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AR# 9344

3.1i Virtex MAP - Some eligible registers are not being packed into IOBs.

Description

Keywords: registers, flops, FFs, -pr ,IOB=TRUE, IOB

Urgency: Standard

General Description:
A case has been seen where 3.1i MAP, when run with the switch "-pr b,"
did not pack as many registers into IOBs as it was able to in 2.1i.

解决方案

1

This problem is fixed in the latest 3.1i Service Pack available at:
http://support.xilinx.com/support/techsup/sw_updates/. The first
service pack containing the fix was Service Pack 1.

2

This problem can be worked around by assigning the same
BLKNM attribute to all comps that belong in the same IOB.
The following is an example of UCF syntax:

INST "pad_name" BLKNM = "IOB1" ;
INST "ibuf_name" BLKNM = "IOB1" ;
INST "inreg_name" BLKNM = "IOB1" ;
etc.

AR# 9344
创建日期 05/23/2000
Last Updated 08/19/2002
状态 Archive
Type 综合文章