Intermediate
30 min

Enhance your electrical control with TPS22918 and STM32L496AG combo

Revolutionize your electrical control with solid-state relays

SolidSwitch Click with Discovery kit with STM32L496AG MCU

Published Jul 22, 2025

Click board™

SolidSwitch Click

Dev. board

Discovery kit with STM32L496AG MCU

Compiler

NECTO Studio

MCU

STM32L496AG

Experience a new era of electrical control with our solid-state relay innovations, designed to meet the demands of modern technology

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Hardware Overview

How does it work?

SolidSwitch Click is based on the TPS22918, a 5.5V 2A load switch from Texas Instruments. To reduce voltage drop for low voltage and high current rails, every TPS22918 implements a low resistance N-channel MOSFET, reducing the drop-out voltage across the device. An ON/OFF input on the ON pin of the TPS22918 controls the switches. The ON pin is compatible with the standard GPIO logic threshold and can be used with any MCU with 1V or higher GPIO voltage. That’s why the control of all switches is established via the port expander, the MAX7323. This Click board™ is designed to operate from an external supply voltage range from 1V to 5.5V. The TPS22918 works regardless of power sequencing order. The order in which

voltages are applied to the VIN terminal and ON pin of the load switch will not damage the device as long as the voltages stay within the absolute maximum operating conditions. SolidSwitch Click communicates with MCU through the MAX7323 port expander using the standard I2C 2-Wire interface with a frequency of up to 400kHz. It also has two address pins (A0 and A1) programmed by the user to determine the value of the last two LSBs of the slave address, selected by onboard SMD jumpers labeled as ADDR SEL to an appropriate position marked as 0 and 1, allowing selection of the slave address LSBs. Also, this Click board™ has a Reset pin, routed to the RST pin on the mikroBUS™ socket, which clears the serial

interface in case of a bus lockup, terminating any serial transaction to or from the MAX7323. Also, it uses an additional pin, the INT pin of the mikroBUS™ socket, which automatically flags data changes on any of the I/O ports of the MAX7323 used as inputs. The interrupt output INT and all transition flags are de-asserted when the MAX7323 is accessed through the serial interface. 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, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

SolidSwitch 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
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

SolidSwitch 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 SolidSwitch Click driver.

Key functions:

  • solidswitch_write_single - SolidSwitch I2C writing logic state function.

  • solidswitch_read_single - SolidSwitch I2C reading logic state function.

  • solidswitch_reset - Click Default Configuration 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 SolidSwitch Click example
 *
 * # Description
 * This example demonstrates the use of SolidSwitch Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger and enables the Click board.
 *
 * ## Application Task
 * Enables different outputs every 3 seconds and displays all enabled 
 * outputs on USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "solidswitch.h"

static solidswitch_t solidswitch;
static log_t logger;

/**
 * @brief Displays all enabled channels on USB UART.
 * @details This function reads logic state of outputs and 
 *          displays all enabled channels on USB UART.
 * 
 * @return None.
 * @note None.
 */
static void solidswitch_display_enabled_channels ( void );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    solidswitch_cfg_t solidswitch_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.

    solidswitch_cfg_setup( &solidswitch_cfg );
    SOLIDSWITCH_MAP_MIKROBUS( solidswitch_cfg, MIKROBUS_1 );
    err_t init_flag = solidswitch_init( &solidswitch, &solidswitch_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    solidswitch_default_cfg ( &solidswitch );
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_ENABLE_OUT0 | SOLIDSWITCH_ENABLE_OUT1 );
    solidswitch_display_enabled_channels( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_ENABLE_OUT6 | SOLIDSWITCH_ENABLE_OUT7 );
    solidswitch_display_enabled_channels( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_ENABLE_ALL_OUTPUTS );
    solidswitch_display_enabled_channels( );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_DISABLE_ALL_OUTPUTS );
    solidswitch_display_enabled_channels( );
    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;
}

static void solidswitch_display_enabled_channels ( void )
{
    uint8_t logic_state;
    uint8_t enabled_flag = 0;
    
    solidswitch_read_single ( &solidswitch, &logic_state );
    log_printf( &logger, " Outputs enabled: " );
    for ( uint8_t cnt = 0; cnt < 8; cnt++ )
    {
        if ( logic_state & 1 )
        {
            if ( enabled_flag == 1 )
            {
                log_printf( &logger, ", %u", ( uint16_t ) cnt );
            }
            else
            {
                log_printf( &logger, " %u", ( uint16_t ) cnt );
            }
            enabled_flag = 1;
        }
        logic_state >>= 1;
    }
    
    if ( enabled_flag == 0 )
    {
        log_printf( &logger, " none" );
    }
    log_printf( &logger, "\r\n-----------------------\r\n" );
}

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

Additional Support

Resources

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