audio.h File Reference

Functions to use the audio channels and microphone from the ARM7. More...

#include <nds/arm7/serial.h>
#include <nds/system.h>
#include <nds/timers.h>

Typedefs
typedef void(*	MIC_BUF_SWAP_CB) (u8 *completedBuffer, int length)
	Callback called whenever one buffer used micStartRecording() is full.

Functions
void	disableSound (void)
	Disable sound hardware.
void	enableSound (void)
	Enable sound hardware and clear sound registers.
void	installSoundFIFO (void)
	Install the libnds sound FIFO handler.
static void	micOff (void)
	Turn the microphone OFF.
static void	micOn (void)
	Turn the microphone ON.
u16	micReadData12 (void)
	Read a 12-bit unsigned value from the microphone.
s16	micReadData16 (void)
	Read a 16-bit signed value from the microphone.
u8	micReadData8 (void)
	Read a 8-bit unsigned value from the microphone.
void	micSetAmp (u8 control, u8 gain)
	Turn amplifier on or off and set the gain in db.
void	micStartRecording (u8 *buffer, int length, int freq, int timer, bool eightBitSample, MIC_BUF_SWAP_CB bufferSwapCallback)
	Start recording data from the microphone.
int	micStopRecording (void)
	Stop recording data, and return the length of data recorded.
void	micTimerHandler (void)
	Routine that must be called from a timer interrupt to get samples from the microphone.
bool	soundExtSetFrequencyTWL (unsigned int freq_khz)
	Set extended sound hardware frequency.

Detailed Description

Functions to use the audio channels and microphone from the ARM7.

Typedef Documentation

MIC_BUF_SWAP_CB

typedef void(* MIC_BUF_SWAP_CB) (u8 *completedBuffer, int length)

Callback called whenever one buffer used micStartRecording() is full.

Parameters

completedBuffer	Pointer to the buffer that has been filled.
length	Size of the buffer in bytes.

Function Documentation

micReadData12()

u16 micReadData12

(

void

)

Read a 12-bit unsigned value from the microphone.

Returns

The 12 bit value.

micReadData16()

s16 micReadData16

(

void

)

Read a 16-bit signed value from the microphone.

Returns

The 16 bit signed value.

micReadData8()

u8 micReadData8

(

void

)

Read a 8-bit unsigned value from the microphone.

Returns

The 8 bit unsigned value.

micSetAmp()

void micSetAmp	(	u8	control,
		u8	gain
	)

Turn amplifier on or off and set the gain in db.

Parameters

control	Use PM_AMP_ON or PM_AMP_OFF.
gain	Use one of PM_GAIN_20, PM_GAIN_40, PM_GAIN_80 or PM_GAIN_160.

micStartRecording()

void micStartRecording	(	u8 *	buffer,
		int	length,
		int	freq,
		int	timer,
		bool	eightBitSample,
		MIC_BUF_SWAP_CB	bufferSwapCallback
	)

Start recording data from the microphone.

Fills the buffer with data from the microphone. The buffer will be signed sound data at 16 kHz. Once the length of the buffer is reached, no more data will be stored. It uses the specified ARM7 timer.

Parameters

buffer	Destination buffer.
length	Destination buffer length in bytes.
freq	Frequency of the recording.
timer	Hardware timer to use to get samples from the microphone.
eightBitSample	Set to true to record 8 bit samples instead of 12 bit.
bufferSwapCallback	Callback called whenver the buffer is filled.

micStopRecording()

int micStopRecording

(

void

)

Stop recording data, and return the length of data recorded.

Returns

Returns the length in bytes.

soundExtSetFrequencyTWL()

bool soundExtSetFrequencyTWL

(

unsigned int

freq_khz

)

Set extended sound hardware frequency.

Parameters

freq_khz

Frequency in KHz. The default is 32, but 47 is allowed too.

Returns

Returns true if the change was successful.