Volume 2 Click

How does it work?

Volume 2 Click as its foundation uses the NJU72341, a 2-channel I2C configurable electronic volume IC with an external mute control from NJRC. The NJU72341 operates as an audio signal processor with many characteristics useful in an audio application, such as low noise typical of 2.0µVrms and low distortion of 0.002%. It controls two independent audio channels with a vast volume control range from 0 to 95dB with 1dB step offering zero-cross detection to protect pop noise. That’s why this Click board™ is suitable for stereo and multi-channel audio systems.

The NJU72341 has to receive a specific supply voltage to operate appropriately, in this case, 12V. Unlike the Volume Click, which has symmetrical power supply, in this case, we have only one positive power supply. Bringing just a positive power supply, the noise generated by that power supply will transmit to the output, representing a side effect. For this purpose, Volume 2 Click employs a boost converter unit made by combining MIC5235 and MIC2606, both from Microchip. MIC5235 provides 13V out of 5V from the mikroBUS™ power rail, which then the MIC2606, with a feature of massive noise suppression, lowers it to 12V and then supplies NJU72341 reducing the noise generated at its output.

Volume 2 Click communicates with MCU using standard I2C 2-Wire interface, with a clock frequency up to 100kHz in the Standard and 400kHz in the Fast Mode. Also, the user has the option of external mute control configurable through the PWM pin of the mikroBUS™ socket labeled as MTE.

This Click board™ operates only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on Volume 2 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	MTE	MUTE Control
	NC	2	RST	INT	15	NC
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
	NC	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Volume 2 Click electrical specifications

Software Support

We provide a library for the Volume 2 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on mikroE github account.

Library Description

This library contains API for Volume 2 Click driver.

Key functions:

• volume2_cfg_setup – Config Object Initialization function.
• volume2_init – Initialization function.
• volume2_default_cfg – Click Default Configuration function.

Examples description

This example shows how Volume 2 Click board™ can be used for controlling the audio channels. Thanks to this, a simple audio effect is created by switching volume from right to left and vice versa.

The demo application is composed of two sections :

void application_task ( void ) {
    for ( rising_vol = 0 ; rising_vol < max_atten ; rising_vol++ ) {
        volume_upd_data.attenuation_ch1 = rising_vol;
        volume_upd_data.attenuation_ch2 = max_atten - rising_vol;
        volume2_update_vol_data( &volume2, volume_upd_data );
        Delay_ms( 50 );
    }
    Delay_ms( 1000 );
    for ( rising_vol = 0 ; rising_vol < max_atten ; rising_vol++ ) {
        volume_upd_data.attenuation_ch1 = max_atten - rising_vol;
        volume_upd_data.attenuation_ch2 = rising_vol;
        volume2_update_vol_data( &volume2, volume_upd_data );
        Delay_ms( 50 );
    }
    Delay_ms( 1000 );
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on mikroE github account.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Volume2

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.