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.
AR# 3585
Date 10/21/2008
Status Archive
Type General Article