1－wire总线在MCS51环境下的研究与开发

1－wire总线在MCS51环境下的研究与开发

文档编号:ZD230 文档字数:14664,页数:42

摘要

本文档主要研究美国DALLAS公司推出的单总线（即1—wire总线）技术的原理和信号传输方式，说明了单总线通信协议，并且对1—wire总线在MCS51环境下的实现机制作进一步研究。
单总线即只有一根数据线，系统中的数据交换、控制都由这根线完成。设备通过一个漏极开路或三态端口连至该数据线，以允许设备在不发送数据时能够释放总线，而让其它设备使用总线。
单线总线是众多现场总线中极具竞争力的一种。它具备能与计算机进行数字通讯、总线负载量大、布线简单、精度高、性能稳定、价格便宜等多方面优点。单总线控制的真正优势在于：作为信号源，无需考虑如何解决通讯协议问题；在绝大多数场合，不用考虑总线上连接的传感器数量；在大多数场合甚至不需另外提供电源。它的最大好处就是让用户更方便。
针对1—wire总线技术特点，应用1—wire器件数字温度传感器DS18B20，在MCS51单片机环境下组成一个温度测量系统。

关键词：1—wire；单片机；DS18B20

Study On the One－wire bus under the environment of MCS51

Abstract
This thesis mainly studies single and total line( namely total line of One- wire) technical principle and signals that the American company of DALLAS release to deliver the way, explaining the single and total line correspondence agreement, and to the total line of One- wire under the environment of MCS51 of carry out the mechanism to make the further research.
The total line of single line is a kind that has the competition ability very much in numerous lines with total the spot. It has and can carry on numerical communication, the total line load's have great capacity with calculator, cloth line JIAN3 LIAN4, accuracy is high, function stability, price cheapness etc. various advantage. It is deluxe state of the industry the spot system design. The real advantage of a glimmer of control lie in: Be the signal source, did not need to be consider how resolve the communication agreement problem; At the great majority situation, need not consideration spread of total and on-line conjunction feeling machine quantity; Even don't need to provide another power supply in most situations. Its biggest advantage is to make the customer more convenient.
Aim at the One- wire total line technique characteristics, apply the One- wire machine number of items word temperature to spread the feeling machine DS18B20, constitute a temperature to measure the system under a machine of MCS51 environment.

Key words: One—wire ； MCU；DS18B20

目录
摘要 ………………………………………………………………………………………Ⅰ
Abstract …………………………………………………………………………………Ⅱ
第1章绪论 ……………………………………………………………………………1
第2章 1－wire总线技术及其应用 ……………………………………………………4
2.1 1－wire总线的工作原理 ………………………………………………………4
2.2 1－wire总线的信号传送方式 …………………………………………………5
2.3 单总线器件介绍 ………………………………………………………………9
第3 章基于DS18B20的温度检测系统的设计 …………………………………………11
3.1 单总线数字温度传感器DS18B20 ………………………………………………12
3.1.1 概述 ………………………………………………………………………12
3.1.2 DS18B20特性简介 …………………………………………………………12
3.1.3 DS18B20的硬件结构 ………………………………………………………13
3.1.4 DS18B20 的电源供电方 …………………………………………………16
3.1.5 DS18B20的测温原理 ………………………………………………………17
3.1.6 DS18B20与主机之间的通信协议 …………………………………………18
3.2 DS18B20与单片机的典型接口设计 …………………………………………21
3.3测温系统的软件设计 …………………………………………………………21
3.3.1 DS18B20 的底层基本操作程序 …………………………………………21
3.3.2 DS18B20 的设备序列号的扫描 …………………………………………25
3.3.3 DS18B20的精确延时问题 …………………………………………………25
3.4 DS18B20设计中应注意的几个问题 ……………………………………………26
结束语 ……………………………………………………………………………………27
参考文献 …………………………………………………………………………………28
致谢 ………………………………………………………………………………………29
附录1测温系统主要芯片介绍……………………………………………………………30
附录2温度检测源程序清单………………………………………………………………36

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