基于单片机的9999秒倒计时器的设计.doc

摘 要 近年来随着计算机在社会领域的渗透，单片机的应用正在不断地走向深入，同时带动着传统控制检测日新月异的更新。由于单片机具有体积小、易于产品化、面向控制、集成度高、功能强、可靠性高、价格低等特点，其在工业控制、机电一体化、智能仪表、通信等诸多领域中得到了广泛的应用。在实时检测和自动控制的单片机应用系统中，单片机往往是作为一个核心部件来使用。但是仅单片机方面知识是不够的，还应根据具体硬件结构，以及针对具体应用对象特点的软件结合，以作完善。 本论文针对倒计时系统的设计的需求，介绍了MCS-51单片机的部分基本原理，如51单片机的接口功能、中断、定时器等等。倒计时系统需要用到锁存器、矩阵键盘、LED数码显示器等主要模块，通过不同的模块之间相互作用，完成倒计时的初步硬件结构。对于倒计时器中的LED数码显示器来说，我为了简化线路、降低成本，采用以软件为主的接口方法，即采用Keil uVision3软件程序进行译码。 本次设计采用C语言编程，通过倒计时子程序模块、矩阵键盘扫描模块、中断等子程序的正确调用，完成了可以随时设置初值的基于51单片机控制的9999秒倒计时系统。 【关键词】倒计时器 单片机 矩阵键盘 Keil uVision3 LED数码显示器  ABSTRACT In recent years, with the penetration of computers in the social sphere, SCM applications are continually deepening, and the traditional control test is driving the rapid update. The size of SCM is very small, and it is easy to be producted. for control, high integration, functionality, high reliability, and so on. So it has been widely used in the area of industrial control, mechatronics, intelligent instruments and communications.In real-time detection and control of the microcomputer application system, the microcontroller is often used as a core component. But if only have the knowledge of SCM is not enough.It should be based on specific hardware architecture, and if the application-specific features of the software objects are combined will be perfect. This paper focuses on the needs of the countdown system design, introduced the MCS-51 MCU of some of the basic principles.Such as the 51 single-chip interface functions, interrupt, timer and so on. Countdown system needs to use latch, matrix keyboard, LED digital display and other major modules, through interaction between different modules to complete the Countdown to the initial hardware. The countdown device in the LED digital display, In order to simplify the circuit, reduce costs, we adopt a software-based interface method, namely using Keil uVision3 software program for decoding. C language programming was used in the design , we c