Beginner
10 min

Seize every moment with BQ32000 and PIC18F27K42

Timekeeping excellence

RTC 3 Click with EasyPIC v7a

Published Nov 01, 2023

Click board™

RTC 3 Click

Dev Board

EasyPIC v7a

Compiler

NECTO Studio

MCU

PIC18F27K42

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

A

A

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 v7a is the seventh generation of PIC development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as the first-ever embedded debugger/programmer over USB-C. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyPIC v7a allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyPIC v7a 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 various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-

established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7a 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 v7a double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

8192

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
RB1
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
2

Take a closer look

Click board™ Schematic

RTC 3 Click Schematic schematic

Step by step

Project assembly

EasyPIC v7a front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7a as your development board.

EasyPIC v7a front image hardware assembly
Rotary B 2 Click front image hardware assembly
MCU DIP 28 hardware assembly
EasyPIC v7a MB 2 - 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
EasyPIC PRO v7a Display Selection Necto Step 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 via UART Mode

1. Once the code example is loaded, pressing the "FLASH" button initiates the build process, and programs it on the created setup.

2. After the programming is completed, click on the Tools icon in the upper-right panel, and select the UART Terminal.

3. After opening the UART Terminal tab, first check the baud rate setting in the Options menu (default is 115200). If this parameter is correct, activate the terminal by clicking the "CONNECT" button.

4. Now terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART_Application_Output

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_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

Love this project?

'Buy This Kit' button takes you directly to the shopping cart where you can easily add or remove products.