Honored Contributor
Honored ContributorRegarding the second question, it's a VHDL string constant. Cause VHDL strings aren't directly synthesizable (at best, they may be casted to a synthesizable type in some cases), they are mainly used as generics with parameterizable components and in simulation.
--- Quote Start --- Why there is error in version 7.1 and no error in version 8.0? Just wonder.. --- Quote End --- Cause I wasn't able to validate the error from the presented code, I can just guess. It may be the case, that the said buffer port isn't driven in the component (so, it isn't actually an output) and that the Quartus behaviour was changed in this respect. I remember some oddities with inconsistent defined buffer ports with previous Quartus versions. The issue can be verified only by interrogating the component code.
