设计的是一个保险柜的数字锁控制电路。首先最主要的问题是安全，也就是开锁的密码被破译的可能性要尽可能小；其次是操作方便，开锁的程序不过于复杂。此外还有一些特殊要求，例如可预置和更改密码，多次输入错误密码应启动报警系统，使用者在拨错号码时可将原拨号码清除重拨，段码显示等。-Design is a digital safe lock control circuit. First, the main problem is security, that is unlocking the password is likely to crack as small as possible　followed by ease of operation, unlocking procedure but in the complex. There are also some special requirements, such as preset and change the password, enter the wrong password several times should start alarm system, the user dialed the wrong number dial the number when the original clear redial, segment display, etc..