Class AudioCodec

AudioCodec Class

Description

A class used for general control and management of the hardware audio codec functions.

Syntax

class AudioCodec

Members

Public Constructors
The public constructor is not recommended to be used as a singleton class. Class is for built-in Audio Codec.
Public Methods
AudioCodec::begin	Configure Audio Codec to start transmitting and receiving operations.
AudioCodec::end	Deinitialize all Audio Codec operations.
AudioCodec::getBufferPageSize	Get byte size per page, and default value is 1024.
AudioCodec::setSampleRate	Set the sample rate for transmitting and receiving.
AudioCodec::setBitDepth	Set the bit depth (bits per sample) for transmitting and receiving.
AudioCodec::setChannelCount	Set the number of channels for transmitting and receiving (Mono or Stereo).
AudioCodec::setInputMicType	Set microphone type input (analog or digital).
AudioCodec::setInputLRMux	Set input for audio multiplexing (left and right).
AudioCodec::setDMicBoost	Set boost gain for digital microphone input
AudioCodec::setAMicBoost	Set boost gain for analog microphone input
AudioCodec::setADCGain	Set Analog Digital Converter (ADC) gain to obtain analog input.
AudioCodec::muteInput	Mute input audio.
AudioCodec::setOutputVolume	Set output audio volume.
AudioCodec::muteOutput	Mute output audio
AudioCodec::writeAvaliable	Check if data buffer is available for data writing.
AudioCodec::writeDataPage	Write audio data to the available data buffer for data transmission.
AudioCodec::readAvaliable	Check for data buffer with audio data to be read.
AudioCodec::readDataPage	Read received audio data from buffer.
AudioCodec::setWriteCallback	Set a callback function to be notified when a data buffer is available for data write.
AudioCodec::setReadCallback	Set a callback function to be notified when there is available data buffer with audio data to be read.
AudioCodec::amplifyReadData	Set amplification value for input audio

AudioCodec::begin

Description

Configure and start the audio codec for transmit and receive operation.

Syntax

void begin(bool input, bool output);

Parameters

input: enable Audio Codec data input output: enable Audio Codec data output

Example Code

Example: BasicInputOutput

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::end

Description

Deinitialize all Audio Codec input and output operations.

Syntax

void end(void);

Example Code

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::getBufferPageSize

Description

Get byte size per page, and default value is 1024 bytes.

Syntax

uint32_t getBufferPageSize(void);

Returns

This function returns the size per page, in number of bytes (default: 1024).

The AudioCodec class includes a Tx and Rx buffer for storing audio sample data while it is being transferred to and from the DAC output and ADC input. The buffer is divided into fixed-size pages, allowing audio data to be read and written one page at a time. A buffer page may contain a different number of audio samples depending on the bit depth (bits per audio sample) and channel count set. “AudioCodec.h” must be included to use the class function.

AudioCodec::setSampleRate

Description

Set the sample rate for transmitting and receiving.

Syntax

void setSampleRate(uint32_t sampleRate);

Parameters

sampleRate: Audio Codec’s sampling rate in Hz. (Default: 48000 Hz). Supported values: 8000, 16000, 32000, 44100, 48000, 88200, 96000 (in Hz).

Returns

NA

Example Code

Example: BasicInputOutput

Note

Higher sample rates beyond 48000Hz will require more frequent buffer read and write operations to keep up with the large amount of data input and output. If there is insufficient processing time dedicated to this task, audio quality will be degraded. “AudioCodec.h” must be included to use the class function.

AudioCodec::setBitDepth

Description

Set the bit depth (bits per sample) for transmitting and receiving.

Syntax

void setBitDepth(uint8_t bitDepth);

Parameters

bitDepth: Number of bits per sample. (Default: 16 bits). Supported values: - 8 bits - 16 bits - 24 bits

Returns

NA

Example Code

NA

Note

Setting a bit depth of 24 bits per sample will require 32 bits (4 bytes) of buffer space for storing each sample, with the most significant byte ignored. “AudioCodec.h” must be included to use the class function.

AudioCodec::setChannelCount

Description

Set the number of channels for transmitting and receiving (Mono or Stereo).

Syntax

void setChannelCount(uint8_t monoStereo);

Parameters

monoStereo: number of channels. (Default: 1). Supported values: - 1 (Mono Channel) - 2 (Stereo Channel)

Returns

NA

Example Code

Example: PlaybackWavFile

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::setInputMicType

Description

Set microphone type input (analog or digital).

Syntax

Void setInputMicType(Mic_Type micType);

Parameters

micType: Input microphone type. (Default: ANALOGMIC). Valid values: - ANALOGMIC - microphone with an analog output - PDMMIC - digital microphone with a PDM output

Returns

NA

Example Code

NA

Note

For analog single-ended output, connect to PA_4 for the left channel and PA_2 for the right channel. For digital PDM output, connect the PDM clock to PB_1 and PDM data to PB_2. “AudioCodec.h” must be included to use the class function.

AudioCodec::setInputLRMux

Description

Set input for audio multiplexing (left and right).

Syntax

void setInputLRMux(uint32_t mux);

Parameters

mux: Left and right audio channel multiplexing setting. (Default value: RX_CH_LL). Valid values: - RX_CH_LR: Rx selected as left and right channel - RX_CH_RL : Rx selected as right and left channel - RX_CH_LL : Rx selected as only left channel - RX_CH_RR : Rx selected as only right channel

Returns

NA

Example Code

NA

Note

In mono channel mode, by selecting RX_CH_LR or RX_CH_LL will result in getting sampling input data from the left channel of the microphone while by selecting RX_CH_RL or RX_CH_RR will result in getting sampling input data from the right channel of the microphone. In stereo channel mode, RX_CH_RL will switch the positions of input data sampled from the microphones. RX_CH_RR and RX_CH_LL will result in duplicated samples from the right and left microphones respectively. “AudioCodec.h” must be included to use the class function.

