noise_nugget.h File Reference

API for the Noise Nugget development board, which offers digital audio processing and synthesis. More...

#include <stdint.h>
#include <stdbool.h>

Include dependency graph for noise_nugget.h:

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Typedefs
typedef void(*	audio_cb_t) (uint32_t **buffer, uint32_t *stereo_point_count)
	Defines a callback type for audio processing.

Functions
bool	audio_init (int sample_rate, audio_cb_t output_callback, audio_cb_t input_callback)
	Initializes the audio system of the Noise Nugget board.
bool	enable_line_out (bool left, bool right)
	Enable line level output.
bool	enable_speakers (bool left, bool right, uint8_t gain)
	Enable speaker amp.
bool	set_line_out_volume (float L2L, float L2R, float R2L, float R2R)
	Set volume for line output (and speakers)
bool	set_adc_volume (float left, float right)
	Set ADC (Analog to Digital Converter) volume.
bool	set_hp_volume (float left, float right)
	Set Headphone output volume.
bool	set_line_in_boost (uint8_t line, uint8_t L2L, uint8_t L2R, uint8_t R2L, uint8_t R2R)
	Set line input boost.
bool	enable_mic_bias (void)
	Enable microphone bias.

Detailed Description

API for the Noise Nugget development board, which offers digital audio processing and synthesis.

This file provides the initialization functions and callback mechanisms needed to interface with the Noise Nugget's audio processing capabilities.

Typedef Documentation

audio_cb_t

audio_cb_t

Defines a callback type for audio processing.

This callback function is used by the Noise Nugget development board to handle audio data processing. The function will be called when audio data needs to be output or input through the board. The callback must return as fast as possible to not interrupt the flow of sample being played/recorded. Therefore any audio synthesis or processing must be done separately, for instance using flip buffers, the callbacks are just here to provide pointers to the next fresh buffers.

Parameters

buffer	Double pointer to the audio data buffer. Set *buffer with the address of the next stereo audio samples (uint32_t) to be played/recorded, or set *buffer to NULL if there is no buffer available.
stereo_point_count	Pointer to the number of stereo points (left-right pairs) available in the buffer. Set *stereo_point_count to specified the size of the buffer to be played/recorded.

Function Documentation

audio_init()

bool audio_init	(	int	sample_rate,
		audio_cb_t	output_callback,
		audio_cb_t	input_callback
	)

Initializes the audio system of the Noise Nugget board.

This function initializes the audio system with a specified sample rate and sets up the necessary callback functions for audio data input and output.

Parameters

sample_rate	The audio sample rate to be configured. Typical values might include 44100 or 21500 Hz.
output_callback	The callback function to be invoked when an audio output buffer is required.
input_callback	The callback function to be invoked when an audio input buffer is required.

Returns

Returns true if the audio system was successfully initialized, false otherwise.

enable_line_out()

bool enable_line_out	(	bool	left,
		bool	right
	)

Enable line level output.

Parameters

left	enable left channel
right	enable right channel

Returns

Returns true on success, false otherwise.

enable_mic_bias()

bool enable_mic_bias

(

void

)

Enable microphone bias.

Mircophone bias is a small voltage providing power to a microphone (typically and electret condenser microphone).

Returns

Returns true on success, false otherwise.

enable_speakers()

bool enable_speakers	(	bool	left,
		bool	right,
		uint8_t	gain
	)

Enable speaker amp.

Parameters

left	enable left channel
right	enable right channel
gain	Amplification gain between 0 and 3

Returns

Returns true on success, false otherwise.

set_adc_volume()

bool set_adc_volume	(	float	left,
		float	right
	)

Set ADC (Analog to Digital Converter) volume.

Parameters

left	left channel volume
right	right channel volume

Returns

Returns true on success, false otherwise.

set_hp_volume()

bool set_hp_volume	(	float	left,
		float	right
	)

Set Headphone output volume.

Parameters

left	left channel volume
right	right channel volume

Returns

Returns true on success, false otherwise.

set_line_in_boost()

bool set_line_in_boost	(	uint8_t	line,
		uint8_t	L2L,
		uint8_t	L2R,
		uint8_t	R2L,
		uint8_t	R2R
	)

Set line input boost.

Both left and right channels of each lines 1 and 3 can be routed to left and/or right line ADC channels. This can used to produce stereo sound from a single microphone.

Parameters

line	Line identifier between 1 and 3
L2L	left input into left channel between 0 (mute) and 10
L2R	left input into right channel between 0 (mute) and 10
R2L	right input into left channel between 0 (mute) and 10
R2R	right input into right channel between 0 (mute) and 10

Returns

Returns true on success, false otherwise.

set_line_out_volume()

bool set_line_out_volume	(	float	L2L,
		float	L2R,
		float	R2L,
		float	R2R
	)

Set volume for line output (and speakers)

Both left and right DAC channels can be routed to left and/or right line outputs. This can used to mix left and right channels into a single speaker for instance.

Parameters

L2L	left channel into left output
L2R	left channel into right output
R2L	right channel into left output
R2R	right channel into right output

Returns

Returns true on success, false otherwise.