verilog　初学者原代码，万事开头难，ＣＰＬＤ也如此，第一个成功的代码测试往往后续学习的信心。需要的朋友请进-beginners verilog source code, everything is hard in the beginning, CPLD is also the case, the first successful test of the code is often the confidence of the follow-up study. Come friend in n