基于 AT89C51 单片机为核心的多路温度采集系统电路设计
目 录
1 课题的背景及其意义 ...................................................................................................................................4
1.1 本毕设主要内容 .........................................................................................................................................4
1.2.1 设计任务与要求 .....................................................................................................................................4
2 总体设计方案 ...............................................................................................................................................5
2.1 方案设计与论证 .........................................................................................................................................5
2.2 传感器部分 .................................................................................................................................................5
2.3 控制部分 .....................................................................................................................................................6
2.4 系统方案 .....................................................................................................................................................6
2.5 系统设计原理 .............................................................................................................................................7
3.1 单片机的选择 .............................................................................................................................................8
3.1.1 AT89C51 单片机的功能特点 ..................................................................................................................8
3.2 温度传感器的选择 ...................................................................................................................................10
3.2.1 DS18B20 的简介 ....................................................................................................................................11
3.2.3 DS18B20 内部结构 ................................................................................................................................12
4 硬件电路设计 .............................................................................................................................................16
4.1 电源............................................................................................................................................................16
4.1.1 电源电路 ...............................................................................................................................................16
4.2 功能按键 ....................................................................................................................................................17
4.2.1 按键电路 ................................................................................................................................................17
4.2.2 液晶显示电路 .......................................................................................................................................17
4.3 温度采集电路 ...........................................................................................................................................18
4.4 报警电路设计 ...........................................................................................................................................19
4.5 基于 AT89C51 简易转数测量系统复位电路...........................................................................................19
4.6 基于 AT89C52 简易转数测量系统时钟电路............................................................................................20
4.5 整体电路 ...................................................................................................................................................21
5 软件设计 .....................................................................................................................................................21
5.1 概述............................................................................................................................................................21
5.2 软件设计总流程 .......................................................................................................................................22
5.3 子程序设计 ...............................................................................................................................................24
5.3.1 初始化 LCD1602 ....................................................................................................................................24
5.4 按键扫描 ...................................................................................................................................................24
5.5 温度的设定子程序 ...................................................................................................................................25