wave.h File Reference

Waveform function generator. More...

#include <stdint.h>
#include "math.h"
#include "midi.h"

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Data Structures
struct	wave_settings
	Wave configuration. More...
struct	wave_state
	Internal state of a wave. More...
struct	wave
	The settings and internal state of a wave. More...

Macros
#define	RANDOM_WAVE_STEP_SIZE   4
	Step size of the random wave. More...
#define	STAIR_WAVE_STEPS   5
	Number of levels in the stair wave. More...
#define	WAVE_STEPS   100
	Number of different output levels of waves. More...
#define	TAP_TEMPO_BUFFER_SIZE   3
	Tap tempo buffer size. More...
#define	TAP_TEMPO_TASK_FREQUENCY   F_TASK_SLOW
	Tap tempo background task frequency. More...

Enumerations
enum	direction { DIRECTION_DOWN, DIRECTION_UP }
	Step counter direction. More...
enum	waveform {   WAVE_OFF, WAVE_SINE, WAVE_TRIANGLE, WAVE_SAW_UP,   WAVE_SAW_DOWN, WAVE_SQUARE, WAVE_STAIRS, WAVE_RANDOM }
	Enumeration of available waveforms. More...

Functions
void	configure_tap_tempo_wave (struct wave *const wave)
	Configures a wave for tap tempo functionality. More...
void	init_wave (struct wave *wave, enum waveform waveform, midi_value_t speed, midi_value_t amplitude, midi_value_t offset)
	Initializes a wave. More...
void	register_tap (void)
	Registers a tempo tap event. More...
void	reset_wave (struct wave *const wave)
	Resets a wave. More...
void	set_frequency (struct wave *wave, fixed_t frequency)
	Updates the frequency of a wave. More...
void	set_speed (struct wave *wave, midi_value_t speed)
	Updates the speed of a wave. More...
void	set_waveform (struct wave *wave, enum waveform waveform)
	Updates the waveform of a wave. More...
void	tap_tempo_task (void)
	Background task for the tap tempo function. More...
midi_value_t	update_wave (struct wave *wave)
	Computes the current wave output value. More...

Detailed Description

Waveform function generator.

Macro Definition Documentation

RANDOM_WAVE_STEP_SIZE

#define RANDOM_WAVE_STEP_SIZE   4

Step size of the random wave.

The output will change in a random direction by this amount

STAIR_WAVE_STEPS

#define STAIR_WAVE_STEPS   5

Number of levels in the stair wave.

TAP_TEMPO_BUFFER_SIZE

#define TAP_TEMPO_BUFFER_SIZE   3

Tap tempo buffer size.

The tempo is computed as an average over this many tapped tempo values.

TAP_TEMPO_TASK_FREQUENCY

#define TAP_TEMPO_TASK_FREQUENCY   F_TASK_SLOW

Tap tempo background task frequency.

See also

F_TASK_SLOW

WAVE_STEPS

#define WAVE_STEPS   100

Number of different output levels of waves.

Enumeration Type Documentation

direction

enum direction

Step counter direction.

Enumerator
DIRECTION_DOWN	The counter is counting down.
DIRECTION_UP	The counter is counting up.

waveform

enum waveform

Enumeration of available waveforms.

Enumerator
WAVE_OFF	No waveform.
WAVE_SINE	Sine wave.
WAVE_TRIANGLE	Triangle wave.
WAVE_SAW_UP	Saw up wave.
WAVE_SAW_DOWN	Saw down wave.
WAVE_SQUARE	Square wave.
WAVE_STAIRS	Stair wave.
WAVE_RANDOM	Random wave.

Function Documentation

configure_tap_tempo_wave()

void configure_tap_tempo_wave

(

struct wave *const

wave

)

Configures a wave for tap tempo functionality.

Parameters

wave	the wave to configure

See also

tap_tempo_task

init_wave()

void init_wave	(	struct wave *	wave,
		enum waveform	waveform,
		midi_value_t	speed,
		midi_value_t	amplitude,
		midi_value_t	offset
	)

Initializes a wave.

Parameters

wave	the wave to initialize
waveform	the initial waveform
speed	the initial speed
amplitude	the amplitude
offset	the static offset

See also

wave

waveform

register_tap()

void register_tap

(

void

)

Registers a tempo tap event.

This function must be called whenever a tempo tap event occurrs. It sets an internal flag to inform the background task about the event.

See also

tap_tempo_task

reset_wave()

void reset_wave

(

struct wave *const

wave

)

Resets a wave.

Re-initializes all internal counters and states of the supplied wave

Parameters

wave	the wave to reset

set_frequency()

void set_frequency	(	struct wave *	wave,
		fixed_t	frequency
	)

Updates the frequency of a wave.

Parameters

wave	the wave to update
frequency	the new frequency

See also

wave

set_speed()

void set_speed	(	struct wave *	wave,
		midi_value_t	speed
	)

Updates the speed of a wave.

Sets the wave frequency to the given speed in [BPM], adding an offset of 15 BPM.

Parameters

wave	the wave to update
speed	the new speed in [BPM]

See also

wave

set_waveform()

void set_waveform	(	struct wave *	wave,
		enum waveform	waveform
	)

Updates the waveform of a wave.

Parameters

wave	the wave to update
waveform	the new waveform

tap_tempo_task()

void tap_tempo_task

(

void

)

Background task for the tap tempo function.

This function must be registered as a slow background task. It computes a frequency from an incrementing internal counter and the task frequency and updates the speed of the wave configured for tap tempo operation.

See also

configure_tap_tempo_wave

register_tap

update_wave()

midi_value_t update_wave

(

struct wave *

wave

)

Computes the current wave output value.

This function must be called in a fast background task. Over time the output value follows the configured waveform.

Parameters

wave	the wave whose output should be computed

Returns

the current output value