AudioCodec Class

AudioCodec Class

Description
A class used for general control and management of the hardware Audio Codec functions.

Syntax
class AudioCodec

Members

AudioCodec::begin

Description
Configure Audio Codec to start transmitting and receiving operations.

Syntax
void begin(bool input, bool output);

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

Returns
NA

Example Code
Example: BasicInputOutput
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

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

AudioCodec::end

Description
Deintialize all Audio Codec input and output operations.

Syntax
void end(void);

Parameters
NA

Returns
NA

Example Code
NA

Notes and Warnings
“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);

Parameters
NA

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

Example Code
NA

Notes and Warnings
Notes and Warnings
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
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

Notes and Warnings
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

Notes and Warnings
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
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/PlaybackWavFile/PlaybackWavFile.ino)

Notes and Warnings
“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

Notes and Warnings
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

Notes and Warnings
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

Notes and Warnings
“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

Notes and Warnings
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

Notes and Warnings
“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

Notes and Warnings
“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
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

Notes and Warnings
“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

Notes and Warnings
“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
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

Notes and Warnings
“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 writting. Otherwise, it will return 0.

Example Code
Example: BasicInputOutput
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

Notes and Warnings
“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
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

Notes and Warnings
“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
(https://github.com/ambiot/ambd_arduino/blob/dev/Arduino_package/hardware/libraries/AudioCodec/examples/BasicInputOutput/BasicInputOutput.ino)

Notes and Warnings
“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

Notes and Warnings
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

Notes and Warnings
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.