Bid farewell to frustrating volume fluctuations thanks to NJU72341 and ATmega1284 combo solution

Experience audio nirvana: Your volume, your way

Published Oct 22, 2023

Click board™

Volume 2 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega1284

Experience a higher level of audio quality and precision with our volume control device, which enhances clarity and fidelity for a more immersive listening experience

Hardware Overview

How does it work?

Volume 2 Click is based on the NJU72341, a 2-channel I2C configurable electronic volume IC with an external mute control from JRC. 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 against pop noise. 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 a symmetrical power supply, we have only one positive power supply in this case. 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 that combines 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 a standard I2C 2-Wire interface, with a clock frequency up to 100kHz in the Standard and 400kHz in the Fast Mode. Also, the user can have external mute control configurable through the PWM pin of the mikroBUS™ socket labeled as MTE. This Click board™ can be operated only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

3.3V

Ground

GND

Mute Control

PD4

PWM

INT

I2C Clock

PC0

SCL

I2C Data

PC1

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyAVR v7 Access DIP MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for Volume 2 Click driver.

Key functions:

volume2_update_vol_data - This function updates the volume by using direct defined structure options
volume2_device_mute - This function is used to set mute on or off by controlling the mte pin
volume2_generic_write - This function writes a desired number of data bytes starting from the selected register by using I2C serial interface

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * @file main.c
 * @brief Volume2 Click example
 *
 * # 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 :
 *
 * ## Application Init
 * UART LOG and I2C drivers are initialized, following the
 * default configuration. By default, both channels are set
 * to 9 dB gain with zero cross detection enabled.
 *
 * ## Application Task
 * The task performs and effect of switching the volume
 * from right to left channel and vice versa. Like playing
 * ping-pong with the sound.
 *
 * @author Stefan Nikolic
 *
 */

#include "board.h"
#include "log.h"
#include "volume2.h"

static volume2_t volume2;
static log_t logger;

static volume2_vol_data_t volume_upd_data;
static uint8_t rising_vol;
static uint8_t max_atten = 60;

void application_init ( void ) {
    log_cfg_t log_cfg;          /**< Logger config object. */
    volume2_cfg_t volume2_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.

    volume2_cfg_setup( &volume2_cfg );
    VOLUME2_MAP_MIKROBUS( volume2_cfg, MIKROBUS_1 );
    err_t init_flag = volume2_init( &volume2, &volume2_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    volume2_default_cfg( &volume2 );
    Delay_ms( 100 );
    log_info( &logger, " Application Task " );
}

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 );
}

void main ( void ) {
    application_init( );

    for ( ; ; ) {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END