Intermediate
30 min

Measure the passage of time with MAX31334 and PIC32MX534F064H

Add time management to your application

RTC 19 Click with PIC32MX clicker

Published Feb 25, 2023

Click board™

RTC 19 Click

Dev Board

PIC32MX clicker

Compiler

NECTO Studio

MCU

PIC32MX534F064H

Keep track of time in the right way and with the right tools

A

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Hardware Overview

How does it work?

RTC 19 Click is based on the MAX31334, an ultra-low power, real-time clock (RTC) time-keeping device from Analog Devices. The MAX31334 is configured to transmit calendar and time data to the MCU (24-hour/12-hour format) based on a 32.768kHz quartz crystal and comes with an integrated interrupt generation function. 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, days, months, year, and date information. The end-of-the-month date is automatically adjusted for months with fewer than 31 days, including corrections for the leap year. The MAX31334 features an integrated high-side power pass switch (detectable through a PSW pin and drawn to the TP1 testpoint for external use), enabling idle, ultra-low power modes on duty-cycled applications by disconnecting power to other devices on the system. The power switch ON/OFF durations can be controlled by periodic

interrupt sources such as a countdown timer, alarms, or by an external interrupt from a DIN pushbutton. The DIN signal represents a digital Schmitt trigger that records timestamps or asserts an interrupt on its falling/rising edge. In addition to the DIN button, the state of this signal can also be changed digitally using the DIN pin, routed on the RST pin of the mikroBUS socket. The selection can be performed using an onboard SMD jumper labeled DIN SEL, placing it in an appropriate position marked as MB or T, where MB stands for mikroBUS and T for the button. 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 an alarm circuitry configured to generate a time-of-day/date interrupt signal. An alarm (interrupt) signal, marked as INA and routed to the INT pin of the mikroBUS socket, allows outputting warning every day or on a specific day visually

indicated by a red LED marked as ALARM. By utilizing an automatic backup switch, when the main supply drops below the programmed threshold voltage, this RTC can use an external power source (220mF supercapacitor), allowing uninterrupted operation. Besides an automatic backup switchover circuit, this board also carries a header for additional alarm/interrupt and a programmable clock output signal for frequencies from 1Hz to 32kHz available on an onboard J1 header. In addition, this signal also exists on the AN pin of the mikroBUS socket marked with INTB. 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. However, the 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 19 Click hardware overview image

Features overview

Development board

PIC32MX Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC32 microcontroller, the PIC32MX534F064H from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Thanks to its compact design with clear and easy-recognizable silkscreen markings, it provides a fluid and immersive working experience, allowing access

anywhere and under any circumstances. Each part of the PIC32MX Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the PIC32MX Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Mini-B connection can provide up to 500mA of current, which is more

than enough to operate all onboard and additional modules. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. PIC32MX Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

PIC32MX clicker double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

64

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

Clock/Alarm Interrupt B
RB3
AN
Schmitt Trigger
RD7
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Power Switch
RD0
PWM
Alarm Interrupt A
RD11
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RF5
SCL
I2C Data
RF4
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

RTC 19 Click Schematic schematic

Step by step

Project assembly

STM32 M4 clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the PIC32MX clicker as your development board.

STM32 M4 clicker front image hardware assembly
Thermo 26 Click front image hardware assembly
Prog-cut hardware assembly
Mini B Connector clicker - 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
Necto_MCU_Select_PICPLC16 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 via Debug Mode

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

2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.

DEBUG_Application_Output

Software Support

Library Description

This library contains API for RTC 19 Click driver.

Key functions:

  • rtc19_set_time This function sets the starting time values - second, minute and hour.

  • rtc19_read_time This function reads the current time values - second, minute and hour.

  • rtc19_read_date This function reads the current date values - day of week, day, month and year.

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 19 Click example
 *
 * # Description
 * This example demonstrates the use of RTC 19 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 performs the click default configuration
 * which resets the device and sets the timer interrupt to 1 Hz. 
 * After that, it sets the starting time and date.
 *
 * ## Application Task
 * Waits for a timer countdown interrupt (1 Hz) and then reads and displays on the USB UART 
 * the current time and date values.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rtc19.h"

static rtc19_t rtc19;
static log_t logger;
static rtc19_time_t time;
static rtc19_date_t date;

/**
 * @brief RTC 19 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 #rtc19_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 char *rtc19_get_day_of_week_name ( uint8_t day_of_week );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rtc19_cfg_t rtc19_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.
    rtc19_cfg_setup( &rtc19_cfg );
    RTC19_MAP_MIKROBUS( rtc19_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == rtc19_init( &rtc19, &rtc19_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( RTC19_ERROR == rtc19_default_cfg ( &rtc19 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    time.hour = 23;
    time.minute = 59;
    time.second = 50;
    if ( RTC19_OK == rtc19_set_time ( &rtc19, &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 = RTC19_SATURDAY;
    date.day = 31;
    date.month = 12;
    date.year = 22;
    if ( RTC19_OK == rtc19_set_date ( &rtc19, &date ) )
    {
        log_printf( &logger, " Set date: %s, %.2u.%.2u.20%.2u.\r\n", 
                    rtc19_get_day_of_week_name ( date.day_of_week ),
                    ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    // Wait for a timer countdown flag configured at 1 Hz
    while ( rtc19_get_inta_pin ( &rtc19 ) );

    Delay_ms ( 100 );
    rtc19_clear_interrupts ( &rtc19 );
    if ( RTC19_OK == rtc19_read_time ( &rtc19, &time ) )
    {
        log_printf( &logger, " Time: %.2u:%.2u:%.2u\r\n", 
                    ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
    }
    if ( RTC19_OK == rtc19_read_date ( &rtc19, &date ) )
    {
        log_printf( &logger, " Date: %s, %.2u.%.2u.20%.2u.\r\n", 
                    rtc19_get_day_of_week_name ( date.day_of_week ),
                    ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
    }
}

void main ( void ) 
{
    application_init( );

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

static char *rtc19_get_day_of_week_name ( uint8_t day_of_week )
{
    switch ( day_of_week )
    {
        case RTC19_MONDAY:
        {
            return "Monday";
        }
        case RTC19_TUESDAY:
        {
            return "Tuesday";
        }
        case RTC19_WEDNESDAY:
        {
            return "Wednesday";
        }
        case RTC19_THURSDAY:
        {
            return "Thursday";
        }
        case RTC19_FRIDAY:
        {
            return "Friday";
        }
        case RTC19_SATURDAY:
        {
            return "Saturday";
        }
        case RTC19_SUNDAY:
        {
            return "Sunday";
        }
        default:
        {
            return "Unknown";
        }
    }
}

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

Additional Support

Resources

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