数字电子课程设计—数字电子时钟

课 程 设 计 报 告 设计题目：数字电子时钟 班级： 学号： 姓名： 指导老师： 设计时间：2009年8月30日 1

摘要 数字电子钟是一种用数字显示秒﹑分﹑时的记时装置，与传统的机械钟相比，他具有走时准确﹑显示直观﹑无机械传动装置等优点，因而得到了广泛的应用：小到人们的日常生活中的电子手表，大到车站﹑码头﹑机场等公共场所的大型数显电子钟。 本课程设计要用通过简单的逻辑芯片实现数字电子钟。要点在于用555芯片连接输出为一秒的多谐振荡器用于时钟的秒脉冲,用74LS160(10进制计数器)74LS00(与非门芯片)等连接成60和24进制的计数器,再通过七段数码管显示，构成了简单数字电子钟。

关键词：数字电子钟、555芯片、计数器、数码管 2

目录

摘要·········································································································1

第1章 概述 ·························································································3 第2章 课程设计任务及要求 ····························································4 2.1 设计任务 ···············································································4 2.2 设计要求 ···············································································4 第3章 系统设计 ··············································································5 3.1方案论证 ················································································5 3.2 系统设计 ·················································································5 3.2.1 结构框图及说明 ·························································5 3.2.2 系统原理图及工作原理 ·············································6 3.3 单元电路设计 ·······································································7 3.3.1单元电路工作原理 ······························································7 3.3.2元件参数选择 ······································································10 第4章 软件仿真 ·················································································13 4.1 仿真电路图 ··············································································13 4.2 仿真过程 ··················································································14 4.3 仿真结果 ··················································································15 第5章 安装调试 ·················································································16 5.1 安装调试过程 ··········································································16 5.2 故障分析 ··················································································18 第6章 结论 ··························································································19 第7章 使用仪器设备清单 ··································································20 参考文献 ································································································20 收获、体会和建议 ················································································21 3

第1章 概述 所谓电子技术,是指“含有电子的、数据的、磁性的、光学的、电磁的、或者类似性能的相关技术”。电子技术可以分为模拟电子技术、数字电子技术两大部分。 模拟电子技术说是整个电子技术的基础，在信号放大、功率放大、整流稳压、模拟量反馈、混频、调制解调电路领域具有无法替代的作用。例如高保真(Hi-Fi)的音箱系统、移动通讯领域的高频发射机等。 与模拟电路相比，数字电路具有精度高、稳定性好、抗干扰能力强、程序软件控制等一系列优点。随着计算机科学与技术突飞猛进地发展，用数字电路进行信号处理的优势也更加突出。为了充分发挥数字电路在信号处理上的强大功能，我们可以先将模拟信号按比例转换成数字信号，然后送到数字电路进行处理，最后再将处理结果根据需要转换为相应的模拟信号输出。自20世纪70年代开始，这种用数字电路处理模拟信号的所谓“数字化”浪潮已经席卷了电子技术几乎所有的应用领域，如数字滤波器等。 很有幸我们这学期学习了电子技术这门学科，并且是我们这个学期的重点课程，在上课和实验的过程中，渐渐的我喜欢上了它。每一节课我都认真学习，每次实验我都认真的去完成。但是做课程设计是第一次做，以前都是照着做，现在所有的都是自己做，真的很有难度。要想做出来一个好的东西，就要去图书馆，到网上去找资料。 根据我自己的自身情况和查阅的资料，我决定做一个数字电子时钟，这个相对比较是比较简单的，由于我们以前的数电实验做过任意进制计数器，所以电子钟计数器制作没有问题，两个60进制计数器，一个24进制计数器。经过不懈的努力终于完成了，在这个过程中收获了很多。 4

第2章 课程设计任务及要求 2.1 设计任务 1、设计一个有“时”，“分”，“秒”（23小时59分59秒）显示且有校时功能的电子钟； 2、 用中小规模集成电路组成电子钟。

2.2 设计要求

1．用555定时器设计一个秒钟脉冲发生器，输入1HZ的时钟；（对已有1kHz频率时钟脉冲进行分频）； 2．能显示时、分、秒，24小时制； 3. 设计晶体震荡电路来输入时钟脉冲； 4.用同步十进制集成计数器74LS160设计一个分秒钟计数器,即六十进制计数器.； 5.用同步十进制集成计数器74LS160设计一个24小时计数器,

6. 译码显示电路显示时间。

5

第3章 系统设计 3.1方案论证 秒、分、时分别为60、60和24进制计数器。秒、分均为六十进制，即显示00~59，它们的个位为十进制，十位为六进制。分秒功能的实现：用两片74LS160组成60进制递增计数器。时为二十四进制计数器，显示为00~23，个位仍为十进制，而十位为三进制，但当十进位计到2，而个位计到4时清零，就为二十四进制了。时功能的实现：用两片74LS160组成24进制递增计数器。

3.2 系统设计 3.2.1 结构框图及说明

图 1 设计框架图 译码显示 译码显示 译码显示

二十四进制时计数器 六十进制 分计数器 六十进制 秒计数器

晶体 振荡器 分频器 6

3.2.2 系统原理图及工作原理 系统原理图，如图2所示。

图 2 系统原理图 用555电路构成的1KHz多谐振荡器，调节电阻R3可以改变输出信号频率。74LS160是二，五，十进制同步加法器，用三片74LS90构成三级十分频器，将1KHz矩形波分频得到1Hz基准秒计时信号。由于74LS160是十进制计数器，分别将个位接成十进制计数器，十位接成六进制计数器，分别将个位的RCO输出端接十位的9脚端，就构成60进制计数器，用两个相同的60进制计数器分别做作为秒，分计时，并在个位和十位输出端接上数码显示管显示小时计数器直接采用整体反馈清零法构成24进制计数器。 工作原理：振荡电路产生的1KHZ脉冲信号经三级十分频电路分频后产生的1HZ脉冲信号输入74LS90N连成的60进制秒计数器，再由秒计数器每60秒进位输出给60进制分钟计数器，分钟计数器满60后产生进位信号输入给24进制小时计数器，从而实现24小时制电子钟的功能。