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Registered: ‎01-26-2010

IP reuse - experiences?



Does anyone have experience of IP reuse in PlanAhead? I am using 11.4.


Basically, I want to replicate the behaviour of RPMs, but using PlanAhead. The PlanAhead Methodology Guide says "We recommend the using LOC flow. There are more issues with re-using a block created in the RPM flow."


So, I used PlanAhead's 'Export IP' to create an EDIF and UCF for the IP. I then created a design in which there are two 'black box' instances of the IP block. I imported the constraints for the first instance, moved the Pblock and then imported the constraints for the second instance. This is fine, but you have to decide where the Pblocks are located. Is there a way to let the tools keep the shape, but have the freedom to place the IP anywhere, like with 'traditional' RPMs?


Incidentally, the PlanAhead training course tells you to 'Unfix Instances' before moving the first IP block. Why is this? Don't you lose the placement by doing so?


I also experimented with using 'Export IP' to create an RPM. However, this doesn't seem to work when there are two instances of the IP, as you end up with duplicated constraints (The exported UCF uses HU_SET). The fix here is to create a separate UCF for each instance, changing the name of the HU_SET. Is this the correct approach?


Thanks for reading! I would be very grateful for any response.


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