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Real Time Clock (RTC)

Helios64 has an on-board RTC clock which is provided by the Power Management IC (PMIC) RK808-D. The RTC functions provided by the PMIC include second/minute/hour/day/month/year information, alarm wake up as well as time calibration.


The SoC receive clock signal from the PMIC RTC and in the meantime access the PMIC RTC functions over I2C bus.

RTC Battery

To save time information and allow the RTC to keep running while system is powered off, the PMIC RTC relies on a dedicated coin battery located at BAT1. The battery holder (BAT1) accepts CR1225 battery model.

RTC Battery


The polarity of the battery holder is indicated on the PCB with '+' signs.

Last update: April 20, 2020