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,