说明：  做电子时钟的思路是直接用单片机的定时计数器，原理是利用单片机芯片的定时器来产生固定时间，模拟时钟的秒，分，时，在调节电子时钟时用了外部中断，当外部中断作用时，由主程序转移到中断程序，此时我们设置了三个按钮分别控制启动调节调节分钟和小时。在设置闹钟电路里，我们设置了参数，当设置的参数和闹钟走的数值相同时，小喇叭会发出警报声音。
(The idea is to make electronic clocks microcontroller timing counter directly, the principle is the use of single chip timer to generate a fixed time, analog clock seconds, minutes, hours, in the regulation of electronic clock with an external interrupt, when the role of the external interrupt , transferred from the main program to interrupt the program at this time we set up three buttons control the start osmotic adjustment minutes and hours. Set the alarm clock in the circuit, we set the parameters, when the set of parameters and values to go with the same alarm clock, small alarm horn will sound.)