Beginner
10 min

Enrich every note and deliver an unparalleled auditory journey using MAX9723 and STM32L496AG

Turn up the quality, not just the volume!

Headphone AMP 2 Click with Discovery kit with STM32L496AG MCU

Published Jul 22, 2025

Click board™

Headphone AMP 2 Click

Dev. board

Discovery kit with STM32L496AG MCU

Compiler

NECTO Studio

MCU

STM32L496AG

Our headphone amplifier is the ultimate companion for those who demand exceptional audio quality.

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Hardware Overview

How does it work?

Headphone AMP 2 Click is based on the MAX9723, a stereo DirectDrive headphone amplifier with BassMax, volume control, and I2C from Analog Devices. The headphone amplifier uses a DirectDrive architecture that produces a ground-referenced output from a single supply, thus eliminating the need for large DC-blocking capacitors. Its outputs are biased at 0V, making the amplifier outputs not have a DC component, improving a low-frequency response. The DirectDrive architecture uses a charge pump to create an internal negative supply voltage, which makes the dynamic range from a single supply almost double. Software-enabled bass boost (BassMax) boosts the bass response of the

amplifier, improving audio reproduction when using inexpensive headphones. This, in particular, comes in handy when reproducing low frequencies, where the limitations of the small physical size of the diaphragm are compensated by increasing the amplifier gain. The maximum amplifier gain on this chip is +6dB. The volume control adjusts the gain of the output amplifiers according to your needs over the software. The amplifier can enter the low-power shutdown mode, where the host MCU controls the shutdown mode. Headphone AMP 2 Click uses a standard 2-Wire I2C interface to communicate with the host MCU, supporting clock rates of up to 400kHz. The shutdown control is available on the SHD pin of

the mikroBUS™ socket. In addition to the 3.5mm input and output audio jacks, there are corresponding two channels input and output headers in case of the need to connect inputs or outputs incompatible with jack connectors (wire types). This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

Headphone AMP 2 Click hardware overview image

Features overview

Development board

The 32L496GDISCOVERY Discovery kit serves as a comprehensive demonstration and development platform for the STM32L496AG microcontroller, featuring an Arm® Cortex®-M4 core. Designed for applications that demand a balance of high performance, advanced graphics, and ultra-low power consumption, this kit enables seamless prototyping for a wide range of embedded solutions. With its innovative energy-efficient

architecture, the STM32L496AG integrates extended RAM and the Chrom-ART Accelerator, enhancing graphics performance while maintaining low power consumption. This makes the kit particularly well-suited for applications involving audio processing, graphical user interfaces, and real-time data acquisition, where energy efficiency is a key requirement. For ease of development, the board includes an onboard ST-LINK/V2-1

debugger/programmer, providing a seamless out-of-the-box experience for loading, debugging, and testing applications without requiring additional hardware. The combination of low power features, enhanced memory capabilities, and built-in debugging tools makes the 32L496GDISCOVERY kit an ideal choice for prototyping advanced embedded systems with state-of-the-art energy efficiency.

Discovery kit with STM32L496AG MCU double side image

Microcontroller Overview

MCU Card / MCU

STM32L496AG Image

Architecture

ARM Cortex-M4

MCU Memory (KB)

1024

Silicon Vendor

STMicroelectronics

Pin count

169

RAM (Bytes)

327680

You complete me!

Accessories

These standard small stereo earphones offer a high-quality listening experience with their top-notch stereo cable and connector. Designed for universal compatibility, they effortlessly connect to all MIKROE mikromedia and multimedia boards, making them an ideal choice for your electronic projects. With a rated power of 100mW, the earphones provide crisp audio across a broad frequency range from 20Hz to 20kHz. They boast a sensitivity of 100 ± 5dB and an impedance of 32Ω ± 15%, ensuring optimal sound quality. The Φ15mm speaker delivers clear and immersive audio. Cost-effective and versatile, these earphones are perfect for testing your prototype devices, offering an affordable and reliable audio solution to complement your projects.

Headphone AMP 2 Click accessories image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Shutdown Mode
PA0
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB8
SCL
I2C Data
PB7
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Headphone AMP 2 Click Schematic schematic

Step by step

Project assembly

Discovery kit with STM32H750XB MCU front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Discovery kit with STM32L496AG MCU as your development board.

Discovery kit with STM32H750XB MCU front image hardware assembly
Thermo 21 Click front image hardware assembly
Prog-cut hardware assembly
Thermo 21 Click complete accessories setup image hardware assembly
Board mapper by product7 hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Discovery kit with STM32H750XB MCU NECTO MCU Selection Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto image step 11 hardware assembly

Software Support

Library Description

This library contains API for Headphone AMP 2 Click driver.

Key functions:

  • headphoneamp2_set_command - Headphone AMP 2 set the command function.

  • headphoneamp2_enable - Headphone AMP 2 enable the device function.

  • headphoneamp2_disable - Headphone AMP 2 disable the device function.

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 Headphone AMP 2 Click example
 *
 * # Description
 * This example demonstrates the use of the Headphone AMP 2 Click board™, 
 * the headphone amplifier with BassMax and volume control.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * The initialization of I2C module and log UART.
 * After driver initialization, the app sets the default configuration.
 *
 * ## Application Task
 * This example demonstrates the use of the Headphone AMP 2 Click board™.
 * The application wakes up the device, enables BassMax and Maximum Gain modes, 
 * and switches the sound volume from level 1 to the max level.
 * Results are being sent to the UART Terminal, where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "headphoneamp2.h"

static headphoneamp2_t headphoneamp2;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    headphoneamp2_cfg_t headphoneamp2_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.
    headphoneamp2_cfg_setup( &headphoneamp2_cfg );
    HEADPHONEAMP2_MAP_MIKROBUS( headphoneamp2_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == headphoneamp2_init( &headphoneamp2, &headphoneamp2_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( HEADPHONEAMP2_ERROR == headphoneamp2_default_cfg ( &headphoneamp2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
    log_printf( &logger, "-------------------------\r\n" );
    Delay_ms ( 100 );
}

void application_task ( void ) 
{
    static headphoneamp2_cmd_t cmd_ctrl;
    cmd_ctrl.wakes_up = HEADPHONEAMP2_CMD_ENABLE;
    cmd_ctrl.bass_max = HEADPHONEAMP2_CMD_ENABLE;
    cmd_ctrl.gain_max = HEADPHONEAMP2_CMD_ENABLE;
    cmd_ctrl.volume   = HEADPHONEAMP2_VOL_MUTE;
    
    log_printf( &logger, " Volume : " );
    for ( uint8_t volume = HEADPHONEAMP2_VOL_LVL_1; volume <= HEADPHONEAMP2_VOL_LVL_MAX; volume++ )
    {
        cmd_ctrl.volume = volume;
        if ( HEADPHONEAMP2_OK == headphoneamp2_set_command( &headphoneamp2, cmd_ctrl ) )
        {
            log_printf( &logger, "|" );
        }
        Delay_ms ( 1000 );
    }
    log_printf( &logger, "\r\n-------------------------\r\n" );
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

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

Additional Support

Resources

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