Beginner
10 min

Ensure precise real-time data tracking with RV-8263-C8 and ATmega328P

Low-power real-time tracking solution for your embedded projects

RTC 15 Click with Arduino UNO Rev3

Published May 06, 2025

Click board™

RTC 15 Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Track precise time and date in embedded projects with ultra-low-power RTC module

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Hardware Overview

How does it work?

RTC 15 Click is based on the RV-8263-C8, a standard commercial-grade real-time clock/calendar module from Micro Crystal, known for its low power consumption and high precision. This CMOS-based device operates with a 32.768kHz clock and includes an offset register that enables fine-tuning of frequency deviations, ensuring reliable timekeeping in long-term applications. Communication with the host MCU is handled via an I2C interface, with automatic register address incrementing after each data transfer for efficient access. Despite its ultra-small and lightweight design, the module offers full calendar functionality, including tracking of year, month, date, weekday, hours, minutes, and seconds, along with support for automatic leap year correction from 2000 to 2099. Additionally, it features built-in timer and alarm capabilities. The RTC 15 Click is ideal for use in IoT systems, industrial and automotive applications, metering solutions, healthcare devices, as well as wearable and portable electronics. RTC 15 Click is designed

in a unique format supporting the newly introduced MIKROE feature called "Click Snap." Unlike the standardized version of Click boards, this feature allows the main sensor area to become movable by breaking the PCB, opening up many new possibilities for implementation. Thanks to the Snap feature, the RV-8263-C8 can operate autonomously by accessing their signals directly on the pins marked 1-8. Additionally, the Snap part includes a specified and fixed screw hole position, enabling users to secure the Snap board in their desired location. This Click board™ uses an I2C interface with clock speeds of up to 400kHz, ensuring fast communication with the host MCU. In addition to the I2C interface pins, RTC 15 Click features an EN pin used to control the MAX40200 ideal diode, which in this design acts as a power switch, and INT pin as interrupt used to output alarm, minute, half minute, countdown timer and compensation Interrupt signals. When the EN pin is activated, it enables the MAX40200 to supply power to sensor on the board. This setup allows power management

by enabling or disabling the sensor as needed, making it especially useful for low-power and battery-operated applications. RTC 15 Click also includes unsoldered OUT pins that can be used for clock signal output, controlled by the CLE pin. When the CLE pin is set HIGH, the OUT pin generates a selectable square wave output with available frequencies of 32.768kHz (default), 16.384kHz, 8.192kHz, 4.096kHz, 2.048kHz, 1.024kHz, or 1Hz, offering flexibility for various timing requirements. If the CLE pin is held LOW, the OUT pin remains LOW, effectively disabling the clock output. 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.

RTC 15 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
Device Enable
PD2
RST
ID COMM
PB2
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Clock Output Enable
PD6
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

RTC 15 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

RTC 15 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 use of the RTC 15 Click board by initializing the device and setting up the current time and date. It continuously reads and displays the updated time and date every second using the timer countdown interrupt pin.

Key functions:

  • rtc15_cfg_setup - This function initializes Click configuration structure to initial values.

  • rtc15_init - This function initializes all necessary pins and peripherals used for this Click board.

  • rtc15_default_cfg - This function executes a default configuration of RTC 15 Click board.

  • rtc15_set_time - This function sets the current time (hours, minutes, seconds) in the RTC.

  • rtc15_read_time - This function reads the current time (hours, minutes, seconds) from the RTC.

  • rtc15_read_date - This function reads the current date (day, day of week, month, year) from the RTC.

Application Init
Initializes the logger and the RTC 15 Click driver, applies the default configuration, and sets the starting time and date.

Application Task
Waits for a 1 Hz interrupt signal and then reads and displays the current time and date.

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 RTC 15 Click example
 *
 * # Description
 * This example demonstrates the use of the RTC 15 Click board by initializing
 * the device and setting up the current time and date. It continuously
 * reads and displays the updated time and date every second using the timer
 * countdown interrupt pin.
 *
 * The demo application is composed of two sections:
 *
 * ## Application Init
 * Initializes the logger and the RTC 15 Click driver, applies the default configuration,
 * and sets the starting time and date.
 *
 * ## Application Task
 * Waits for a 1 Hz interrupt signal and then reads and displays the current time and date.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rtc15.h"

static rtc15_t rtc15;
static log_t logger;
static rtc15_time_t time;
static rtc15_date_t date;

/**
 * @brief RTC 15 get day of week name function.
 * @details This function returns the name of day of the week as a string.
 * @param[in] ctx : Click context object.
 * See #rtc15_t object definition for detailed explanation.
 * @param[in] day_of_week : Day of week decimal value.
 * @return Name of day as a string.
 * @note None.
 */
static uint8_t *rtc15_get_day_of_week_name ( uint8_t day_of_week );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rtc15_cfg_t rtc15_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.
    rtc15_cfg_setup( &rtc15_cfg );
    RTC15_MAP_MIKROBUS( rtc15_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == rtc15_init( &rtc15, &rtc15_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( RTC15_ERROR == rtc15_default_cfg ( &rtc15 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    time.hour = 23;
    time.minute = 59;
    time.second = 50;
    if ( RTC15_OK == rtc15_set_time ( &rtc15, &time ) )
    {
        log_printf( &logger, " Set time: %.2u:%.2u:%.2u\r\n", 
                    ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
    }
    date.day_of_week = RTC15_TUESDAY;
    date.day = 31;
    date.month = 12;
    date.year = 24;
    if ( RTC15_OK == rtc15_set_date ( &rtc15, &date ) )
    {
        log_printf( &logger, " Set date: %s, %.2u.%.2u.20%.2u.\r\n", 
                    rtc15_get_day_of_week_name ( date.day_of_week ),
                    ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    }

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

void application_task ( void ) 
{
    // Wait for a timer countdown flag configured at 1 Hz
    while ( rtc15_get_int_pin ( &rtc15 ) );

    if ( RTC15_OK == rtc15_read_time ( &rtc15, &time ) )
    {
        log_printf( &logger, " Time: %.2u:%.2u:%.2u\r\n", 
                    ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
    }
    if ( RTC15_OK == rtc15_read_date ( &rtc15, &date ) )
    {
        log_printf( &logger, " Date: %s, %.2u.%.2u.20%.2u.\r\n\n", 
                    rtc15_get_day_of_week_name ( date.day_of_week ),
                    ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    }
    Delay_ms ( 100 );
}

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;
}

static uint8_t *rtc15_get_day_of_week_name ( uint8_t day_of_week )
{
    switch ( day_of_week )
    {
        case RTC15_MONDAY:
        {
            return "Monday";
        }
        case RTC15_TUESDAY:
        {
            return "Tuesday";
        }
        case RTC15_WEDNESDAY:
        {
            return "Wednesday";
        }
        case RTC15_THURSDAY:
        {
            return "Thursday";
        }
        case RTC15_FRIDAY:
        {
            return "Friday";
        }
        case RTC15_SATURDAY:
        {
            return "Saturday";
        }
        case RTC15_SUNDAY:
        {
            return "Sunday";
        }
        default:
        {
            return "Unknown";
        }
    }
}

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

Additional Support

Resources

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