7.　　设计一个6位（时、分、秒显示）的电子钟，可以调整时间

8.　　可以控制用电器在设定的时间接通电源（打铃），一天中可以设定不少于20次的打铃时间，每次持续时间可以由程序设定

9.　　断电时可以保护电子钟走时正确，通电自动恢复正常工作

4. 要求电路用单片机来完成

-7. to design a six (hours, minutes and seconds display) of the electronic clock, you can adjust the time

8. can control the use of electrical power at a set time (a bell), the day can be set to ring a bell 20 times less than the time duration for each set by the program

9. power to protect the electronic clock when travel time is correct, power automatically resume normal operation

4. required to complete the circuit with a microcontroller