Class espos_audio::NullAudio¶

ClassList > espos_audio > NullAudio

#include <espos_audio/null_audio.h>

Inherits the following classes: espos_audio::AudioDriver

Public Functions¶

Type	Name
virtual void	init () override
virtual void	play_pcm (const int16_t * samples, size_t frames) override Enqueue `frames` signed-16-bit mono samples for playback.
virtual bool	ready () override const True once init() brought the codec up successfully.
virtual uint32_t	sample_rate () override const Sample rate the driver expects play_pcm() buffers to be in.

Public Functions inherited from espos_audio::AudioDriver¶

See espos_audio::AudioDriver

Type	Name
virtual bool	begin_stream (uint32_t, uint8_t, uint8_t) Begin a stream at `rate` Hz /`bits` per sample /`channels` .
virtual bool	can_capture () const True if this board can capture (a mic is wired to the codec ADC and init brought it up).
virtual uint32_t	capture_rate () const Sample rate of record_pcm() buffers.
virtual void	end_stream () End the active stream: drain the codec so the last chunk doesn't loop on the DMA ring, then leave the codec open for the next stream/clip.
virtual void	init () = 0
virtual float	mic_gain_db () const
virtual void	play_cue (const int16_t * samples, size_t frames) Like play_pcm() , but for a clip that must NOT be silently dropped: the wake cue is the user's only feedback that the panel heard them, and it fires exactly when the pipeline is taking the mic, so the disposable-clip policy (drop on a busy codec) loses precisely the one sound that matters.
virtual void	play_pcm (const int16_t * samples, size_t frames) = 0 Enqueue `frames` signed-16-bit mono samples for playback.
virtual bool	probe_mic_channels (MicLevels &)
virtual bool	ready () const = 0 True once init() brought the codec up successfully.
virtual size_t	record_pcm (int16_t , size_t) Read up to* `max_frames` signed-16-bit mono samples into`out` , BLOCKING until that many are captured (or a codec error).
virtual size_t	record_pcm2 (int16_t , size_t) Read up to* `max_frames` 2-channel interleaved [MIC1,MIC2] int16 frames into`out` (so`out` holds`2 * max_frames` samples), BLOCKING until that many frames are captured (or a codec error).
virtual uint32_t	sample_rate () const = 0 Sample rate the driver expects play_pcm() buffers to be in.
virtual void	set_enabled (bool) Mute / unmute without tearing down the codec.
virtual void	set_mic_gain_db (float) Analog mic preamp gain in dB, applied on the next capture open.
virtual void	set_volume (uint8_t) Output volume 0-100. Applied at the codec. Default no-op.
virtual void	start_capture () Start / stop the ADC capture path.
virtual void	start_capture2 () Open / close the 2-channel capture handle.
virtual void	stop_capture ()
virtual void	stop_capture2 ()
virtual bool	supports_dual_mic () const True if this board exposes a 2-channel [MIC1,MIC2] capture path (start_capture2/record_pcm2/stop_capture2).
virtual size_t	write_stream (const int16_t , size_t) Write* `frames` signed-16-bit mono samples into the active stream.
virtual	~AudioDriver () = default

Public Functions Documentation¶

function init¶

inline virtual void espos_audio::NullAudio::init () override

Implements espos_audio::AudioDriver::init

function play_pcm¶

Enqueue frames signed-16-bit mono samples for playback.

inline virtual void espos_audio::NullAudio::play_pcm (
    const int16_t * samples,
    size_t frames
) override

Copies the buffer and returns immediately; the samples play on the driver's audio task. Passing a null buffer or zero frames is a no-op. If the queue is full the buffer is dropped (a chime is disposable — never block the caller waiting for audio).

Implements espos_audio::AudioDriver::play_pcm

function ready¶

True once init() brought the codec up successfully.

inline virtual bool espos_audio::NullAudio::ready () override const

False if the board has no audio or init failed (play_pcm then no-ops). Lets a status endpoint report audio health without racing the boot log.

Implements espos_audio::AudioDriver::ready

function sample_rate¶

Sample rate the driver expects play_pcm() buffers to be in.

inline virtual uint32_t espos_audio::NullAudio::sample_rate () override const

Callers synthesise / resample to this. 16 kHz is plenty for alert tones and speech.

Implements espos_audio::AudioDriver::sample_rate

The documentation for this class was generated from the following file espos_audio/include/espos_audio/null_audio.h