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  3. AR# 9406: EXEMPLAR - "ERROR:Pack:679 - Unable to obey design constraints"

AR# 9406

EXEMPLAR - "ERROR:Pack:679 - Unable to obey design constraints"

Description

Keywords: NGDBuild, