说明：  1．掌握8251芯片结构和编程,掌握单片机通讯的编制,2．了解实现串行通讯的硬环境,数据格式的协议,数据交换的协议,3
(1. Master the structure and programming of 8251 chip, master the programming of MCU communication, 2. Understand the hardware environment of serial communication, the protocol of data format, the protocol of data exchange, 3.)