摘要:本文介绍了一种由AT89S51编程实现的控制电路，该系统由单片机系统、矩阵键盘(4×4)、LCD1602液晶显示屏和报警系统组成，具有按键提示、输入错误提示、超次锁定、密码有效指示、控制开锁、控制报警等功能。可以在意外泄密的情况下即使修改密码，具有保密性强、灵敏度高、适用范围广等优点。

关键词：AT89S51; 矩阵键盘; LCD液晶显示; 报警系统;

Abstract: This article describes a AT89S51 programming of the control circuit . The system consists of a single-chip system , martrix keyboard (4×4) , the LCD1602 display and alarm system . With push-button prompt , enter the error , subharmonic and ultra lock , the password is valid instructions , control lock , control , alarm and other functions . In the case of accidental leaks promptly change your password , with confidentiality , high sensitivity for a wide range . 　

Key words : AT89S51 ; matrix keyboard ; LCD liquid crystal display ; alarm system