单片机基础外文文献翻译

SCM development history

1.The general situation of list slice machine

The single chip microcomputer referred to as SCM, is typical of embedded micro- controller (SCM Unit), the commonly used letters of the abbreviation MCU MCU, it was first used in the fie ld of industrial control. Master SCM technology to enable more people in the industry, students, enthusiasts, product developers, and the question arose due to the extensive application of SCM in the field of industrial control, SCM development board, the more famous such as e- DZR - 01A SCM development board. SCM evolved by the only dedicated processor CPU chip. The first design concept by a large number of peripherals and CPU integrated in a single chip, the computer system is smaller, and more easily integrated into complex and require strict control equipment on the volume. INTEL Z80 is the first processor designed in accordance with this idea, since then, the development of SCM and dedicated processor has grown apart.

Early SCM are 8 or 4. One of the most successful is the INTEL 8031, because the simple and reliable performance good a lot of praise. Later in 8031 on the development of MCS51 series SCM system. Is still in wide use of SCM system based on this system until now. Began with the industrial control area requires improvement of a 16-bit SCM, but not ideal because the price has not been a very wide range of applications. The 1990s, consumer electronics, SCM technology has been a huge increase. With the INTEL The i960 series, especially the ARM series of widely used 32- bit SCM quickly replaced the 16-bit single - chip high-end status, and enter the mainstream market. Traditional 8-bit MCU performance has also been a rapid increase processing capacity than a few times in the 1980s. At present, high-end 32-bit SCM clocked more than 300MHz, performance, catching up with a dedicated processor in the mid-1990s, while the ordinary model prices drop to $ 1, the most high-end model is only $ 10. Contemporary SCM system is no longer only in the bare metal environment to develop and use a large number of dedicated embedded operating system is widely used in a full range of SCM. As handheld computers and mobile phones core processing high-end SCM can even use a dedicated Windows and Linux operating systems.

The SCM is more than a dedicated processor for embedded systems, so it has been up to the application. In fact SCM is the world’s largest number of computer. Of modern human life in almost every electronic and mechanical products will be integrated SCM. Mobile phone, telephone, calculator, household appliances, electronic toys, handheld computers, as well as mouse and other

computer accessories with 1-2 Ministries SCM. The PC will have a large number of SCM work. Generally equipped with more than 40 single-chips in the car, even in complex industrial control systems may have hundreds of single chip at the same time! The number of SCM is not only far more than the sum of PC and other computing even more than the number of human beings even more .

The single-chip, also known as single-chip SCM, it is not the completion of a logical function of the chip, but a computer system integrated onto one chip. Equivalent to a mini- computer and computer, SCM only the lack of me / O devices. Speaking in general terms: a chip has become a computer. Its small size, light weight, inexpensive, and provide favorable conditions for learning, application and development. At the same time, learning to use the SCM is the best choice for the understanding of computer theory and structure.

Internal SCM with a similar module and the computer functions, such as CPU, memory, parallel bus, the same memory and hard disk role, different performance of these components are relatively weak a lot of our home computer, but the price is low generally not more than 10 Yuan can be use it for control appliances of a class is not very complex work enough. We are using household appliances inside of the drum fully automatic washing machine, exhaust hood, VCD and so on can be seen in its presence, and it is mainly as part of the core parts.

It is an online real-time control computer, on-line site control need is a strong anti-jamming capability, lower cost, this is also off-line computer (such as home PC) the main difference.

SCM rely on the program is running, and can be modified. Different functions through different programs, especially the special unique function, which is the other devices, require much effort to do, while others make great efforts it is difficult to do. A not very complex functions us ing pure hardware to get the words of the 1950s developed 74 series, or 60 during the CD4000 series, the circuit must be a big PCB board! If successful on the market in the United States in the 1970s series of SCM, the result will be different! Just because a program written by the MCU through you can achieve high intelligence, high efficiency and high reliability!

