RTC Click

How does it work?

RTC Click is based on the PCF8583, a clock, and a calendar with 240x8-bit RAM from NXP Semiconductors. It is a low-power, full binary-coded decimal (BCD) clock/calendar which takes care of a 4-year calendar and a 24h/12h time format that works in several modes. The PCF8583’s counter function mode consists of a clock and event-counter modes. In clock mode, the hundredths of a second, seconds, minutes, hours, date, month (four-year calendar), and weekday are stored in a BCD format. The timer register stores for up to 99 days. The event counter mode counts pulses applied to the oscillator input. The event counter stores up to 6 digits of data.

The alarm function mode consists of a dated alarm, a daily alarm, a weekday alar, or a timer alarm, which can be programmed. When an alarm event occurs, the alarm flag is set and will remain set until directly reset by a write operation. The alarm function can be disabled. The timer function can also be enabled. The timer counts from 0 (or a programmed value) up to 99, after which the timer resets to 0. In addition, a timer can be programmed so that when the value of the timer equals the pre-programmed value, the alarm will be triggered.

This Click board™ communicates with the MCU using the standard I2C 2-Wire interface to read data and configure settings with up to 100kHz frequency. The interrupt occurs when the alarm or the timer flag is set, with the corresponding interrupt signaled over the INT pin of the mikroBUS™ socket. The RTC Click also features a 3V/230mA lithium battery as a backup power supply, ensuring that timekeeping operation continues even when the main power supply goes off.

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the 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.

Specifications

Pinout diagram

This table shows how the pinout on RTC 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	SC	I2C Clock
	NC	6	MOSI	SDA	11	SD	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

RTC Click electrical specifications

Software Support

We provide a library for the RTC 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 RTC Click driver.

Key functions

• rtc_c_set_time Function sets time: hours, minutes and seconds data to the target register address of PCF8583 chip on RTC Click.

• rtc_c_get_time Function gets time: hours, minutes and seconds data from the target register address of PCF8583 chip on RTC Click.

• rtc_c_enable_disable_counting Function that enables or disables counting on RTC Click.

Example Description

This application enables setup and measurement of time with RTC Click.

 void application_task ( void ) 
 { 
     static uint8_t time_seconds_new = 0xFF; 

     rtc_c_get_time( &rtc_c ); 

     if ( time_seconds_new != rtc_c.time.time_seconds ) 
     { 
         log_printf( &logger, " Time : %.2u:%.2u:%.2urn",  
                     ( uint16_t ) rtc_c.time.time_hours,  
                     ( uint16_t ) rtc_c.time.time_minutes,  
                     ( uint16_t ) rtc_c.time.time_seconds ); 

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

         time_seconds_new = rtc_c.time.time_seconds; 
     } 

     Delay_ms ( 500 ); 
 }

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.Rtc

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.