Intermediate
30 min

Transform your time management with MAX31341B and PIC32MZ2048EFM100

Tick-tock, seize the day

RTC 7 Click with Curiosity PIC32 MZ EF

Published Oct 20, 2023

Click board™

RTC 7 Click

Dev Board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Experience the power of precise timekeeping in your engineering projects by integrating state-of-the-art real-time clock solution

A

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Hardware Overview

How does it work?

RTC 7 Click is based on the MAX31341B, a low-current Real-Time Clock with I2C interface and power management from Analog Devices. Thanks to its high integration level, this module provides high time accuracy, 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. The small dimension of the MAX31341B module itself, allow it to be used in very space-constrained applications, including wearables, medical equipment, and similar. In addition to the MAX31341B, RTC 7 click is equipped with the 220mF super capacitor. 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 180nA of current, it can be operated with the mentioned supercapacitor almost indefinitely.

In addition, a trickle charge system will replenish the super capacitor while the MAX31341B is powered over the main power terminals (VDD, VSS). The voltage of the main power supply can range between 1.6V up to 3.6V. The MAX31341B 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 MAX31341B, INTA and INTB, 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 two mentioned interrupt pins are routed to INT and AN pins of the mikroBUS™ socket, respectively. 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). Besides other functions, RTC 7 click have one analog and one digitital external input, labeled AIN and DIN. These universal inputs can be wired to any kind of external trigger, which needs to trigger one of the interrupts. The digital input can be configured to detect rising or falling edge, while the analog input, besides the edge detection, supports the programmable threshold too. For detailed information on interrupts and external triggers, refer to the MAX31341B datasheet. 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 7 Click top side image
RTC 7 Click bottom side image

Features overview

Development board

Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand

functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,

which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.

Curiosity PIC32MZ EF double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

Interrupt B
RPB4
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 A
RF13
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RPA14
SCL
I2C Data
RPA15
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

RTC 7 Click Schematic schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

Curiosity PIC32MZ EF front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Curiosity PIC32 MZ EF MB 1 Access - 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
Curiosity PIC32 MZ EF 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 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 7 Click driver.

Key functions:

  • rtc7_check_interrupt - This function returns the interrupt state, state of INTA pin

  • rtc7_read_reg - This function writes one byte data to the register

  • rtc7_get_local_time - This function gets the local time data including the determined time zone in calculations

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 RTC7 Click example
 * 
 * # Description
 * This app is used to accurately measure time with low power consumption.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes device.
 * 
 * ## Application Task  
 * Waits for a second count-up interrupt and then reads and logs the current
 * time and date on the USB UART.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtc7.h"

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

static rtc7_t rtc7;
static log_t logger;

rtc7_time_t time_set;
rtc7_time_t time_date;

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

void rtc7_display_results ( rtc7_t *ctx )
{
    log_printf( &logger, " %.2u:%.2u:%.2u\r\n", 
                ( uint16_t ) time_date.hours, ( uint16_t ) time_date.minutes, ( uint16_t ) time_date.seconds );

    log_printf( &logger, " %.2u/%.2u/%.2u ", 
                ( uint16_t ) time_date.monthday, ( uint16_t ) time_date.month, ( uint16_t ) time_date.year );
    switch ( time_date.weekdays )
    {
        case 1:
        {
            log_printf( &logger, "MONDAY" );
            break;
        }
        case 2:
        {
            log_printf( &logger, "TUESDAY" );
            break;
        }
        case 3:
        {
            log_printf( &logger, "WEDNESDAY" );
            break;
        }
        case 4:
        {
            log_printf( &logger, "THURSDAY" );
            break;
        }
        case 5:
        {
            log_printf( &logger, "FRIDAY" );
            break;
        }
        case 6:
        {
            log_printf( &logger, "SATURDAY" );
            break;
        }
        case 7:
        {
            log_printf( &logger, "SUNDAY" );
            break;
        }
        default:
        {
            break;
        }
    }
    log_printf( &logger, "\r\n-------------------\r\n" );
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    rtc7_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.
    rtc7_cfg_setup( &cfg );
    RTC7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rtc7_init( &rtc7, &cfg );
    Delay_ms ( 300 );
    
    time_set.seconds = 40;
    time_set.minutes = 59;
    time_set.hours = 23;
    time_set.weekdays = 1;
    time_set.monthday = 31;
    time_set.month = 12;
    time_set.year = 22;
    
    err_t error_flag = rtc7_reset( &rtc7 );
    error_flag |= rtc7_init_time ( &rtc7, 0 );
    error_flag |= rtc7_set_gmt_time( &rtc7, &time_set );
    error_flag |= rtc7_set_osc( &rtc7, RTC7_ENABLE_OSC, RTC7_INPUT_FREQ_32768HZ, RTC7_OUTPUT_FREQ_32768HZ );
    error_flag |= rtc7_write_reg( &rtc7, RTC7_TIMER_INIT_REG, 15 );
    error_flag |= rtc7_set_timer( &rtc7, RTC7_TIMER_EN, RTC7_TIMER_FREQ_16HZ );
    Delay_ms ( 100 );
    if ( RTC7_ERROR == error_flag )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    // Wait for timer count-down interrupt which is set to 1Hz
    while ( rtc7_check_interrupt ( &rtc7 ) );

    // Clear interrupt status
    uint8_t int_status = 0;
    rtc7_read_reg( &rtc7, RTC7_INT_STATUS_REG, &int_status, 1 );
    
    // Read time
    if ( RTC7_OK == rtc7_get_local_time( &rtc7, &time_date ) )
    {
        // Display time
        rtc7_display_results( &rtc7 );
    }
}

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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