A: Fundamentals of Single-chip Microcomputer
The single-chip microcomputer is the culmination of both the development of the digital computer and the integrated circuit arguably the tow most significant inventions of the 20th century [1].
These tow types of architecture are found in single-chip microcomputer. Some employ the split program/data memory of the Harvard architecture, shown in Fig.3-5A-1, others follow the philosophy, widely adapted for general-purpose computers and microprocessors, of making no logical distinction between program and data memory as in the Princeton architecture, shown in Fig.3-5A-2.
In general terms a single-chip microcomputer is characterized by the incorporation of all the units of a computer into a single device, as shown in Fig3-5A-3.

單片機是電腦和集成電路發(fā)展的巔峰，有據(jù)可查的是他們也是20世紀最有意義的兩大發(fā)明。
這兩種特性在單片機中得到了充分的體現(xiàn)。一些廠家用這兩種特性區(qū)分程序內存和數(shù)據(jù)內存在硬件中的特性，如圖3-5A-1，依據(jù)同樣的原理廣泛的適用于一般目的的電腦和微電腦，一些廠家在程序內存和數(shù)據(jù)內存之間不區(qū)分的像Princeton特性，展示如圖3-5A-2.
只讀存貯器(ROM). ROM是通常的永久性的，非應用程序的易失性存儲器。不少微機和單片機用于大批量應用，因此，經濟的設備制造要求的程序存儲器的內容是在制造期間永久性的刻錄在芯片中，這意味著嚴謹?shù)姆椒?，因為修改ROM代碼不能制造之后發(fā)展。這一發(fā)展過程可能涉及仿真,使用硬件仿真功能以及強大的軟件工具使用先進的開發(fā)系統(tǒng)。