Foxconn NF4UK8AA series User Manual page 31

PE_REFCLK Select Jumper: J3A1
This jumper is used to select the resource for PCI
Express PLL reference clock.
Common Mode Level Select Jumper: J1G1
This jumper is used to select common-mode level
range for PCI Express external reference clock input
pins.
Recovery Jumper: J1E1
This jumper is reserved for technology support,
please do not change the jumper.
Chapter 2 Installation Instructions
External
clock
reference
Internal clock
reference
(Default)
PE_REFCLK Select Jumper
Common
mode above
VDD/2
Common
mode below
VDD/2
(Default)
Common Mode Level
Closed
(Default)
Open
Select Jumper
1
2
1
2
Recovery Jumper
23