Beginner
10 min

Create dynamic visual indicators, counters, and notifications with IS31FL3733 and ATmega328P

Compact and versatile red LED matrix solution for dynamic visual indicators and displays

16x12 R Click with Arduino UNO Rev3

Published Sep 22, 2025

Click board™

16x12 R Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Go-to solution for any application requiring precise and versatile red LED matrix management

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Hardware Overview

How does it work?

16x12 R Click is based on the IS31FL3733 matrix driver from ISSI, a general-purpose 12×16 LEDs driver with a 1/12 cycle rate. This board integrates a 16x12 red LED display and allows full control of each LED for ON/OFF switching and brightness adjustment, making it an ideal solution for creating advanced visual indicators, status displays, and animation effects. Each of the 192 LEDs can be dimmed individually with 8-bit PWM data, providing 256 steps of linear dimming resolution for precise brightness control. Communication with the host MCU is achieved through the standard I2C 2-Wire interface, supporting Standard-Mode (100 kHz),

Fast-Mode (400 kHz), and Fast-Mode Plus (1 MHz) operation, ensuring compatibility and flexibility across a wide range of applications. The user can configure the I2C address via onboard SMD jumpers labeled ADDR SEL, which set the last three LSBs of the I2C address, allowing multiple devices to coexist on the same bus. In addition to the I2C communication pins, the IS31FL3733 also uses an INT pin for interrupt signaling, RST pin for chip reset, and an SDB pin for shutdown control, further enhancing functionality and power management. With its ability to manage large LED arrays, 16x12 R Click is suitable for applications

such as information panels, event counters, gaming devices, audio spectrum displays, notification systems, and other embedded solutions requiring detailed LED matrix control. 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.

16x12 R Click hardware overview image

Features overview

Development board

Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an

ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the

first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.

Arduino UNO Rev3 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

You complete me!

Accessories

Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Arduino UNO accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset / ID SEL
PD2
RST
Shutdown Control / ID COMM
PB2
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PC3
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC5
SCL
I2C Data
PC4
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

16x12 R Click Schematic schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Click Shield for Arduino UNO front image hardware assembly
Arduino UNO Rev3 front image hardware assembly
Charger 27 Click front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Board mapper by product8 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
Arduino UNO MCU Step 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

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

16x12 R Click demo application is developed using the NECTO Studio, ensuring compatibility with mikroSDK's open-source libraries and tools. Designed for plug-and-play implementation and testing, the demo is fully compatible with all development, starter, and mikromedia boards featuring a mikroBUS™ socket.

Example Description
This example demonstrates the usage of the 16x12 R Click board which features a high-brightness red LED matrix display. It displays characters, rotates them in different orientations, prints a scrolling string, and renders a graphical image (MIKROE logo).

Key functions:

  • c16x12r_cfg_setup - This function initializes Click configuration structure to initial values.

  • c16x12r_init - This function initializes all necessary pins and peripherals used for this Click board.

  • c16x12r_default_cfg - This function executes a default configuration of 16x12 R Click board.

  • c16x12r_write_char - This function writes a single ASCII character to the display.

  • c16x12r_write_string - This function scrolls a null-terminated ASCII string across the display.

  • c16x12r_draw_picture - This function draws a picture on the display from a 12-column buffer.

Application Init
Initializes the logger and the Click board and sets the default configuration.

Application Task
Displays single characters and a string in multiple rotations, followed by drawing and inverting the MIKROE logo image.

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 16x12 R Click example
 *
 * # Description
 * This example demonstrates the usage of the 16x12 R Click board which features a high-brightness
 * red LED matrix display. It displays characters, rotates them in different orientations,
 * prints a scrolling string, and renders a graphical image (MIKROE logo).
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the logger and the Click board and sets the default configuration.
 *
 * ## Application Task
 * Displays single characters and a string in multiple rotations, followed by
 * drawing and inverting the MIKROE logo image.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "c16x12r.h"
#include "c16x12r_resources.h"

static c16x12r_t c16x12r;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    c16x12r_cfg_t c16x12r_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.
    c16x12r_cfg_setup( &c16x12r_cfg );
    C16X12R_MAP_MIKROBUS( c16x12r_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == c16x12r_init( &c16x12r, &c16x12r_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( C16X12R_ERROR == c16x12r_default_cfg ( &c16x12r ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    log_printf( &logger, " Writing digits\r\n\n" );
    c16x12r.text_rotation = C16X12R_ROTATION_H_0;
    for ( uint8_t digit = '0'; digit <= '9'; digit++ )
    {
        c16x12r_write_char ( &c16x12r, digit );
        Delay_ms ( 500 );
    }

    log_printf( &logger, " Rotating char\r\n\n" );
    c16x12r.text_rotation = C16X12R_ROTATION_H_0;
    c16x12r_write_char ( &c16x12r, 'R' );
    Delay_ms ( 500 );
    c16x12r.text_rotation = C16X12R_ROTATION_H_180;
    c16x12r_write_char ( &c16x12r, 'R' );
    Delay_ms ( 500 );
    c16x12r.text_rotation = C16X12R_ROTATION_V_0;
    c16x12r_write_char ( &c16x12r, 'R' );
    Delay_ms ( 500 );
    c16x12r.text_rotation = C16X12R_ROTATION_V_180;
    c16x12r_write_char ( &c16x12r, 'R' );
    Delay_ms ( 500 );
    c16x12r.text_rotation = C16X12R_ROTATION_H_0;
    c16x12r_write_char ( &c16x12r, 'R' );
    Delay_ms ( 500 );

    log_printf( &logger, " Writing text\r\n\n" );
    c16x12r.text_rotation = C16X12R_ROTATION_H_0;
    c16x12r_write_string ( &c16x12r, "MIKROE - 16x12 R Click", 50 );
    Delay_ms ( 1000 );

    log_printf( &logger, " Writing text\r\n\n" );
    c16x12r.text_rotation = C16X12R_ROTATION_H_180;
    c16x12r_write_string ( &c16x12r, "MIKROE - 16x12 R Click", 50 );
    Delay_ms ( 1000 );
    log_printf( &logger, " Writing text\r\n\n" );
    c16x12r.text_rotation = C16X12R_ROTATION_V_0;
    c16x12r_write_string ( &c16x12r, "MIKROE - 16x12 R Click", 50 );
    Delay_ms ( 1000 );

    log_printf( &logger, " Writing text\r\n\n" );
    c16x12r.text_rotation = C16X12R_ROTATION_V_180;
    c16x12r_write_string ( &c16x12r, "MIKROE - 16x12 R Click", 50 );
    Delay_ms ( 1000 );

    log_printf( &logger, " Drawing MIKROE logo\r\n\n" );
    c16x12r_draw_picture ( &c16x12r, c16x12r_img_mikroe );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    log_printf( &logger, " Drawing inverted MIKROE logo\r\n\n" );
    c16x12r_draw_picture ( &c16x12r, c16x12r_img_mikroe_inv );
    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;
}

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

Additional Support

Resources

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