时钟电路：连接在引脚XTAL1、XTAL2和GND间的电路是时钟电路(XTAL = External Crystal Oscillator，表示外接晶振)。前面的电源比较好理解，但是什么是时钟电路呢?它有什么用处呢?时钟电路就像是人的心脏一样，每时每刻不断跳动着，对于单片机来说是至关重要的。

The STM8AF board can perform both CAN and LIN communications with the MCU powered at 5 V and is ready to be connected into a network with its integrated transceiver. The STM8AL board manages LIN slave ...