kobol-wiki/docs/helios64/rtc.md
Gauthier Provost 5ba93f2c13
Helios64 Hardware Detailed Info (#27)
* Add detailed hardware info for Helios64
    - Button
    - Ethernet
    - Front Panel
    - GPIO
    - I2C
    - Jumper
    - LED
    - M.2
    - PMIC
    - PWM Fan
    - RTC
    - SATA
    - SPI
    - UEXT
    - UPS
    - USB

* Cosmetic upgrade and adapt to latest mkdocs-material version

Co-authored-by: nurix <nurix@pnsnc.local>
Co-authored-by: Aditya Prayoga <aditya@kobol.io>
2020-04-20 16:06:24 +08:00

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Markdown

# 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.
![RTC](/helios64/img/rtc/rtc_diagram.jpg)
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](/helios64/img/rtc/rtc_battery.jpg)
!!! Note
The polarity of the battery holder is indicated on the PCB with **'+'** signs.