Occasional Contributor
Super Contributor1) Yes. The routing region extends around the placement region. Usually you set the size of it to be just 1 block larger than the placement region (fixed with expansion = 1).
2) Reserved routing is not inferred. As the option says, if that's turned off, the Fitter is free to place other design logic in the routing region. Turning it on prevents that from happening, making the region boundary completely prevent outside logic from being placed in there. If it's taking you that much longer to compile, your region placement perhaps is blocking access to certain resources needed for the rest of the design. Hard to tell.
3) Yes, routing for the static region can still go through the PR region. I don't think it's possible to prevent this. It would potentially add a lot of extra delay to route around a region.
Occasional ContributorThanks to the reply. 1) and 3) are resolved.
2) Yes, I understand what the option says. But let's say that we create the exact same size of Route region as Place region(fixed with expansion = 0). Then, if "Reserved Placement" setting is on, it prevents the outside logic from being placed in the Place region, and because Place region is the same as Route region, it prevents the outside logic from being placed in the Route region too. This is why I assume that if they are equal-sized, "Reserved Routing" is inferred from "Reserved Placement."
However, in the experiment that I have the same Place region and Route region, "Reserved Routing" seems to do something different. Based on the option description, it should do the exact same thing as "Reserved Placement" in this case. My guess is that it might do something similar to my question on 3)... For instance, "Reserved Routing" may be the option to prevent static routing to use routing resources in the PR region?
Super ContributorHmm, that reserved routing option is relatively new (I haven't done much PR stuff since 2020 so I know this option wasn't there back then) and I haven't played with it so you may be right. Maybe the description is supposed to say "Prevent Fitter from placing non-member *routing* in routing region".
Occasional ContributorYeah, something like that... I am not sure. But thanks a lot!!
