UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 13177

4.1i Virtex-II MAP - Packer creates shapes that are inconsistent with carry logic placement, leading to unroutes and "WARNING:Place:1855"

Description

Keywords: WARNING:Place:1855, carry, unrouted, unroutable

Urgency: Standard

General Description:
MAP is creating shapes that made it impossible for the placer to align the carry chain involved. This leads to the following warning from the placer:

"WARNING:Place:1855 - The structured logic associated with a carry chain could not be placed in such a way as to use all of the fast carry connections due to a placement constraint. A sub optimal placement will be performed. You may wish to verify that the sub-optimal placement will be satisfactory."

Solution

This problem is fixed in the latest 4.1i Service Pack, available at:
http://support.xilinx.com/support/techsup/sw_updates.
The first service pack containing the fix is 4.1i Service Pack 3.
AR# 13177
Date Created 11/13/2001
Last Updated 08/20/2003
Status Archive
Type General Article