杭州电子科技大学信息工程学院毕业设计（论文）外文文献翻译
毕业设计（论文）题目用单片机实现的数字时钟电路设计文献综述题目单片机控制系统系电子工程
专业电子信息科学与技术
姓名郭筱楠
班级08091911
学号08919115
指导教师王维平
单片机控制系统
广义地说，微型计算机控制系统（单片机控制系统）是用于处理信息的，这种被用于处理的信息可以是电话交谈，也可以是仪器的读数或者是一个企业的帐户，但是各种情况下都涉及到相同的主要操作：信息的处理、信息的存储和信息的传递。在常规的电子设计中，这些操作都是以功能平台方式组合起来的，例如计数器，无论是电子计数器还是机械计数器，都要存储当前的数值，并且按要求将该数值增加1。一个系统例如采用计数器的电子钟之类的任一系统要使其存储和处理能力遍布整个系统，因为每个计数器都能存储和处理一些数字。
现如今，以微处理器为基础的系统从常规的处理方法中分离了出来，它将信息的处理，信息的存储和信息的传输三个功能分离形成不同的系统单元。这种主要将系统分成三个主要单元的分离方法是冯-诺依曼在20世纪40年代所设想出来的，并且是针对微计算机的设想。从此以后基本上所有制成的计算机都是用这种结构设计的，尽管他们包含着宽广的物理形式与物理结构，但从根本上来说他们均是具有相同基本设计的计算机。
在以微处理器为基础的系统中，处理是由以微处理器为基础的系统自身完成的。存储是利用存储器电路，而从系统中输入和输出的信息传输则是利用特定的输入/输出（I/O）电路。要在一个以微处理器为基础的时钟中找出执行具有计数功能的一个特殊的硬件组成部分是不可能的，因为时间存储在存储器中，而在固定的时间间隔下由微处理器控制增值。但是，规定系统运转过程的软件却规定了包含实现计数器计数功能的单元部分。由于系统几乎完全由软件所定义，所以对微处理器结构和其辅助电路这种看起来非常抽象的处理方法使其在应用时非常灵活。这种设计过程主要是软件工程，而且在生产软件时，就会遇到产生于常规工程中相似的构造和维护问题。
图1.1 微型计算机的三个组成部分
图1.1显示出了微型计算机中这三个单元在一个微处理器控制系统中是如何按照机器中的信息通信方式而联接起来的。该系统由微处理器控制，微处理器能够对其自身的存储器和输入/输出单元的信息传输进行管理。外部的连接部分与
工程系统中的其余部分（即非计算机部分）有关。
尽管图中显示的只有一个存储单元，但是在实际中却有RAM和ROM两种不同的存储器被使用。在每一种情况下，由于概念上的计算机存储器更像一个公文柜，上述的“存储器”一词是非常不恰当的；信息被存放在一系列已数字标记过的的“箱子”中，而且可以按照问题由“箱子”的序列号进行相关信息的参考定位。
微计算机控制系统经常使用RAM（随机存取存储器），在RAM中，数据可以被写入，并且在需要的时候，可以被再次读出。这种数据能以任意一种所希望的次序从存储器中读出，而不必按照写入时的相同次序读出，所以有“随机”存取存储器。另一类型ROM（只读存储器）是用来保持信息的，它们是不受微处理器影响的固定的信息标本；这些信息在电源切断后不会丢失，并通常用来保存规定微处理器化系统运转过程的程序。ROM可像RAM一样被读取，但与RAM不一样的是不能用来存储可变的信息。有些ROM在制造时将其数据标本放入，而另外的则可通过特殊的设备由用户编程，所以称为可编程ROM。被广泛使用的可编程ROM可利用特殊紫外线灯察除，并被成为E
PROM，即可察除可编程只读存储器的缩写。另有新类型的期器件不必用紫外线灯而用电察除，所以称为电可察除可编程只读存储器EEPROM。
微处理器在程序控制下处理数据，并控制流向和来自存储器和输入/输出装置的信息流。有些输入/输出装置是通用型的，而另外一些则是设计来控制如磁盘驱动器的特殊硬件，或控制传给其他计算机的信息传输。大多数类型的I/O装置在某种程度下可编程，允许不同形式的操作，而有些则包含特殊用途微处理器的I/O装置不用主微处理器的直接干预，就可实施非常复杂的操作。
假如应用中不需要太多的程序和数据存储量，微处理器、存储器和输入/输出可全被包含在同一集成电路中。这通常是低成本应用情况，例如用于微波炉和自动洗衣机的控制器。当商品被大量地生产时，这种单一芯片的使用就可节省相当大的成本。当技术进一步发展，更强更强的处理器和更大更大数量的存储器被包含形成单片微型计算机，结果使最终产品的装配成本得以节省。但是在可预见的未来，当需要大量的存储器或输入/输出时，还是有必要继续将许多集成电路相互联结起来，形成微计算机。
微计算机的另一主要工程应用是在过程控制中。这是，由于装置是按特定的应用情况由微机编程实现的，对用户来说微计算机的存在通常就更加明显。在过程控制应用中，由于这种设备以较少的数量生产，将整个系统安装在单个芯片上
所获取的利益常比不上所涉及的高设计成本。而且，过程控制器通常更为复杂，所以要将他们做成单独的集成电路就更为困难。可采用两种处理，将控制器做成一种通用的微计算机，正像较强版本的业余计算机那样；或者做成“包裹”式系统，按照像电磁继电器那样的较老式的技术进行设计，来取代控制器。对前一种情况，系统可以用常规的编程语言来编程，正如以后要介绍的语言那样；而另一种情况，可采用特殊用途的语言，例如那种使控制器功能按照继电器相互连接的方法进行描述。两种情况下，序均能存于RAM，这让程序能按应用情况变化时进行相应的变化，但是这使得总系统易受掉电影响而工作不正常，除非使用电池保证供电连续性。另一种选择是将程序在ROM中，这样他们就变成电子“硬件”的一部分并常被称为“固件”。
尽管大规模集成电路的应用使小型和微型计算机的差别变得“模糊”，更复杂的过程控制器需要小型计算机实现他们的过程。各种类型的产品和过程控制器代表了当今微计算机应用的广泛性，而具体的结构取决于对“产品”一词的解释。实际上，计算机的所有工程和科学上的应用都能指定来进行这些种类的某一或某些工作。而在本设计中压力和压力变送器当某一力加到某一面积上，就形成压力，假如这力是1牛顿均匀地加在1平方米的面积上，这压力被定义为1帕斯卡。压力是一种普遍的工艺状态，它也是这个星球上的一个生活条件：我们生活在向上延伸许多英里的大气海洋的底部。空气物质是有重量的，而且这种下压的重量形成大气压。水，是生活的必需品，也是在压力之下提供给我们中的大多数人。在典型的过程工厂中，压力影响沸点温度、凝固点温度、过程效率、消耗和其他重要因数。压力的测量和控制，或者压力的不足—真空，在典型的过程控制中是极为重要的。
工厂中的工作仪器通常包括压力计、精密纪录仪、以及气动和电动的压力变送器。压力变送器实现压力测量并产生正比于所传感压力的气动或电信号输出。
在过程工厂中，将控制仪表远远放在过程的附近是不现实的，并且大多数测量是不容易从远处传来的。压力测量是一个例外，但是，如果要离测量点几百英尺外指示或记录某种危险化学品的高压，就会有来自这个压力所载的化学品所引发的危险。为了消除这一问题，开发了一种信号传输系统。这种系统常常可是气动或者电动的。使用这种系统，就可以在某一地点安装大多数的指示、记录和控制仪器。这也是最少数量的操作者有效的运行工厂成为现实。
