RTC 18 Click Board

Product Description

How Does The RTC 18 Click Board™ Work?

The RTC 18 Click Board™ is based on the RV-3032-C7, a highly accurate real-time clock/calendar module optimized for low power operations from Micro Crystal AG. The RV-3032-C7 comes with a built-in 32.768kHz “Tuning Fork” crystal oscillator and HF oscillator and has counters for hundredths of seconds, seconds, minutes, hours, date, month, year, and weekday. Its temperature compensation circuitry is factory calibrated and results in the highest time accuracy of ±2.5ppm over the entire temperature range from -40 to +85°C, with an additional non-volatile aging offset correction.

The RTC 18 Click Board™ also comes with an integrated digital thermometer for actual internal temperature measurement in °C with a typical accuracy of ±1°C, resolution of 0.0625°C/step, and a programmable alarm on top and bottom temperature limits. Alongside all these features, it also supports an automatic leap year correction. The calendar year will automatically be identified as a leap year when its last two digits are a multiple of 4. Consequently, leap years up to the year 2099 can automatically be recognized.

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. It also incorporates an alarm circuitry configured to generate an interrupt signal for Periodic Countdown Timer and Periodic Time Update (seconds, minutes), date/hour/minute alarm, and an external event registered with the CS pin on the mikroBUS™ socket. An alarm (interrupt) signal routed to the INT pin of the mikroBUS™ socket allows outputting warning every day or on a specific day visually indicated by a red LED marked as ALARM.

The RV-3032-C7 also includes an automatic backup switchover circuit allowing it to be used with a single button cell battery for an extended period. The activation of this feature can be made by positioning SMD jumpers labelled as BATT SEL in an appropriate position marked as OFF or ON. Besides an automatic backup switchover circuit, it also has a trickle charger with a charge pump providing full RTC functions with programmable counters, alarm, selectable interrupt, and programmable clock output functions for frequencies from 1Hz to 52MHz available on an onboard header labelled CLKO.

Te RTC 18 Click Board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to 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 of the RTC 18 Click Board™ 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
External Event Interrupt	EVI	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
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 18 CLICK ELECTRICAL SPECIFICATIONS

Software Support

void application_task ( void )
 {
 float temperature;
 // Wait for a second count-up interrupt
 while ( rtc18_get_int_pin ( &rtc18 ) );
 Delay_ms ( 10 );
 rtc18_clear_periodic_interrupt ( &rtc18 );
 if ( RTC18_OK == rtc18_read_time ( &rtc18, &time ) )
 {
 log_printf( &logger, " Time: %.2u:%.2u:%.2urn",
 ( uint16_t ) time.hour, ( uint16_t ) time.minute, ( uint16_t ) time.second );
 }
 if ( RTC18_OK == rtc18_read_date ( &rtc18, &date ) )
 {
 log_printf( &logger, " Date: %s, %.2u.%.2u.20%.2u.rn",
 rtc18_get_day_of_week_name ( date.day_of_week ),
 ( uint16_t ) date.day, ( uint16_t ) date.month, ( uint16_t ) date.year );
 }
 if ( RTC18_OK == rtc18_read_temperature ( &rtc18, &temperature ) )
 {
 log_printf( &logger, " Temperature: %.2f Crnn", temperature );
 }
 }

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