17 lines
783 B
Markdown
17 lines
783 B
Markdown
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# Real Time Clock (RTC)
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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.
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The SoC receive clock signal from the PMIC RTC and in the meantime access the PMIC RTC functions over I2C bus.
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## RTC Battery
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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.
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!!! Note
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The polarity of the battery holder is indicated on the PCB with **'+'** signs.
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