当使用气动传送系统时，测量信号就由变送器将比例为0%～100%的测量值
转换为气动信号。变送器安装在靠近过程中的测量点上。变送器输出—对气动变送器是输出压力—通过管道传给记录或控制仪表。气动变送器的标准输出范围是20～100kPa ，这信号几乎在全球使用。
当使用电子压力变送器时，压力就被转换成电流或电压形式的电信号。其标
准范围对电流来说是4～20mA DC ，对电压信号来说是1～5V DC 。当今，另一种电信号形式变的越来越常用，就是数字或离散信号。基于计算机或微处理器的仪器或控制系统的应用正推动这类信号的应用不断增加。有时，分析获取描述传感器/变送器特性的参数是很重要的。当量程已知，去获取增益就非常简单。假定电子压力传感器的量程为0～600kPa ，增益定义为输出变化除以输入变化。这里，输出的电信号（4～20mA DC ），而输入的过程压力（0～600kPa ），这样增益就为：
此外我们在本设计中还必须对温度进行测量，温度测量在工业控制中是很重
要的，因为它作为系统或产品状态的直接指标，或者作为如反应率、能量流、涡轮机效率和润滑质量等间接指标。现行的温度分度已使用了约200年，最初的仪器是基于气体和液体的热膨胀。现在尽管有许多其他类型的仪器在使用，这些填充式系统仍常用于直接的温度测量。有代表性的温度传感器包括：填充式热系统、玻璃液体温度计、热电偶、电阻温度探测器、热敏电阻、双金属器件、光学和辐射高温计和热敏涂料。
电气系统的优点包括高的精度和灵敏度，能实现开关切换或扫描多个测量
点，可在测量元件和控制器之间长距离传输，出现事故时可调换元件，快速响应，以及具有测量高温的能力。其中热电偶和电阻温度探测器则被最广泛的使用。
说明
该AT89C51是一种低功耗，高性能CMOS 8位4K 的闪存可编程和可擦除只读存储器（PEROM ）字节的微型计算机。该设备是采用Atmel 的高密度非易失性内存技术，并与行业标准的MCS - 51指令集和引脚兼容。片上闪存程序存储器可以编程就可以在系统或由传统的非易失性存储器编程。通过将集成在一个芯片上通用的8位闪存的CPU ，Atmel 的AT89C51是一个强大的微型计算机提供了一个高度灵活和成本有效的解决方案为许多嵌入式控制应用。
功能特点
kPa
mA
kPa mA
kPa kPa mA
mA Kr 027.0600160600420==--=
AT89S51内提供了以下标准特性：4K字节闪存，128字节RAM，32个I / O线，两个16位定时器/计数器，一个五向量两级中断结构，一个全双工串行口，片上振荡器和时钟电路。此外，AT89C51是静态逻辑设计与操作频率下降到零，并支持两种软件可选的节电模式。空闲模式时CPU停止工作，而RAM，定时/计数器，串行口和中断系统继续工作。掉电模式保存RAM的内容，但冻结振荡器关闭，直到下一个硬件复位芯片其它功能。
引脚说明
Vcc：电源电压。
接地：接地。
P0口：
P0口为一个8位漏级开路双向I/O口，每脚可吸收8TTL门电流。当P0口的管脚第一次写1时，被定义为高阻输入。P0能够用于外部程序数据存储器，它可以被定义为数据/地址的第八位。在FIASH编程时，P0 口作为原码输入口，当FIASH进行校验时，P0输出原码，此时P0外部必须被拉高。
P1口：
P1口是一个内部提供上拉电阻的8位双向I/O口，P1口缓冲器能接收输出4TTL门电流。P1口管脚写入1后，被内部上拉为高，可用作输入，P1口被外部下拉为低电平时，将输出电流，这是由于内部上拉的缘故。在FLASH编程和校验时，P1口作为第八位地址接收。
P2口：
P2口为一个内部上拉电阻的8位双向I/O口，P2口缓冲器可接收，输出4个TTL门电流，当P2口被写“1”时，其管脚被内部上拉电阻拉高，且作为输入。并因此作为输入时，P2口的管脚被外部拉低，将输出电流。这是由于内部上拉的缘故。P2口当用于外部程序存储器或16位地址外部数据存储器进行存取时，P2口输出地址的高八位。在给出地址“1”时，它利用内部上拉优势，当对外部八位地址数据存储器进行读写时，P2口输出其特殊功能寄存器的内容。P2口在FLASH编程和校验时接收高八位地址信号和控制信号。
P3口：
P3口管脚是8个带内部上拉电阻的双向I/O口，可接收输出4个TTL门电流。当P3口写入“1”后，它们被内部上拉为高电平，并用作输入。作为输入，
由于外部下拉为低电平，P3口将输出电流（ILL）这是由于上拉的缘故。
RST
复位输入。此管脚上出现两个机器周期的高电平，而振荡器运行将使器件复位。进修/编
地址锁存使能锁存在访问外部存储器地址的低字节输出脉冲。该引脚也是在flash 编程脉冲输入programming.In正常运行的ALE（编）是在1 / 6振荡器频率恒定的速率发射，并可能对外部定时或时钟的用途。请注意，但是，一个ALE脉冲被跳过在每次访问外部数据存储器。
如果需要时，ALE操作可以通过设置位SFR的位置8EH 0。随着位设置，ALE 为活跃，只有在执行MOVX或MOVC指令。否则，脚弱拉高。设置的ALE -
禁用位微控制器没有影响，如果在外部执行模式。
ALE/PROG：当访问外部存储器时，地址锁存允许的输出电平用于锁存地址的地位字节。在FLASH编程期间，此引脚用于输入编程脉冲。在平时，ALE端以不变的频率周期输出正脉冲信号，此频率为振荡器频率的1/6。因此它可用作对外部输出的脉冲或用于定时目的。然而要注意的是：每当用作外部数据存储器时，将跳过一个ALE脉冲。如想禁止ALE的输出可在SFR8EH地址上置0。此时，ALE只有在执行MOVX，MOVC指令是ALE才起作用。另外，该引脚被略微拉高。如果微处理器在外部执行状态ALE禁止，置位无效。
PSEN：外部程序存储器的选通信号。在由外部程序存储器取指期间，每个机器周期两次/PSEN有效。但在访问外部数据存储器时，这两次有效的/PSEN信号将不出现。
EA/VPP：当/EA保持低电平时，则在此期间外部程序存储器
（0000H-FFFFH），不管是否有内部程序存储器。注意加密方式1时，/EA将内部锁定为RESET；当/EA端保持高电平时，此间内部程序存储器。在FLASH编程期间，此引脚也用于施加12V编程电源（VPP）。
XTAL1：反向振荡放大器的输入及内部时钟工作电路的输入。XTAL2：来自反向振荡器的输出。
振荡器特性:XTAL1和XTAL2分别为反向放大器的输入和输出。该反向放大器可以配置为片内振荡器。石晶振荡和陶瓷振荡均可采用。如采用外部时钟源驱动器件，XTAL2应不接。有余输入至内部时钟信号要通过一个二分频触发器，
因此对外部时钟信号的脉宽无任何要求，但必须保证脉冲的高低电平要求的宽度。
Microcomputer Systems
