I can't find any specification for absolute frequency / jitter / etc for the CLKUSR input (other than it shall be 100MHz). Looking at options for removing emissions @ 100MHz that appears to be related to crystal oscillator. Figure that spread spectrum clock would help, but don't know for sure if A10 input can handle it. I believe that this CLKUSR simply runs state machines / PreSICE, so don't believe it needs to be super accurate, but want to confirm.
Any help would be appreciated.
I had checked there, but doesn't appear to give me any insight into the frequency accuracy of the 100MHz clock. If I use spread-spectrum and the center spread is 98-102MHz, will that violate timing or anything else related to CLKUSR functionality? It calls out that it needs a "stable" clock, but it doesn't say how stable it needs to be. That is what I'm looking for (freq accuracy + jitter specs).