B.3 rtc overview, B.3.1 how to calculate the battery life, Verview – IEI Integration ICE-DB-T6 User Manual
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Type 6 Carrier Board Design Guide
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Step 4:
Restart the system and check the BIOS menu. The BIOS version has been
changed to MR11.
Figure B-11: BIOS Main Menu – Updated BIOS Version (MR11)
B.3 RTC Overview
A Real-time clock (RTC) is a basic hardware device that keeps track of the current time of
the computer. A RTC can be built in a chip or embedded in the system. When the
computer is turned off, the battery on the motherboard provides power to the RTC to keep
track of the current time. The RTC is usually used in personal computers and embedded
systems.
B.3.1 How to Calculate the Battery Life
The RTC requires an external battery connection to maintain functionality and its RAM
while the south bridge is not powered by the system.
The battery life can be calculated by dividing the capacity by the average current required.
For example, if the battery storage capacity is 170 mAh (assumed usable) and the
average current required is 6 μA, the battery life will be at least:
170,000μAh / 6 μA=28,333 h=3.2 years
The voltage oh the battery can affect the RTC accuracy. In general, when the battery
voltage decays, the RTC accuracy also decreases.