1.1.1 AK4953 CODEC Driver Library Help

The interface to the AK4953 Codec Driver library is defined in the audio/driver/codec/AK4953/drv_AK4953.h header file. Any C language source (.c) file that uses the AK4953 Codec Driver library should include this header.

Library Source Files:

The AK4953 Codec Driver library source files are provided in the audio/driver/codec/AK4953/src directory. This folder may contain optional files and alternate implementations. Please refer to Configuring the Library for instructions on how to select optional features and to Building the Library for instructions on how to build the library.

This topic describes system initialization, implementations, and includes a system access code example.

Description

The system performs the initialization of the device driver with settings that affect only the instance of the device that is being initialized. During system initialization in the system_init.c file, each instance of the AK4953 module would be initialized with the following configuration settings (either passed dynamically at run time using DRV_AK4953_INIT or by using Initialization Overrides) that are supported by the specific AK4953 device hardware:

• Device requested power state: one of the System Module Power States. For specific details please refer to Data Types and Constants in the Library Interface section.
• I2C driver module index. The module index should be same as the one used in initializing the I2C Driver
• I2S driver module index. The module index should be same as the one used in initializing the I2S Driver
• Sampling rate
• Volume
• Audio data format. The audio data format should match with the audio data format settings done in I2S driver initialization
• Determines whether or not the microphone input is enabled

The DRV_AK4953_Initialize API returns an object handle of the type SYS_MODULE_OBJ. The object handle returned by the Initialize interface would be used by the other system interfaces such as DRV_AK4953_Deinitialize, DRV_AK4953_Status and DRV_I2S_Tasks.

This topic describes driver initialization and provides a code example.

Description

For the application to start using an instance of the module, it must call the DRV_AK4953_Open function. The DRV_AK4953_Open function provides a driver handle to the AK4953 Codec Driver instance for operations. If the driver is deinitialized using the function DRV_AK4953_Deinitialize, the application must call the DRV_AK4953_Open function again to set up the instance of the driver.

For the various options available for IO_INTENT, please refer to Data Types and Constants in the Library Interface section.

Example:

DRV_HANDLE handle; SYS_STATUS ak4953Status;

ak4953Status Status = DRV_AK4953_Status(sysObjects.ak4953Status DevObject); if (SYS_STATUS_READY == ak4953Status)

{

\/\/ The driver can now be opened.

appData.ak4953Client.handle = DRV_AK4953_Open

(DRV_AK4953_INDEX_0, DRV_IO_INTENT_WRITE | DRV_IO_INTENT_EXCLUSIVE); if(appData.ak4953Client.handle != DRV_HANDLE_INVALID)

{

appData.state = APP_STATE_AK4953_SET_BUFFER_HANDLER;

}

else

{

SYS_DEBUG(0, "Find out what's wrong \r\n");

}

}

else

{

\/* AK4953 Driver Is not ready *\/

}

This topic provides information on client operations.

Description

Client operations provide the API interface for control command and audio data transfer to the AK4953 Codec.

The following AK4953 Codec specific control command functions are provided:

• DRV_AK4953_SamplingRateSet
• DRV_AK4953_SamplingRateGet
• DRV_AK4953_VolumeSet
• DRV_AK4953_VolumeGet
• DRV_AK4953_MuteOn
• DRV_AK4953_MuteOff

These functions schedule a non-blocking control command transfer operation. These functions submit the control command request to the AK4953 Codec. These functions submit the control command request to I2C Driver transmit queue, the request is processed immediately if it is the first request, or processed when the previous request is complete.

DRV_AK4953_BufferAddWrite, DRV_AK4953_BufferAddRead, and DRV_AK4953_BufferAddWriteRead are buffered data operation functions. These functions schedule non-blocking audio data transfer operations. These functions add the request to I2S Driver transmit or receive buffer queue depends on the request type, and are executed immediately if it is the first buffer, or executed later when the previous buffer is complete. The driver notifies the client with

DRV_AK4953_BUFFER_EVENT_COMPLETE, DRV_AK4953_BUFFER_EVENT_ERROR, or DRV_AK4953_BUFFER_EVENT_ABORT events.

The configuration of the I2S Driver Library is based on the file configurations.h, as generated by the MCC.

This header file contains the configuration selection for the I2S Driver Library. Based on the selections made, the I2S Driver Library may support the selected features. These configuration settings will apply to all instances of the I2S Driver Library.

This header can be placed anywhere; however, the path of this header needs to be present in the include search path for a successful build. Refer to the Applications Help section for more details.

Provides examples on how to configure the MPLAB Code Configurator (MCC) for a specific driver.

Description

When building a new application, start by creating a 32-bit MPLAB Harmony 3 project in MPLAB X IDE by selecting File > New Project. Chose the Configuration name the based on the BSP, and select the appropriate processor.

In the MCC, under Available Components select the appropriate BSP. Under Audio>Templates, double-click on a codec template such as AK4953. Answer Yes to all questions.

You should end up with a project graph that looks like this, after rearranging the boxes:

Click on the AK4953 Driver component (not AK4953 Codec) and the following menu will be displayed in the Configurations Options:

• I2C Driver Used will display the driver instance used for the I2C interface.
• I2S Driver Used will display the driver instance used for the I2S interface.
• Usage Mode indicates whether the AK4953 is a Host (supplies I2S clocks) or a Client (MCU supplies I2S clocks).
• Number of AK4953 Clients indicates the maximum number of clients that can be connected to the AK4953 Driver.
• Sampling Rate indicates the number of samples per second per channel, 8000 to 96,000.
• Volume indicates the volume in a linear scale from 0-255.

• Audio Data Format is either

• 24-bit Left Justified (ADC), 24-bit Right-justified(DAC)
• 24-bit Left Justified (ADC), 16-bit Right-justified(DAC)
• 24-bit Left Justified (ADC), 24-bit Left-justified(DAC)
• 24/16-bit I2S

It must match the audio protocol and data length set up in either the SSC or I2S PLIB.

• Microphone/Line Input selects which microphone or line input is selected, either:
• Internal Mic (mounted on the AK4953 daughterboard)
• External Mic Input
• Line Input

If External Mic input or Line Input is selected, then the following option is provided:

• Ext Mic Gain in dB range 0(min) to 31(max)

If External Mic input is selected, then the following option is provided:

• Enable Microphone Bias should be checked if using an electret microphone.

You can also bring in the AK4953 Driver by itself, by double clicking AK4953 under Audio_->Driver->Codec_ in the Available Components list. You will then need to add any additional needed components manually and connect them together.

Note that the AK4953 requires the TCx Peripheral Library and TIME System Service in order to perform some of its internal timing sequences.

This section lists the files that are available in the AK4953 Codec Driver Library.

Description

This section lists the files that are available in the src folder of the AK4953 Codec Driver. It lists which files need to be included in the build based on either a hardware feature present on the board or configuration option selected by the system.

The following three tables list and describe the header (.h) and source (.c) files that implement this library. The parent folder for these files is audio/driver/codec/AK4953\. Interface File(s)

This table lists and describes the header files that must be included (i.e., using #include) by any code that uses this library.

Client Setup Functions

Data Transfer Functions

Data Types and Constants

Other Functions

Settings Functions

System Interaction Functions