目 录
1 引言 ··································· 1 2 数字钟的系统概述 ····························· 1
2.1 总体方案设计 ······················································································· 2 3 AT89C2051单片机及其引脚说明 ······················· 3
3.1 内部结构 ····························································································· 4
3.2 程序保密 ····························································································· 4 3.3 软硬件的开发 ······················································································· 4 3.4 引脚说明 ····························································································· 4 3.5 主要性能 ····························································································· 5 4 电路的硬件设计 ······························ 6
4.1 复位电路 ····························································································· 6 4.2 时钟电路 ····························································································· 6 4.3 按键电路 ······························································································ 7 4.4 迅响电路及输入、输出电路 ········································································ 7 4.5 数码管显示电路 ····················································································· 9
4.5.1 LED数码管结构及工作原理 ······························································ 9 4.5.2 显示原理 ······················································································ 9 4.6稳压电路 ······························································································ 9 5 软件设计 ································ 10
5.1 主程序系统结构 ····················································································· 9 5.2 软件任务分析 ························································································ 9 5.3 软件流程图 ··························································································· 9 6安装与调试 ······························· 10
6.1 安装、焊接到电路板上 ·········································································· 10 6.2 测试与调试 ························································································· 11 7 结束语 ································· 18 参考文献 ································· 18 致谢 ··································· 19 附录 1 ·································· 19 附录 2 ·································· 19
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基于
AT89C2051六位数字钟
摘要：本设计论文介绍了用AT89C2051单片机控制的数字钟的硬件结构与软件设计。此数字钟是一个将“时”、“分”、“秒”显示于人的视觉器官的计时装置。它的计时周期为24小时，显示满刻度为23时59分59秒，另外应有校时功能。电路由时钟脉冲发生器、时钟计数器、译码驱动电路和数字显示电路以及时间调整电路组成。用晶体振荡器产生时间标准信号，这里采用石英晶体振荡器。根据60秒为1分、60分为1小时、24小时为1天的计数周期，分别组成两个60进制（秒、分）、一个24进制（时）的计数器。构成秒、分、时的计数，实现计时的功能。显示器件选用LED七段数码管。在译码显示电路输出的驱动下，显示出清晰、直观的数字符号。针对数字钟会产生走时误差的现象，在电路中就设计有有校准时间功能的电路。
关键词：单片机，AT89C2051，数字钟，计时
英文摘要
Based on SCM multi-purpose digital clock design
(Institute of Economic and Technological,Anhui Agricultural University, Hefei 230036) Abstract: The paper mainly presents the hardware and software design of the digital clock using AT89C2051. This digital clock is a time-device, which can display \Its time period is 24 hours and the full scale of the display is 23 hours, 59 minutes, 59 seconds and it has the function of time adjustment. The circuit consists of the clock pulse generator, the clock counter, decoding drive circuit, digital display circuit and the time adjustment circuit. It generates time standard signal using crystal oscillator, here is the quartz crystal oscillator. Because 60 seconds is 1 minute, 60 minutes is 1 hour and 24 hours is 1 day, we uses two counters of 60 parts and a counter of 12 part separately to constitute the count of percentage of second, second, minute, and hour. So it can realize time function. Display component selects seven-segment numerical tube LED. Driven by decoding output circuit, it can display showing clear and intuitive figures. Due to walking error of digital clock, we design time calibration circuit in the system.
Key words：Single-chip microcomputer， AT89C2051， Digital clock，Time
1 引言
钟表的数字化给人们生产生活带来了极大的方便，而且大大地扩展了钟表原先的报时功能。诸如定时自动报警、按时自动打铃、时间程序自动控制、定时广播、定时启闭电路、定时开关烘箱、通断动力设备，甚至各种定时电气的自动启用等，所有这些，都是以钟表数字化为基础的。
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随着数字集成电路的出现和飞速发展，以及石英晶体振荡器的广泛应用，使得数字钟的精度稳定度远远超过了老式的机械表，用数字电路实现对“时”、“分”、“秒”数字显示的数字钟在数字显示方面，目前已有集成的计数、译码电路，它可以直接驱动数码显示器件，也可以直接采用才COMS--LED光电组合器件，构成模块式石英晶体数字钟。本设计主要是用中、小规模集成电路设计的一台能显示时、分、秒的数字电子钟。是由晶振电路产生1HZ标准信号，分、秒为00--59六十进制计数器，时为00--23二十四进制计数器，可手动校正，且具有整点报时功能。因此，研究数字钟及扩大其应用，有着非常现实的意义。
2 数字钟的系统概述
2.1总体方案设计
数字电子钟是用数字电路实现“时”、“分”、“秒”数字显示的计时装置，主要由振荡器、分频器、计数器、译码显示器、校时电路等部分组成。而数字钟想准确的计时则是由振荡器产生的时脉冲送到分频器，分频电路将时标信号分成每秒一次的方波信号。秒脉冲发生器产生频率稳定很高的秒脉冲，秒脉冲被送到一个六十进制秒计数器计数，将计数结果送至秒个位和十位译码器，译码结果分别由两只七段数码管以十进制数形式显示来。当秒六十进制计数器累计到第59秒时，若再来一个秒脉冲，秒计数器的进位输出就产生进位脉冲（分计数脉冲），同时，秒计数器的十位和个位都复位到零。分计数脉冲又被送到分六十进制计数器计数，经译码电路译码后数码管显示相应的分数。当计满59分59秒时，若再来一个秒脉冲，则分计数器便向时计数器送出时计数脉冲，同时，分、秒计数器均复位到零。时计数器是一个二十四进制计数器，当计数显示23时59分59秒时，若再来一个秒脉冲，则时、分、秒计数器都应回到零，并显示（00:00:00）表示已到达午夜零点，第二天开始继续计数。其主要的功能模块如图2-1所示。
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基于AT89C2051六位数字钟
