30 min

Gain real-time insights into the behavior of electrical currents using ACS70331 and MK20DN128VFM5

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Current 4 Click with UNI Clicker

Published Aug 12, 2023

Click board™

Current 4 Click

Development board

UNI Clicker


NECTO Studio



Achieve operational excellence by utilizing our current measurement solution to track current variations, enabling you to make data-driven decisions for improved efficiency and reduced downtime



Hardware Overview

How does it work?

Current 4 Click is based on the INA250, a current-sense amplifier with a high-precision, low-drift shunt resistor, which can deliver highly accurate measurements over a wide temperature range from Texas Instruments. The INA250 measures the voltage developed across the internal current-sensing resistor when current passes through it. The integrated 2mΩ shunt resistor offers 0.1% tolerance and a low drift of 15pmm/°C, enabling the higher performance of the end equipment. This amplifier allows for high-accuracy current measurements at common-mode voltages and offers a maximum error of 0.84% over a wide temperature range. Current 4 Click communicates with MCU using only one pin routed on the AN pin of the mikroBUS™ socket. The output analog

signal from INA250 is forwarded to the input of the operational amplifier, the LMV321 low-voltage rail-to-rail OpAmp from Texas Instruments, representing the most cost-effective solution for applications where low voltage operation is needed. The output of the LMV321 OpAmp has a stable unity gain, acting as a buffer so that the host MCU can sample the output voltage of the INA250 via the AN pin of the mikroBUS™ socket. The INA250 can be configured to measure both unidirectional and bidirectional currents through the reference voltage level. For unidirectional operation, the reference pin should be tied to the ground. When the current increases, the output signal increases upwards from this reference voltage (or ground in this case). For bidirectional

currents, an external voltage source can be used as the reference voltage; in this case, a low dropout linear regulator AP7331 from Diodes Incorporated provides the 2.5V reference supply voltage for the INA250. The reference voltage level can be selected by positioning the SMD jumper labeled VREF SEL to an appropriate position choosing between 2.5V provided by AP7331 or GND. 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.

Current 4 Click hardware overview image
Current 4 Click Current Warning image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Analog Signal
Power Supply
Power Supply

Take a closer look


Current 4 Click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Current 4 Click driver.

Key functions:

  • current4_read_load_current - Read load current

  • current4_read_an_pin_voltage - Read AN pin voltage level function

  • current4_read_an_pin_value - Read AN pin value 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 Current 4 Click Example.
 * # Description
 * This example showcases the ability of the Current 4 Click board.
 * It configures Host MCU for communication and reads the voltage 
 * of AN pin and calculates current on load output.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initialization of the communication modules(ADC and UART).
 * ## Application Task
 * In span on 500ms reads voltage and calculates the current on load.
 * @author Luka Filipovic

#include "board.h"
#include "log.h"
#include "current4.h"

static current4_t current4;   /**< Current 4 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void )
    log_cfg_t log_cfg;  /**< Logger config object. */
    current4_cfg_t current4_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.
    current4_cfg_setup( &current4_cfg );
    CURRENT4_MAP_MIKROBUS( current4_cfg, MIKROBUS_1 );
    if ( ADC_ERROR == current4_init( &current4, &current4_cfg ) )
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    log_info( &logger, " Application Task " );

void application_task ( void ) 
    float current4_load_current = 0;

    if ( ADC_ERROR != current4_read_load_current ( &current4, &current4_load_current ) ) 
        log_printf( &logger, " > Load current : %.2f[A]\r\n", current4_load_current );
        log_printf( &logger, "**********************\r\n" );

    Delay_ms( 500 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support