Error: Can't generate netlist output files because the file "<file name>" is an OpenCore Plus time-limited file
查遍了QuartusII的help也没有找到答案，于是到了http://www.altera.com/support/kdb/solutions/rd03232011_903.html去寻找解决方法
解决的方法是：
Description
You will get this error message when trying to generate IBIS models in the Quartus® II software when you have an un-licensed OpenCore Megafunction in your design.
To get around this, you can remove the un-licensed OpenCore Megafunction from your design and generate the IBIS models. Or you can fully license the OpenCore Megafunction.
This is scheduled to be fixed in a future version of the Quartus II software.