Intermediate
30 min

Take control of your time with RV-3028-C7 and PIC18F57Q43

Ticking with purpose

RTC 8 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

RTC 8 Click

Dev Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Achieve seamless coordination and synchronization of events in your applications with our cutting-edge real-time clock solution

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Hardware Overview

How does it work?

RTC 8 Click is based on the RV-3028-C7, an extreme low power real-time clock/calendar (RTC) module from Micro Crystal Switzerland. Thanks to its high integration level, this module provides high time accuracy, factory calibrated to 1 ppm, with a very low count of external components required. It has a full RTC function, offering programmable counters, alarms, and an interrupt engine with selectable event reporting sources. In addition to a standard clock output function, it also offers a 32-bit UNIX Time counter. The operational parameters are stored within the internal non-volatile memory (EEPROM) allowing their persistence in the event of the complete power failure. The small dimension of the RV-3028-C7 module itself, allow it to be used in very space-constrained applications, including wearables, medical equipment, and similar. In addition to the RV-3028-C7, RTC 8 click is equipped with the button cell battery holder compatible with the CR1225 battery. By utilizing an automatic backup switch, the IC is able to use an external battery power source when there is no power supply on its main power terminals, thus

allowing for uninterrupted operation. Draining as low as 40nA of current, it can be operated with the standard button cell battery almost indefinitely. In addition, a trickle charge system will replenish the battery power while the RV-3028-C7 is powered over the main power terminals (VDD, VSS). The voltage of the main power supply can range between 1.2V up to 5.5V. The RV-3028-C7 uses the I2C communication protocol for the communication with the host MCU. Besides the I2C bus lines, two additional pins are also available on the RV-3028-C7, allowing an interrupt to be reported to the host MCU, but also to capture an external event and marking it with an automatic timestamp. The user is able to set up standard clock and calendar functions (including seconds, minutes, hours, weekdays, date, months, years with leap year correction), as well as the interrupt functions for the periodic countdown timer, periodic time update, alarm, external event, automatic backup switchover and power on reset (POR) events. All these features are available when the module is operated over the backup power supply (battery). A group of configuration registers

is used to set up all the various working parameters of the device. To additionally prevent any unintentional changes of the internal registers, the RV-3028-C7 offers password protection of its configuration. If the password protection is set by an enable register in the non-volatile memory, each time the register configuration is attempted, the user will be required to enter the password first. Naturally, reading out the password registers will return 0 values; this register is write-only. Besides other functions, EEPROM memory holds the offset correction values. Offset correction is required for fine-tuning the internal 32.768 kHz XTAL, as well as for compensating the aging phenomenon. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. 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 8 Click top side image
RTC 8 Click bottom side image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
External Event Input
PD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PA6
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB1
SCL
I2C Data
PB2
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

RTC 8 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Barometer 13 Click front image hardware assembly
PIC18F57Q43 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Curiosity Nano with PICXXX 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
PIC18F57Q43 Curiosity 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for RTC 8 Click driver.

Key functions:

  • rtc8_set_time - Set new time - 24 hour format

  • rtc8_set_date - Set new date

  • rtc8_get_time_and_date - Get RTC data ( Time and Data )

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 Rtc8 Click example
 * 
 * # Description
 * Demo application shows the operation of RTC 8 clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Configuring clicks and log objects.
 * Settings the click in the default configuration.
 * Sets new: Time, Date, UNIX time and alarm data.
 * 
 * ## Application Task  
 * Read current Time, Date and UNIX time and checks if the alarm is active.
 * 
 * @note
 * Comment out the lines for setting date and time if you would like the 
 * module to keep counting time after a reset or shut down.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtc8.h"

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

static rtc8_t rtc8;
static log_t logger;

static rtc8_time_t time_s;
static rtc8_date_t date_s;
static rtc8_alarm_t alarm_s;

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

void display_weekday ( uint8_t weekday )
{
    switch ( weekday )
    {
        case 0: 
        {
            log_printf( &logger, "      Monday      \r\n" );
            break;
        }
        case 1: 
        {
            log_printf( &logger, "      Tuesday     \r\n" );
            break;
        }
        case 2: 
        {
            log_printf( &logger, "     Wednesday    \r\n" );
            break;
        }
        case 3: 
        {
            log_printf( &logger, "     Thursday     \r\n" );
            break;
        }
        case 4: 
        {
            log_printf( &logger, "      Friday      \r\n" );
            break;
        }
        case 5: 
        {
            log_printf( &logger, "     Saturday     \r\n" );
            break;
        }
        case 6: 
        {
            log_printf( &logger, "      Sunday      \r\n" );
            break;
        }
    }
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    rtc8_cfg_t rtc8_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.
    rtc8_cfg_setup( &rtc8_cfg );
    RTC8_MAP_MIKROBUS( rtc8_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == rtc8_init( &rtc8, &rtc8_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    if ( RTC8_ERROR == rtc8_default_cfg ( &rtc8 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }

    // 24h format - HH,MM,SS
    time_s.hours = 23;
    time_s.minutes = 59;
    time_s.seconds = 50;

    rtc8_set_time( &rtc8, &time_s );

    // Set date format
    date_s.weekdays = 5;
    date_s.day = 31;
    date_s.month = 12;
    date_s.year = 22;

    rtc8_set_date( &rtc8, &date_s );

    // Set UNIX time
    rtc8_set_unix_time( &rtc8, 1672527590ul );

    // Set alarm format
    alarm_s.weekdays = 6;
    alarm_s.hours = 0;
    alarm_s.minutes = 0;

    rtc8_set_alarm( &rtc8, &alarm_s );

    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    static uint8_t time_seconds = 0xFF;
    uint8_t alarm = 0;
    uint32_t unix_time = 0;
    
    err_t error_flag = rtx8_get_time_and_date( &rtc8, &time_s, &date_s );
    error_flag |= rtc8_get_uinx_time( &rtc8, &unix_time );
    error_flag |= rtc8_get_alarm_flag( &rtc8, &alarm );

    if ( ( RTC8_OK == error_flag ) && ( time_seconds != time_s.seconds ) )
    {
        display_weekday ( date_s.weekdays );
        log_printf( &logger, " Time: %.2u:%.2u:%.2u\r\n Date: %.2u.%.2u.20%.2u.\r\n", 
                    ( uint16_t ) time_s.hours, ( uint16_t ) time_s.minutes,
                    ( uint16_t ) time_s.seconds, ( uint16_t ) date_s.day, 
                    ( uint16_t ) date_s.month, ( uint16_t ) date_s.year );
        log_printf( &logger, " UNIX: %lu\r\n", unix_time );
        if ( RTC8_ALARM_IS_ACTIVE == alarm )
        {
            log_info( &logger, " Alarm Activated!!! " );
            rtc8_reset_alarm_flag( &rtc8 );
        }
        log_printf( &logger, "------------------\r\n" );
        time_seconds = time_s.seconds;
    }
    Delay_ms ( 200 );
}

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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