论文总字数：23377字

摘 要

由于科技的进步，单片机已普及到生活的方方面面。温度计在生活和其他领域，是最普通和最重要的测量仪表，占据生活和工作的重要地位。传统温度敏感元件将温度信号转化为电信号，然后经过模数转化电路，转换为数字信号，而DS18B20直接输出数字信号，无需放大电路和AD转换电路。它像一只三极管，传感元件和转换电路都在其内部的电路中。它与单片机的接口是一条线，电路设计简单，成本低，测量精度高。控制器将处理后的温度送给显示电路显示，可以实现温度的及时显示，可以在程序中任意设置上下限报警温度，随着温度的实时更新，用液晶屏显示温度变化曲线。

此次设计，用PROTUES仿真软件，设计并绘制硬件电路图，用C语言设计相关软件编程，达到仿真的结果。基于AT89C51的数字温度计设计，设计电路简单，无论在多么艰苦的环境下，都不会影响它正常的工作，具有广阔的发展空间。这次数字温度计的设计，一方面它的测量范围很广，设计电路简单，易于实现，且用到的元器件，都很普遍，价格低廉，精度很高，设计的实物很小，便于携带。另一方面能够显示温度变化曲线，及时监测温度的变化情况，若用到工业生产中，可以了解温度变化的趋势，及时采取控制措施，防止生产影响产品的质量。

关键字：数字温度计 AT89C51 DS18B20温度传感器 PROTUES

Design and Realization of Digital Thermometer

Abstract

With the progress of science and technology, microcontroller has become popular in all aspects of life. Thermometer is the most common and most important measuring instruments in life and other fields, which occupy the important position in life and work. The temperature signal is converted into electric signal by the traditional temperature sensing element and then converted to digital signal through the analog digital conversion circuit, however the DS18B20 output digital signal directly without the need of amplification circuit and AD conversion circuit. It is like a three transistor, sensing element and the conversion circuit in its internal circuit. The interface of the single chip microcomputer is a line, the circuit design is simple, the cost is low, and the measurement precision is high. The controller sends the processed temperature to the display circuit, which can realize the temperature timely display and can arbitrarily set up in the program alarm temperature, with the temperature of real-time updates, with the LCD screen display temperature change curve.

Using PROTUES simulation software, design and draw the hardware circuit diagram, using C language design software programming, to achieve the results of the simulation in the design. AT89C51 has a broad space for development based digital thermometer design, the design of the circuit is simple, will not affect its normal work no matter how hard the environment. The design of the digital thermometer, on the one hand, its measuring range is very wide, design of the circuit is simple, easy to implement, and the use of components that are common to all, low price, high precision, physical design is small, easy to carry. On the other hand to show the change curve of temperature and timely monitoring of changes in temperature, if used in the industrial production can understand the trend of temperature change, to take timely measures to control and prevent production affect the product quality.

Key Words：Digital thermometer;AT89C51;DS18B20 temperature sensor; PROTUES

目 录

摘 要 I

ABSTRACT II

第一章 绪论 1

1.1课题背景 1

1.2数字温度计的发展史 1

1.3课题研究的目的和意义 2

第二章 温度传感器 4

2.1 温度传感器的发展趋势 4

2.2温度传感器的分类 4

2.3 DS18B20数字温度传感器 5

2.3.1 DS18B20的简介 5

2.3.2 DS18B20内部结构 6

2.4 DS18B20测温原理 9

第三章 硬件电路设计 11

3.1AT89C51单片机 11

3.1.1简介 11

3.1.2封装与引脚功能 11

3.1.3 AT89C51的内部结构和主要特性 13

3.1.4 AT89C51芯片擦除 14

3.2单片机控制部分 15

3.2.1晶振电路 15

3.2.2复位电路 15

3.2.3报警电路 16

3.3 DS18B20硬件电路部分 16

3.4 数码管显示部分 17

3.5 LCD液晶屏显示部分 18

3.6 硬件PCB图和3D图 19

第四章 软件程序设计 23

4.1 主程序 23

4.2 各子程序 24

4.2.1初始化子程序 24

4.2.2 读取温度子程序 25

4.2.3 温度转换子程序 25

4.2.4 报警子程序 26

第五章 Proteus仿真与实现 28

5.1 Proteus虚拟仿真过程 28

5.1.1 集成环境ISIS 28

5.1.2绘制原理图 28

5.2仿真结果 31

第六章 设计总结 35

参考文献 36

致谢 38

附录 39

第一章 绪论

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