SCM for cost sensitive, so accounting for the dominance of the software or the lowest level assembly language, which is the lowest level than binary machine code language, since such low-level why use it? A lot of high-level language has reached a level of visual programming, why not? The reason is simple, is the SCM does not have a home computer as the CPU, also not as hard

as mass storage devices. A visual high-level language to write small programs inside even if there is only one button, will reach tens of K of size! Nothing in terms of home Pac’s hard drives, but for SCM in terms of is not acceptable. SCM in the utilization of hardware resources must be high, so the compilation of the original while still in heavy use. The same reason , if the computer giant 's operating system and application software to get home PC run up to the home PC can not afford .It can be said that the twentieth century across the three "power " era of the electrical era , the electronic age and has now entered the computer age . However, such a computer usually refers to a personal computer, or PC. It is by the host, keyboard, monitor, and so on. Another type of computer, not how most people are familiar with. This computer is smart to give a variety of mechanical SCM (also known as micro- controller). The name suggests, the smallest of this computer system using only one IC to make a simple calculation and control. Because of its small, usually hidden in a controlled mechanical "stomach”. Throughout the device, it plays like the role of the human mind, it is wrong, the entire device was paralyzed. Now, this single chip field of use has a very wide, such as smart meters, real-time industrial control, communications equipment, navigation systems, and home appliances and so on. A variety of products using the SCM, you can play the effect of product upgrades, often preceded by an adjective in front of the product name - "sma rt”, such as smart washing machines. Some factories or other amateur electronics developers to engage in out of certain products, not the circuit is too complicated, too simple and can easily be imitation. The reason may be stuck in the product does not use a SCM or other programmable logic devices.

2．MCU classification

SCM as an important area of computer development, the application of a more scientific classification. According to the current development situation from different angles SCM can be divided into universal / special type, bus / bus and industrial type / home appliance type.

2.1．Universal / private type

Universal / private type which is to distinguish between the scopes of application by SCM. For example, 80C51 is a general-purpose MCU , it is not some kind of post use ; Dedicated MCU for a product or a product designed and manufactured , for example , in order to meet the requirements of the electronic thermometer in the integrated on-chip ADC interface and other functions temperature measurement and control circuit .

2.2．Bus / bus

Bus / bus whether to provide single-chip parallel bus to distinguish. Bus SCM is generally set parallel address bus, data bus, control bus, these pins to extend parallel peripheral devices can be connected through the serial port and MCU In addition, many of the SCM has the required peripheral devices and peripheral interfaces integrated one, so in many cases do not parallel expansion bus, greatly reduce the province of package cost and chip size, the type of SCM called the non- bus -type SCM.

2.3. Controlled / appliance type

Controlled / appliance type this distinction in accordance with the SCM broadly applied field. In general, the industrial -type addressing range, computing power; SCM for home appliances and more special type, usually the high integration of the small package, low prices, peripheral devices, and peripheral interfaces. Obviously, these categories are not the only and strict. 80C51 class SCM, for example, both general-purpose buses, but also for industrial use.

3. The course of their work

The course of their work SCM automatically complete the tasks entrusted to it , that is, single-chip implementation of the program process , the process of an article of instructions executed , the so-called instruction is in the form of single-chip implementation of a variety of operating with the command to write down , which is designer assigned to it by the instruction set , an instruction corresponds to a basic operation; Full instructions can be executed by the SCM , the SCM instruction set , the different types of single-chip , and its instruction set is also different . So that the SCM can automatically complete a specific task, the problem to be solved must be compiled into a series of instructions (these instructions must be selected SCM to the identification and implementation of the Directive), a collection of this series of instructions to become the program, the program need to pre- stored in the components - memory storage capabilities. Memory is composed by a number of storage units ( the smallest unit of storage ) , like a large building has many rooms composed of the same , the instructions stored in these units , the instruction fetch unit and perform like the rooms of large buildings, each assigned to only a room number , eac h memory cell must be assigned to a unique address number , the address is known as the address of the storage unit , so as long as you know the address of the storage unit , you can find the storage unit that stores instructions can be removed, and then be executed .

