Beginner
10 min

Seize every moment with BQ32000 and ATmega328P

Timekeeping excellence

RTC 3 Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

RTC 3 Click

Dev Board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Incorporate a high-performance real-time clock into your solution and boost your timing control

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Hardware Overview

How does it work?

RTC 3 Click is based on the BQ32000, a real-time clock from Texas Instruments presenting a compatible replacement for industry standard real-time clocks. The BQ32000 features an automatic backup supply with an integrated trickle charger for an automatic switchover to a backup power supply providing additional reliability (the circuit maintains the backup charge with an onboard supercapacitor). It also comes with a programmable calibration adjustment from –63ppm to +126ppm and clock frequency derived from an onboard 32.768KHz oscillator. The BQ32000 communicates with the MCU using the standard I2C 2-Wire interface with a maximum

frequency of 400kHz. Its time registers are updated once per second, with registers updated simultaneously to prevent a time-keeping glitch. It should be noted that when the BQ32000 switches from the main power supply to the backup supply, the time-keeping register cannot be accessed via the I2C interface. The access to these registers is only with supply voltage present. The time-keeping registers can take up to one second to update after the device switches from the backup power supply to the main power supply. The BQ32000 also includes an automatic leap year correction and general interrupt or oscillator fail flag indicating the status of the RTC oscillator

routed to the INT pin of the mikroBUS™ socket. The RTC classifies a leap year as any year evenly divisible by 4. Using this rule allows for reliable leap-year compensation until 2100. The host MCU must compensate for years that fall outside this rule. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

RTC 3 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
NC
NC
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
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

RTC 3 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
Barometer 13 Click front image hardware assembly
Prog-cut hardware assembly
Arduino UNO Rev3 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

This Click board can be interfaced and monitored in two ways:

  • Application Output - Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.

Software Support

Library Description

This library contains API for RTC 3 Click driver.

Key functions:

  • rtc3_set_time - Function sets time: hours, minutes and seconds data to the target register address of PCF8583 chip on RTC 3 Click

  • rtc3_get_time - Function gets time: hours, minutes and seconds data from the target register address of PCF8583 chip on RTC 3 Click

  • rtc3_set_calibration - Function set calibration by write CAL_CFG1 register of BQ32000 chip

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 Rtc3 Click example
 * 
 * # Description
 * This application enables time measurment over RTC3 click.
 *
 * 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 3 Click board.
 * RTC 3 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:* 
 * Time stats measuring correctly but from 0 seconds, after 10 seconds.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtc3.h"

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

static rtc3_t rtc3;
static log_t logger;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

void display_log_day_of_the_week ( uint8_t day_of_the_week )
{
    if ( day_of_the_week == 1 )
    {
        log_printf( &logger, "      Monday      \r\n" );
    }        
    if ( day_of_the_week == 2 )
    {
        log_printf( &logger, "      Tuesday     \r\n" );
    }        
    if ( day_of_the_week == 3 )
    {
        log_printf( &logger, "     Wednesday    \r\n" );
    }        
    if ( day_of_the_week == 4 )
    {
        log_printf( &logger, "     Thursday     \r\n" );
    }        
    if ( day_of_the_week == 5 )
    {
        log_printf( &logger, "      Friday      \r\n" );
    }        
    if ( day_of_the_week == 6 )
    {
        log_printf( &logger, "     Saturday     \r\n" );
    }
    if ( day_of_the_week == 7 )
    {
        log_printf( &logger, "      Sunday      \r\n" );
    }
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    rtc3_cfg_t cfg;

    /** 
     * 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.

    rtc3_cfg_setup( &cfg );
    RTC3_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rtc3_init( &rtc3, &cfg );

    /// Set Time: 23h, 59 min, 50 sec

    rtc3.time.time_hours = 23;
    rtc3.time.time_minutes = 59;
    rtc3.time.time_seconds = 50;

    rtc3_set_time( &rtc3 );

    // Set Date: 1 ( Day of the week ), 31 ( day ), 12 ( month ) and 2018 ( year )

    rtc3.date.day_of_the_week = 1;
    rtc3.date.date_day = 31;
    rtc3.date.date_month = 12;
    rtc3.date.date_year = 2018;

    rtc3_set_date( &rtc3 );

    // Start counting
   
    rtc3_enable_disable_counting( &rtc3, 1 );
    Delay_100ms( );
    
    Delay_ms( 1000 );
}

void application_task ( void )
{
    //  Task implementation.

    uint8_t time_seconds_new = 0xFF;
    
     

    rtc3_get_time( &rtc3 );

    rtc3_get_date( &rtc3 );

    if ( time_seconds_new != rtc3.time.time_seconds )
    {
        if ( ( ( rtc3.time.time_hours | rtc3.time.time_minutes | rtc3.time.time_seconds ) == 0 )  && ( ( rtc3.date.date_day | rtc3.date.date_month ) == 1 ) )
        {
            log_printf( &logger, "  Happy New Year  \r\n" );
            log_printf( &logger, "------------------\r\n" );
        }

        log_printf( &logger, " Time : %d:%d:%d \r\n Date: %d.%d.20%d.\r\n------------------\r\n", (uint16_t)rtc3.time.time_hours, (uint16_t)rtc3.time.time_minutes,
                                                                                            (uint16_t)rtc3.time.time_seconds, 
                                                                                            (uint16_t)rtc3.date.date_day, (uint16_t)rtc3.date.date_month, (uint16_t)rtc3.date.date_year );

        time_seconds_new = rtc3.time.time_seconds;
    }

    Delay_ms( 200 );
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


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

Additional Support

Resources

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