关于晶体振荡器电路布线引发的问题（Layout Issues），解释如下：

Good layout practices are fundamental to the correct operation and reliability of the oscillator. It is critical to locate the oscillator’s components very close to the XTAL and EXTAL pins to minimize routing distances. Long traces in the oscillator circuit are a very common source of problems. Don’t route other signals across the oscillator circuit, and make sure power and high-frequency traces are routed as far away as possible to avoid crosstalk and noise coupling. Power supply decoupling capacitors should be located very close to the microcontroller’s power pins.

良好的布局方式是晶体振荡器正确工作和可靠性的基础。至关重要的一个规则是：使晶体振荡器尽可能接近XTAL和EXTAL引脚，以最大程度减少布线距离。晶体振荡器布线过长，是导致问题发生的最常见根源之一。不要在振荡器电路上布线其它信号，并确保电源和高频线路的布线尽可能远，以避免串扰和噪声耦合。电源去耦电容应该靠近微控制器的电源引脚。

Avoid the use of vias; if the routing becomes very complex, it is much better to use 0 Ω resistors as bridges to go over other signals. Vias in the oscillator circuit should only be used for connections to the ground plane. Don’t share ground connections; instead, make a separate connection to ground for each component that requires grounding. If possible, place multiple vias in parallel for each connection to the ground plane.

避免使用过孔；如果布线变得非常复杂，最好使用0Ω电阻作为桥接器，以跨越它他信号。振荡器电路中的通孔只能用于连接到地平面。不要共用接地端；相反，为每个需要接地的组件建立单独的接地连接。如果可能的话，将多个过孔并联放置在每个接地平面的连接端。

Especially in the Colpitts configuration, the oscillator is very sensitive to capacitance in parallel with the crystal or resonator. Therefore, the layout must be designed to minimize stray capacitance across the crystal or resonator. For example, in the Colpitts configuration, it’s possible to remove the ground plane from all layers under the EXTAL trace and to leave considerable spacing from the EXTAL trace to all other traces and planes. When stray capacitance appears across capacitors C1 and C2, they should be resized to compensate for this added capacitance. Be sure to take into account both printed circuit board (PCB) and pin capacitance.

特别是在Colpitts结构中，振荡器对平行于晶体或谐振器的电容非常敏感。因此，电路布线设计必须尽量减少横跨晶体或谐振器的杂散电容。例如，在Colpitts配置中，可以将接地平面（ground plane）从EXTAL线路的所有层中移除，并在EXTAL线路中给所有其它线路和平面留下相当大的间隔。当外接电容C1和C2之间出现杂散电容时，应调整它们的大小以补偿所增加的电容。请务必同时考虑到电路板(PCB)和引脚电容。

The use of high-quality components in the oscillator circuit is equally important to achieve correct and reliable operation. Capacitors should be high-quality capacitors with very low ESR, designed for use in high-frequency applications. If a resonator is used, it is critical to choose a very high-quality resonator. Remember that poor layout practices (like long traces) can also contribute to EMC susceptibility and unintentional electromagnetic radiation.

在晶体振荡器电路中，选择并使用高质量元件对于实现振荡器电路的正确运作及性能可靠性能同样重要。电容应该是具有非常低ESR的高质量电容器，以便用于高频应用的设计。如果使用的是谐振器方案，那么，选择高质量的晶体谐振器尤为关键。切记：糟糕的晶振布线设计（如信号线布线过长）也会导致EMC易感性和意料之外的电磁辐射。