毕业设计

摘 要

摘 要：

LED显示屏（LED panel）：LED就是light emitting diode ，发光二极管的英文缩写，简称LED。它是一种通过控制半导体发光二极管的显示方式，其大概的样子就是由很多个通常是红色的发光二极管组成，靠灯的亮灭来显示字符。用来显示文字、图形、图像、动画、行情、视频、录像信号等各种信息的显示屏幕。LED电子显示屏是新型信息显示媒体，集电子技术、光电子技术、计算机技术、信息处理技术于一体，以其色彩鲜艳，使用范围广，亮度高，寿命长，工作稳定可靠等优点，广泛应用于商业广告、体育场馆、港口机场、客运站、高速公路、新闻发布、证券交易等方面。led显示屏利用发光二极管构成的点阵模块或像素单元组成大面积显示屏幕，以环境适应能力强、性能价格比高、使用成本低等特点，在短短的十来年中，迅速成为平板显示领域的主流产品，也是目前国际上比较先进的显示媒体之一。

LED点阵电子显示屏制作简单，安装方便，被广泛应用于各种公共场合，如汽车报站器、广告屏以及公告牌等。本文介绍的是一种可用在值班室外等场合的公告牌的LED点阵电子显示屏设计。公告内容随时可以更新，能够实时显示温度和日期时间，并具有自动亮度调节功能。

南京机电职业技术学院毕业设计

2 Abstract：

The LED display (LED panel) : LED emitting diode, is light emitting diode,

referred to the abbreviation of LED. It is a semiconductor light-emitting

diodes by controlling the display mode, its probably like by many is usually

is composed of the red leds on the bright lights, destroyed to display

characters. Used to display text, graphics, video, animation, video, video

signal market, various information display screen.

LED electronic display is the new information display media, integrate

electronic technology, optoelectronic technology, computer technology and

information processing technology in the integral whole, with its

colourful, use range, high brightness, long life, stable and reliable work,

widely used in commercial advertising, stadiums, port airport, passenger,

highway, press conference, securities trading, etc. The led display using

light-emitting diodes constitute matrix modules or pixel display screen

large area of elements, with environment adaptiveness, high

performance-to-price, use cost low characteristic, in just ten years,

rapidly becoming the mainstream of flat-panel displays field, it is also

the product of the more advanced international display media one.

Of LED dot matrix electronic display screen making simple, convenient

installation, widely applied in all kinds of public occasions, such as the

car stops device, advertising screen and bulletin boards. This paper is

a usable on the bulletin board of the applications outside of LED dot matrix

electronic display design. Announcement content can always change, can

real-time display temperature and date and time, and possesses automatic

brightness adjusting function.

