Intermediate
30 min
0

Always be on time with AB0815 and PIC18F87J50

RTC: Your silent reminder in a noisy world

RTC 11 Click with EasyPIC PRO v7

Published Oct 20, 2023

Click board™

RTC 11 Click

Development board

EasyPIC PRO v7

Compiler

NECTO Studio

MCU

PIC18F87J50

Integrate reliable real-time clock into your solution to enable precise event sequencing and accurate time measurement

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Hardware Overview

How does it work?

RTC 11 Click is based on the AB0815, an ultra-low-power coupled with a highly sophisticated feature set, the real-time clock from Abracon. The AB0815 is a full-function RTC and includes three feature groups: baseline and advanced timekeeping features and power management. Functions from each feature group may be controlled via I/O offset mapped registers accessed through the SPI serial interface. The baseline timekeeping feature group supports the standard 32.786 kHz crystal oscillation mode for maximum frequency accuracy with an ultra-low current draw of 22nA. This feature includes standard counters for minutes, hours, dates, months, years, and weekdays. A complement of countdown timers and alarms may additionally be set to initiate interrupts or

resets on several outputs. The most common configuration on this Click board™ is a battery-backed-up RTC, which maintains time and may hold data in RAM. In addition to the AB0815, the RTC 11 Click is equipped with a button cell battery holder compatible with the 3000TR battery holder, suitable for 12mm Coin Cell batteries. By utilizing an automatic backup switch, the AB0815 can use an external battery power source when there is no power supply on its main power terminals, thus allowing for uninterrupted operation. The AB0815 communicates with MCU using the standard SPI serial interface that supports modes 0 and 3 with a maximum frequency of 2 MHz. The flexible inputs of the AB0815 can be used to aggregate various interrupt sources, including external digital inputs,

analog levels, timers, and alarms, into a single interrupt source to an MCU. Based on this, functions like external interrupt or watchdog timer reset could be found on this Click board™ routed on the RST and AN pins of the mikroBUS™ socket labeled as EXI and WDI, as well as the primary and secondary interrupt outputs routed on the INT and PWM pins of the mikroBUS™ socket labeled as IT1 and IT2. 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. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

RTC 11 Click top side image
RTC 11 Click bottom side image

Features overview

Development board

EasyPIC PRO v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. 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. With two different connectors for each port, EasyPIC PRO v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of the EasyPIC PRO v7 development board contains

the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of 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-B (USB-B) connector. Communication options such as USB-UART, RS-232, and Ethernet are also included, including the well-established

mikroBUS™ standard, two display options (graphical and character-based LCD), and a standard TQFP socket for the seventh-generation MCU cards. This socket covers a wide range of 8-bit PIC MCUs, from PIC18LF, PIC16LF, PIC16F, and PIC18F families. EasyPIC PRO v7 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 PRO v7 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

7th Generation

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

80

RAM (Bytes)

3904

Used MCU Pins

mikroBUS™ mapper

Watchdog Timer Reset
RA0
AN
External Interrupt
RC0
RST
SPI Chip Select
RE0
CS
SPI Clock
RC3
SCK
SPI Data OUT
RC4
MISO
SPI Data IN
RC5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Secondary Interrupt
RC1
PWM
Primary Interrupt
RB0
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

RTC 11 Click Schematic schematic

Step by step

Project assembly

EasyPIC PRO v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC PRO v7 as your development board.

EasyPIC PRO v7 front image hardware assembly
Buck 22 Click front image hardware assembly
EasyPIC PRO v7 MCUcard with PIC18F8520 front image hardware assembly
EasyPIC PRO v7 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
EasyPIC PRO v7a MCU Selection Necto Step 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

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 11 Click driver.

Key functions:

  • rtc11_set_time - Set time hours, minutes and seconds function

  • rtc11_get_time - Get time hours, minutes and seconds function

  • rtc11_set_date - Set date day of the week, day, month and year function

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 RTC11 Click example
 *
 * # Description
 * This is an example that demonstrates the use of the RTC 11 click board™.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initalizes SPI, performs software reset, sets 
 * system time and date, and starts clocking system.
 *
 * ## Application Task
 * Demonstrates use of RTC 11 click board by reading and
 * displaying time and date via USART terminal.
 * 
 * Additional Functions :
 * 
 * void disp_day_of_the_week ( uint8_t w_day ) - Writes the day of the week on 
 * USART terminal.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "rtc11.h"

static rtc11_t rtc11;
static log_t logger;

static rtc11_time_t time;
static rtc11_date_t date;

uint8_t sec_flag = 0xFF;

void disp_day_of_the_week ( uint8_t w_day ) {
    switch ( w_day )
    {
        case 0 :
        {
            log_printf( &logger, "Monday" );
            break;
        }
        case 1 :
        {
            log_printf( &logger, "Tuesday" );
            break;
        }
        case 2 :
        {
            log_printf( &logger, "Wednesday" );
            break;
        }
        case 3 :
        {
            log_printf( &logger, "Thursday" );
            break;
        }
        case 4 :
        {
            log_printf( &logger, "Friday" );
            break;
        }
        case 5 :
        {
            log_printf( &logger, "Saturday" );
            break;
        }
        case 6 :
        {
            log_printf( &logger, "Sunday" );
            break;
        }
        default :
        {
        break;
        }
    }
}
void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    rtc11_cfg_t rtc11_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.

    rtc11_cfg_setup( &rtc11_cfg );
    RTC11_MAP_MIKROBUS( rtc11_cfg, MIKROBUS_1 );
    err_t init_flag  = rtc11_init( &rtc11, &rtc11_cfg );
    if ( SPI_MASTER_ERROR == init_flag ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    log_printf( &logger,"------------------------\r\n" );
    log_printf( &logger," Software reset \r\n" );
    rtc11_soft_rst( &rtc11 );
    Delay_ms( 100 );
    
    time.hours = 23;
    time.min = 59;
    time.sec = 55;
    log_printf( &logger,"------------------------\r\n" );
    log_printf( &logger," Setting time: %.2d:%.2d:%.2d \r\n", ( uint16_t ) time.hours, ( uint16_t ) time.min, ( uint16_t ) time.sec );
    rtc11_set_time ( &rtc11, time );
    Delay_ms( 100 );
    
    date.day_of_week = 0;
    date.day = 19;
    date.month = 7;
    date.year = 21;
    log_printf( &logger,"------------------------\r\n" );
    log_printf( &logger," Setting date: %.2d/%.2d/%.2d \r\n", ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    rtc11_set_date( &rtc11, date );
    Delay_ms( 100 );
    
    rtc11_stp_sys_slk ( &rtc11, RTC11_PROP_DIS );
    log_info( &logger, " Application Task " );
    log_printf( &logger,"------------------------\r\n" );
}

void application_task ( void ) {
    rtc11_get_time ( &rtc11, &time );
    Delay_ms( 10 );
    rtc11_get_date ( &rtc11, &date );
    Delay_ms( 10 );
    
    if ( sec_flag != time.sec ) {
        log_printf( &logger, " Date: " );
        disp_day_of_the_week( date.day_of_week );
        log_printf( &logger, " %.2d/%.2d/20%.2d \r\n", ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
        log_printf( &logger, " Time: %.2d:%.2d:%.2d \r\n", ( uint16_t ) time.hours, ( uint16_t ) time.min, ( uint16_t ) time.sec );
        log_printf( &logger,"--------------------------\r\n" );
    }
    sec_flag = time.sec;
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources