怎样去设计一种基于单片机的数字时钟系统

#include  #define uchar unsigned char#define uint  unsigned intuchar sec = 6, min = 6, hou = 6, a = 0, b = 0, c = 0;uchar num = 0, cmd = 0;uint time = 0;uint flag = 0; ***it P30 = P3^0;***it P35 = P3^5;***it P32 = P3^2;