Electronic systems are used for handing information in the most general sense; this information may be telephone conversation, instrument read or a company?s accounts, but in each case the same main type of operation are involved: the processing, storage and transmission of information. in conventional electronic design these operations are combined at the function level; for example a counter, whether electronic or mechanical, stores the current and increments it by one as required. A system such as an electronic clock which employs counters has its storage and processing capabilities spread throughout the system because each counter is able to store and process numbers.
Present day microprocessor based systems depart from this conventional approach by separating the three functions of processing, storage, and transmission into different section of the system. This partitioning into three main functions was devised by V on Neumann during the 1940s, and was not conceived especially for microcomputers. Almost every computer ever made has been designed with this structure, and despite the enormous range in their physical forms, they have all been of essentially the same basic design.
In a microprocessor based system the processing will be performed in the microprocessor itself. The storage will be by means of memory circuits and the communication of information into and out of the system will be by means of special input/output(I/O) circuits. It would be impossible to identify a particular piece of hardware which performed the counting in a microprocessor based clock because the time would be stored in the memory and incremented at regular intervals but the microprocessor. However, the software which defined the system?s behavior would contain sections that performed as counters. The apparently rather abstract approach to the architecture of the microprocessor and its associated circuits allows it to be very flexible in use, since the system is defined almost entirely software. The design process is largely one of software engineering, and the similar problems of construction and maintenance which occur in conventional engineering are encountered when producing software.
The figure1.1 illustrates how these three sections within a microcomputer are connected in
terms of the communication of information within the machine. The system is controlled by the microprocessor which supervises the transfer of information between itself and the memory and input/output sections. The external connections relate to the rest (that is, the non-computer part) of the engineering system.
Fig.1.1 Three Sections of a Typical Microcomputer
Although only one storage section has been shown in the diagram, in practice two distinct types of memory RAM and ROM are used. In each case, the word …memory? is rather inappropriate since a computers memory is more like a filing cabinet in concept; information is stored in a set of numbered …boxes? and it is referenced by the serial number of the …box? in question.
