03-06-2009 06:58 PM
when I set the offset in constraints, no matter how much I set the value is, at last, the timing analyzer will ignore the constraints, why? when set the "offset in" constraints, what need to consider more than "offset out" constaints?
03-08-2009 07:23 AM
Two things: 1. the reference clock needs to come from an external clock input. 2. the clock used to register the input can be traced back to the reference clock input (via DCM, PLL, BUFG, etc).
03-10-2009 07:46 AM
03-31-2009 01:43 AM