要求其实现的功能如下（其中定时要求采取中断方式）：

1、用6位数码管显示秒表时间，最左边2位显示分，中间2位显示秒，最右边2位显示秒的小数位（0.00~0.99秒），秒与小数位之间要显示小数点。

2、两个按键：

（1）计时/停止按键：首次按下从0开始计时，再次按下暂停计时，之后每次按下按键实现‘继续计时、暂停计时，继续计时、暂停计时……’。（继续计时即从上次暂停时的时间开始继续计时）

（2）复位按键：按下后全部清0，等待下次按下‘计时/停止按键’时重新开始计时。-Its implementation requires the following functions (which take interrupt timing requirements):

1, with 6 digital display stopwatch time display leftmost two points in the middle two seconds to display the rightmost two decimal places displayed in seconds (0.00 to 0.99 seconds), between the second and the number of decimal places to display the decimal point.

2, two buttons:

(1) Timing/Stop button: Press first start counting from 0, press the pause timer again, press the button after each realization　to continue timing, pause time, continue timing, pause timing ...... . (Continue counting starts continue counting from the time when the last pause)

(2) reset button: After pressing all cleared, waiting for the next time you press the　timer/stop button　re-start timing.