RCInput::add_srxl_input(), and srxl_decode().

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Variable Documentation

◆ buffer

uint8_t buffer[SRXL_FRAMELEN_MAX]
static

Definition at line 56 of file srxl.cpp.

Referenced by AP_InertialSensor_L3G4200D::_accumulate(), Linux::RCInput_Navio2::_timer_tick(), F4Light::SPIDevice::apply_speed(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::available(), BM_Crop8bpp(), BM_YuyvToGrey(), AP_GPS_Backend::broadcast_gps_type(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::clear(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::empty(), F4Light::USBDriver::flush(), DataFlash_Backend::Log_Write(), AP_GPS_NOVA::name(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::ObjectBuffer(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::peek(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::pop(), ChibiOS::AnalogIn::power_status_flags(), AP_HAL::BetterStream::println(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::push(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::push_force(), AP_GPS_GSOF::requestBaud(), AP_GPS_GSOF::requestGSOF(), ChibiOS::RCOutput::scale_esc_to_unity(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::space(), srxl_channels_get_v1v2(), srxl_channels_get_v5(), srxl_decode(), AP_Compass_IST8310::timer(), AP_Compass_QMC5883L::timer(), F4Light::UART_OSD::tx_pending(), HALSITL::UARTDriver::tx_pending(), F4Light::UARTDriver::txspace(), AP_SBusOut::update(), ObjectBuffer< GCS_MAVLINK::pending_param_request >::update(), AnalogSource_Navio2::voltage_average(), AP_GPS_Backend::Write_DataFlash_Log_Startup_messages(), and ObjectBuffer< GCS_MAVLINK::pending_param_request >::~ObjectBuffer().

◆ buflen

uint8_t buflen
static

Definition at line 57 of file srxl.cpp.

Referenced by SITL::JSBSim::drain_control_socket(), SITL::Gazebo::drain_sockets(), SITL::JSBSim::send_servos(), and srxl_decode().

◆ channels

uint16_t channels[SRXL_MAX_CHANNELS]
static

Definition at line 59 of file srxl.cpp.

Referenced by Linux::RCInput_SoloLink::_timer_tick(), SRV_Channels::adjust_trim(), SRV_Channels::channel_function(), SRV_Channels::constrain_pwm(), SRV_Channels::copy_radio_in_out(), SRV_Channels::copy_radio_in_out_mask(), SRV_Channels::enable_aux_servos(), SRV_Channels::find_channel(), SRV_Channels::get_channel_for(), SRV_Channels::get_output_norm(), SRV_Channels::get_output_pwm(), SRV_Channels::limit_slew_rate(), SRV_Channels::move_servo(), SRV_Channels::output_ch_all(), RC_Channels::rc_channel(), SRV_Channels::set_angle(), SRV_Channels::set_aux_channel_default(), SRV_Channels::set_default_function(), SRV_Channels::set_esc_scaling_for(), SRV_Channels::set_failsafe_limit(), SRV_Channels::set_failsafe_pwm(), SRV_Channels::set_output_limit(), SRV_Channels::set_output_pwm(), SRV_Channels::set_output_pwm_first(), SRV_Channels::set_output_pwm_trimmed(), SRV_Channels::set_output_to_trim(), SRV_Channels::set_range(), SRV_Channels::set_rc_frequency(), SRV_Channels::set_safety_limit(), SRV_Channels::set_trim_to_min_for(), SRV_Channels::set_trim_to_pwm_for(), SRV_Channels::set_trim_to_servo_out_for(), SRV_Channels::srv_channel(), srxl_channels_get_v1v2(), srxl_channels_get_v5(), SRV_Channels::update_aux_servo_function(), SRV_Channels::upgrade_motors_servo(), and SRV_Channels::upgrade_parameters().

◆ crc_fmu

uint16_t crc_fmu = 0U
static

Definition at line 65 of file srxl.cpp.

Referenced by srxl_decode().

◆ crc_receiver

uint16_t crc_receiver = 0U
static

Definition at line 66 of file srxl.cpp.

Referenced by srxl_decode().

◆ decode_state

uint8_t decode_state = STATE_IDLE
static

Definition at line 63 of file srxl.cpp.

Referenced by srxl_decode().

◆ decode_state_next

uint8_t decode_state_next = STATE_IDLE
static

Definition at line 64 of file srxl.cpp.

Referenced by srxl_decode().

◆ frame_header

uint8_t frame_header = 0U
static

Definition at line 61 of file srxl.cpp.

Referenced by srxl_decode().

◆ frame_len_full

uint8_t frame_len_full = 0U
static

Definition at line 62 of file srxl.cpp.

Referenced by srxl_channels_get_v1v2(), and srxl_decode().

◆ last_data_us

uint64_t last_data_us
static

Definition at line 58 of file srxl.cpp.

Referenced by srxl_decode().

◆ max_channels

uint16_t max_channels
static

Definition at line 69 of file srxl.cpp.

Referenced by srxl_channels_get_v5().

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