Thank you very much! You provide a good test method.
I test 3 .hdl files in projects/03/a/test separately and they all function well.
I tested in another way:
In Projects/03/a, when Register.hdl is
Register test is OK, but RAM8 test failed.
and when I modify it to
in projects/03/a, Register and RAM8 are all OK.
It seems the problem is solved, but could you please explain the reason?? Why can't I use the built-in chip?