Microcomputers use RAM (Random Access Memory) into which data can be written and from which data can be read again when needed. This data can be read back from the memory in any sequence desired, and not necessarily the same order in which it was written, hence the expression …random? access memory. Another ty pe of ROM (Read Only Memory) is used to hold fixed patterns of information which cannot be affected by the microprocessor; these patterns are not lost when power is removed and are normally used to hold the program which defines the behavior of a microprocessor based system. ROMs can be read like RAMs, but unlike RAMs they cannot be used to store variable information. Some ROMs have their data patterns put in during manufacture, while others are programmable by the user by means of special equipment and are called programmable ROMs. The widely used programmable ROMs are erasable by means of special ultraviolet lamps and are referred to as EPROMs, short for Erasable Programmable Read Only Memories. Other new types of device can be erased electrically without the need for ultraviolet light, which are called Electrically Erasable Programmable Read Only Memories, EEPROMs.
The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc
drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to permit quite complex operations to be carried out without directly involving the main microprocessor.
The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to permit quite complex operations to be carried out without directly involving the main microprocessor.
The microprocessor , memory and input/output circuit may all be contained on the same integrated circuit provided that the application does not require too much program or data storage . This is usually the case in low-cost application such as the controllers used in microwave ovens and automatic washing machines . The use of single package allows considerable cost savings to e made when articles are manufactured in large quantities . As technology develops , more and more powerful processors and larger and larger amounts of memory are being incorporated into single chip microcomputers with resulting saving in assembly costs in the final products . For the foreseeable future , however , it will continue to be necessary to interconnect a number of integrated circuits to make a microcomputer whenever larger amounts of storage or input/output are required.
Another major engineering application of microcomputers is in process control. Here the presence of the microcomputer is usually more apparent to the user because provision is normally made for programming the microcomputer for the particular application. In process control applications the benefits lf fitting the entire system on to single chip are usually outweighed by the high design cost involved, because this sort lf equipment is produced in smaller quantities. Moreover, process controllers are usually more complicated so that it is more difficult to make them as single integrated circuits. Two approaches are possible; the controller can be implemented as a general-purpose microcomputer rather like a more robust version lf a hobby computer, or as a …packaged? system, signed for replacing controllers based on older technologies such as electromagnetic relays. In the former case the system would probably be programmed in
conventional programming languages such as the ones to9 be introduced later, while in the other case a special-purpose language might be used, for example one which allowed the function of the controller to be described in terms of relay interconnections, In either case programs can be stored in RAM, which allows them to be altered to suit changes in application, but this makes the overall system vulnerable to loss lf power unless batteries are used to ensure continuity of supply. Alternatively programs can be stored in ROM, in which case they virtually become part of the electronic …hardware? and are often referred to as firmware. More sophisticated process controllers require minicomputers for their implementation, although the use lf large scale integrated circuits …the distinction between mini and microcomputers, Products and process controllers of various kinds represent the majority of present-day microcomputer applications, the exact figures depending on one?s interpretation of the word …product?. V irtually all engineering and scientific uses of microcomputers can be assigned to one or other of these categories. But in the system we most study Pressure and Pressure Transmitters. Pressure arises when a force is applied over an area. Provided the force is one Newton and uniformly over the area of one square meters, the pressure has been designated one Pascal. Pressure is a universal processing condition. It is also a condition of life on the planet: we live at the bottom of an atmospheric ocean that extends upward for many miles. This mass of air has weight, and this weight pressing downward causes atmospheric pressure. Water, a fundamental necessity of life, is supplied to most of us under pressure. In the typical process plant, pressure influences boiling point temperatures, condensing point temperatures, process efficiency, costs, and other important factors. The measurement and control of pressure or lack of it-vacuum-in the typical process plant is critical.
The working instruments in the plant usually include simple pressure gauges, precision recorders and indicators, and pneumatic and electronic pressure transmitters. A pressure transmitter makes a pressure measurement and generates either a pneumatic or electrical signal output that is proportional to the pressure being sensed.
In the process plant, it is impractical to locate the control instruments out in the place near the process. It is also true that most measurements are not easily transmitted from some remote location. Pressure measurement is an exception, but if a high pressure of some dangerous chemical is to be indicated or recorded several hundred feet from the point of measurement, a hazard may be from the pressure or from the chemical carried.
To eliminate this problem, a signal transmission system was developed. This system is
usually either pneumatic or electrical. And control instruments in one location. This makes it practical for a minimum number of operators to run the plant efficiently.
When a pneumatic transmission system is employed, the measurement signal is converted into pneumatic signal by the transmitter scaled from 0 to 100 percent of the measurement value. This transmitter is mounted close to the point of measurement in the process. The transmitter output-air pressure for a pneumatic transmitter-is piped to the recording or control instrument. The standard output range for a pneumatic transmitter is 20 to 100kPa, which is almost universally used.
When an electronic pressure transmitter is used, the pressure is converted to electrical signal that may be current or voltage. Its standard range is from 4 to 20mA DC for current signal or from 1 to 5V DC for voltage signal. Nowadays, another type of electrical signal, which is becoming common, is the digital or discrete signal. The use of instruments and control systems based on computer or forcing increased use of this type of signal.
Sometimes it is important for analysis to obtain the parameters that describe the sensor/transmitter behavior. The gain is fairly simple to obtain once the span is known. Consider an electronic pressure transmitter with a range of 0～600kPa.The gain is
defined as the change in output divided by the change in input. In this case, the output is electrical signal (4～20mA DC) and the input is process pressure (0～600kPa). Thus the gain. Beside we must measure Temperature Temperature measurement is important in industrial control, as direct indications of system or product state and as indirect indications of such factors as reaction rates, energy flow, turbine efficiency, and lubricant quality. Present temperature scales have been in use for about 200 years, the earliest instruments were based on the thermal expansion of gases and liquids. Such filled systems are still employed, although many other types of instruments are available. Representative temperature sensors include: filled thermal systems, liquid-in-glass thermometers, thermocouples, resistance temperature detectors, thermostats, bimetallic devices, optical and radiation pyrometers and temperature-sensitive paints.
