Intermediate
30 min

Experience time in its truest form with BU9873 combined with STM32F030R8

Seize the moment with real-time accuracy

RTC 16 Click with Nucleo-64 with STM32F030R8 MCU

Published Feb 26, 2024

Click board™

RTC 16 Click

Dev Board

Nucleo-64 with STM32F030R8 MCU

Compiler

NECTO Studio

MCU

STM32F030R8

Integrate real-time clock into your system for accurate timestamping and precise event sequencing

A

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Hardware Overview

How does it work?

RTC 16 Click is based on the BU9873, an I2C configurable real-time clock/calendar optimized for low-power operations from Rohm Semiconductors. The BU9873 is configured to perform the serial transmission of calendar and time data to the MCU and comes with an integrated interrupt generation function. It also contains a built-in high-precision oscillation adjustment circuit, which enables the adjustment of time counts with a digital method and correct deviations in the oscillation frequency of the crystal oscillator. An automatic leap year recognition also characterizes this RTC until the future 2099 year. 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. An alarm and interrupt function is also available that outputs an interrupt signal to the INT pin of the mikroBUS™ socket when the day of the week, hour, or minute matches with the preset time. An alarm may be selectable between ON and OFF for each day of the week, allowing outputting warning every day or on a specific day indicated by a red LED marked as ALARM. Besides, the RTC 16 Click also has an onboard header labeled CLKOUT, which provides clock pulses of 32kHz. Like this one, the most common RTC configuration is a

battery-backed-up, which maintains time and continues its work without interruption in the event of a power failure. That’s why, besides the BU9873, the RTC 16 Click has a button cell battery holder compatible with the 3000TR battery holder, suitable for 12mm Coin Cell batteries. 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 as a reference for further development.

RTC 16 Click hardware overview image

Features overview

Development board

Nucleo-64 with STM32F030R8 MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin

headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is

provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.

Nucleo 64 with STM32F030R8 MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

64

Silicon Vendor

STMicroelectronics

Pin count

64

RAM (Bytes)

8192

You complete me!

Accessories

Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Nucleo-64 accessories 1 image

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
Interrupt
PC14
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB8
SCL
I2C Data
PB9
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

RTC 16 Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-64 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F030R8 MCU as your development board.

Click Shield for Nucleo-64 front image hardware assembly
Nucleo 64 with STM32F401RE MCU front image hardware assembly
EEPROM 13 Click front image hardware assembly
Prog-cut hardware assembly
Nucleo-64 with STM32XXX MCU MB 1 Mini B Conn - 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 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 16 Click driver.

Key functions:

  • rtc16_set_time - This function sets the starting time values - second, minute and hour

  • rtc16_read_time - This function reads the current time values - second, minute and hour

  • rtc16_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 RTC16 Click example
 *
 * # Description
 * This example demonstrates the use of RTC 16 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 sets 24h time mode and interrupt to be synchronized with second count-up.
 * And after that setting the starting time and date.
 *
 * ## Application Task
 * Waits for the second count-up interrupt and then reads and displays the current
 * time and date values on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rtc16.h"

static rtc16_t rtc16;
static log_t logger;
static rtc16_time_t time;
static rtc16_date_t date;

/**
 * @brief RTC 16 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 #rtc16_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 *rtc16_get_day_of_week_name ( uint8_t day_of_week );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rtc16_cfg_t rtc16_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.
    rtc16_cfg_setup( &rtc16_cfg );
    RTC16_MAP_MIKROBUS( rtc16_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == rtc16_init( &rtc16, &rtc16_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( RTC16_ERROR == rtc16_default_cfg ( &rtc16 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }

    time.hour = 23;
    time.minute = 59;
    time.second = 50;
    if ( RTC16_OK == rtc16_set_time ( &rtc16, &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 = RTC16_SUNDAY;
    date.day = 31;
    date.month = 12;
    date.year = 22;
    if ( RTC16_OK == rtc16_set_date ( &rtc16, &date ) )
    {
        log_printf( &logger, " Set date: %s, %.2u.%.2u.20%.2u.\r\n", 
                    rtc16_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 interrupt which is synchronized with second count-up
    while ( rtc16_get_int_pin ( &rtc16 ) );
    
    rtc16_clear_interrupts ( &rtc16 );
    if ( RTC16_OK == rtc16_read_time ( &rtc16, &time ) )
    {
        log_printf( &logger, " Time: %.2u:%.2u:%.2u\r\n", 
                    ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
    }
    if ( RTC16_OK == rtc16_read_date ( &rtc16, &date ) )
    {
        log_printf( &logger, " Date: %s, %.2u.%.2u.20%.2u.\r\n\n", 
                    rtc16_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 *rtc16_get_day_of_week_name ( uint8_t day_of_week )
{
    switch ( day_of_week )
    {
        case RTC16_MONDAY:
        {
            return "Monday";
        }
        case RTC16_TUESDAY:
        {
            return "Tuesday";
        }
        case RTC16_WEDNESDAY:
        {
            return "Wednesday";
        }
        case RTC16_THURSDAY:
        {
            return "Thursday";
        }
        case RTC16_FRIDAY:
        {
            return "Friday";
        }
        case RTC16_SATURDAY:
        {
            return "Saturday";
        }
        case RTC16_SUNDAY:
        {
            return "Sunday";
        }
        default:
        {
            return "Unknown";
        }
    }
}

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

Additional Support

Resources

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