Crystal socket Q1 schematics below:
J4 and J5: GND connection points
In case a good ground connection is required, connection points bridge J4 and pin J5 provide
easy access to the Emulation Adapter's GND potential.
J6 and J7: VFLEX and VAREF
VFLEX
- If the target’s VFLEX pin isn’t exposed, bridge the jumper J6 to connect VEXT from the
target to power VFLEX.
Setting the jumper when emulating the BGA device may prevent establishing a debug
connection or, in the worst case, can damage the Target board.
VAREF
- If the target’s VAREF2 pin isn’t exposed, bridge the jumper J7 to connect VAREF1 from
the target to power VAREF2