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Zero-Heap SBUS (Futaba/FrSky) 16-Channel Receiver Decoder Implementation.

  • #include "syntropic/proto/syn_sbus.h"
  • #include <string.h>

Public Functions

Type Name
SYN_Status syn_sbus_decode_buffer (const uint8_t buf, SYN_SBUS_Frame * frame)
Decode raw 25-byte SBUS frame buffer into channel outputs.
SYN_Status syn_sbus_init (SYN_SBUS_Parser * parser)
Initialize SBUS parser state machine.
SYN_Status syn_sbus_parse_byte (SYN_SBUS_Parser * parser, uint8_t byte, SYN_SBUS_Frame * frame)
Process single incoming byte from UART.
uint16_t syn_sbus_raw_to_us (uint16_t raw_val)
Convert raw 11-bit SBUS channel value to pulse width in microseconds (us).

Public Functions Documentation

function syn_sbus_decode_buffer

Decode raw 25-byte SBUS frame buffer into channel outputs. 

SYN_Status syn_sbus_decode_buffer (
    const uint8_t buf,
    SYN_SBUS_Frame * frame
)

Decode raw 25-byte SBUS frame buffer directly.

Parameters:

  • buf Pointer to 25-byte raw SBUS frame buffer.
  • frame Pointer to output SBUS decoded frame structure.

Returns:

SYN_OK on success, SYN_INVALID_PARAM or SYN_ERROR on header mismatch.

function syn_sbus_init

Initialize SBUS parser state machine. 

SYN_Status syn_sbus_init (
    SYN_SBUS_Parser * parser
)

Parameters:

  • parser Pointer to parser struct.

Returns:

SYN_OK on success.

function syn_sbus_parse_byte

Process single incoming byte from UART. 

SYN_Status syn_sbus_parse_byte (
    SYN_SBUS_Parser * parser,
    uint8_t byte,
    SYN_SBUS_Frame * frame
)

Parameters:

  • parser Pointer to parser struct.
  • byte Incoming serial byte.
  • frame Pointer to output frame struct (populated when a complete valid 25-byte frame is decoded).

Returns:

SYN_OK if complete frame decoded, SYN_BUSY if byte accepted but frame incomplete, SYN_ERROR on header mismatch.

function syn_sbus_raw_to_us

Convert raw 11-bit SBUS channel value to pulse width in microseconds (us). 

uint16_t syn_sbus_raw_to_us (
    uint16_t raw_val
)

Standard mapping: * 172 raw -> 1000 us * 992 raw -> 1500 us * 1811 raw -> 2000 us

Parameters:

  • raw_val 11-bit raw SBUS channel value (172..1811).

Returns:

Pulse width in microseconds (clamped 1000..2000 us).

The documentation for this class was generated from the following file src/syntropic/proto/syn_sbus.c