Intermediate
30 min

Improve your audio experience with KT403A and STM32L496AG

Your favorite tunes, just a click away

MP3 2 Click with Discovery kit with STM32L496AG MCU

Published Jul 22, 2025

Click board™

MP3 2 Click

Dev. board

Discovery kit with STM32L496AG MCU

Compiler

NECTO Studio

MCU

STM32L496AG

Our cutting-edge MP3 solution empowers you to immerse yourself in the world of music with unparalleled clarity and convenience. It's your ultimate companion for enjoying your favorite tunes anytime, anywhere.

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Hardware Overview

How does it work?

MP3 2 Click is based on the KT403A, a SOC chip solution with intergraded MCU, hardware audio MP3/WAV decoder and DSP, from Shenzhen Qianle Microelectronics Technology, as a main integrated circuit, micro SD card connector, and 3.5mm Audio Jack connector. Basically, it is a complete solution for a DAP (digital audio player) on a Click board, which can be controlled over the UART communication interface, using RX and TX pins of the mikroBUS™ socket. The default baud rate is 9600bps and it is customizable. On the MP3 2 Click, KT403A serves as a brain. It is complete SOC, which integrates16-bit MCU, audio decoder, and a 24-bit DSP. It also integrates the complete SD card interface and therefore, this click board

contains the connector onboard for an external micro SD card. Thanks to that, the user can insert a fair amount of memory if the long, continuous playback time is needed. MP3 2 Click has two status indication LEDs, onboard. The first one is named “SD Card” and it serves as an indication that the SD Card is present in the slot. The other one is “Chip Correct” and it indicates that the SD Card is correct and that the communication between the KT403A and the SD Card sucseeded. Besides the indicatora, there is one 3.5mm headphone jack onboard, so that MP3 2 Click can be connected directly to the next stage of the music playback system, ie. audio amplifier. Using the predefined command set, MP3 2 Click can be

fully controlled. One can Play/Pause a song, play a specific track, change a Volume Up and Volume Down between 0% and 100%, play the next or the previous song, repeat the current song, and more. Besides that, several sound effects are also supported, mentioned for different types of music: Normal, Jazz, Classic, Pop, and Rock. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. 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.

MP3 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

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PB2
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
UART TX
PG10
TX
UART RX
PB6
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
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Take a closer look

Click board™ Schematic

MP3 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

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 MP3 2 Click driver.

Key functions:

  • mp32_hw_reset - Reset the device function

  • mp32_rx_cmd - Received response data function

  • mp32_tx_cmd - Write command 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 
 * \brief Mp32 Click example
 * 
 * # Description
 * This example demonstates the use of MP3 2 Click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes the driver and enables the Click board.
 * Then sets the device to play songs from SD Card, and after that sets volume, and equalizer.
 * 
 * ## Application Task  
 * Demonstrates the use of play, play next, and pause modes.
 * Each step will be logged on the USB UART where you can track the program flow.
 * 
 * @note
 * A valid microSD Card that contains at least one mp3 sound on it needs to be 
 * inserted into the Click board.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "mp32.h"
#include "string.h"

// ------------------------------------------------------------------ VARIABLES

static mp32_t mp32;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    mp32_cfg_t cfg;

    /** 
     * 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.

    mp32_cfg_setup( &cfg );
    MP32_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    mp32_init( &mp32, &cfg );

    Delay_ms ( 500 );

    log_printf( &logger, "-------------------------\r\n" );
    log_printf( &logger, "       MP3 2 Click       \r\n" );
    log_printf( &logger, "-------------------------\r\n" );
    Delay_100ms( );

    mp32_hw_reset( &mp32 );
    Delay_ms ( 100 );
    
    mp32_set_device( &mp32, MP32_SDCARD );
    mp32_set_volume( &mp32, 50 );
    mp32_set_eq( &mp32, MP32_EQ_NORMAL );
    Delay_ms ( 100 );
}

void application_task ( void )
{
    log_printf( &logger, " >>> Play\r\n" );
    mp32_play_mode( &mp32 );
    // 10 seconds delay
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, " >>> Next song\r\n" );
    mp32_play_next( &mp32 );
    // 10 seconds delay
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, " >>> Pause\r\n" );
    mp32_pause_mode( &mp32 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );         
}

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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