摘要：随着电子产品向智能化和微型化的不断发展，单片机已成为电子产品研制和开发中首选的控制器。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的尤其的突出，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。

　　本文从经济实用的角度出发，采用美国Atmel公司的单片机STC89C52RC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、显示、报警、开锁等电路，用汇编语言编写主控芯片的控制程序，设计了一款可以多次更改密码具有报警功能的电子密码锁。

　　经实验证明，该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，符合住宅、办公室用锁要求，具有推广价值。

关键词：密码锁    单片机    报警

Abstract：As electronic products are developing towards intelligence and minimization, single—chip computers (SCM ) have become the first choice for controllers in the development of electronic products. With the improvement of people's living standards, it has become particularly prominent about how to achieve Anti-theft family. [11]The traditional mechanical lock has such shortcoming as simple structure , Low security, it can't meet people's demands.

　　For practicality, this paper designs a new electronic cipher lock, which has the function of alarm and whose cipher can be changed many times. This cipher lock uses STC89C52RC SCM and E2PROM AT24C02 as main chip and data memory cell . The author made this ciphor lock by use of making controlled program of master CMOS with periphery electrocircuit of keyboard input, display, alarm and unlock.

　　Experiments show that the designed cipher lock is characterized by its reasonable designing methods, simple operation, low cost and property of safety and practicality．Besides，it works well as a residence lock and has great potential for commercial development．

Key words:  Cipher lock    SCM    Alarm