密码锁设计。

4*4键盘（0-9、清除，输入、更改），一个独立键，用于系统复位，密码掉电保存。

用LCD显示，密码用*显示，要求六位密码。

A：更改时提示“输入原密码：”要求两次；正确后，要求给出提示：输入新密码,此操作也为2次，如果输入不合法（少于6位），提示更改不成功。

B，输入时，如果连续三次不成功，蜂鸣器报警，并锁定键盘。不能出入，直到复位；

密码输入成功是，从一个端口输出1，同时给出一小段音乐。（2人）-Password lock design. 4* 4 keypad (0-9, clear, entered, changed), a separate button for system reset, password-down save. With LCD display, display the password using the* required six passwords. A: When you change the prompt " Enter the old password:"　requires twice　correctly, required to give prompt: Enter the new password, this operation is also 2 times, if you enter invalid (less than 6), suggesting that change is unsuccessful. B, input, three consecutive unsuccessful, buzzer alarm and lock the keypad. Not out until reset　password is entered successfully, the output from a port 1, and gives a short music. (2)