Ensure that all the
timing constraints for the core were properly incorporated and that all constraints were met
during implementation.
- Does it work in post-place and route timing simulation? If problems are seen in hardware but not in timing simulation, this could indicate a PCB issue. Ensure that all clock sources are active and clean.
- If using MMCMs in the design, ensure that all
MMCMs have obtained lock by monitoring the
locked
port. - If your outputs go to 0, check your licensing.