Programs are usually executed in the order , instruction program is a sequential storage ,

single-chip in the implementation of the program to be able to a section of these instructions out and be implemented , there must be a component to track the address of instruction where this part the program counter PC ( included in the CPU ), the start of program execution , endowed the address where the first instruction of the program to the PC , and then made for each command to execute the content into the PC will automatically increase , increase the amount is determined by the instruction length of this article may be 2 or 3, to point to the starting address of the next instruction to ensure the implementation of the instruction sequence .

4. SCM history

SCM was born in 1971, has gone through three major phases of the SCM, the MCU SOC.

4.1. The basic structure of the SCM

The basic structure of the SCM constitutes the computing device, controller, memory, input output devices.

4.2. The first model of SCM

1. SCM stage of the single chip microcomputer (Single Chip Microcomputer), seeking a monolithic form of embedded systems architecture. Innovative model to be successful, and laid a completely different path of development of the SCM and the general-purpose computer. Independent path of development to create an embedded system, Intel denied.

2. MCU SCM (Micro Controller Unit). Stage, the main direction of technology development: expanding a variety of peripheral circuits and interface circuits, embedded applications are met, the object system requirements and to highlight the intelligent control capabilities of its object. It is involved in the field with the object system, therefore, the important task of the MCU development will inevitably fall on electrical and electronics manufacturers. From this perspective, Intel is gradually fading out the MCU development of objective factors. When Philips in the development of MCU, the most famous manufacturers.

Philips Company with its huge advantage in embedded applications, the MCS 51 from the single-chip microcomputer, the rapid development of the micro- controller. Therefore, when we look back at the path of development of embedded systems, do not forget the historical achievements of Intel and Philips.

5. Embedded systems

SCM is the road of independent development of embedded systems, an important factor to the

MCU stages of development, is seeking applications on the chip to maximize the settlement; dedicated SCM development of natural Sock trend. With the development of microelectronics technology, IC design, EDA tools, Sock-based SCM applications development. Therefore, understanding of the SCM from the single-chip microcomputer single-chip SCM extends to the single-chip applications.

6. SCM development history

Intel Corporation in 1971 developed the world's first 4-bit microprocessor ; Hoff of Intel Corporation to develop the success of the world's first 4 - bit microprocessor chip , the Intel 4004 , the advent marks the first generation of microprocessor , the microprocessor and The computer era began . The invention of microprocessors, Hough was the British "Economist" magazine as one of the most influential since World War II seven scientists.

In November 1971 , Intel introduced the MCS -4 micro- computer system ( including the 4001 ROM chips , the 4002 RAM chip, 4003 shift register chip , and 4004 microprocessor ) of which 4004 (below) contains 2300 transistors , sizes 3mm × 4mm, the computational performance far exceeds that of the ENIAC , was originally priced at $ 200 .

In April 1972, Hough, who developed the first 8 -bit microprocessor, the Intel 8008. Since 8008 is a P-channel MOS microprocessor, so still the first generation of microprocessors.

Intel Corporation in 1973 developed the 8-bit microprocessor 8080; August 1973, Hoff, who developed the 8-bit microprocessor the Intel 8080 and replaced by a P-channel N-channel MOS circuit, the second generation of microprocessor device thereon was born.

Frequency 2MHz 8080 chip computation speed 10 times faster than 8008 , you can access the 64KB memory , using 6000 transistors , based on a 6 - micron technology , processing speed 0.64MIPS ( Million the Instructions Per Second) .

In April 1975, the MITS released the first general-purpose the Altair 8800, priced at $ 375, with 1KB memory. This is the world's first micro-computer.

Intel Corporation in 1976 developed the MCS -48 series of 8-bit SCM, the advent of the SCM.

Silo Z80 microprocessor developed in 1976, is widely used in microcomputers and industrial automation equipment. At that time, the three pillars of Silo, Motorola and Intel in microprocessors.

The early 1980s, the Intel Corporation on the basis of the MCS - 48 series SCM, the introduction of the MCS-51 series of eight high-end devices. MCS-51 series MCU on-chip RAM

capacity, I / O port function, the system expansion has been greatly improved.

