目 录
摘 要 ························································································· 1 ABSTRACT ················································································· 2 前 言 ························································································· 3 第1章 系统方案设计 ···································································· 4
1.1 系统总体设计方案 ··························································· 4 1.2 基本功能简介 ································································· 4 1.3 系统程序········································································ 4 第2章 8051单片机原理分析及硬件电路 ··········································· 6
2.1 8051单片机简述 ······························································ 6
2.1.1 8051单片机的基本组成 ············································· 6 2.1.2 8051的信号引脚 ······················································ 8 2.2 晶体振荡电路 ································································ 10 2.3 上电复位电路 ································································ 11 2.4 8051单片机的并行I/O口 ················································· 12 2.5 8051单片机的中断系统 ···················································· 12 2.6 8051单片机的定时/计数器 ················································ 13
2.6.1 定时/计数器的定时功能 ············································ 13 2.6.2 用于定时/计数器控制的寄存器 ··································· 14
第3章 8051单片机与8155的接口设计 ·········································· 15
3.1 并行I/O接口8155 ·························································· 15
3.1.1 8155内部功能结构及引脚 ········································· 15 3.1.2 作片外RAM使用 ······················································ 16 3.1.3 作扩展I/O口使用 ··················································· 16 3.1.4 I/O口的工作方式 ···················································· 18 3.1.5 定时/计数器使用 ···················································· 18 3.2 8051单片机并行I/O扩展 ················································ 19
I
3.2.1 8051并行扩展总线 ·················································· 19 3.2.2 8051单片机与8155的接口 ······································· 19
第4章 单片机与8155的接口设计的应用 ········································ 21
4.1 LED显示······································································· 21 4.2 按键扫描 ······································································ 22 第5章 结论 ············································································· 24 参考文献 ················································································ 26 毕业设计小结 ·········································································· 27 附录 ······················································································ 28
II
摘 要
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。学习单片机的最有效方法就是理论与实践并重，本文将用单片机8051和外围接口8155、发光二极管、晶振、复位、电源等电路以及必要的软件组成的以8051为核心，辅以简单的设备和必要的电路，设计了一款简易的流水灯，并编写简单的程序，使其能够自动工作。
关键词：单片机8051，外围接口8155，流水灯。
前 言
随着电子技术的日益进步，微型计算机的发展突飞猛进。其发展之一就是将微处理器及其外围芯片，如程序存储器、并行、串行I/O口、定时器/计数器、中断控制器及其它控制部件集成在一个芯片之中，制成单片机。而近年来推出的一些高档单片机还包含有许多特殊功能单元。因此，只要外加一些扩展电路及必要的通道接口就可以构成各种计算机应用系统，并具有集成度高、可靠性高、性能价格比高、适应温度范围宽、抗干扰能力强、小巧灵活、易于实现机电一体化等优点，已广泛应用于智能化仪器仪表的检测、控制以及生产设备自动化、家用电器等领域。
1