利用keil c去實現一個小時鐘

*動作：由四位數七段顯示器顯示電子鐘的分及秒時間值

*接線：Data=七段顯示器低電位輸出=Pgfedcba

* 低電位掃描：S3~0=千、百、十、個位數

*硬體：SW1-1(SEG7)ON-Use keil c to achieve a small clock

* Action: the four-digit seven-segment display electronic clock minutes, and seconds time value

* Wiring: Data = seven segment display lower potential output = Pgfedcba

* Low potential sweep: S3 ~ 0 = one thousand, one hundred, ten, single-digit

* Hardware: SW1-1 (SEG7) ON