7. Hardware features

1. A single-chip integration of high. Single-chip , including CPU , 4KB capacity ROM ( 8031 Nil) , 128 B, the capacity of RAM , 16 - bit counter / timers , four 8-bit parallel port full-duplex serial line port .

2. The system is simple, easy to use, modular;

3. single-chip high reliability, can work to 10 ^ 6-10 ^ 7 hours of trouble-free;

4. The processing functions and speed.

5. Low voltage, low power consumption, ease of production of portable products

6. The control function

8. Application

MCU to infiltrate all areas of life, almost difficult to find which areas of the SCM trail. Navigation device of the missile , aircraft , various instrument control , computer network communications and data transmission , industrial automation and process real-time control and data processing , widely used smart card IC , civil luxury car security system , VCR , cameras, the control of automatic washing machines , and program - controlled toys , electronic pets , etc. , which are inseparable from the SCM. Not to mention the field of automatic control, robotics, intelligent instruments, medical equipment and a variety of intelligent mechanical. There fore, the learning, development and application of the SCM will create a number of computer applications and intelligent control of the scientists, engineers.

The SCM is widely used in the field of instrumentation, home appliances, medical equipment, aerospace, equipment for the intelligent management and process control, generally can be divided into the following categories:

8.1. On smart instrumentation

The SCM has a small size, low power consumption, and control functions , and expansion of the advantages of flexibility, miniaturization and easy to use , widely used in instrumentation , combined with different types of sensors can be realized such as voltage , power, frequency , humidity, temperature , flow, speed, thickness, angle , length , hardness , elements , pressure and other physical measurement . SCM makes the digital instrumentation, intelligent, miniaturization and more powerful function than the use of electronic or digital circuits. Such as precision

measuring equipment (power meter, oscilloscope, analyzer).

8.2. In industrial control applications

MCU can constitute various forms of control systems, data acquisition systems. Such as factory assembly line of intelligent pipe chip, lift intelligent control, and various alarm systems, and computer networking constitute the two control systems.

8.3. In Household Appliances

It can be said that the household appliances is basically using the MCU control, from rice cookers, washing machines , refrigerators , air conditioners , color TVs , audio and video equipment to the electronic weighing equipment , multifarious , ubiquitous .

8.4. In the field of computer networks and communication

Modern SCM with universal communication interface can be easily and computer data communications , provides excellent material for use in computer networks and communication devices , communication equipment basically to the MCU intelligent control from the mobile phones, telephones , small program-controlled switchboards , building automated communications call systems , train radio communications, and then to the ubiquitous mobile phones in their daily work , trucking mobile communication radios .

8.5. Chip in the field of medical equipment

The SCM uses in medical devices is also quite extensive, such as medical ventilator , a variety of analyzers , monitors , ultrasound diagnostic equipment and hospital beds call system and so on .

8.6. Modular applications in a variety of large appliances

Some dedicated SCM designed for specific functions, modular applications in a variety of circuit, without requiring the use of personnel to understand its internal structure. Integrated single-chip, such as music, seemingly simple function, miniature pure electronic chip (as opposed to the principle of the tape drive), you need a complex similar to the principle of the computer. Such as: the music signal in digital form in memory (similar to the ROM), read by the SCM into analog music signal (similar to the sound card).

In large circuits , this modular application greatly reduce the size , simplifying the circuit , reducing the damage , error rate , is also convenient to replace .

8.7. Chip in the field of automotive equipment

The SCM is widely used in automotive electronics, such as automotive engine controllers,

intelligent electronic controller based on CAN bus automotive engine, GPS navigation system, abs anti-lock systems, braking systems, etc.

MCU basis [Revision] [series of textbooks SCM and embedded systems.]