Advantages of electrical systems include high accuracy and sensitivity, practicality of switching or scanning several measurements points, larger distances possible between measuring elements and controllers, replacement of components(rather than complete system), fast response, and ability to measure higher temperature. Among the electrical temperature sensors, kPa
mA
kPa mA
kPa kPa mA
mA Kr 027.0600160600420==--=
thermocouples and resistance temperature detectors are most widely used.
Description
The A T89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel?s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel A T89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.
Function characteristic
The A T89C51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition, the A T89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.
Pin Description
VCC：Supply voltage.
GND：Ground.
Port 0：
Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as highimpedance inputs.Port 0 may also be configured to be the multiplexed loworder address/data bus during accesses to external program and data memory. In this mode P0 has internal pullups.Port 0 also receives the code bytes during Flash programming,and outputs the code bytes during programverification. External pullups are required during programverification.
Port 1
Port 1 is an 8-bit bi-directional I/O port with internal pullups.The Port 1 output buffers can sink/source four TTL inputs.When 1s are written to Port 1 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 1 also receives the low-order address bytes during Flash programming and verification.
Port 2
Port 2 is an 8-bit bi-directional I/O port with internal pullups.The Port 2 output buffers can sink/source four TTL inputs.When 1s are written to Port 2 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 2 pins that are externally being pulled low will source current, because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses. In this application, it uses strong internal pullupswhen emitting 1s. During accesses to external data memory that use 8-bit addresses, Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.
Port 3
Port 3 is an 8-bit bi-directional I/O port with internal pullups.The Port 3 output buffers can sink/source four TTL inputs.When 1s are written to Port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the A T89C51 as listed below:
Port 3 also receives some control signals for Flash programming and verification.
RST
Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device.
ALE/PROG
Address Latch Enable output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.In
normal operation ALE is emitted at a constant rate of 1/6 the oscillator frequency, and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external Data Memory.
If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.
PSEN
Program Store Enable is the read strobe to external program memory.When the A T89C51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.
EA/VPP
External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset.EA should be strapped to VCC for internal program executions.This pin also receives the 12-volt programming enable voltage(VPP) during Flash programming, for parts that require12-volt VPP.
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2
Output from the inverting oscillator amplifier.
Oscillator Characteristics
XTAL1 and XTAL2 are the input and output, respectively,of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 1.Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 2.There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.
AT89C51外文翻译 Description The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash Programmable and Erasable Read Only Memory (PEROM). The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard MCS-51? instruction-set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications. Features ? Compatible with MCS-51? Products ? 4K Bytes of In-System Reprogrammable Flash Memory – Endurance: 1,000 Write/Erase Cycles ? Fully Static Operation: 0 Hz to 24 MHz ? Three-Level Program Memory Lock ? 128 x 8-Bit Internal RAM ? 32 Programmable I/O Lines ? Two 16-Bit Timer/Counters ? Six Interrupt Sources ? Programmable Serial Channel ? Low Power Idle and Power Down Modes The AT89C51 provides the following standard features: 4K bytes of Flash,128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.
外文文献： Knowledge of the stepper motor What is a stepper motor： Stepper motor is a kind of electrical pulses into angular displacement of the implementing agency. Popular little lesson: When the driver receives a step pulse signal, it will drive a stepper motor to set the direction of rotation at a fixed angle (and the step angle). You can control the number of pulses to control the angular displacement, so as to achieve accurate positioning purposes; the same time you can control the pulse frequency to control the motor rotation speed and acceleration, to achieve speed control purposes. What kinds of stepper motor sub-： In three stepper motors: permanent magnet (PM), reactive (VR) and hybrid (HB) permanent magnet stepper usually two-phase, torque, and smaller, step angle of 7.5 degrees or the general 15 degrees; reaction step is generally three-phase, can achieve high torque output, step angle of 1.5 degrees is generally, but the noise and vibration are large. 80 countries in Europe and America have been eliminated; hybrid stepper is a mix of permanent magnet and reactive advantages. It consists of two phases and the five-phase: two-phase step angle of 1.8 degrees while the general five-phase step angle of 0.72 degrees generally. The most widely used Stepper Motor. What is to keep the torque (HOLDING TORQUE) How much precision stepper motor? Whether the cumulative： The general accuracy of the stepper motor step angle of 3-5%, and not cumulative.
