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一、概述微型计算机已经在各行各业尤其是科研、生产和工业产品等方面得到广泛地应用。单片微型计算机由于其体积小、功能全和抗干扰能力强,也已经深入到各个领域。随着微型计算机应用范围的不断扩大,对单片机与单片机、单片机与其它微型计算机(如PC机)和PC机与PC机之间的远程通信的要求日益迫切。我们知道,PC机(IBM PC或其它兼容机)上都带有8250可编程串行通信接口并配接RS-232C标准接口;MCS-51系列的单片机也带有可编程的串行接口,但它们均不符合远程通信的要求。根据美国电子工业协会(EIA)对RS-232C接口的标准规定,在采用标准屏蔽导线时(电容量为150pF/m的不平衡导线),波
First, an overview Micro-computer has been widely used in all walks of life, especially scientific research, production and industrial products. Monolithic microcomputer due to its small size, full-featured and anti-interference ability, has also been in-depth to all fields. With the continuous expansion of the application range of microcomputers, the requirements for the remote communication between a single-chip microcomputer and a single-chip microcomputer, a single-chip microcomputer and other micro-computers (such as a PC) and a PC and a PC are becoming more and more urgent. We know that the PC (IBM PC or other compatible) has a 8250 programmable serial communication interface with a standard RS-232C interface; the MCS-51 family of microcontrollers also has a programmable serial interface, but None of them meet the requirements of telecommunications. According to the standard of the American Electronics Industry Association (EIA) on the RS-232C interface, when using standard shielded wires (unbalanced wires with a capacitance of 150 pF / m), the wave