PC4-PRESTO • CompactPCI
®
PlusIO • 4
th
Generation Intel
®
Core™-4xxx Processor
RTC Reset (J-RTC)
The jumper J-RTC may be used to reset certain register bits of the battery backed RTC core within the
PCH QM87. This can be necessary under rare conditions (e.g. battery undervoltage), if the CPU fails to
enter the BIOS POST after power on. Note that installing of jumper J-RTC will neither set UEFI BIOS
Setup to EKF Factory Defaults nor resets the time and date register values of the RTC (Real Time Clock).
To reset the RTC core the board must be removed from the system rack. Short-circuit the pins of J-RTC
for about 1 sec. Thereafter reinstall the board to the system and switch on the power. It is important
to accomplish the RTC reset while the board has no power. The pin header J-RTC is not stuffed on the
PC4-PRESTO by default.
J-RTC
Function
Jumper Removed
1)
Normal operation
Jumper Installed
RTC reset performed
1)
This setting is the factory default.
1
J-RTC
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