说明：  虽然FPGA实现并口输出是一个最简单的，但还是考虑用parameter的参数化方法来配置，这样在使用多个并口时，可以配置并口的宽度和并口的地址，应该更加方便。
(Although FPGA parallel output is one of the most simple thing, but still consider using the parametric method to configure it, so that the use of multiple parallel port, parallel port can be configured the width of the parallel and the port address. It could be more convenient.)