Intermediate
30 min

Experience RTC excellence today with PT7C4311 and PIC18F2585

Timing is everything: Elevate your projects with our RTC solution

RTC 21 Click with EasyPIC v8

Published Nov 01, 2023

Click board™

RTC 21 Click

Dev Board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18F2585

Integrate efficient real-time clock into your solution for precise event timing and seamless synchronization

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Hardware Overview

How does it work?

RTC 21 Click is based on the PT7C4311, an ultra-low power, real-time clock (RTC) time-keeping device from Diodes Incorporated. The PT7C4311 is configured to transmit calendar and time data to the MCU (24-hour format) based on a 32.768kHz quartz crystal and comes with 56 bytes of general-purpose RAM. It reads and writes clock/calendar data from and to the MCU in units ranging from seconds to the last two digits of the calendar year, providing seconds, minutes, hours, dates, days, months, year, and century information.

The end-of-the-month date is automatically adjusted for months with fewer than 31 days, including corrections for the leap year until 2100. This Click board™ communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting a Fast Mode operation up to 400kHz. It also incorporates one open-drain output labeled FT, which can be used as a frequency test signal (512Hz square-wave password for frequency test purposes) or as a register-configurable output DC level when

square-wave is disabled. The PT7C4311 also includes an automatic backup switchover circuit, allowing it to be used with a single-button cell battery for an extended period. 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 for further development.

RTC 21 Click top side image
RTC 21 Click bottom side 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

default

Architecture

PIC

MCU Memory (KB)

48

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3328

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
Frequency Test/DC Level
RB1
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
Power Supply
5V
5V
Ground
GND
GND
2

Take a closer look

Click board™ Schematic

RTC 21 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
Rotary B 2 Click front image hardware assembly
MCU DIP 28 hardware assembly
EasyPIC v8 28pin-DIP - 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 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 21 Click driver.

Key functions:

  • rtc21_set_time - This function sets the starting time values - second, minute and hour

  • rtc21_set_date - This function sets the starting date values - day of week, day, month and year

  • rtc21_read_time - This function reads the current time values - second, minute and hour

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 main.c
 * @brief RTC 21 Click example
 *
 * # Description
 * This example demonstrates the use of RTC 21 click board by reading and displaying
 * the time and date values.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger and then sets the starting time and date.
 *
 * ## Application Task
 * Reads and displays on the USB UART the current time and date values once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rtc21.h"

static rtc21_t rtc21;
static log_t logger;
static rtc21_time_t time;
static rtc21_date_t date;

/**
 * @brief RTC 21 get day of week name function.
 * @details This function returns the name of day of the week as a string.
 * @param[in] ctx : Click context object.
 * See #rtc21_t object definition for detailed explanation.
 * @param[in] day_of_week : Day of week decimal value.
 * @return Name of day as a string.
 * @note None.
 */
static uint8_t *rtc21_get_day_of_week_name ( uint8_t day_of_week );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rtc21_cfg_t rtc21_cfg;  /**< Click config object. */

    /** 
     * 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.
    rtc21_cfg_setup( &rtc21_cfg );
    RTC21_MAP_MIKROBUS( rtc21_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == rtc21_init( &rtc21, &rtc21_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    time.hour = 23;
    time.minute = 59;
    time.second = 50;
    if ( RTC21_OK == rtc21_set_time ( &rtc21, &time ) )
    {
        log_printf( &logger, " Set time: %.2u:%.2u:%.2u\r\n", 
                    ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
    }
    date.day_of_week = RTC21_SATURDAY;
    date.day = 31;
    date.month = 12;
    date.year = 22;
    if ( RTC21_OK == rtc21_set_date ( &rtc21, &date ) )
    {
        log_printf( &logger, " Set date: %s, %.2u.%.2u.20%.2u.\r\n", 
                    rtc21_get_day_of_week_name ( date.day_of_week ),
                    ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    }
    Delay_ms ( 100 );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    if ( RTC21_OK == rtc21_read_time ( &rtc21, &time ) )
    {
        log_printf( &logger, " Time: %.2u:%.2u:%.2u\r\n", 
                    ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
    }
    if ( RTC21_OK == rtc21_read_date ( &rtc21, &date ) )
    {
        log_printf( &logger, " Date: %s, %.2u.%.2u.20%.2u.\r\n", 
                    rtc21_get_day_of_week_name ( date.day_of_week ),
                    ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    }
    Delay_ms ( 1000 );
}

void main ( void ) 
{
    application_init( );

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

static uint8_t *rtc21_get_day_of_week_name ( uint8_t day_of_week )
{
    switch ( day_of_week )
    {
        case RTC21_MONDAY:
        {
            return "Monday";
        }
        case RTC21_TUESDAY:
        {
            return "Tuesday";
        }
        case RTC21_WEDNESDAY:
        {
            return "Wednesday";
        }
        case RTC21_THURSDAY:
        {
            return "Thursday";
        }
        case RTC21_FRIDAY:
        {
            return "Friday";
        }
        case RTC21_SATURDAY:
        {
            return "Saturday";
        }
        case RTC21_SUNDAY:
        {
            return "Sunday";
        }
        default:
        {
            return "Unknown";
        }
    }
}

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

Additional Support

Resources

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