10 min

Master time management with DS1307 and STM32F746ZG

Keep track of time in various electronic applications

RTC 2 Click with UNI-DS v8

Published Oct 20, 2023

Click board™

RTC 2 Click

Development board



NECTO Studio



Compact time-tracking solution that maintains accurate time records, suitable for applications like IoT, wearables, data logging, and industrial devices



Hardware Overview

How does it work?

RTC 2 Click is based on the DS1307, a 64x8 serial I2C Real-Time clock from Analog Devices. It is a low-power, full binary-coded decimal (BCD) clock/calendar with 56 bytes of NV SRAM. The end of months is automatically adjusted for months with fewer than 31 days, including corrections for the leap year. The clock can operate in either a 24-hour or 12-hour format with an AM/PM indicator. The RTC has a built-in power-sense circuit that automatically switches to the backup power

supply when it detects a power failure. The RTC 2 comes equipped with a 3V/230mA lithium battery, ensuring timekeeping continues even when the main power supply goes OFF. The RTC 2 Click uses an I2C 2-Wire interface for communication with the host MCU, with a clock rate of up to 400kHz. The interrupt INT pin of this Click board™ outputs one of four square-wave frequencies (1Hz, 4kHz, 8kHz, and 32kHz). When enabled, it outputs frequency depending on values set in configuration

bits. This Click board™ can be operated only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. 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 2 Click hardware overview image

Features overview

Development board

UNI-DS v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the UNI-DS v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART, USB

HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. UNI-DS v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI-DS v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M7

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

I2C Clock
I2C Data
Power Supply

Take a closer look


RTC 2 Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI-DS v8 as your development board.

Fusion for PIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
v8 SiBRAIN 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 Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for RTC 2 Click driver.

Key functions:

  • rtc2_read_byte - Generic read byte of data function

  • rtc2_write_byte - Generic write byte of data function

  • rtc2_enable_counting - Enable counting 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 
 * \brief Rtc2 Click example
 * # Description
 * This application give time and date information.
 * The demo application is composed of two sections :
 * ## Application Init 
 *  Initialization driver enable's - I2C,set start time and date, enable counting and start write log.
 * ## Application Task  
 * This is a example which demonstrates the use of RTC 2 Click board.
 *    RTC 2 Click communicates with register via I2C by write to register and read from register,
 *    set time and date, get time and date, enable and disable counting
 *    and set frequency by write configuration register.
 *    Results are being sent to the Usart Terminal where you can track their changes.
 *    All data logs write on usb uart changes for every 1 sec.
 * *note:* 
 * Additional Functions :
 * - void displayDayOfTheWeek( uint8_t dayOfTheWeek ) - Write day of the week log on USART terminal.
 * - void displayLogUart( uint8_t value ) - Write the value ( time or date ) of a two-digit number.
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtc2.h"

// ------------------------------------------------------------------ VARIABLES

static rtc2_t rtc2;
static log_t logger;
static rtc2_data_t date;

uint8_t time_hours;
uint8_t time_minutes;
uint8_t time_seconds;
uint8_t day_of_the_week;
uint8_t date_day;
uint8_t date_month;
uint16_t date_year;
uint8_t time_seconds_new = 0;

void display_day_of_the_week ( uint8_t day_of_the_week )
    if ( day_of_the_week == 1 )
        log_printf( &logger, "      Monday      " );
    if ( day_of_the_week == 2 )
        log_printf( &logger, "      Tuesday     " );
    if ( day_of_the_week == 3 )
        log_printf( &logger, "     Wednesday    " );
    if ( day_of_the_week == 4 )
        log_printf( &logger, "     Thursday     " );
    if ( day_of_the_week == 5 )
        log_printf( &logger, "      Friday      " );
    if ( day_of_the_week == 6 )
        log_printf( &logger, "     Saturday     " );
    if ( day_of_the_week == 7 )
        log_printf( &logger, "      Sunday      " );

void display_log_uart ( uint8_t value )
    log_printf( &logger,"%u", ( uint16_t )( value / 10 ) );
    log_printf( &logger,"%u", ( uint16_t )( value % 10 ) );

void application_init ( void )
    log_cfg_t log_cfg;
    rtc2_cfg_t cfg;
    date.day_of_the_week = 1;
    date.date_day = 31;
    date.date_month = 12;
    date.date_year = 2018;

     * 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.

    rtc2_cfg_setup( &cfg );
    rtc2_init( &rtc2, &cfg );

    rtc2_set_time( &rtc2, 23, 59, 50 );
    rtc2_set_date( &rtc2, &date );
    rtc2_enable_counting( &rtc2 );

void application_task ( void )
    rtc2_get_time( &rtc2, &time_hours, &time_minutes, &time_seconds );

    rtc2_get_date( &rtc2, &date );

    if ( time_seconds_new !=  time_seconds )
        log_printf( &logger, " Time : " );

        display_log_uart( time_hours );
        log_printf( &logger, ":" );

        display_log_uart( time_minutes );
        log_printf( &logger, ":" );

        display_log_uart( time_seconds );
        log_printf( &logger, "" );

        display_day_of_the_week( date.day_of_the_week );

        log_printf( &logger, " Date: " );

        display_log_uart( date.date_day );
        log_printf( &logger, "." );

        display_log_uart( date.date_month );
        log_printf( &logger, "." );

        log_printf( &logger, "20" );

        display_log_uart( date.date_year );
        log_printf( &logger, ".\r\n" );

        log_printf( &logger, "-------------------\r\n" );

        time_seconds_new =  time_seconds;

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support