Intermediate
30 min

Stay ahead of time with DS3231M and STM32F031K6

Clocking in: The secret to precise timekeeping

RTC 10 Click with Nucleo 32 with STM32F031K6 MCU

Published Oct 01, 2024

Click board™

RTC 10 Click

Dev. board

Nucleo 32 with STM32F031K6 MCU

Compiler

NECTO Studio

MCU

STM32F031K6

Ensure accurate timestamping and synchronization of data with advanced real-time clock, elevating the performance of your solution

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Hardware Overview

How does it work?

RTC 10 Click is based on the DS3231M, a low-cost, extremely accurate, I2C real-time clock (RTC) from Analog Devices. Thanks to its high integration level, it 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 dimensions of the DS3231M itself, allow it to be used in very space-constrained applications, including wearables, medical equipment, and similar. In addition to the DS3231M, RTC 10 click is equipped with the button cell battery holder compatible with the 3000TR batteryholder, suitable for 12mm Coin Cell batteries. 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. The RTC maintains seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months

with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. Two programmable time-of day alarms and a 1Hz output are provided. Address and data are transferred serially through an I2C bidirectional bus. A precision temperature-compensated voltage reference and comparator circuit monitors the status of VCC to detect power failures, to provide a reset output, and to automatically switch to the backup supply when necessary. Additionally, the RST pin is monitored as a pushbutton input for generating a microprocessor reset and is routed to the RST pin on the mikroBUS™ socket. The temperature sensor, oscillator, and digital adjustment controller logic form the highly accurate time base. The controller reads the output of the on-board temperature sensor and adjusts the final 1Hz output to maintain the required accuracy. The device is trimmed at the factory to maintain a tight accuracy over the operating temperature range.

When the device is powered by VCC, the adjustment occurs once a second. When the device is powered by VBAT, the adjustment occurs once every 10s to conserve power. Adjusting the 1Hz time base less often does not affect the device’s long-term timekeeping accuracy. The device also contains an Aging Offset register that allows a constant offset (positive or negative) to be added to the factory-trimmed adjustment value. The I2C interface is accessible whenever either VCC or VBAT is at a valid level. If a microcontroller connected to the device resets because of a loss of VCC or other event, it is possible that the microcontroller and device’s I2C communications could become unsynchronized. e.g., the microcontroller resets while reading data from the device. When the microcontroller resets, the device’s I2C interface can be placed into a known state by toggling SCL until SDA is observed to be at a high level. At that point the microcontroller should pull SDA low while SCL is high, generating a START condition.

RTC 10 Click top side image
RTC 10 Click bottom side image

Features overview

Development board

Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The

board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,

and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.

Nucleo 32 with STM32F031K6 MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

32

Silicon Vendor

STMicroelectronics

Pin count

32

RAM (Bytes)

4096

You complete me!

Accessories

Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.

Click Shield for Nucleo-32 accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Analog ECG Output
PA0
AN
Reset
PA11
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
PA12
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB6
SCL
I2C Data
PB7
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

RTC 10 Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-144 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo 32 with STM32F031K6 MCU as your development board.

Click Shield for Nucleo-144 front image hardware assembly
Nucleo 144 with STM32L4A6ZG MCU front image hardware assembly
2x4 RGB Click front image hardware assembly
Prog-cut hardware assembly
Nucleo-32 with STM32 MCU 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
Clicker 4 for STM32F4 HA 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

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for RTC 10 Click driver.

Key functions:

  • rtc10_generic_write - Generic write function.

  • rtc10_generic_read - Generic read function.

  • rtc10_hw_reset - Hardware reset function.

