数电课程设计：电子时钟

设计一个数字电子钟,要求:

1. 时间以12或24小时为一个周期；

2. 正常显示时、分、秒；

3. 具有校时功能，可以分别对时及分进行单独校时，使其校正到标准时间；

4. 计时过程具有报时功能，当时间到达整点前10秒进行蜂鸣报时；

5. 为了保证计时的稳定及准确须由晶体振荡器提供表针时间基准信号。

6. 完成闹钟功能。

-Curriculum design for digital circuits: design of a digital electronic clock electronic clock, requires: 1. Time to 12 or 24 hours for a period　2. Normal display hours, minutes and seconds　3. Juyou timing function, respectively, and sub-time separate school, it corrected to standard time　4. timekeeping process has timekeeping function, the whole point when time reaches 10 seconds before the buzzer timekeeping　5. In order to ensure a stable and accurate timing by the time the crystal oscillator Biaozhen reference signal. 6. Complete the alarm clock function.