30 min

Enhance your electrical control with TPS22918 and STM32L152RE combo

Revolutionize your electrical control with solid-state relays

SolidSwitch Click with Fusion for ARM v8

Published Oct 18, 2023

Click board™

SolidSwitch Click

Development board

Fusion for ARM v8


NECTO Studio



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



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

Fusion for ARM v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different ARM® Cortex®-M based MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for ARM v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the Fusion for ARM v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for ARM v8 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.

Fusion for ARM v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M3

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Power Supply
I2C Clock
I2C Data

Take a closer look


SolidSwitch Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for ARM v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

 * @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 ( 3000 );
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_ENABLE_OUT6 | SOLIDSWITCH_ENABLE_OUT7 );
    solidswitch_display_enabled_channels( );
    Delay_ms ( 3000 );
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_ENABLE_ALL_OUTPUTS );
    solidswitch_display_enabled_channels( );
    Delay_ms ( 3000 );
    solidswitch_write_single ( &solidswitch, SOLIDSWITCH_DISABLE_ALL_OUTPUTS );
    solidswitch_display_enabled_channels( );
    Delay_ms ( 3000 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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 );
                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