[强烈推荐]基于单片机的万年历设计毕业论文设计 - 图文(2)

3.3红外遥控电路设计 ··········································································· 1

3.3.1红外发射系统 ········································································· 1

3.3.2红外接收系统 ········································································· 2

3.3.3主要程序分析 ········································································· 2

3.4 DS18B20温度传感器电路设计 ··························································· 2

3.4.1 DS18B20温度传感器概述 ························································· 2

3.4.2 DS18B20温度传感器的主要特性 ················································ 2

3.4.3 DS18B20温度传感器基本原理 ··················································· 2

3.4.4 DS18B20温度传感器配置寄存器 ················································ 2

3.4.5 DS18B20温度传感器暂存器中温度数值的储存形式 ························ 2

3.4.6 DS18B20温度传感器工作时序 ··················································· 2

3.4.7 控制器对DS18B20操作流程 ····················································· 2

3.4.8 DS18B20芯片内部ROM操作指令 ············································· 2

3.4.9 DS18B20温度传感器芯片内部存储器RAM操作指令 ····················· 2

3.4.10 DS18B20温度传感器典型工作方式············································ 2

3.4.11 温度传感器DS18B20主要程序分析 ·········································· 2

3.5键盘调时电路设计 ··········································································· 3

4 总体设计与制作 ················································································· 3

4.1总体原理图绘制 ·············································································· 3

4.2 软件开发与调试 ·············································································· 3

4.2.1使用Keil软件编写系统程序 ······················································ 3

4.2.2 系统调试 ·············································································· 3

4.3 搭建系统实物 ················································································· 3

4.4系统实物展示 ················································································· 3

5 收获与体会 ······················································································· 3

6 结论································································································· 3

附录A ·································································································· 3

附录B ·································································································· 3

附录C ·································································································· 4

参考文献 ·································································································· 5

致谢 ········································································································ 5

1 引言

电子是推动人类社会文明、进步与发展的巨大动力，随着电子产品的飞速发展，现已将人类带入了智能化的生活。传统的机械表由于做工的高精细要求，造价的昂贵，材料的限制，时间指示精度的限制，使用寿命，以及其它方面的限制，已不能满足人们的需求。另外从人们的日常生活到工厂的自动控制，从民用时钟到科学发展所需的时钟，现代人对时间的精度和观察时间的方便有了越来越多的需求。人们要求随时随地都能快速准确的知道时间，并且要求时钟能够更直观、更可靠、价格更便宜。这种要求催生了新型电子时钟的产生。

1.1课题的来源和意义

电子技术的飞速发展，微机已开始向社会的各个领域渗透，同时大规

模集成电路获得高速发展，单片机的应用正在不断地走向深入，由传统的8位单片机发展到后来的16位，诸如AVR系列、PIC系列、430系列等，再到如今的高级单片机ARM体系下配合操作系统实现智能化，这无疑体现了单片机在我们生活中已占据了核心的地位。本设计核心控制芯片采用了STC89C52微控制芯片，该芯片具有功能强、体积小、功耗低、价格便宜，工作可靠，使用方便等优点，因此特别适合于与控制有关的系统，越来越广泛地应用于自动控制，智能化仪器、仪表、数据采集、军工产品以及家用电器等各个领域。

另外，单片机的重要运用意义还在于，它从根本上改变了传统的控制系统设计思想和设计方法。从前必须由模拟电路或数字电路实现的大部分功能，现在已能用单片机通过软件的方法来实现了，这种软件替代硬件的控制技术也称为微控制技术，是传统控制技术的一次革命。

单片机模块中最常见的是数字钟，数字钟是一种用数字电路技术实现的时、分、秒计时的装置，与机械式时钟相比具有更高的准确性和直观性，且无机械装置，具有更长的使用寿命，因此得到了广泛的使用。 数字钟是采用数字电路实现对时、分、秒数字显示的计时装置，广泛运用于个人家庭、车站、码头、办公室等公共场所，成为了人们日常生活中必不可少的必需品，由于数字集成电路的发展和石英晶体振荡器的广泛运用，使得数字钟的精度，远远超过老式钟表。钟表的数字化给人们生活带来了极大的方便，而且大大地扩展了钟表原先的报警功能，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、自动开关路灯、定时开关烘箱、通断动力设备、甚至各种定时电气的自动启动等。所有这些，都是以时钟为基础的。因此，研究数字时钟具有非常的现实意义。 1.2系统总体方案介绍

本设计以核心控制芯片AT89C52为中心，外挂接美国DALLAS公司生产的DS12C887实时时钟芯片和DS18B20温度传感器装置，实时时钟为系统提供实时的时间。温度传感器为系统实时反馈当前环境下的温度。在大型公共场所，当不方便使用调时键盘直接调时时，红外遥控装置用于方便远距离调时。1602液晶实时的为MCU处理的数据进行显示。系统总框图如图1.2

1.2系统总框图

2方案论证

2.1时钟芯片的选择

方案一：采用单片机本身作为时钟控制芯片来模拟时钟时间。单片机在工作时，需要外接一个石英晶体振荡器来为单片机提供一个脉冲信号，振荡电路产生的振荡脉冲的频率为f（也可称为主频OSC），其并不直接使用，而是经过分频后为系统所用，振荡脉冲在片内通过一个时钟发生器二分频后才作为系统的时钟信号，时钟脉冲信号的频率为f2；时钟脉冲六分频后为机器周期，由此可见，一个机器周期的频率为f12，那么一个机器周期单片机执行一条指令，则每执行一条指令定时计数器数值加1；因此，利用单片机内部定时计数器可以实现秒脉冲信号，然后通过编程来模拟时钟。这种方案的好处是外围元器件少，电路简单清晰，设计方便易于实现，出问题的故障几率小。但是这种方案需由大量的程序来模拟时、分、秒、

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