RTC 2 Click

How does it work?

RTC 2 Click is based on the DS1307, a 64×8 serial I2C Real-Time clock from Analog Devices. It is a low-power, full binary-coded decimal (BCD) clock/calendar with 56 bytes of NV SRAM. The end of months is automatically adjusted for months with fewer than 31 days, including corrections for the leap year. The clock can operate in either a 24-hour or 12-hour format with AM/PM indicator. The RTC has a built-in power-sense circuit that automatically switches to the backup power supply when it detects a power failure. The RTC 2 comes equipped with a 3V/230mA lithium battery, ensuring timekeeping continues even when the main power supply goes OFF.

The RTC 2 Click uses an I2C 2-Wire interface for communication with the host MCU, with a clock rate of up to 400KHz. The interrupt INT pin of this Click board™ outputs one of four square-wave frequencies (1Hz, 4KHz, 8KHz, and 32KHz). When enabled, it outputs frequency depending on values set in configuration bits.

This Click board™ can be operated only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on RTC 2 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
	NC	2	RST	INT	15	INT	Interrupt
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
	NC	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

RTC 2 Click electrical specifications

Software Support

We provide a library for the RTC2 Click as well as a demo application (example), developed using MIKROE compilers. The demo can run on all the main MIKROE development boards.

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

Library Description

This library contains API for RTC2 Click driver.

Key functions

• Generic read byte of data function.

• Generic write byte of data function.

• Enable counting function.

Example Description

This application give time and day information.

 void application_task ( void ) 
 { 
     rtc2_get_time( &rtc2, &time_hours, &time_minutes, &time_seconds ); 

     rtc2_get_date( &rtc2, &day_of_the_week, &date_day, &date_month, &date_year ); 

     if ( time_seconds_new !=  time_seconds ) 
     { 
         log_printf( &logger, " Time : " ); 

         display_log_uart( time_hours ); 
         log_printf( &logger, ":" ); 

         display_log_uart( time_minutes ); 
         log_printf( &logger, ":" ); 

         display_log_uart( time_seconds ); 
         log_printf( &logger, "" ); 

         display_day_of_the_week( day_of_the_week ); 

         log_printf( &logger, " Date: " ); 

         display_log_uart( date_day ); 
         log_printf( &logger, "." ); 

         display_log_uart( date_month ); 
         log_printf( &logger, "." ); 

         log_printf( &logger, "20" ); 

         display_log_uart( date_year ); 
         log_printf( &logger, "." ); 

         log_printf( &logger, "-------------------" ); 

         time_seconds_new =  time_seconds; 
     } 
 }

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

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Rtc2

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 MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.