Assignment Recommendation
Start with device and pin assignments. Beware, your pin assignments might affect performance. Ideally, you should let MAX+PLUS II choose the pin assignments. If you have pin assignments, you might want to compile your design once without your pin assignments to see if they affect your performance.
Compile design. Check device utilization and performance.
If you need to adjust device utilization or performance try the other assignments. Try the synthesis style assignments first.
Assignments can only be made to “hard” nodes or lower-level designs that contains hard nodes. Hard nodes are objects that translate directly into objects in silicon e.g. Flip-flops, LCELLs and I/O pins