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LED Driver 15 Click with UNI Clicker

Published Sep 09, 2023

Click board™

LED Driver 15 Click

Development board

UNI Clicker


NECTO Studio



Our LED driver solution harmoniously powers up to 8 white LEDs in series, offering a brilliant and energy-efficient lighting experience for various applications



Hardware Overview

How does it work?

LED Driver 15 Click is based on the MP3309C, a white LED step-up converter from Monolithic Power Systems that uses peak current mode to regulate the current through the LED string using an external low-side resistor. The MP3309C offers high efficiency and features a programmable switching frequency to optimize efficiency. It delivers up to 40mA of LED current supporting up to 8 white LEDs in series connected to the LED terminal. The MP3309C also has integrated protection circuitry to guard against thermal overstress and electrical damage, featuring LED

open protection, cycle-by-cycle current limit protection, under-voltage protection (UVP), and thermal shutdown protection. The MP3309C provides two dimming methods, PWM and analog dimming mode. It uses a PWM signal from the mikroBUS™ socket for PWM dimming. When the PWM signal is in a low logic state, the MP3309C stops switching and resumes Normal operation when the PWM signal is in a high logic state. Using a 100Hz to 2kHz PWM dimming frequency for most dimming ratio requests is recommended. The MP3309C set the LED current amplitude for

analog dimming through the I2C interface. LED Driver 15 Click communicates with MCU using the standard I2C 2-Wire interface that supports Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operation. 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.

LED Driver 15 Click top side image
LED Driver 15 Click bottom side 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



MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Power Supply
PWM Signal
I2C Clock
I2C Data
Power Supply

Take a closer look


LED Driver 15 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 LED Driver 15 Click driver.

Key functions:

  • leddriver15_set_i2c_dimming - This function sets the LEDs dimming level in I2C mode

  • leddriver15_enable_device - This function enables the device by setting the EN pin to high logic state

  • leddriver15_disable_device - This function disables the device by setting the EN pin to low logic state.

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 LED Driver 15 Click example
 * # Description
 * This example demonstrates the use of LED Driver 15 click board by changing
 * the LEDs dimming level.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initializes the driver and performs the click default configuration.
 * ## Application Task
 * Changes the LEDs dimming level in I2C mode every 500ms. The dimming level will be
 * displayed on the USB UART.
 * @note
 * It is recommended to connect 8 LEDs in series (40mA) to the output connector.
 * @author Stefan Filipovic

#include "board.h"
#include "log.h"
#include "leddriver15.h"

static leddriver15_t leddriver15;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    leddriver15_cfg_t leddriver15_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.
    leddriver15_cfg_setup( &leddriver15_cfg );
    LEDDRIVER15_MAP_MIKROBUS( leddriver15_cfg, MIKROBUS_1 );
    if ( LEDDRIVER15_OK != leddriver15_init( &leddriver15, &leddriver15_cfg ) ) 
        log_error( &logger, " Communication init." );
        for ( ; ; );
    if ( LEDDRIVER15_OK != leddriver15_default_cfg ( &leddriver15 ) )
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    log_info( &logger, " Application Task " );

void application_task ( void ) 
    static uint8_t dimming = LEDDRIVER15_I2C_DIMMING_MIN;
    if ( LEDDRIVER15_OK == leddriver15_set_i2c_dimming ( &leddriver15, dimming ) )
        log_printf( &logger, " Dimming level: %u\r\n\n", ( uint16_t ) dimming );
    if ( ++dimming > LEDDRIVER15_I2C_DIMMING_MAX )
        dimming = LEDDRIVER15_I2C_DIMMING_MIN;
    Delay_ms( 500 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support