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * \file 
 * \brief Rtc10 Click example
 * 
 * # Description
 * This application is a real-time clock module.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initialization driver enable's - I2C,
 * hardware reset, set start time and date, enable counting also, write log.
 * 
 * ## Application Task  
 * This is an example which demonstrates the use of RTC 10 Click board.
 * RTC 10 Click communicates with register via I2C interface,
 * set time and date, enable counting and display time and date values,
 * also, display temperature value for every 1 sec.
 * Results are being sent to the Usart Terminal where you can track their changes.
 * All data logs write on Usart Terminal changes for every 1 sec.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtc10.h"

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

static rtc10_t rtc10;
static log_t logger;

uint8_t sec_flag;

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

void display_day_of_the_week( uint8_t day_of_the_week )
{
    if ( day_of_the_week == 1 )
    {
        log_printf( &logger, "      Monday    \r\n\n " );
    }
    if ( day_of_the_week == 2 )
    {
        log_printf( &logger, "      Tuesday   \r\n\n " );
    }
    if ( day_of_the_week == 3 )
    {
        log_printf( &logger, "     Wednesday  \r\n\n " );
    }
    if ( day_of_the_week == 4 )
    {
        log_printf( &logger, "     Thursday   \r\n\n " );
    }
    if ( day_of_the_week == 5 )
    {
        log_printf( &logger, "      Friday    \r\n\n " );
    }
    if ( day_of_the_week == 6 )
    {
        log_printf( &logger, "     Saturday   \r\n\n " );
    }
    if ( day_of_the_week == 7 )
    {
        log_printf( &logger, "      Sunday    \r\n\n " );
    }        
}

void application_init ( void )
{
    log_cfg_t log_cfg;
    rtc10_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.

    rtc10_cfg_setup( &cfg );
    RTC10_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rtc10_init( &rtc10, &cfg );

    Delay_ms( 1000 );
    
    sec_flag = 0xFF;

    log_printf( &logger, "------------------- \r\n" );
    log_printf( &logger, "  Hardware  Reset   \r\n" );
    rtc10_hw_reset(  &rtc10 );
    Delay_ms( 1000 );

    // Set Time: 23h, 59 min and 50 sec
    rtc10_set_time(  &rtc10, 23, 59, 50 );
    Delay_ms( 10 );

    // Set Date: 6 ( Day of the week: Saturday ), 31 ( day ), 8 ( month ) and 2019 ( year )
    rtc10_set_date(  &rtc10,  6, 31, 8, 2019 );
    Delay_ms( 100 );

    log_printf( &logger, "-------------------  \r\n" );
    log_printf( &logger, "  Enable Counting  \r\n" );
    log_printf( &logger, "------------------- \r\n" );
    log_printf( &logger, "     Start RTC      \r\n" );
    log_printf( &logger, "------------------- \r\n" );
    rtc10_enable_counting(  &rtc10 );
    Delay_ms( 100 );
}

void application_task ( void )
{
    uint8_t i;
    uint8_t time_hours = 0;
    uint8_t time_minutes = 0;
    uint8_t time_seconds = 0;

    uint8_t day_of_the_week = 0;
    uint8_t date_day = 0;
    uint8_t date_month = 0;
    uint8_t date_year = 0;
    
    float temperature;
    
    rtc10_get_time( &rtc10, &time_hours, &time_minutes, &time_seconds );
    Delay_ms( 100 );

    rtc10_get_date( &rtc10, &day_of_the_week, &date_day, &date_month, &date_year );
    Delay_ms( 100 );

    if ( sec_flag !=  time_seconds )
    {
        log_printf( &logger, " \r\n\n Time: %u:%u:%u  ", (uint16_t)time_hours, (uint16_t)time_minutes, (uint16_t)time_seconds );
        
        log_printf( &logger, "Date: %u. %u. 20%u. ", (uint16_t)date_day, (uint16_t)date_month, (uint16_t)date_year );
        display_day_of_the_week( day_of_the_week );
        
        if ( time_seconds == 0 )
        {
            temperature = rtc10_get_temperature( &rtc10 );

            log_printf( &logger, "\r\n\n Temp.:%.2f C", temperature);
        }
        log_printf( &logger, "--------------------------------------------" );

        sec_flag =  time_seconds;
    }
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources

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