KBox C-103-CFL-x - User Guide, Rev. 1.0
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4.1.
RTC (GoldCap)
The baseboard of the KBox C-103-CFL provides an RTC chip connected via the I
2
C Bus. An RTC chip of type
RV-8803-C7 or compatible is used. To provide a valid date and time when no power is connected to the system, the
carrier is equipped with a goldcap buffer.
4.1.1.
RTC Buffer Time
The RTC buffer time is depending of the ambient temperature. For a better understanding the different behavior of
the goldcap buffer integrated in your system, refer to the diagram below:
Figure 3: RTC buffer time depending on temperature
If the time is not valid this is indicated by a status bit in the RTC registers. For details see the RV-8803-C7 application
manual.
To get the maximum buffer time, it is necessary to have the system a certain time powered
on. This ensures that the buffer capacitors are fully loaded.
The buffer time depends on the ambient temperature and on how long the system is
connected to the power supply.
4.1.2.
Setting the RTC
External RTC will be automatically updated by setting time/date via EFI shell time/date command, or via BIOS Aptio
Setup Main Menu (refer to chapter 11.2.1 “Main Setup Menu”).
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
0 °C
25 °C
50 °C
RTC Threshold
time / days
vo
lt
age
/
V
