10 min

Seize every moment with BQ32000 and PIC18F45K50

Timekeeping excellence

RTC 3 Click with EasyPIC v8

Published Jun 22, 2023

Click board™

RTC 3 Click

Dev Board

EasyPIC v8


NECTO Studio



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



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

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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 DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC 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.

EasyPIC v8 horizontal image

Microcontroller Overview

MCU Card / MCU




MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Power Supply
I2C Clock
I2C Data

Take a closer look


RTC 3 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

EasyPIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
MCU DIP 40 hardware assembly
EasyPIC v8 DIP 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 DIP 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 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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

 * \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_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 ) = 1; = 31; = 12; = 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 )  && ( ( | ) == 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), (uint16_t), (uint16_t) );

        time_seconds_new = rtc3.time.time_seconds;

    Delay_ms( 200 );

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support