会计内部控制中英文对照外文翻译文献(文档含英文原文和中文翻译)
内部控制透视：理论与概念 摘要：内部控制是会计程序或控制系统，旨在促进效率或保证一个执行政策或保护资产或避免欺诈和错误。内部是一个组织管理的重要组成部分。它包括计划、方法和程序使用，以满足任务，目标和目的，并在这样做，支持基于业绩的管理。内部控制是管理阶层的平等与控制可以帮助管理者实现资源的预期的有效管理的结果通过。内部控制应减少或违规错误的风险关联未被发现的，但设计和建立有效的内部控制不是一个简单的任务，不可能是一个实现通过快速修复短套。在此讨论了内部文件的概念的不同方面的内部控制和管制。 关键词：内部控制，管理控制，控制环境，控制活动，监督 1、介绍 环境需要新的业务控制变量不为任何潜在的股东和管理人士的响应因子为1，另外应执行/她组织了一个很大的控制权。控制是管理活动的东西或以上施加控制。思想的产生和近十年的发展需要有系统的商业资源和控制这种财富一个新的关注。主题之一热一回合管制的商业资源是分析每个控制成本效益。 作为内部控制和欺诈的第一道防线，维护资产以及预防和侦查错误。内部控制，我们可以说是一种控制整个系统的财务和其他方面的管理制定了为企业的顺利运行;它包括内部的脸颊，内部审计和其他形式的控制。 COSO的内部控制描述如下。内部控制是一个客观的方法用来帮助确保实现。在会计和组织理论，内部控制是指或目标目标的过程实施由组织的结构，工作和权力流动，人员和具体的管理信息系统，旨在帮助组织实现。这是一种手段，其中一个组织的资源被定向，监控和测量。它发挥着无形的（重要的作用，预防和侦查欺诈和保护组织的资源，包括生理（如，机械和财产）和乙二醇，声誉或知识产权，如商标）。在组织水平，内部控制目标与可靠性的目标或战略的财务报告，及时反馈业务上的成就，并遵守法律，法规。在具体的交易水平，内部控制是指第三方采取行动以实现一个具体目标（例如，如何确保本组织的款项，在申请服务提供有效的。）内部控制程序reduce程变异，导
杭州电子科技大学信息工程学院毕业设计（论文）外文文献翻译 毕业设计（论文）题目用单片机实现的数字时钟电路设计文献综述题目单片机控制系统系电子工程 专业电子信息科学与技术 姓名郭筱楠 班级08091911 学号08919115 指导教师王维平
单片机控制系统 广义地说，微型计算机控制系统（单片机控制系统）是用于处理信息的，这种被用于处理的信息可以是电话交谈，也可以是仪器的读数或者是一个企业的帐户，但是各种情况下都涉及到相同的主要操作：信息的处理、信息的存储和信息的传递。在常规的电子设计中，这些操作都是以功能平台方式组合起来的，例如计数器，无论是电子计数器还是机械计数器，都要存储当前的数值，并且按要求将该数值增加1。一个系统例如采用计数器的电子钟之类的任一系统要使其存储和处理能力遍布整个系统，因为每个计数器都能存储和处理一些数字。 现如今，以微处理器为基础的系统从常规的处理方法中分离了出来，它将信息的处理，信息的存储和信息的传输三个功能分离形成不同的系统单元。这种主要将系统分成三个主要单元的分离方法是冯-诺依曼在20世纪40年代所设想出来的，并且是针对微计算机的设想。从此以后基本上所有制成的计算机都是用这种结构设计的，尽管他们包含着宽广的物理形式与物理结构，但从根本上来说他们均是具有相同基本设计的计算机。 在以微处理器为基础的系统中，处理是由以微处理器为基础的系统自身完成的。存储是利用存储器电路，而从系统中输入和输出的信息传输则是利用特定的输入/输出（I/O）电路。要在一个以微处理器为基础的时钟中找出执行具有计数功能的一个特殊的硬件组成部分是不可能的，因为时间存储在存储器中，而在固定的时间间隔下由微处理器控制增值。但是，规定系统运转过程的软件却规定了包含实现计数器计数功能的单元部分。由于系统几乎完全由软件所定义，所以对微处理器结构和其辅助电路这种看起来非常抽象的处理方法使其在应用时非常灵活。这种设计过程主要是软件工程，而且在生产软件时，就会遇到产生于常规工程中相似的构造和维护问题。 图1.1 微型计算机的三个组成部分 图1.1显示出了微型计算机中这三个单元在一个微处理器控制系统中是如何按照机器中的信息通信方式而联接起来的。该系统由微处理器控制，微处理器能够对其自身的存储器和输入/输出单元的信息传输进行管理。外部的连接部分与
附录A
附录B 如何监测内部控制 内部控制是任何组织有效运行的关键,董事会、执行长和内部审计人员都为实现这个企业的目标而工作;该内部控制系统是使这些团体确保那些目标的达成的一种手段。控制帮助一个企业有效率地运转。此外,运用一种有效的风险系统,风险可被降低到最小。同时,控制促进经营和与经营有关的信息的可靠性。全美反舞弊性财务报告委员会发起组织(COSO；1992) 在它发布的具有开创性的文件《内部控制整合框架》中,将内部控制定义为：企业风险管理是一个过程，受企业董事会、管理层和其他员工的影响，包括内部控制及其在战略和整个公司的应用，旨在为实现经营的效率和效果、财务报告的可靠性以及法规的遵循提供合理保证。该委员会还指出,一个的内部控制的系统包括五个要素。它们是：控制环境、风险评估、信息和沟通、控制活动、监控。 COSO的定义及五个要素已被证明确实对不同的团体,如董事会和首席执行官起到作用。这些群体对内部控制系统的监管以及系统设计与运行有责任。而且,内部审计人员已经发现COSO的指导是有用的。这群人员可能会被董事会或管理层要求去测试控制。COSO最近发布的一份讨论文件，指出五个要素监控,其中的五个要素的确定在1992 frame work COSO原本。中国发展简报的题为《内部控制-整合框架：内部控制体系监督指南》(COSO，2007)。在文件中,COSO 强调监控的重要性，以及这些信息常常被没有充分利用。 因为董事会、执行长,和内部审计人员都在一个公司的内部控制中扮演着重要角色，内部控制的各要素,包括监测,都对所有的团体有着非常重要的意义。同时,外审计人员对监测有兴趣。《萨班斯-奥克斯利法案》（2002）为外部审计师创建了一个新的监督体制。所有的五个要素,包括监测,必须加以考虑。另外,内部控制审计必须结合对财务报告的检查。在一体化审计之前，在首席执行官的领导下，也许也在内部审计活动的支持下的管理，评估了内控制体系的有效性。随后外部审计人员对控制出具意见。起监督角色的董事会，将阅读内部审计、管理层和首席执行官出具的报告。文件关于监测对每一个团体的指导起了帮助,因为他们分别为各自的角色而劳动。 第一，什么是监测。监测的组成可评估内部控制系统在过去一段时间发挥效用的质量。其对控制功能的评估有助于企业确定其控制在有效地运作中。在执行监测活动时，相关人员参与审查系统的设计及其运行效果。这种检查必须进行及时,目的是为了提供给企业最大的利益。管理层负责做出适当的行动以回应这些结果。当事人对内部控制有兴趣,可以充分依赖这个内部控制系统,如果合适的监
The Introduction of AT89C51 Description The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications. Function characteristic The AT89C51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, one 5 vector two-level interrupt architecture, a full duplex serial port, one-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset. Pin Description VCC：Supply voltage. GND：Ground.