AudioCodec::setDMicBoost

Description

Set boost gain for digital microphone input.

Syntax

void setDMicBoost(uint32_t leftBoost, uint32_t rightBoost);

Parameters

leftBoost: boost gain for left channel digital microphone input (Default: 0). rightBoost: boost gain for right channel digital microphone input (Default: 0). Valid boost gain values:

0 : 0dB
1 : 12dB
2 : 24dB
3 : 36dB

Returns

NA

Example Code

NA

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::setAMicBoost

Description

Set boost gain for analog microphone input.

Syntax

void setAMicBoost(uint32_t leftBoost, uint32_t rightBoost);

Parameters

leftBoost: boost gain for left channel analog microphone input (Default: 0). rightBoost: boost gain for right channel analog microphone input (Default: 0). Valid boost gain values:

0 : 0dB
1 : 20dB
2 : 30dB
3 : 40dB

Returns

NA

Example Code

NA

Note

Only use this function if additional gain is required after using setADCGain function. “AudioCodec.h” must be included to use the class function.

AudioCodec::setADCGain

Description

Set Analog Digital Converter (ADC) gain to obtain analog input.

Syntax

void setADCGain(uint32_t leftGain, uint32_t rightGain);

Parameters

leftGain: Gain for left channel ADC (Default: 0). rightGain: Gain for right channel ADC (Default: 0). Valid value range is from 0x00 to 0x7f. Gain increases by 0.375dB for every increment in value:

0x00 : -17.625dB
0x01 : -17.25dB
0x2f : 0dB
0x30 : 0.375dB
0x7f : 30dB

Returns

NA

Example Code

NA

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::muteInput

Description

Mute input audio.

Syntax

void muteInput(uint8_t leftMute, uint8_t rightMute);

Parameters

leftMute: 1 to mute left channel input, 0 to unmute (Default: 1). rightMute: 1 to mute right channel input, 0 to unmute (Default: 1).

Returns

NA

Example Code

NA

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::setOutputVolume

Description

Set output audio volume. Valid value ranges from 0 to 100 corresponding to a volume of -65.625dB to 0dB. If value > 100, it will be taken as 100.

Syntax

void setOutputVolume(uint8_t leftVol, uint8_t rightVol);

Parameters

leftVol: left channel output volume rightVol: right channel output volume

Returns

Na

Example Code

Example: BasicInputOutput

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::muteOutput

Description

Mute output audio.

Syntax

void muteOutput(uint8_t leftMute, uint8_t rightMute);

Parameters

leftMute: 1 to mute left channel output, 0 to unmute (Default: 1). rightMute: 1 to mute right channel output, 0 to unmute (Default: 1).

Returns

NA

Example Code

NA

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::writeAvaliable

Description

Check if data buffer is available for data writing.

Syntax

bool writeAvaliable(void);

Parameters

NA

Returns

This function returns true if there is a data buffer available for writing data. It returns false if no data buffers are available.

Example Code

Example: BasicInputOutput

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::writeDataPage

Description

Write audio data to the available data buffer for data transmission.

Syntax

uint32_t writeDataPage(int8_t* src, uint32_t len);
uint32_t writeDataPage(int16_t* src, uint32_t len);

Parameters

src: pointer to array containing audio samples to write to Audio Codec. len: number of audio samples in array.

Returns

This function returns the total number of audio samples written to the Audio Codec if there is available data buffer for data writing. Otherwise, it will return 0.

Example Code

Example: BasicInputOutput

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::readAvaliable

Description

Check for data buffer with audio data to be read.

Syntax

bool readAvaliable(void);

Parameters

NA

Returns

This function returns true if there is a data buffer with new data to be read. It returns false if all pages are empty.

Example Code

Example: BasicInputOutput

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::readDataPage

Description

Read received audio data from data buffer.

Syntax

uint32_t readDataPage(int8_t* dst, uint32_t len);
uint32_t readDataPage(int16_t* dst, uint32_t len);

Parameters

dst: pointer to array to contain audio samples read from Audio Codec. len: number of audio samples to read.

Returns

This function returns the total number of audio samples read from Audio Codec if data buffer with new data is present. Otherwise, it will return 0.

Example Code

Example: BasicInputOutput

Note

“AudioCodec.h” must be included to use the class function.

AudioCodec::setWriteCallback

Description

Set a callback function to be notified when a data buffer is available for data write.

Syntax

void setWriteCallback(void(*writeCB)(void));

Parameters

writeCB: function to be called when data buffer becomes available for data write. Takes no arguments and returns nothing.

Returns

NA

Example Code

NA

Note

After starting the Audio Codec with AudioCodec::begin(), the callback function will be called each time the Audio Codec finishes outputting the data in a buffer page. “AudioCodec.h” must be included to use the class function.

AudioCodec::setReadCallback

Description

Set a callback function to be notified when there is available data buffer with audio data to be read.

Syntax

void setReadCallback(void(*readCB)(void));

Parameters

readCB: function to be called when data buffer with new data becomes available for data read. Takes no arguments and returns nothing.

Returns

NA

Example Code

NA

Note

After starting the Audio Codec with AudioCodec::begin(), the callback function will be called each time the Audio Codec fills up a buffer page with newly acquired audio samples. “AudioCodec.h” must be included to use the class function.

AudioCodec::amplifyReadData

Description

To set amplification value for input audio data.

Syntax

void amplifyReadData(int16_t* dst, uint32_t len, uint8_t m);