RTC 18 Click is a compact add-on board that accurately keeps the time of a day. This board features the RV-3032-C7, an I2C-configurable real-time clock module that incorporates an integrated CMOS circuit and an XTAL from Micro Crystal AG. The RV-3032-C7 is a temperature compensated RTC with premium accuracy (0.22 sec/day) and extremely low power consumption, allowing it to be used with a single button cell battery for an extended period. It can measure temperature with a typical accuracy of ±1°C and a resolution of 0.0625°C/step with a programmable alarm on top and bottom temperature limits. It features standard RTC functions with automatic leap year correction, and standard interrupt for Periodic Countdown Timer and Periodic Time Update (seconds, minutes), date/hour/minute alarm, and an external event. This Click board™ is suitable for various time-keeping applications, including daily alarms, metering applications, and others requiring an accurate RTC for their operation.

RTC 18 Click as its foundation uses 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.

This RTC 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 labeled 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 labeled CLKO.

This 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.

• Interface: I²C
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V or 5V
• Supply Voltage: Min. 3.3V, Max. 5V
• RTC Accuracy: 0.22 sec/day
• Temperature Accuracy: ±1°C
• Resolution: 0.0625 °C/step
• Clock Output CLKO: Min. 1 MHz, Max. 52 MHz
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +85°C

• Schematic
• RV-3032-C7 Datasheet
• mikroSDK
• LibStock