audio.c File Reference

Audio Subsystem. More...

#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include "libdragon.h"
#include "regsinternal.h"

Defines
#define	TV_TYPE_LOC   0x80000300
	Memory location to read which determines the TV type.
#define	NUM_BUFFERS   4
	Number of buffers the audio subsytem allocates and manages.
#define	CALC_BUFFER(x)   ( ( ( ( x ) / 25 ) >> 3 ) << 3 )
	Macro that calculates the size of a buffer based on frequency.
DAC rates for different regions
#define	AI_NTSC_DACRATE   48681812
	NTSC DAC rate.
#define	AI_PAL_DACRATE   49656530
	PAL DAC rate.
#define	AI_MPAL_DACRATE   48628316
	MPAL DAC rate.
AI Status Register Values
#define	AI_STATUS_BUSY   ( 1 << 30 )
	Bit representing that the AI is busy.
#define	AI_STATUS_FULL   ( 1 << 31 )
	Bit representing that the AI is full.
Functions
void	audio_init (const int frequency, int numbuffers)
	Initialize the audio subsystem.
void	audio_close ()
	Close the audio subsystem.
void	audio_write (const short *const buffer)
	Write a chunk of audio data.
void	audio_write_silence ()
	Write a chunk of silence.
volatile int	audio_can_write ()
	Return whether there is an empty buffer to write to.
int	audio_get_frequency ()
	Return actual frequency of audio playback.
int	audio_get_buffer_length ()
	Get the number of stereo samples that fit into an allocated buffer.

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Detailed Description

Audio Subsystem.