摘要:随着人们生活水平的提高，如何实现家庭防盗这一问题也变得尤为突出，传统的机械锁，由于其构造的简单，安全性能低，无法满足人们的需要。在科学技术不断发展的今天，电子密码防盗锁作为防盗卫士的作用显得日趋重要。本次设计是基于单片机的电子密码锁的设计，系统由STC89C52与低功耗CMOS型E²PROM AT24C02作为主控芯片与数据存储器单元，结合外围的键盘输入、LCD显示、报警、开锁等电路模块。它主要具备正确输入密码前提下开锁、错误输入密码情况下报警、密码可以根据用户需要更改等功能。本密码锁具有设计方法合理，简单易行，成本低，安全实用等特点，具有一定的推广价值。60531

毕业论文关键词： 电子密码锁，STC89C52，报警，液晶显示

Abstract:With the development of the people's living standard, how to achieve the family security is becoming important in particular. The traditional mechanical lock is unable to meet the people's needs because of its simple structure, low security. Nowadays, with the continuous development of the science and technology，Electronic password anti-theft lock plays a more important role as the security guards.The main paper is about the design electronic code lock based on the MCU. The system is composed with STC89C52, E²PROM AT24C02, data memory element and the peripheral circuits such as LCD display, alarming circuit. It can accomplish the following function: open the lock with a correctly password, give an alarm with the mistake password, change the password if the host want.The lock has some features like a reasonable design methods, simple to work, low cost and security. It also has some promotion value.

Key words:    Electronic code lock，STC89C52，Alarm，LCD display

1 绪论 4

1.1 课题背景 4

1.2 课题设计目标 4

2 系统方案论证 5

2.1 主控部分的选择 5

2.2 密码输入方式的选择 5

3 系统总体设计和主要芯片介绍 6

3.1 系统总体设计 6

3.2 主要芯片介绍 6

3.2.1 STC89C52 6

3.2.2 存储芯片AT24C02 8

3.2.3 LCD1602显示器 9

4 硬件设计 10

4.1  键盘输入模块 10

4.2  密码存储模块 11

4.3  复位部分 12

4.4  晶振部分 12

4.5  显示模块 13

4.6  报警部分 13

4.7  开锁部分 14

5 系统软件设计 15

5.1 系统程序流程图 15

5.1.1 主程序流程图 15

5.1.2 键功能程序流程图 15

5.1.3 开锁程序流程图 16

5.2 子程序举例 17

5.2.1 开锁子程序 17

5.2.2 按键扫描子程序 19

5.2.3 密修改码子程序 21