File syn_ppm.h¶

FileList > input > syn_ppm.h

Zero-Heap PPM (Pulse-Position Modulation) Multi-Channel RC Receiver Decoder. More...

#include "syntropic/common/syn_defs.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Classes¶

Type	Name
struct	SYN_PPM_Decoder

Public Functions¶

Type	Name
uint16_t	syn_ppm_get_channel (const SYN_PPM_Decoder * ppm, uint8_t channel_idx) Get pulse width (us) for specified 0-indexed channel.
SYN_Status	syn_ppm_init (SYN_PPM_Decoder * ppm) Initialize PPM decoder instance.
SYN_Status	syn_ppm_process_pulse (SYN_PPM_Decoder * ppm, uint16_t pulse_us) Process high-resolution measured pulse width (us) from Timer Input Capture interrupt.

Macros¶

Type	Name
define	SYN_PPM_MAX_CHANNELS `12`
define	SYN_PPM_SYNC_MIN_US `2700U`

Detailed Description¶

PPM Protocol Specifications: * Single-wire pulse train consisting of 4..12 channel pulse widths (1000..2000 us). * Sync gap: Pulse width > 2700 us demarcates frame boundary. * Pulse separator: Short low pulse (e.g. 300..500 us).

Public Functions Documentation¶

function syn_ppm_get_channel¶

Get pulse width (us) for specified 0-indexed channel.

uint16_t syn_ppm_get_channel (
    const SYN_PPM_Decoder * ppm,
    uint8_t channel_idx
)

Parameters:

ppm Pointer to decoder struct.
channel_idx 0-indexed channel index (0..11).

Returns:

Pulse width in microseconds (clamped 1000..2000 us, or 1500 us default if unreceived).

function syn_ppm_init¶

Initialize PPM decoder instance.

SYN_Status syn_ppm_init (
    SYN_PPM_Decoder * ppm
)

Parameters:

ppm Pointer to decoder struct.

Returns:

SYN_OK on success.

function syn_ppm_process_pulse¶

Process high-resolution measured pulse width (us) from Timer Input Capture interrupt.

SYN_Status syn_ppm_process_pulse (
    SYN_PPM_Decoder * ppm,
    uint16_t pulse_us
)

Parameters:

ppm Pointer to decoder struct.
pulse_us Measured pulse width in microseconds (us).

Returns:

SYN_OK when a complete multi-channel PPM frame is finished, SYN_BUSY during channel reception.

Macro Definition Documentation¶

define SYN_PPM_MAX_CHANNELS¶

#define SYN_PPM_MAX_CHANNELS `12`

Maximum supported PPM channels (12)

define SYN_PPM_SYNC_MIN_US¶

#define SYN_PPM_SYNC_MIN_US `2700U`

Minimum sync pulse gap in microseconds (2700 us)

The documentation for this class was generated from the following file src/syntropic/input/syn_ppm.h