单片机基础

1.单片机概况

单片微型计算机简称单片机，是典型的嵌入式微控制器（SCM Unit），常用英文字母的缩写MCU表示单片机，它最早是被用在工业控制领域。由于单片机在工业控制领域的广泛应用，为使更多的业内人士、学生、爱好者，产品开发人员掌握单片机这门技术，于是产生单片机开发板，比较有名的例如电子人DZR-01A单片机开发板。单片机由芯片内仅有CPU的专用处理器发展而来。最早的设计理念是通过将大量外围设备和CPU集成在一个芯片中，使计算机系统更小，更容易集成进复杂的而对体积要求严格的控制设备当中。INTEL的Z80是最早按照这种思想设计出的处理器，从此以后，单片机和专用处理器的发展便分道扬镳。

早期的单片机都是8位或4位的。其中最成功的是INTEL的8031，因为简单可靠而性能不错获得了很大的好评。此后在8031上发展出了MCS51系列单片机系统。基于这一系统的单片机系统直到现在还在广泛使用。随着工业控制领域要求的提高，开始出现了16位单片机，但因为性价比不理想并未得到很广泛的应用。90年代后随着消费电子产品大发展，单片机技术得到了巨大提高。随着INTEL i960系列特别是后来的ARM系列的广泛应用，32位单片机迅速取代16位单片机的高端地位，并且进入主流市场。而传统的8位单片机的性能也得到了飞速提高，处理能力比起80年代提高了数百倍。目前，高端的32位单片机主频已经超过300MHz，性能直追90年代中期的专用处理器，而普通的型号出厂价格跌落至1美元，最高端的型号也只有10美元。当代单片机系统已经不再只在裸机环境下开发和使用，大量专用的嵌入式操作系统被广泛应用在全系列的单片机上。而在作为掌上电脑和手机核心处理的高端单片机甚至可以直接使用专用的Windows和Linux操作系统。

单片机比专用处理器更适合应用于嵌入式系统，因此它得到了最多的应用。事实上单片机是世界上数量最多的计算机。现代人类生活中所用的几乎每件电子和机械产品中都会集成有单片机。手机、电话、计算器、家用电器、电子玩具、掌上电脑以及鼠标等电脑配件中都配有1-2部单片机。而个人电脑中也会有为数不少的单片机在工作。汽车上一般配备40多部单片机，复杂的工业控制系统上甚至可能有数百台单片机在同时工作！单片机的数量不仅远超过PC机和其他计算的总和，甚至比人类的数量还要多。

单片机又称单片微控制器，它不是完成某一个逻辑功能的芯片，而是把一个计算机系统集成到一个芯片上。相当于一个微型的计算机，和计算机相比，单片机只缺少了I/O设备。

概括的讲：一块芯片就成了一台计算机。它的体积小、质量轻、价格便宜、为学习、应用和开发提供了便利条件。同时，学习使用单片机是了解计算机原理与结构的最佳选择。

单片机内部也用和电脑功能类似的模块，比如CPU，内存，并行总线，还有和硬盘作用相同的存储器件，不同的是它的这些部件性能都相对我们的家用电脑弱很多，不过价钱也是低的，一般不超过10元即可，用它来做一些控制电器一类不是很复杂的工作足矣了。我们现在用的全自动滚筒洗衣机、排烟罩、VCD等等的家电里面都可以看到它的身影，它主要是作为控制部分的核心部件。

它是一种在线式实时控制计算机，在线式就是现场控制，需要的是有较强的抗干扰能力，较低的成本，这也是和离线式计算机的（比如家用PC）的主要区别。

单片机是靠程序运行的，并且可以修改。通过不同的程序实现不同的功能，尤其是特殊的独特的一些功能，这是别的器件需要费很大力气才能做到的，有些则是花大力气也很难做到的。一个不是很复杂的功能要是用美国50年代开发的74系列，或者60年代的CD4000系列这些纯硬件来搞定的话，电路一定是一块大PCB板！但是如果要是用美国70年代成功投放市场的系列单片机，结果就会有天壤之别！只因为单片机的通过你编写的程序可以实现高智能，高效率，以及高可靠性！

