毕业设计论文基于单片机的秒表/时钟计时器设计摘 要近年来，随着科学技术的进步和时代的发展，人们对时钟的功能和精度提出了越来越高的要求，各种时钟的设计也越来越重要。秒表/时钟计时器是在一种计时器上实现两种基本功能的一种器件。它广泛应用于各种场所，同时，它以其小巧，价格低廉，走时精度高，使用方便，功能多，便于集成化，而受到广大消费者的喜爱。本文介绍了一种以AT89S51单片机为核心的秒表/时钟计时器的设计，实时时钟芯片DS1302提供实时时间，6位LED动态显示时、分、秒，并在计时过程中具有报时功能, 定时时间到时，音乐电路播放悦耳的乐曲。该数字钟设有五个按键: K1, K2，K3，K4和K5键,使之具备了校时、定时功能，在设计中分别介绍了它们的工作特点、原理和使用方法，并给出了它们与单片机AT89S51的接口电路。单片机和集成芯片的应用使得本设计硬件电路简化、编程方便，同时功能也更稳定。由于单片机可以重新写入不同程序这就便于时钟功能的扩充和改变，同时时钟芯片时间精确度高可以保证系统的精度。关键词：单片机；秒表；时钟；实时时钟芯片；动态LED显示；The Design Of Stopwatch/Electronic-Clock System Based On Single-Chip-MicrocomputerAbstractIn recent years, with the scientific progress and the development of the times, people requirements of the clock function and accuracy are more and more high. The various design of the clock also becomes increasingly important. As long as the existence of timing、counting ,the clock will be used. Meanwhile ,in daily lives, with its feature of compact, low price ,high accuracy, ease to use, multi-functional, ease of integration, the digital clock are fond of majority of consumers.This paper introduces the design of digital alarming clock ,which was based on the core of single-chip microcomputer AT89S51.Real-time clock chip DS1302 provides real-time, six bit LED display hours, minutes and seconds dynamically, the clock also having the function of timekeeping in the process of timing .When timing time, the music circuit broadcast delightful music. The digital clock with five keys: the button of K1, K2, K3, K4, with these keys, the digital clock has the function of regulating & timing. This design introduces their characteristics,principles,using methods, and gives them the interface circuit with SCM AT89S51.The circuit of hardware for this design become easy and the system function become powerful along with MCU and integrated chip used. Because the monolithic integrated circuit may reread in different procedure this at your convenience to the clock function expansion and the change, simultaneously the Real-time clock chip precision is high may guarantee the system the precision. Keywords:SCM;Stopwatch;Clock;Real-time clock chip;Dynamic LED display;目 录引 言 1第1章 绪论 21.1 概述 21.2 课题的总体设计及思路 2第2章 硬件电路设计 42.1 单片机最小系统 42.1.1单片机的介绍及选择 42.1.2 AT89S51单片机性能与应用 42.1.3 单片机的时钟电路 62.1.4 单片机的复位电路 72.2 实时时钟电路 72.3 显示电路 82.3.1 LED显示的基本原理 92.3.2 显示电路原理图 92.4 键盘电路 102.5 闹铃电路 11第3章 系统软件设计 133.1 主程序流程图 133.2读DS1302程序流程图 143.3 显示程序流程图 143.4 秒表计时子程序流程图 143.5 时钟计时子程序流程图 153.6 设定时间子程序流程图 153.7 闹钟子程序流程图 17第4章 调试 18结论与展望 19致 谢 20参考文献 21附录A：系统原理图 22附录B：外文文献及其译文 23附录C：主要