RTC 16 Click

RTC 16 Click is a compact add-on board that accurately keeps the time of a day. This board features the BU9873, a CMOS real-time clock that has a built-in interrupt generation function from Rohm Semiconductors. The BU9873 provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768kHz quartz crystal. This RTC is connected to the MCU through an I2C interface and configured to serial transmit time and calendar data. It also has an alarm function that outputs an interrupt signal to the MCU when the day of the week, hour, or minute matches with the preset time.

Click Product page

Click library

• Author : Stefan Filipovic
• Date : Mar 2022.
• Type : I2C type

Software Support

We provide a library for the RTC 16 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for RTC 16 Click driver.

Standard key functions :

• rtc16_cfg_setup Config Object Initialization function.

  void rtc16_cfg_setup ( rtc16_cfg_t *cfg );

• rtc16_init Initialization function.

  err_t rtc16_init ( rtc16_t *ctx, rtc16_cfg_t *cfg );

• rtc16_default_cfg Click Default Configuration function.

  err_t rtc16_default_cfg ( rtc16_t *ctx );

Example key functions :

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

  err_t rtc16_set_time ( rtc16_t *ctx, rtc16_time_t *time );

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

  err_t rtc16_read_time ( rtc16_t *ctx, rtc16_time_t *time );

• rtc16_read_date This function reads the current date values - day of week, day, month and year.

  err_t rtc16_read_date ( rtc16_t *ctx, rtc16_date_t *date );

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.

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 " );
}

Application Task

Waits for the second count-up interrupt and then reads and displays the current time and date values on the USB UART.

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 );
    }
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.RTC16

Additional notes and informations

Depending on the development board you are using, you may need USB UART Click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.