Hitachi HF-W7500, Instruction Manual

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5. SPECIFICATION
5-18
5.8 Hardware System Clock
This equipment has a hardware system clock that uses an RTC (real-time clock) IC.
The clock has a built-in calendar and continues to work using a backup battery even when
the system power is off.
Table 5-19 Hardware System Clock Specification
Item Specifications
Time function
Hour/Minute/Second
(24-hours clock)
Date function Year/Month/Date
Precision ± 4 seconds per day (*)
Battery
backup
Lithium battery
(*) Rough estimates when the ambient temperature is 25

C.
For your information, the system program normally updates the internal clock by using a
periodic timer. The internal clock is adjusted by reading the time and date from the hardware
clock when, for example, the system starts.