由于单片机对成本是敏感的，所以目前占统治地位的软件还是最低级汇编语言，它是除了二进制机器码以上最低级的语言了，既然这么低级为什么还要用呢？很多高级的语言已经达到了可视化编程的水平为什么不用呢？原因很简单，就是单片机没有家用计算机那样的CPU，也没有像硬盘那样的海量存储设备。一个可视化高级语言编写的小程序里面即使只有一个按钮，也会达到几十K的尺寸！对于家用PC的硬盘来讲没什么，可是对于单片机来讲是不能接受的。单片机在硬件资源方面的利用率必须很高才行，所以汇编虽然原始却还是在大量使用。一样的道理，如果把巨型计算机上的操作系统和应用软件拿到家用PC上来运行，家用PC的也是承受不了的。

可以说，二十世纪跨越了三个“电”的时代，即电气时代、电子时代和现已进入的电脑时代。不过，这种电脑，通常是指个人计算机，简称PC机。它由主机、键盘、显示器等组成。还有一类计算机，大多数人却不怎么熟悉。这种计算机就是把智能赋予各种机械的单片机（亦称微控制器）。顾名思义，这种计算机的最小系统只用了一片集成电路，即可进行简单运算和控制。因为它体积小，通常都藏在被控机械的“肚子”里。它在整个装置中，起着有如人类头脑的作用，它出了毛病，整个装置就瘫痪了。现在，这种单片机的使用领域已十分广泛，如智能仪表、实时工控、通讯设备、导航系统、家用电器等。各种产品一旦用上了单片机，就

能起到使产品升级换代的功效，常在产品名称前冠以形容词——“智能型”，如智能型洗衣机等。现在有些工厂的技术人员或其它业余电子开发者搞出来的某些产品，不是电路太复杂，就是功能太简单且极易被仿制。究其原因，可能就卡在产品未使用单片机或其它可编程逻辑器件上

2.单片机的分类

单片机作为计算机发展的一个重要领域，应用一个较科学的分类方法。根据目前发展情况，从不同角度单片机大致可以分为通用型/专用型、总线型/非总线型及工控型/家电型。2.1．通用型/专用型

这是按单片机适用范围来区分的。例如，80C51是通用型单片机，它不是为某种专用途设计的；专用型单片机是针对一类产品甚至某一个产品设计生产的，例如为了满足电子体温计的要求，在片内集成ADC接口等功能的温度测量控制电路。

2.2．总线型/非总线型

这是按单片机是否提供并行总线来区分的。总线型单片机普遍设置有并行地址总线、数据总线、控制总线，这些引脚用以扩展并行外围器件都可通过串行口与单片机连接，另外，许多单片机已把所需要的外围器件及外设接口集成一片内，因此在许多情况下可以不要并行扩展总线，大大减省封装成本和芯片体积，这类单片机称为非总线型单片机。

2.3.控制型/家电型

这是按照单片机大致应用的领域进行区分的。一般而言，工控型寻址范围大，运算能力强；用于家电的单片机多为专用型，通常是小封装、低价格，外围器件和外设接口集成度高。显然，上述分类并不是惟一的和严格的。例如，80C51类单片机既是通用型又是总线型，还可以作工控用。

3.工作过程

单片机自动完成赋予它的任务的过程，也就是单片机执行程序的过程，即一条条执行的指令的过程，所谓指令就是把要求单片机执行的各种操作用的命令的形式写下来，这是在设计人员赋予它的指令系统所决定的，一条指令对应着一种基本操作；单片机所能执行的全部指令，就是该单片机的指令系统，不同种类的单片机，其指令系统亦不同。为使单片机能自动完成某一特定任务，必须把要解决的问题编成一系列指令（这些指令必须是选定单片机能识别和执行的指令），这一系列指令的集合就成为程序，程序需要预先存放在具有存储功能的

部件——存储器中。存储器由许多存储单元（最小的存储单位）组成，就像大楼房有许多房间组成一样，指令就存放在这些单元里，单元里的指令取出并执行就像大楼房的每个房间的被分配到了唯一一个房间号一样，每一个存储单元也必须被分配到唯一的地址号，该地址号称为存储单元的地址，这样只要知道了存储单元的地址，就可以找到这个存储单元，其中存储的指令就可以被取出，然后再被执行。

