uchar haosec,sec,min,flag;
void key3scan()
{
		if(flag==1)
		{	
			flag=0;
			haosec++;
			if(haosec==100)
			{
				haosec=0;
				sec++;
				if(sec==60)
				{ 
					sec=0;
					min++;
					if(min==60)
					min=0;
					write_yr(0,min);
				}
			write_yr(3,sec);
			}
		write_yr(6,haosec);
		}

}