通过本例程了解 DS1302时钟芯片的基本原理和使用 ,理解并掌握DS1302时钟芯片，驱动程序的编写以及实现数字字符在数码管中的显示-By understanding the basic principles and the routine use DS1302 clock chip, understand and master the written DS1302 clock chip, the driver and the digital characters in the digital tube display