南京机电职业技术学院毕业设计

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目 录

摘 要„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„ 1-2

目 录„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„ 3

第一章 LED显示屏

1.1 设计要求„„„„„„„„„„„„„„„„„„„„„„„1

1.2 设计目的„„„„„„„„„„„„„„„„„„„„„„„1

1.3 总体思路„„„„„„„„„„„„„„„„„„„„„„„1

1.4 方 案„„„„„„„„„„„„„„„„„„„„„„„ 1

第二章 单片机的相关介绍

2.1 单片机的发展历史„„„„„„„„„„„„„„„„„„„„2

2.2 单片机的发展趋势„„„„„„„„„„„„„„„„„„„3-4

2.3 单片机的特点„„„„„„„„„„„„„„„„„„„„„„5

2.4 单片机的应用„„„„„„„„„„„„„„„„„„„„„5-6

2.5 单片机的基本系统结构„„„„„„„„„„„„„„„„„„6

第三章 AT89S52单片机

3.1主要性能„„„„„„„„„„„„„„„„„„„„„„„„7

3.2 单片机时钟电路和复位电路„„„„„„„„„„„„„„„7-8

3.3 控制电路设计„„„„„„„„„„„„„„„„„„„„ 9-13

3.4系统供电电源„„„„„„„„„„„„„„„„„„„„„„14

第四章 系统软件设计

4.1 软件设计应用环境„„„„„„„„„„„„„„„„„„„„15

4.2 单片机指令„„„„„„„„„„„„„„„„„„„„„ 15-16

4.3源程序：„„„„„„„„„„„„„„„„„„„„„„ .17-20

第五章 硬件制作

5.1 元器件清单„„„„„„„„„„„„„„„„„„„„„„„21

5.2 制作与调试„„„„„„„„„„„„„„„„„„„„„„„22

第六章 总结…………………………………………… 23

致谢„„„„„„„„„„„„„„„„„„„„„„„„„24

参考文献„„„„„„„„„„„„„„„„„„„„„„„25南京机电职业技术学院毕业设计

1 第一章 LED显示屏

1.1 设计要求

1利用单片机设计一16*16点阵式显示屏。滚动显示“南京机电职业技术学院”字符；

2 提交开题报告、毕业实习报告、绘出电路原理图、电路印制版图、电路仿真和调试、软件流程图、完成设计论文。

1.2 设计目的

1 巩固、加深和扩大单片机应用的知识面，提高综合及灵活运用所学知识解决一般控制的能力；

2 培养针对课题需要、选择和查阅有关手册、图表及文献资料的自学能力、提高组成系统、编程、调试的动手能力；

3 通过对课题设计方案的分析、选择、比较、熟悉单片机应用系统的开发、研制的过程、软硬件设计的方法、内容及步骤；

4 掌握KEIL C，89S52单片机，Protel等相关软件的应用。

1.3 总体思路

本次设计以单片机89S52为核心，利用4—16译码器74HC154和串入并出芯片（带锁存功能）74HC154E对单片机进行I/O扩展，去分别控制16*16点阵电子显示屏中每一个发光二极管的亮灭,从而在显示屏上组合出所需要的图像，实现设计所需要的功能。

1.4 方案

在方案的选取上，主要考虑了以下几个方面：

1 单片机型号的选则。在这次设计中，首先自己选则了C51单片机来对系统进行设计开发，并在Protenus中进行模拟仿真，在进行了一周的编程验证后，发现C51单片机128字节的RAM成为了软件编程的一个瓶颈，它会导致系统的软件编写过于复杂也及系统可扩充性能较差，为了解决这个问题，故选用了S52单片机，它具有8K的RAM，较好地解决了这个问题。

2 单片机外围器件的选取。 89S2有40个引脚，由于16*16点阵需要16根行线和16根列线，用单片机的I/O端口去真接控制显然不可能，在这里，采用了4—16译码器74HC154，对16根行线的控制仅用了四个I/O端口，而对16根列线的控制，则采用了2块串入并出（带锁存功能）的74HC595串联来实现，这样，点阵显示的数据传输线一共才占用单片机的5个I/0端口资源。 南京机电职业技术学院毕业设计

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第二章 单片机的相关介绍

2.1 单片机的发展历史

1970年微型计算机研制成功后，随着就出现了单片机。美国Intel公司在1971推出了4位单片机4004；1972年推出雏形8位单片机8008。特别是在1976年推出MCS-48单片机以后的30年中，单片机及其相关技术的发展经历了数次的更新换代。其发展大约每三、四年要更新一代，集成度增加一倍，功能翻番。 尽管单片机出现的历史并不长，但以8位单片机的推出为起点，单片机的发展已经历了4个阶段。

第一阶段(1976-1978年)：初级单片机阶段。这个阶段的单片机以Intel公司的MC-48为代表。这个系列的单片机内集成有8位CPU、I/O接口、8位定时器/计数器，寻址范围不大于4KB，具有简单的中断功能，无串行接口。

第二阶段(1978-1982年)：单片机完善阶段。在这一阶段推出的单片机其功能有较大的增强，能够应用于更多的场合。这个阶段的单片机普遍带有串行I/O口，多级中断处理系统，16位定时器/计数器，片内集成的RAM、ROM容量加大，寻址范围可达64KB。一些单片机片内还集成了A/D转换接口。这类单片机的典型代表有Intel公司的MCS-51、Motorola公司的6081和Zilog公司的Z8等。

第三阶段(1982-1992)：8位单片机巩固发展及16位高级单片机发展阶段。在此阶段，尽管8位单片机的应用已广泛普及，但为了更好地满足测控系统嵌入式应用的要求，单片机集成的外围接口电路有了更大的扩充。这个阶段的代表为8051系列。许多半导体公司和生产厂以MCS-51的8051内核，推出了满足各种嵌入式应用的多种类型和型号的单片机。其主要技术发展如下： 1 外围功能集成。满足模拟量直接输入的ADC接口；满足伺服驱动的PWM；保证程序可靠运行的程序监控定时器WDT(俗称看门狗)。 2 出现了为满足串行外围扩展要求的串行扩展总线和接口，如SPI、I2C总线、单总线(1-Wire)等。 3 出现了满足分布系统并突出控制功能的现场总线接口，如CAN等。 4 在程序存储器方面广泛使用了片内程序存储器技术，出现了片内集成EPROM、EEPROM、Flash ROM、Mask ROM、OTP ROM等各种类型的单片机，以满足不同产品开发和生产的需要，也为最终取消外部储存器扩展奠定了良好的基础。 与此同时，一些面向更高层次的应用，推出了16位单片机，典型代表有Intel公司的MCS-96系列单片机