河南科技大学本科毕业设计（论文）
DS18B20数字温度计的设计
摘 要
温度是一种最基本的环境参数，人们生活与环境温度息息相关，在工业生产过程中需要实时测量温度，在工业生产中也离不开温度的测量，因此研究温度的测量方法和控制具有重要的意义。
本论文介绍了一种以单片机为主要控制器件，以DS18B20为温度传感器的新型数字温度计。主要包括硬件电路的设计和系统程序的设计。硬件电路主要包括主控制器，测温控制电路和显示电路等，主控制器采用单片机AT89C52，温度传感器采用美国DALLAS半导体公司生产的DS18B20，显示电路采用8位共阴极LED数码管，ULN2803A为驱动的动态扫描直读显示。测温控制电路由温度传感器和预置温度值比较报警电路组成，当实际测量温度值大于预置温度值时，发出报警信号，即发光二极管亮。系统程序主要包括主程序，测温子程序和显示子程序等。DS18B20新型单总线数字温度传感器是DALLAS 公司生产的单线数字温度传感器, 集温度测量和 A /D转换于一体 ,直接输出数字量,具有接口简单、精度高、抗干扰能力强、工作稳定可靠等特点。
由于采用了改进型智能温度传感器DS18B20作为检测元件，与传统的温度计相比,本数字温度计减少了外部的硬件电路，具有低成本和易使用的特点。DS18B20温度计还可以在高温报警、远距离多点测温控制等方面进行应用开发，具有很好的发展前景。此外，还介绍了系统的调试和性能分析。
关键词：显示电路,单片机，AT89C52，温度传感器，DS18B20 ,单总线
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河南科技大学本科毕业设计（论文）
The Design of DS18B20 Digit Thermometer
ABSTRACT
Temperature is a basic parameters of the environment, people's lives and the environment are closely related to temperature. in the course of industrial production immediate need for temperature measurement in industrial production has to do with temperature measurement, The study of the temperature measurement and control is of great significance.
The paper introduced one kind new digital thermometer that take the Micro Controller Unit as the primary control component and take DS18B20 as the temperature sensor. Mainly included the design of the hardware electric circuit and the design of the system program .The hardware electric circuit mainly included the master controller, the temperature measured electric circuit and the display circuit and so on, the master controller used Micro Controller Unit AT89C52, the temperature sensor used DS18B20 which the American DALLAS semiconductor company produces, the display circuit used 8 altogether anodes LED numerical code tube by the dynamic scanning method straight to read the demonstration.ULN2803A-driven
dynamic
scan
showed
straight
time.
Temperature control circuit from temperature sensors and preset temperature value compared alarm circuit components, When measured temperature greater than preset temperature value, issued warning signal that the bright light emitting diodes. The system program mainly included the master routine, the temperature subroutine, the data renovates subroutine and so on. DS18B20 is a digital temperature sensor of single bus .It is producted by DALLAS cooperation . DS18B20 assembles temperature measure and A /D converter, exports digital signal directly, operation easily, better precise, protecting disturb, running steably and so on.
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河南科技大学本科毕业设计（论文）
Because used the advanced version intelligence temperature sensor
DS18B20 as the examine part, compared with the traditional thermometer, this digital thermometer reduced the exterior hardware electric circuit, has characteristic that the low cost and was easy to use. The DS18B20 thermometer also may used to the high temperature warning, the long-distance range multi- spots temperature measured aspect and so on temperature control carries on the application development, has the very good prospects for development. In addition, introduced the system debugging and the performance analysis.
KEY WORDS: Display Circuit, Microcontroller Unit , AT89C52,
Temperature Sensor, DS18B20，1-Wire
III
河南科技大学本科毕业设计（论文）
目 录
前 言 .................................................................................................. 1 第1章 设计任务及方案分析............................................................. 2
§1.1 设计任务及要求 ................................................................. 2 §1.2 设计总体方案及方案论证.................................................. 2 §1.3 温度测量的方案与分析 ..................................................... 2
§1.3.1 芯片选择 .................................................................... 2 §1.3.2 实现方法简介............................................................. 3 §1.3.3 测温流程图................................................................. 3
第2章 芯片功能简介 ........................................................................ 4
§2.1 AT89C52的功能简介 .......................................................... 4
§2.1.1 AT89C52芯片简介 ..................................................... 4 §2.1.2 引脚功能说明............................................................. 4 §2.2 DS18B20的功能简介 .......................................................... 7
§2.2.1 芯片简介 .................................................................... 7 §2.2.2 DS18B20外形和内部结构 ......................................... 8 §2.2.3 DS18B20的工作时序 ............................................... 11 §2.2.4 DS18B20与单片机的典型接口设计 ....................... 12 §2.2.5 DS18B20的各个ROM命令 .................................... 13
第3章 系统硬件电路的设计........................................................... 15
§3.1 主控制电路和测温控制电路原理图................................ 15 §3.2 驱动电路模块原理图 ....................................................... 16 §3.3 显示模块原理图 ............................................................... 17 第4章 软件编程调试及性能分析................................................... 18
§4.1 主程序流程图 ................................................................... 18 §4.2 主程序 ............................................................................... 19 §4.3 温度子程序 ....................................................................... 21
§4.3.1 DS18B20复位子程序 ............................................... 22
IV
河南科技大学本科毕业设计（论文）
§4.3.2 读DS18B20子程序 ................................................. 23 §4.3.3 写DS18B20子程序 ................................................. 25 §4.3.4 比较报警子程序....................................................... 26 §4.3.5 按键子程序............................................................... 27 §4.4 显示子程序 ....................................................................... 27 §4.5 调试性能分析和注意事项................................................ 29
§4.5.1 调试性能分析........................................................... 29 §4.5.2 DS18B20使用中的注意事项 ................................... 30
结 论 ................................................................................................ 31 参考文献 ............................................................................................ 32 致 谢 ................................................................................................ 33 附 录 ................................................................................................ 34
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