RTC 11 Click is a compact add-on board that contains a real-time clock IC designed to maximize battery life and reduce overall battery requirements in wearable applications. This board features the AB0815, an ultra-low-power coupled with a highly sophisticated feature set the real-time clock from Abracon LLC. The AB0815 includes on-chip oscillator to provide low power consumption, full RTC functions such as battery backup, programmable counters, and alarms for timer and watchdog functions. Its power requirements are lower than any other industry RTC (as low as 22 nA) and communicate with MCU using the SPI interface. This Click board™ is suitable for applications such as portable applications, wearables, medical equipment, and similar.

RTC 11 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

RTC 11 Click is based on the AB0815, an ultra-low-power coupled with a highly sophisticated feature set, the real-time clock from Abracon LLC. The AB0815 serves as a full-function RTC and includes 3 feature groups: baseline and advanced timekeeping features, and power management. Functions from each feature group may be controlled via I/O offset mapped registers accessed through SPI serial interface. The baseline timekeeping feature group supports the standard 32.786 kHz crystal oscillation mode for maximum frequency accuracy with an ultra-low current draw of 22nA. This feature also includes a standard set of counters for minutes, hours, dates, months, years, and week-days. A complement of countdown timers and alarms may additionally be set to initiate interrupts or resets on several of the outputs.

The most common configuration as performed on this Click board™ is a battery backed up RTC, which maintains time and may hold data in RAM. In addition to the AB0815, the RTC 11 Click is equipped with the button cell battery holder compatible with the 3000TR battery holder, suitable for 12mm Coin Cell batteries. By utilizing an automatic backup switch, the AB0815 can use an external battery power source when there is no power supply on its main power terminals, thus allowing for uninterrupted operation.

The AB0815 communicates with MCU using the standard SPI serial interface that supports modes 0 and 3 with a maximum frequency of 2 MHz. The flexible inputs of the AB0815 can be used to aggregate a variety of interrupt sources, including external digital inputs, analog levels, timers, and alarms into a single interrupt source to an MCU. Based on this, functions like external interrupt or watchdog timer reset could be found on this Click board™ routed on the RST and AN pins of the mikroBUS™ socket labeled as EXI and WDI, as well as the primary and secondary interrupt outputs routed on the INT and PWM pins of the mikroBUS™ socket labeled as IT1 and IT2.

This Click board™ is designed to be operated only with a 3.3V logic voltage level. A proper logic voltage level conversion should be performed before the Click board™ is used with MCUs with different logic levels. However, the Click board™ comes equipped with a library that contains easy to use functions and an example code that can be used as a reference for further development.

• Interface: SPI
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V
• Supply Voltage: Min. -0.3V, Typ. 3.3V, Max. 3.8V
• Battery Supply Voltage: Min. 1.4V, Max. 3.6V
• Maximum Output Current: Min. -20mA, Max. 20mA
• SPI Clock Frequency: 2 MHz
• Operating Temperature Range: Min. -40°C, Max. +85°C

• Schematic
• AB08X5 Datasheet
• mikroSDK
• GitHub