一个简单的基于赛灵思公司的nexys3的秒表计时器。能够实现计时的开始、暂停、复位、切换显示百分秒。无需连接任何其他的硬件。-Based on a simple Xilinx nexys3 stopwatch timer. Start timing can be achieved, pause, reset, switch the display percentile seconds. Without connecting any additional hardware.