Intermediate
30 min

Switch on to a new era of user-friendly interfaces with IQS2692A and STM32L496AG

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ProxFusion 3 Click with Discovery kit with STM32L496AG MCU

Published Jul 22, 2025

Click board™

ProxFusion 3 Click

Dev. board

Discovery kit with STM32L496AG MCU

Compiler

NECTO Studio

MCU

STM32L496AG

Add a touch of elegance to your solutions with our capacitive touch buttons, which provide a visually appealing and futuristic element to any electronic project

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Hardware Overview

How does it work?

ProxFusion 3 Click is based on the IQS269A, an eight-channel ProxFusion® capacitive, proximity, and touch controller with additional Hall-effect and inductive sensing, best-in-class signal-to-noise ratio, and low power consumption from Azoteq. The ProxFusion® module detects the capacitance change with a charge-transfer method. In effect, the IQS269A represents a low-power microcontroller that features ProxFusion® technology for high-end proximity and touch applications and provides a highly integrated capacitive-touch solution with flexibility, unique combination sensing, and long-term stability. The ProxFusion® module can periodically wake the CPU during low power mode based on a ProxFusion® timer source. Other features include automatic tuning and differential offset

compensation for sense electrodes. The Click board™ has eight PCB pads to sense touch or proximity events. These pads are the only elements on the top side of the board, allowing placement of the protective acrylic plexiglass layer. These pads can be programmed to generate a touch event when pressed and released. If a touch event is detected on one of the onboard pads, the state of the corresponding channel will be changed, indicating an activated channel; more precisely, touch has been detected on that specific channel. ProxFusion 3 Click communicates with MCU using a standard two-wire I2C interface that supports Fast Mode with a frequency of up to 400kHz. In addition to these pins, the IQS269A has a ready interrupt line, routed on the INT pin of the mikroBUS™ socket, that indicates a

communication window, and one general-purpose pin labeled as GP and routed on the PWM pin of the mikroBUS™ socket. The GP pin represents a custom touch-out/sync-in function with which one can assign a touch flag state of any channel. Besides, it also allows the choice of the least significant bit (LSB) of its I2C slave address by positioning the SMD jumper labeled as ADDR SEL to an appropriate position marked as 0 and 1. This Click board™ is designed to be operated only with a 3.3V logic voltage level. A proper logic voltage level conversion should be performed before the Click board™ is used 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.

ProxFusion 3 Click top side image
ProxFusion 3 Click bottom side 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
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Touch-Out/Sync-In
PA0
PWM
Interrupt
PH2
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

ProxFusion 3 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
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 ProxFusion 3 Click driver.

Key functions:

  • proxfusion3_get_touch - ProxFusion 3 get touch function

  • proxfusion3_check_touch_event - ProxFusion 3 check touch event function

  • proxfusion3_get_version_info - ProxFusion 3 get version info data 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 ProxFusion3 Click example
 *
 * # Description
 * Display information about the last detected touch.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes I2C driver, read and display version info value
 * and start to write log.
 *
 * ## Application Task
 * This is an example that demonstrates the use of the ProxFusion 3 Click board.
 * In this example, we check the touch event and display the last detected touch. 
 * Results are being sent to the Usart Terminal where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "proxfusion3.h"

static proxfusion3_t proxfusion3;
static log_t logger;

static uint8_t product_number;
static uint8_t software_version;

void application_init ( void ) {
    log_cfg_t log_cfg;                  /**< Logger config object. */
    proxfusion3_cfg_t proxfusion3_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_printf( &logger, "\r\n---------------------------\r\n" );
    log_info( &logger, " Application Init " );

    // Click initialization.

    proxfusion3_cfg_setup( &proxfusion3_cfg );
    PROXFUSION3_MAP_MIKROBUS( proxfusion3_cfg, MIKROBUS_1 );
    err_t init_flag = proxfusion3_init( &proxfusion3, &proxfusion3_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    proxfusion3_default_cfg ( &proxfusion3 );
    log_info( &logger, " Application Task " );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms ( 500 );
    
    proxfusion3_get_version_info( &proxfusion3, &product_number, &software_version );
    log_printf( &logger, "  Product Number   : 0x%.2X \r\n", ( uint16_t ) product_number );
    log_printf( &logger, "  Software Version : 0x%.2X \r\n", ( uint16_t ) software_version );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms ( 1000 );
    log_printf( &logger, "      Touch Detection      \r\n" );
    log_printf( &logger, "---------------------------\r\n" );
}

void application_task ( void ) {
    if ( proxfusion3_check_touch_event( &proxfusion3 ) == PROXFUSION3_EVENT_TOUCH ) {        
        uint8_t touch_data = proxfusion3_get_touch( &proxfusion3 );
        Delay_ms ( 100 );
        
        switch ( touch_data ) {
            case PROXFUSION3_TOUCH_POS_8: {
                log_printf( &logger, "       >>>   8   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_7: {
                log_printf( &logger, "       >>>   7   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_6: {
                log_printf( &logger, "       >>>   6   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_5: {
                log_printf( &logger, "       >>>   5   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_4: {
                log_printf( &logger, "       >>>   4   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_3: {
                log_printf( &logger, "       >>>   3   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_2: {
                log_printf( &logger, "       >>>   2   <<<       \r\n" );
                break;
            }
            case PROXFUSION3_TOUCH_POS_1: {
                log_printf( &logger, "       >>>   1   <<<       \r\n" );
                break;
            }
            default: {
                Delay_ms ( 10 );
                break;
            }
        }
        
        Delay_ms ( 10 );
    } else {
        Delay_ms ( 10 );
    }
}

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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