Tool/software:
the datasheet says，Crystal oscillator (X1 and X2) ground pin. When using an external crystal, do not connect this pin to the board ground. Instead, connect it to the ground reference of the external crystal oscillator circuit. If an external crystal is not used, this pin may be connected to the board ground.
we use external crystal， but We now have a problem, our board ground and the external crystal ground are the same ground, if connected together, is it OK？
How should we connect the VSSOSC pin？Is this pin hanging ok？
