实现时钟程序，要求开始时DS1、DS2显示分钟，DS2的小数点亮，DS3、DS4显示秒，初始时都显示0；运行后DS4每隔一秒钟数字加1，加到10后变为0，DS3加1，DS3、DS4加到60后变为00，DS2加1；DS1、DS2加到60后，切换到小时状态：DS1、DS2显示小时，DS2的小数点亮，DS3、DS4显示分钟，DS4的小数点亮每隔一秒亮灭一次，亮灭分别30次后，DS4加1。-Realization clock procedure, request beginning hour DS1, DS2 manifestation minute, the decimal point of DS2 be bright, DS3, DS4 manifestation second, beginning start hour all manifestation 0 After circulate DS4 every 1 second numeral add 1, add 10 empress change into 0, the DS3 add 1, the DS3, DS4 change into after add to 6000, the DS2 add 1 The DS1, DS2 after add 60 cut over the appearance in hour:DS1, DS2 manifestation hour, the decimal point of DS2 be bright, DS3, DS4 manifestation minute, the decimal point of DS4 be bright each separate one bright put out once, bright after putting out difference 30 times, the DS4 add 1.