Answers Database

M1 PAR: Is there a way to prevent route-thrus?


Record #3585

Product Family:  Software

Product Line:  Merged Core

Problem Title:
M1 PAR:	Is there a way to prevent route-thrus?


Problem Description:
Keywords: par, route-thru, route-through,

Urgency: standard

General Description:
Is there a way to prevent route-thrus?

There is no command line option to prevent PAR from generating
route-thrus.  However there are a couple of things you can
try, depending on the situation.


Solution 1:

Map the logic explicitly using FMAPs, HMAPs, and location
constraints.

If all combinational logic and I/O are explicitly constrained, there is less pot
ential for generating route-thrus.

If you can pinpoint the logic associated with the route-thru,
you may be able to do this on a more limited subset of the
logic.




Solution 2:

If you observe *bonded* IOBs being used as route-thrus, this
would be a bug in the software.

For XC3000 or XC5200 designs, there is a PAR patch that
corrects the problem.



End of Record #3585