AR# 3585: M1 PAR: Is there a way to prevent route-thrus?
AR# 3585
M1 PAR: Is there a way to prevent route-thrus?
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 potential 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.
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.