audio.h File Reference

Audio. More...

#include <stdint.h>

Functions
uint16_t	ac97GetReg (uint8_t reg)
	Read register value from AC97 codec. More...
void	ac97SetReg (uint8_t reg, uint16_t value)
	Set register value in AC97 codec. More...
void	ac97Start ()
	Start AC97 codec. More...
void	ac97Stop ()
	Stop AC97 codec. More...
bool	audioHeadphonesConnected ()
	Check if headphones are connected (F100 only). More...
void	audioInit (int dmaChannel)
	Initialise audio subsystem. More...
void	audioMuteHeadphones ()
	Mute headphones. More...
void	audioMuteSpeakers ()
	Mute speakers. More...
void	audioPlaySample (uint16_t bytes, void *data)
	Play a PCM sample. More...
bool	audioSamplePlaying ()
	Check if a sample is currently playing. More...
void	audioSetSampleRate (uint16_t khz)
	Set sample rate for AC97 codec. More...
void	audioSetVolume (uint8_t left, uint8_t right)
	Set volume. More...
void	audioUnmuteHeadphones ()
	Unmute headphones. More...
void	audioUnmuteSpeakers ()
	Unmute speakers. More...

Function Documentation

ac97GetReg()

uint16_t ac97GetReg

(

uint8_t

reg

)

Read register value from AC97 codec

Note

Must have called ac97Start() or audioInit() before using this.

Parameters

reg	Register to read

Returns

Register value

See also

ac97Start

audioInit

ac97SetReg()

void ac97SetReg	(	uint8_t	reg,
		uint16_t	value
	)

Set register value in AC97 codec.

Note

Must have called ac97Start() or audioInit() before using this.

Parameters

reg	Register to set
value	Value to set

See also

ac97Start

audioInit

ac97Start()

void ac97Start

(

)

Start AC97 codec, will restart codec if it was previously started.

Note

DMA channels must have been set up before calling this.

ac97Stop()

void ac97Stop

(

)

Stop AC97 codec.

audioHeadphonesConnected()

bool audioHeadphonesConnected

(

)

Check if headphones are connected. This works on the F100 only, the F200 physically switches the DAC output between the speakers and headphones when you insert the jack.

Note

F100 only

Returns

true if headphones are connected, false otherwise

audioInit()

void audioInit

(

int

dmaChannel

)

Initialise auto subsystem.

Parameters

dmaChannel

DMA channel to use for audio (0 - 15, recommend 0 - 3)

audioMuteHeadphones()

void audioMuteHeadphones

(

)

Mute headphones.

audioMuteSpeakers()

void audioMuteSpeakers

(

)

Mute speakers.

audioPlaySample()

void audioPlaySample	(	uint16_t	bytes,
		void *	data
	)

Play a PCM sample. Non-blocking, see if the sample has finished playing with audioSamplePlaying().

Parameters

bytes	Number of bytes in sample (max 0xFFFF)
data	Pointer to sample data

See also

audioSamplePlaying

audioSamplePlaying()

bool audioSamplePlaying

(

)

Check if a sample is currently playing.

Returns

true if a sample is currently playing, false otherwise

audioSetSampleRate()

void audioSetSampleRate

(

uint16_t

khz

)

Set sample rate for AC97 codec.

Note

Must have called audioInit() before using this.

Parameters

khz	Sample rate to set

See also

ac97Start

audioInit

audioSetVolume()

void audioSetVolume	(	uint8_t	left,
		uint8_t	right
	)

Set volume.

@warn You may not wish to allow the volume to reach 31, with headphones connected this could do damage to somebody's hearing!

Parameters

left	Volume level for left channel (0 [lowest] - 31 [highest])
right	Volume level for right channel (0 [lowest] - 31 [highest])

audioUnmuteHeadphones()

void audioUnmuteHeadphones

(

)

Unmute headphones.

audioUnmuteSpeakers()

void audioUnmuteSpeakers

(

)

Unmute speakers.