--- Quote Start ---
That being said, I strongly recommend against adding the false paths. They don't help in any way and can only hurt. Let's go back to the same edge transfer example.
--- Quote End ---
Altera documentation clearly states that the default DDR behaviour of TimeQuest is that each launch edge is checked against the two latch edges. and that you must set false paths on irrelevant edges. There are plenty diagrams on that in document "source synchronous interfaces".
This default behaviour is internal to the tool just like asynchronous clocks are assumed related unless you set otherwise. Obviously this is safe behaviour and in case of DDR the tool doesn't know which edge you are latching.
As to the OP may Vlrean meant how to decide? That is matter of design. you can choose to capture same edge or opposite edges. When doing so you must take account of data order (odd/even).
Honored Contributor
