1、程序目的：使用定时器学习秒表计时，中断0控制走表，中断1控制清零

　　　　　　 2、硬件要求：数码管、晶振12M

　　　　　　 功能，按S19，数码管秒表开始计时，再按S19，数码管暂停。-1, the purpose of the program: use learning stopwatch, timer interrupt 0 control table, 1 control reset interrupt 2, hardware requirements, digital tube, vibration crystal 12 m Function, according to the S19, digital tube stopwatch timing starts, then S19, digital tube suspension.