Beginner
10 min

Creates dynamic red visual outputs with MAX7129 and ATmega328P

Serial 8x8 red LED matrix display

8x8 R Click with Arduino UNO Rev3

Published Mar 09, 2025

Click board™

8x8 R Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Create dynamic red LED matrix display perfect for indicators, animations, and real-time visual feedback

A

A

Hardware Overview

How does it work?

8x8 R Click is a compact 64 red LED matrix display Click board™, featuring a MAX7129 LED driver for precise control. It enables independent LED control, 16-step digital brightness adjustment, and glitch-free startup by blanking the display on power-up. With a fast SPI interface, 8x8 R Click ensures smooth data transmission and quick

response. The MAX7129 IC integrates 8x8 RAM storage, a 16-bit data shifter, a constant current source, and a PWM intensity control register, allowing efficient LED matrix operation. Designed for easy integration, the board requires only one external resistor for current control, simplifying the design. The 800Hz refresh rate ensures flicker-free

performance, while daisy-chaining support allows expansion with multiple modules. Ideal for LED matrix displays, bar graphs, and panel meters, 8x8 R Click provides a reliable solution for visual output in embedded applications.

8x8 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
NC
NC
RST
SPI Chip Select
PB2
CS
SPI Clock
PB5
SCK
SPI Data OUT
PB4
MISO
SPI Data IN
PB3
MOSI
NC
NC
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

8x8 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
Arduino UNO Rev3 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
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

8x8 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 demo example shows a drawing of Image, new create string and character on the screen.

Key functions:

  • c8x8r_cfg_setup - Config Object Initialization function.

  • c8x8r_init - Initialization function.

  • c8x8r_default_cfg - Click Default Configuration function.

  • c8x8r_write_cmd - This function writes a desired number of data bytes starting from the selected register by using SPI serial interface.

  • c8x8r_display_refresh - The function switches off all LEDs.

  • c8x8r_display_byte - This function displayes one character to the display.

Application Init
Configuring Clicks and log objects. Settings the Click in the default configuration.

Application Task
Shows one byte, then scrolls the string and image, every 1 sec.

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 8x8 R Click example
 *
 * # Description
 * This demo example shows a drawing of Image, new create string and character on the screen.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Configuring Clicks and log objects.
 * Settings the Click in the default configuration.
 * 
 * ## Application Task  
 * Shows one byte, then scrolls the string and image, every 1 sec.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "c8x8r.h"

static c8x8r_t c8x8r;
static log_t logger;

uint8_t demo_string[ 11 ] = { ' ', '-', 'M', 'i', 'k', 'r', 'o', 'E', '-', ' ', 0 };
uint8_t demo_img_on[ 8 ] = { 0x08, 0x1c, 0x36, 0x22, 0x08, 0x1c, 0x36, 0x22 };
uint8_t demo_img_off[ 8 ] = { 0xf7, 0xe3, 0xc9, 0xdd, 0xf7, 0xe3, 0xc9, 0xdd };
char demo_char = 'A';

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    c8x8r_cfg_t c8x8r_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.

    c8x8r_cfg_setup( &c8x8r_cfg );
    C8X8R_MAP_MIKROBUS( c8x8r_cfg, MIKROBUS_1 );
    err_t init_flag  = c8x8r_init( &c8x8r, &c8x8r_cfg );
    if ( init_flag == SPI_MASTER_ERROR ) {
        log_info( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    c8x8r_default_cfg ( &c8x8r );
    log_info( &logger, " Application Task " );
    Delay_ms ( 1000 );
}

void application_task ( void ) {
    c8x8r_display_byte( &c8x8r, demo_char );
    Delay_ms ( 1000 );
    
    c8x8r_display_string( &c8x8r, &demo_string[ 0 ] );
    Delay_ms ( 1000 );

    c8x8r_display_image( &c8x8r, &demo_img_on[ 0 ] );
    Delay_ms ( 1000 );

    c8x8r_display_image( &c8x8r, &demo_img_off[ 0 ] );
    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

Love this project?

'Buy This Kit' button takes you directly to the shopping cart where you can easily add or remove products.