1 引 言 ········································································································· 1
1.1 课题研究背景 ···························································································· 1
1.2 课题研究内容 ···························································································· 1
2 系统方案设计 ······························································································ 1
2.1 方案一 ····································································································· 1
2.2 方案二 ····································································································· 1
2.3 方案选择 ·································································································· 2
3 系统硬件电路 ······························································································ 2
3.1 89C51 单片机简介······················································································· 2
3.1.1 89C51 单片机的内部结构 ··········································································· 2
3.1.2 89C51 单片机的引脚说明 ··········································································· 3
3.2 数字温度传感器 DS18B20 介绍 ····································································· 5
3.2.1 DS18B20 的基本特性················································································· 5
3.2.2 DS18B20 的内部结构················································································· 6
3.2.3 DS18B20 的电源供电方式··········································································· 8
3.3 系统框图 ·································································································· 8
3.4 水位显示电路设计 ······················································································ 8
3.4.1 水位检测电路·························································································· 9
3.4.2 水位显示电路图····················································································· 10
3.5 水温显示电路设计 ···················································································· 10
3.5.1 LED 数码管显示器的构造及特点 ······························································· 10
3.5.2 LED 数码管显示器的基本原理 ···································································11
3.5.3 LED 数码管显示器的显示方法 ·································································· 12
3.5.4 水温显示电路图····················································································· 13
3.6 蜂鸣器电路 ····························································································· 13
4 系统软件设计 ···························································································· 14
4.1 主程序图 ································································································ 14
4.2 水位控制程序图 ······················································································· 15
4.3 水温控制程序图 ······················································································· 15
