用8位数码管组成显示电路提示信息，当输入密码时，只显示“8.”，当密码位数输入完毕按下确认键时，对输入的密码与设定的密码进行比较，若密码正确，则门开，此处用LED发光二极管亮一秒钟做为提示，同时发出“叮咚”声；若密码不正确，禁止按键输入3秒，同时发出“嘀、嘀”报警声；若在3秒之内仍有按键按下，则禁止 -With 8-bit digital tube display circuit message, when the input password, only shows "8.", When

从开关输入两个8位二进制数，求其和,用LED数码管显示结果-Enter the two 8-bit binary number from the switch, and seeking its display results with LED digital tube

设计一个8位数字频率计，频率测量范围10Hz到25MHz，测量精度为1Hz；并将测量结果用8个数码管显示。-Design an 8-bit digital frequency meter, frequency range 10Hz to 25MHz, measurement accuracy of 1Hz the measurement results with 8 digital display.