程序通常是顺序执行的，所以程序中的指令也是一条条顺序存放的，单片机在执行程序时要能把这些指令一条条取出并加以执行，必须有一个部件能追踪指令所在的地址，这一部件就是程序计数器PC（包含在CPU中），在开始执行程序时，给PC赋以程序中第一条指令所在的地址，然后取得每一条要执行的命令，PC之中的内容就会自动增加，增加量由本条指令长度决定，可能是1、2或3，以指向下一条指令的起始地址，保证指令顺序执行。

4.单片机历史

单片机诞生于1971年，经历了SCM、MCU、SOC三大阶段。

4.1.单片机的基本结构

单片机由运算器、控制器、存储器、输入输出设备构成。

4.2.起初模型

1.SCM即单片微型计算机（Single Chip Microcomputer）阶段，主要是寻求最佳的单片形态嵌入式系统的最佳体系结构。“创新模式”获得成功，奠定了SCM与通用计算机完全不同的发展道路。在开创嵌入式系统独立发展道路上，Intel公司功不可没。

2.MCU即微控制器（Micro Controller Unit）阶段，主要的技术发展方向是：不断扩展满足嵌入式应用时，对象系统要求的各种外围电路与接口电路，突显其对象的智能化控制能力。它所涉及的领域都与对象系统相关，因此，发展MCU的重任不可避免地落在电气、电子技术厂家。从这一角度来看，Intel逐渐淡出MCU的发展也有其客观因素。在发展MCU方面，最著名的厂家当数Philips公司。

Philips公司以其在嵌入式应用方面的巨大优势，将MCS-51从单片微型计算机迅速发展到微控制器。因此，当我们回顾嵌入式系统发展道路时，不要忘记Intel和Philips的历史功绩。

5.嵌入式系统

单片机是嵌入式系统的独立发展之路，向MCU阶段发展的重要因素，就是寻求应用系统在芯片上的最大化解决；因此，专用单片机的发展自然形成了SOC化趋势。随着微电子技术、IC设计、EDA工具的发展，基于SOC的单片机应用系统设计会有较大的发展。因此，对单

片机的理解可以从单片微型计算机、单片微控制器延伸到单片应用系统。

6.单片机发展史

1971年Intel公司研制出世界上第一个4位的微处理器；Intel公司的霍夫研制成功世界上第一块4位微处理器芯片Intel 4004，标志着第一代微处理器问世，微处理器和微机时代从此开始。因发明微处理器，霍夫被英国《经济学家》杂志列为“二战以来最有影响力的7位科学家”之一。

1971年11月，Intel推出MCS-4微型计算机系统（包括4001 ROM芯片、4002 RAM芯片、4003移位寄存器芯片和4004微处理器）其中4004（下图）包含2300个晶体管，尺寸规格为3mm×4mm，计算性能远远超过当年的ENIAC，最初售价为200美元。

1972年4月，霍夫等人开发出第一个8位微处理器Intel 8008。由于8008采用的是P沟道MOS微处理器，因此仍属第一代微处理器。

1973年Intel公司研制出8位的微处理器8080；1973年8月，霍夫等人研制出8位微处理器Intel 8080，以N沟道MOS电路取代了P沟道，第二代微处理器就此诞生。

主频2MHz的8080芯片运算速度比8008快10倍，可存取64KB存储器，使用了基于6微米技术的6000个晶体管，处理速度为0.64MIPS（Million Instructions Per Second ）。

1975年4月，MITS发布第一个通用型Altair 8800，售价375美元，带有1KB存储器。这是世界上第一台微型计算机。

1976年Intel公司研制出MCS-48系列8位的单片机，这也是单片机的问世。

Silo公司于1976年开发的Z80微处理器，广泛用于微型计算机和工业自动控制设备。当时，Silo、Motorola和Intel在微处理器领域三足鼎立。

20世纪80年代初，Intel公司在MCS-48系列单片机的基础上，推出了MCS-51系列8位高档单片机。MCS-51系列单片机无论是片内RAM容量，I/O口功能，系统扩展方面都有了很大的提高。