外文文献一单片机简介 单片机是一种集成在电路芯片，是采用超大规模集成电路技术把具有数据处理能力的中央处理器CPU随机存储器RAM、只读存储器ROM、多种I/O口和中断系统、定时器/计时器等功能（可能还包括显示驱动电路、脉宽调制电路、模拟多路转换器、A/D转换器等电路）集成到一块硅片上构成的一个小而完善的计算机系统。单片机也被称为微控制器（Microcontroller），是因为它最早被用在工业控制领域。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。 二、单片机的发展趋势 现在可以说单片机是百花齐放，百家争鸣的时期，世界上各大芯片制造公司都推出了自己的单片机，从8位、16位到32位，数不胜数，应有尽有，有与主流C51系列兼容的，也有不兼容的，但它们各具特色，互成互补，为单片机的应用提供广阔的天地。 纵观单片机的发展过程，可以预示单片机的发展趋势，大致有： 1.低功耗CMOS MCS-51系列的8031推出时的功耗达630mW，而现在的单片机普遍都在100mW左右，随着对单片机功耗要求越来越低，现在的各个单片机制造商基本都采用了CMOS(互补金属氧化物半导体工艺)。象80C51就采用了HMOS(即高密度金属氧化物半导体工艺)和CHMOS(互补高密度金属氧化物半导体工艺)。CMOS虽然功耗较低，但由于其物理特征决定其工作速度不够高，而CHMOS则具备了高速和低功耗的特点，这些特征，更适合于在要求低功耗象电池供电的应用场合。所以这种工艺将是今后一段时期单片机发展的主要途径。 2.微型单片化 现在常规的单片机普遍都是将中央处理器(CPU)、随机存取数据存储(RAM)、只读程序存储器(ROM)、并行和串行通信接口，中断系统、定时电路、时钟电路集成在一块单一的芯片上，增强型的单片机集成了如A/D转换器、PMW(脉宽调制电路)、WDT(看门狗)、有些单片机将LCD(液晶)驱动电路都集成在单一的芯片上，这样 单片机包含的单元电路就更多，功能就越强大。甚至单片机厂商还可以根据用户的要求量身定做，制造出具有． 自己特色的单片机芯片。此外，现在的产品普遍要求体积小、重量轻，这就要求单片机除了功能强和功耗低外，还要求其体积要小。现在的许多单片机都具有多种封装形式，其中SMD(表面封装)越来越受欢迎，使得由单片机构成的系统正朝微型化方向发展。 3.主流与多品种共存 现在虽然单片机的品种繁多，各具特色，但仍以80C51为核心的单片机占主流，兼容其结构和指令系统的有PHILIPS公司的产品，ATMEL公司的产品和中国台湾
中小企业内部控制_外文参考文献 安徽工业大学毕业设计外文翻译 Private Enterprises of the intenal control issues Pulin Chang Economic Review. 2008, (5) Third, the promotion of private SMEs in the internal control system strategy (A) change management and business owners the concept of development. The majority of private small and medium enterprises in the family business, the success of these enterprises depends largely on internal control or entrepreneur leadership attention and level of implementation. Over the years, by traditional Chinese culture, business owners believe in Sincerity, fraternal loyalty permeate many aspects of enterprise management, strengthen internal controls that will affect the organization the members of distrust, resulting in internal control. Many private business owners that rely on business to do business benefits out of, rather than out of the internal financial management control; that the market is the most important internal control will be bound himself and staff development. Understanding of the bias, so that these leaders neglected the internal control system on the production and operation activities. Internal control can really become the leader of the internal needs of enterprise internal control system is the key to whether a mere formality. The internal control to make the internal needs of the enterprise depends largely on two points: First, determine
外文资料翻译 STC89C52 processi ng chip Prime features: With MCS - 51 SCM product compatibility, 8K bytes in the system programmable Flash memory, 1000 times CaXie cycle, the static operation: 0Hz ~ 33Hz, triple encryption program memory, 32 programmed I/O port, three 16 timer/counter, the eight uninterrupted dual-career UART serial passage, low power consumption, leisure and fall after fall electric power mode can be awakened and continuous watchdog timer and double-number poin ter, power ide ntifier. Efficacy: characteristics STC89C52 is one kind of low power consumption, high CMOS8 bit micro-co ntroller, 8K in system programmable Flash memory. Use high-de nsity nonv olatile storage tech no logy, and in dustrial 80C51 product in structi on and pin fully compatible. The Flash memory chips allows programs in the system, also suitable for programmable conventional programming. In a single chip, have clever 8 bits CPU and on li ne system programmable Flash, in crease STC89C52 for many embedded control system to provide high vigorous application and useful solutions. STC89C52 has following standard efficacy: 8k byte Flash RAM, 256 bytes, 32 I/O port, the watchdog timer, two, three pointer numerical 16 timer/counter, a 6 vector level 2 continuous structure, the serial port, working within crystals and horological circuit. In addition, 0Hz AT89S52 can drop to the static logic operation, support two software can choose power saving mode. Idle mode, the CPU to stop working, and allows the RAM, timer/c oun ters, serial, continu ous to work. Protectio n asa na patter n, RAM content is survival, vibrators frozen, SCM, until all the work under a continuous or hardware reset. 8-bit microcontrollers 8K bytes in the system programmable Flash AT89S52 devices. Mouth: P0 P0 mouth is a two-way ope n drain I/O. As export, each can drive eight TTL logic level. For P0 port to write "1", foot as the high impeda nee in put. When access to exter nal programs and nu merical memory, also known as
SCM is an integrated circuit chip, is the use of large scale integrated circuit technology to a data processing capability of CPU CPU random access memory RAM, read-only memory ROM, a variety of I / O port and interrupt system, timers / timer functions (which may also include display driver circuitry, pulse width modulation circuit, analog multiplexer, A / D converter circuit) integrated into a silicon constitute a small and complete computer systems. SCM is also known as micro-controller (Microcontroller), because it is the first to be used in industrial control. Only a single chip by the CPU chip developed from a dedicated processor. The first design is by a large number of peripherals and CPU on a chip in the computer system, smaller, more easily integrated into a complex and demanding on the volume control device which. The Z80 INTEL is the first designed in accordance