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沈阳理工大学学士学位论文

摘 要

摘要:在日常生活及工业生产过程中，经常要用到温度的检测及控制，温度是生产过程和科学实验中普遍而且重要的物理参数之一。传统的测温元件有热电偶和二电阻。而热电偶和热电阻测出的一般都是电压，再转换成对应的温度，这些方法相对比较复杂，需要比较多的外部硬件支持。我们用一种相对比较简单的方式来测量。

采用美国DALLAS半导体公司推出的一种改进型智能温度传感器DS18B20作为检测元件，温度范围为-55~125 oC,最高分辨率可达0.0625 oC。DS18B20可以直接读出被测温度值，而且采用三线制与单片机相连，减少了外部的硬件电路，具有低成本和易使用的特点。

基于STC89C52单片机的温度测量及报警电路,电路采用DS18B20作为温度监测元件，测量范围0℃-～50℃，使用LCD模块显示，能设置温度报警上下限。着重介绍软硬件系统的各部分电路，介绍了集成温度传感器DS18B20的原理，STC89C52单片机功能和应用。该电路设计新颖、功能强大、结构简单。

关键词：温度测量 报警 DS18B20 STC89C52

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沈阳理工大学学士学位论文

Abstract

Abstract：In daily life and industrial production process, often used in the detection and control of temperature, temperature is the production process and scientific experiments in general and one of the important physical parameter. Traditional thermocouple and temperature components are the second resistor. The thermocouple and thermal resistance are generally measured voltage, and then replaced by the corresponding temperature, these methods are relatively complex, requiring a relatively large number of external hardware support. We use a relatively simple way to measure.

Use the United States following DALLAS Semiconductor DS1820 improved after the introduction of a smart temperature sensor DS18B20 as the detection element, a temperature range of -55 o C ~ 125 o C, up to a maximum resolution of 0.0625 o C. DS18B20 can be directly read out the temperature on the north side, and three-wire system with single-chip connected to a decrease of the external hardware circuit, with low-cost and easy use.

The introduction of a cost-based STC89C52 MCU a temperature measurement circuits, the circuits used DS18B20 high-precision temperature sensor, measuring scope 0 o C～+100 o C, can set the warning limitation, the use of seven segments LCD that can be display the current temperature. The paper focuses on providing a software and hardware system components circuit, introduced the theory of DS18B20, the functions and applications of AT89C51 .This circuit design innovative, powerful, can be expansionary strong.

Key words: Temperature measurement warning DS18B20 STC89C52

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沈阳理工大学学士学位论文

目 录

1 绪论………………………………………………………………………………………1 1.1 引言……………………………………………………………………………………1 1.2 设计内容及要求............................................................................................................1 1.3主体的部分……………………………………………………………….2 2 AT89S52单片机介绍及应用………………………………………………………………4 2.1 AT89S52的主要功能………………………………………………………………….4 2.2 引脚结构及说明………………………………………………………………………5 2.2.1方框图…………………………………………………………………………….6 2.2.2 引脚说明…………………………………………………………………………7 2.3 特殊功能寄存器……………………………………………………………………10 2.4 存储器结构..................................................................................................................13 2.5 软件看门狗及串口…………………………………………………………………14 2.5.1 WDT的使用………………………………………………………………………..14 2.5.2 掉电和空闲方式下的WDT……………………………………………………..15 2.5.3 定时器2………………………………………………………………………..15 2.6 其他功能介绍………………………………………………………………………16 3 系统软件的设计................................................................................................................23 3.1 程序设计语言………………………………………………………………………..23 3.2 主程序………………………………………………………………………………..23 3.3 显示子程序…………………………………………………………………………..24 3.4 定时器T0中断服务程序……………………………………………………………25 3.5 T1中断服务程序……………………………………………………………………..25 3.6 调时功能程序……………………………………………………………………….25 3.7 时钟/秒表功能程序…………………………………………………………………25 4 硬件电路的操作和显示……………………………………………………………….26 4.1 硬件工作过程………………………………………………………………………26 4.2 LED的性能特点………………………………………………………………….27 5 其他外围电路设计………………………………………………………….28

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