7.硬件特性

1、单片机集成度高。单片机包括CPU、4KB容量的ROM（8031 无）、128 B容量的RAM、2个16位定时/计数器、4个8位并行口、全双工串口行口。

2、系统结构简单，使用方便，实现模块化；

3、单片机可靠性高，可工作到10^6 ~10^7小时无故障；

4、处理功能强，速度快。

5、低电压，低功耗，便于生产便携式产品

6、控制功能强

8.应用

目前单片机渗透到我们生活的各个领域，几乎很难找到哪个领域没有单片机的踪迹。导弹的导航装置，飞机上各种仪表的控制，计算机的网络通讯与数据传输，工业自动化过程的实时控制和数据处理，广泛使用的各种智能IC卡，民用豪华轿车的安全保障系统，录像机、摄像机、全自动洗衣机的控制，以及程控玩具、电子宠物等等，这些都离不开单片机。更不用说自动控制领域的机器人、智能仪表、医疗器械以及各种智能机械了。因此，单片机的学习、开发与应用将造就一批计算机应用与智能化控制的科学家、工程师。

单片机广泛应用于仪器仪表、家用电器、医用设备、航空航天、专用设备的智能化管理及过程控制等领域，大致可分如下几个范畴：

8.1.在智能仪器仪表上的应用

单片机具有体积小、功耗低、控制功能强、扩展灵活、微型化和使用方便等优点，广泛应用于仪器仪表中，结合不同类型的传感器，可实现诸如电压、功率、频率、湿度、温度、流量、速度、厚度、角度、长度、硬度、元素、压力等物理量的测量。采用单片机控制使得仪器仪表数字化、智能化、微型化，且功能比起采用电子或数字电路更加强大。例如精密的测量设备（功率计，示波器，各种分析仪）。

8.2.在工业控制中的应用

用单片机可以构成形式多样的控制系统、数据采集系统。例如工厂流水线的智能化管芯片，电梯智能化控制、各种报警系统，与计算机联网构成二级控制系统等。

8.3.在家用电器中的应用

可以这样说，现在的家用电器基本上都采用了单片机控制，从电饭煲、洗衣机、电冰箱、空调机、彩电、其他音响视频器材、再到电子秤量设备，五花八门，无所不在。

8.4.在计算机网络和通信领域中的应用

现代的单片机普遍具备通信接口，可以很方便地与计算机进行数据通信，为在计算机网络和通信设备间的应用提供了极好的物质条件，现在的通信设备基本上都实现了单片机智能控制，从手机，电话机、小型程控交换机、楼宇自动通信呼叫系统、列车无线通信、再到日常工作中随处可见的移动电话，集群移动通信，无线电对讲机等。

8.5.单片机在医用设备领域中的应用

单片机在医用设备中的用途亦相当广泛，例如医用呼吸机，各种分析仪，监护仪，超声

诊断设备及病床呼叫系统等等。

8.6.在各种大型电器中的模块化应用

某些专用单片机设计用于实现特定功能，从而在各种电路中进行模块化应用，而不要求使用人员了解其内部结构。如音乐集成单片机，看似简单的功能，微缩在纯电子芯片中（有别于磁带机的原理），就需要复杂的类似于计算机的原理。如：音乐信号以数字的形式存于存储器中（类似于ROM），由微控制器读出，转化为模拟音乐电信号（类似于声卡）。

在大型电路中，这种模块化应用极大地缩小了体积，简化了电路，降低了损坏、错误率，也方便于更换。

8.7.单片机在汽车设备领域中的应用

单片机在汽车电子中的应用非常广泛，例如汽车中的发动机控制器，基于CAN总线的汽车发动机智能电子控制器，GPS导航系统，abs防抱死系统，制动系统等等。

《单片机基础》［修订版］[系列教材单片机与嵌入式系统.]