Beginner
10 min

Master time management with DS1307 and STM32F302VC

Keep track of time in various electronic applications

RTC 2 Click with CLICKER 4 for STM32F302VCT6

Published Jul 22, 2025

Click board™

RTC 2 Click

Dev. board

CLICKER 4 for STM32F302VCT6

Compiler

NECTO Studio

MCU

STM32F302VC

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

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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

Clicker 4 for STM32F3 is a compact development board designed as a complete solution, you can use it to quickly build your own gadgets with unique functionalities. Featuring a STM32F302VCT6, four mikroBUS™ sockets for Click boards™ connectivity, power managment, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core, there is a STM32F302VCT6 MCU, a powerful microcontroller by STMicroelectronics, based on the high-

performance Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the development

board much simpler and thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution which can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws. For most applications, a nice stylish casing is all that is needed to turn the Clicker 4 development board into a fully functional, custom design.

CLICKER 4 for STM32F302VCT6 double image

Microcontroller Overview

MCU Card / MCU

STM32F302VC Image

Architecture

ARM Cortex-M4

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

40960

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
NC
NC
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PD0
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB10
SCL
I2C Data
PB11
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

RTC 2 Click Schematic schematic

Step by step

Project assembly

PIC32MZ MXS Data Capture Board front image hardware assembly

Start by selecting your development board and Click board™. Begin with the CLICKER 4 for STM32F302VCT6 as your development board.

PIC32MZ MXS Data Capture Board front image hardware assembly
Thermo 21 Click front image hardware assembly
Board mapper by product6 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
PIC32MZ MXS Data Capture Board NECTO MCU Selection Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto image step 11 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

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

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 
 * \brief Rtc6 Click example
 * 
 * # Description
 * This application enables usage of Real-TIme clock and calendar with alarm on RTC 6 Click.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver init, sets time zone, sets UTC-GMT time and alarm time
 * 
 * ## Application Task  
 * Reads GMT time and Local time. Checks if the alarm is activated. 
 * If the alarm is active, it disable alarm and adjusts the new one within 20 seconds.
 * Logs this data on USBUART every 900ms.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtc6.h"

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

static rtc6_t rtc6;
static log_t logger;
static rtc6_time_t utc_time;
static rtc6_time_t alarm_time;
static rtc6_time_t local_time;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    rtc6_cfg_t cfg;
    int8_t time_zone = 2;

    /** 
     * 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.

    rtc6_cfg_setup( &cfg );
    RTC6_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rtc6_init( &rtc6, &cfg );

    // Set UTC time

    utc_time.seconds  = 40;
    utc_time.minutes  = 59;
    utc_time.hours    = 23;
    utc_time.monthday = 14;
    utc_time.month    = 12;
    utc_time.year     = 18;
    
    // Set alarm time
    
    alarm_time.seconds  = 0;
    alarm_time.minutes  = 0;
    alarm_time.hours    = 0;
    alarm_time.weekdays  = 0;
    alarm_time.monthday = 15;
    alarm_time.month    = 12;
    alarm_time.year     = 18;

    rtc6_default_cfg( &rtc6, time_zone, &utc_time, &alarm_time );
    log_info( &logger, " ----- Init successfully ----- " );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

void application_task ( void )
{
    //  Task implementation.

    rtc6_get_gmt_time( &rtc6, &utc_time );
    rtc6_get_local_time( &rtc6, &local_time );
    
    log_printf( &logger, "--- UTC time ---\r\nTime : %u %u %u\r\n", ( uint16_t )utc_time.hours, ( uint16_t )utc_time.minutes, ( uint16_t )utc_time.seconds );
    
    log_printf( &logger, "Date : %u %u %u\r\n", ( uint16_t )utc_time.monthday, ( uint16_t )utc_time.month, utc_time.year );
    
    log_printf( &logger, "--- Local time ---\r\nTime : %u %u %u\r\n", ( uint16_t )local_time.hours, ( uint16_t )local_time.minutes, ( uint16_t )local_time.seconds );

    log_printf( &logger, "Date : %u %u %u\r\n \r\n", ( uint16_t )local_time.monthday, ( uint16_t )local_time.month, local_time.year );
    
    if ( rtc6_is_active_alarm( &rtc6 ) != 0 )
    {
        log_printf( &logger, " ----- Active alarm ----- \r\n" );
        rtc6_disable_alarm( &rtc6, RTC6_ALARM_0 );
        rtc6_repeat_alarm( &rtc6, RTC6_ALARM_0, 20 );
    }

    Delay_ms ( 900 );
}

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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