File syn_encoder.h¶

FileList > input > syn_encoder.h

Quadrature rotary encoder decoder. More...

#include "../common/syn_defs.h"
#include "../drivers/syn_gpio.h"
#include "../dsp/syn_signal.h"
#include <stdbool.h>

Classes¶

Type	Name
struct	SYN_Encoder Quadrature encoder instance — pins, position, delta.

Public Types¶

Type	Name
enum	SYN_EncoderDir Encoder rotation direction.

Public Functions¶

Type	Name
int32_t	syn_encoder_get_delta (SYN_Encoder * enc) Get accumulated delta since last call and reset it.
void	syn_encoder_init (SYN_Encoder * enc, SYN_GPIO_Pin pin_a, SYN_GPIO_Pin pin_b) Initialize encoder.
void	syn_encoder_set_stats (SYN_Encoder * enc, SYN_Signal * stats) Attach a signal statistics window for velocity tracking.
void	syn_encoder_set_steps_per_detent (SYN_Encoder * enc, uint8_t spd) Set steps-per-detent (default = 1).
void	syn_encoder_update (SYN_Encoder * enc) Sample pins and update position.

Public Static Functions¶

Type	Name
SYN_EncoderDir	syn_encoder_direction (const SYN_Encoder * enc) Get last direction.
int32_t	syn_encoder_position (const SYN_Encoder * enc) Get absolute position.
void	syn_encoder_set_position (SYN_Encoder * enc, int32_t pos) Set absolute position.

Detailed Description¶

Decodes A/B quadrature signals from rotary encoders. Supports: * Direction detection (CW/CCW) * Accumulated position * Delta since last read * Optional push-button (use syn_button for debouncing)

Call syn_encoder_update() from a timer ISR or fast loop (≥4× the maximum encoder frequency).

** **

SYN_Encoder enc;
syn_encoder_init(&enc, PIN_A, PIN_B);

// In timer ISR or fast loop:
syn_encoder_update(&enc);

// In main loop:
int32_t delta = syn_encoder_get_delta(&enc);
if (delta != 0) {
    volume += delta;
}

Public Types Documentation¶

enum SYN_EncoderDir¶

Encoder rotation direction.

enum SYN_EncoderDir {
    SYN_ENCODER_NONE = 0,
    SYN_ENCODER_CW = 1,
    SYN_ENCODER_CCW = -1
};

Public Functions Documentation¶

function syn_encoder_get_delta¶

Get accumulated delta since last call and reset it.

int32_t syn_encoder_get_delta (
    SYN_Encoder * enc
)

Parameters:

enc Encoder instance.

Returns:

Number of steps (positive = CW, negative = CCW).

function syn_encoder_init¶

Initialize encoder.

void syn_encoder_init (
    SYN_Encoder * enc,
    SYN_GPIO_Pin pin_a,
    SYN_GPIO_Pin pin_b
)

Parameters:

enc Encoder instance.
pin_a Channel A GPIO.
pin_b Channel B GPIO.

function syn_encoder_set_stats¶

Attach a signal statistics window for velocity tracking.

void syn_encoder_set_stats (
    SYN_Encoder * enc,
    SYN_Signal * stats
)

Each call to syn_encoder_get_delta() pushes the delta value into the signal window, giving you velocity min/max/mean/variance.

Parameters:

enc Encoder.
stats Initialized SYN_Signal, or NULL to detach.

function syn_encoder_set_steps_per_detent¶

Set steps-per-detent (default = 1).

void syn_encoder_set_steps_per_detent (
    SYN_Encoder * enc,
    uint8_t spd
)

Many mechanical encoders generate 2 or 4 state changes per physical detent. Setting this to 4 means position and delta only increment once per detent rather than once per state change.

Parameters:

enc Encoder instance.
spd Steps per detent (1, 2, or 4).

function syn_encoder_update¶

Sample pins and update position.

void syn_encoder_update (
    SYN_Encoder * enc
)

Call from a timer ISR or fast polling loop. Must be called at ≥4× the encoder's maximum rotation speed.

Parameters:

enc Encoder instance.

Public Static Functions Documentation¶

function syn_encoder_direction¶

Get last direction.

static inline SYN_EncoderDir syn_encoder_direction (
    const SYN_Encoder * enc
)

Parameters:

enc Encoder.

Returns:

Last detected direction.

function syn_encoder_position¶

Get absolute position.

static inline int32_t syn_encoder_position (
    const SYN_Encoder * enc
)

Parameters:

enc Encoder.

Returns:

Accumulated position.

function syn_encoder_set_position¶

Set absolute position.

static inline void syn_encoder_set_position (
    SYN_Encoder * enc,
    int32_t pos
)

Parameters:

enc Encoder.
pos New position value.

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