1) support PHASE_AND_DELAY + SHIFTREG feedback, which uses a 4x VCO multiplier behind the scenes
2) allow overriding clock constraints, just in case you like to live on the edge. my testing suggests that the 10 MHz F_pfd minimum is highly flexible, for example
1) support PHASE_AND_DELAY + SHIFTREG feedback, which uses a 4x VCO multiplier behind the scenes
2) allow overriding clock constraints, just in case you like to live on the edge. my testing suggests that the 10 MHz F_pfd minimum is highly flexible, for example