File syn_audio.h¶

FileList > audio > syn_audio.h

Codec-Agnostic PCM Double-Buffered Audio Playback Engine. More...

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

Classes¶

Type	Name
struct	SYN_Audio Audio Playback Engine Instance State.
struct	SYN_Audio_Config Audio Playback Configuration.

Public Types¶

Type	Name
typedef void(*	SYN_Audio_OutputFn Hardware output callback function signature.

Public Functions¶

Type	Name
size_t	syn_audio_feed (SYN_Audio * audio, const int16_t * samples, size_t count) Feed decoded PCM audio samples into the stream buffer.
SYN_Status	syn_audio_init (SYN_Audio * audio, const SYN_Audio_Config * cfg) Initialize an Audio Streaming Engine instance.
void	syn_audio_isr_complete (SYN_Audio * audio) Hardware ISR Handler for DMA Transfer-Complete Interrupt.
void	syn_audio_isr_half (SYN_Audio * audio) Hardware ISR Handler for DMA Half-Transfer Interrupt.
SYN_Status	syn_audio_start (SYN_Audio * audio) Start audio playback streaming.
SYN_Status	syn_audio_stop (SYN_Audio * audio) Stop audio playback streaming.

Detailed Description¶

Provides a zero-malloc, hardware-decoupled PCM streaming engine designed to feed audio samples to microcontroller DMA, I2S, SAI, or DAC peripherals.

Uses double-buffering (ping-pong halves) to allow uninterrupted audio decoding while the hardware transfers the alternate half-buffer to the DAC via DMA.

Public Types Documentation¶

typedef SYN_Audio_OutputFn¶

Hardware output callback function signature.

typedef void(* SYN_Audio_OutputFn) (const int16_t *samples, size_t count, void *ctx);

Called when a buffer half is ready to be submitted to DMA or DAC hardware.

Parameters:

samples Pointer to PCM sample array (16-bit linear PCM).
count Number of samples in the array.
ctx User context pointer.

Public Functions Documentation¶

function syn_audio_feed¶

Feed decoded PCM audio samples into the stream buffer.

size_t syn_audio_feed (
    SYN_Audio * audio,
    const int16_t * samples,
    size_t count
)

Parameters:

audio Pointer to Audio instance.
samples Input 16-bit PCM sample array.
count Number of samples to push.

Returns:

Number of samples actually written to the buffer.

function syn_audio_init¶

Initialize an Audio Streaming Engine instance.

SYN_Status syn_audio_init (
    SYN_Audio * audio,
    const SYN_Audio_Config * cfg
)

Parameters:

audio Pointer to Audio instance.
cfg Configuration structure pointer.

Returns:

SYN_OK on success, or SYN_INVALID_PARAM.

function syn_audio_isr_complete¶

Hardware ISR Handler for DMA Transfer-Complete Interrupt.

void syn_audio_isr_complete (
    SYN_Audio * audio
)

Call this function from your hardware DMA interrupt when the entire circular buffer transfer completes (SYN_DMA_EVENT_COMPLETE).

Parameters:

audio Pointer to Audio instance.

function syn_audio_isr_half¶

Hardware ISR Handler for DMA Half-Transfer Interrupt.

void syn_audio_isr_half (
    SYN_Audio * audio
)

Call this function from your hardware DMA interrupt when half of the circular buffer transfer completes (SYN_DMA_EVENT_HALF_COMPLETE).

Parameters:

audio Pointer to Audio instance.

function syn_audio_start¶

Start audio playback streaming.

SYN_Status syn_audio_start (
    SYN_Audio * audio
)

Parameters:

audio Pointer to Audio instance.

Returns:

SYN_OK on success, or SYN_INVALID_PARAM.

function syn_audio_stop¶

Stop audio playback streaming.

SYN_Status syn_audio_stop (
    SYN_Audio * audio
)

Parameters:

audio Pointer to Audio instance.

Returns:

SYN_OK on success, or SYN_INVALID_PARAM.

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