with this idea processor, then on the development of microcontroller and dedicated processors will be parting ways. Are 8-bit microcontroller early or 4 bits. One of the most successful is the INTEL 8031, for a simple, reliable and good performance was a lot of praise. Then developed in 8031 out of MCS51 MCU Systems. SCM systems based on this system until now is still widely used. With the increased requirements of industrial control field, began a 16-bit microcontroller, but not ideal because the cost has not been very widely used. After 90 years with the great development of consumer electronics, microcontroller technology has been a huge increase. With INTEL i960 series, especially the later series of widely used ARM, 32-bit microcontroller quickly replace high-end 16-bit MCU status and enter the mainstream market. The traditional 8-bit microcontroller performance have been the rapid increase capacity increase compared to 80 the number of times. Currently, high-end 32-bit microcontroller clocked over 300MHz, the performance catching the mid-90s dedicated processor, while the average model prices fall to one U.S. dollar, the most high-end [1] model only 10 dollars. Modern SCM systems are no longer only in the development and use of bare metal environment, a large number of proprietary embedded operating system is widely used in the full range of SCM. The handheld computers and cell phones as the core processing of high-end microcontroller can even use a dedicated Windows and Linux operating systems. SCM is more suitable than the specific processor used in embedded systems, so it was up to the application. In fact the number of SCM is the world's largest computer. Modern human life used in almost every piece of electronic and mechanical products will be integrated single chip. Phone, telephone, calculator, home appliances, electronic toys, handheld computers and computer accessories such as a mouse with a 1-2 in both the Department of SCM. Personal computer will have a large number of SCM in the work. General car with more than 40 microcontroller, a complex industrial control systems may even hundreds of single chip at the same time work! SCM is not only far exceeds the number of PC and other computing the sum, or even more than the number of human beings. Single chip, also known as single-chip microcontroller, it is not complete a certain logic chips, but to a computer system integrated into a chip. Equivalent to a
外文翻译---51系列单片机的结构和功能
外文资料翻译 英文原文： Structure and function of the MCS-51 series Structure and function of the MCS-51 series one-chip computer MCS-51 is a name of a piece of one-chip computer series which Intel Company produces. This company introduced 8 top-grade one-chip computers of MCS-51 series in 1980 after introducing 8 one-chip computers of MCS-48 series in 1976. It belong to a lot of kinds this line of one-chip computer the chips have such as 8051, 8031, 8751, 80C51BH, 80C31BH,etc., their basic composition, basic performance and instruction system are all the same. 8051 daily representatives- 51 serial one-chip computers . An one-chip computer system is made up of several following parts: (1) One microprocessor of 8 (CPU). (2) At slice data memory RAM (128B/256B),it use not depositing not can reading /data that write, such as result not middle of operation, final result and data wanted to show, etc. (3) Procedure memory ROM/EPROM (4KB/8KB ), is used to preserve the procedure , some initial data and form in slice. But does not take ROM/EPROM within some one-chip computers, such as 8031 , 8032, 80C ,etc.. (4) Four 8 run side by side I/O interface P0 four P3, each mouth can use as introduction, may use as exporting too. (5) Two timer / counter, each timer / counter may set up and count in the way, used to count to the external incident, can set up into a timing way too, and can according to count or result of timing realize the control of the computer. (6) Five cut off cutting off the control (universal asynchronous receiver/transmitter (UART) ), is it realize one-chip computer or one-chip computer and serial communication of computer to use for. (8) Stretch oscillator and clock produce circuit, quartz crystal finely tune electric capacity need outer. Allow oscillation frequency as 12 megahertz now at most. Every the above-mentioned part was joined through the inside data bus .Among them, CPU is a core of the one-chip computer, it is the control of the computer and command center, made up of such parts as arithmetic unit and controller , etc.. The arithmetic unit can carry on 8 persons of arithmetic operation and unit ALU of logic operation while including one, the 1 storing devices temporarily of 8, storing device 2 temporarily, 8's accumulation device ACC, register B and procedure state register PSW, etc. Person who accumulate ACC count by 2 input ends entered of checking etc. temporarily as one operation often, come from person who store 1 operation is it is it make operation to go on to count temporarily , operation result and loop back ACC with another one. In addition, ACC is often regarded as the transfer station of data transmission on 8051 inside. The same as general microprocessor, it is the busiest register. Help remembering that agreeing with a expresses in the order. The controller includes the procedure counter, the order is deposited, the