Guys, I'm using ISE 7.1.04i . In PAR I get this error:-
ERROR:Par:228 - At least one timing constraint is impossible to meet because component delays alone exceed the constraint. A physical timing constraint summary follows. This summary will show a MINIMUM net delay for the paths. The "Actual" delays listed in this summary are the UNROUTED delays with a
100ps timing budget for each route, NOT the achieved timing. However, it's only failing because the tool thinks there's 100ps delay between each element in the carry chains. So, for a 32 bit carry chain the damn thing's subtracting 3.2ns from my timing budget. ISTR having this problem before and fixing it, can anyone remind me, Google couldn't.
Similar stuff in another project is fine.
TIA, Syms.