I am working in a digital design. The functional, post synthesis and post P&R without IO pads are all working fine, i.e., functionally and with clean timing reports "no setup/hold violations". I just added the IO pads to the same design, I had to change the timing constraints a bit for the synthesis but I have a clean design at SOC Encounter, i.e., clean DRC and clean timing reports "no setup/hold violations". However, when I perform simulation using the exported net-list from SOC Encounter together with SDF exported from the same tool, I got a lot of hold violations. Consequently, the design is not funcitioning.
Why and how I can overcome or trobleshoot this issue?
In waiting for your feedback and comments.