说明：  SCI（SerialCommunicationInterface)意为“串行通信接口”，是相对于并行通信的，是串行通信技术的一种总称，最早由Motorola公司提出的。它是一种通用异步通信接口UART，与MCS‐51的异步通信功能基本相同。
(SCI (SerialCommunicationInterface) means "serial communication interface", is relative to the parallel communication, serial communication technology is a general term, the first proposed by the Motorola company. It is a universal asynchronous communication interface UART, and MCS-51 asynchronous communication function is basically the same.)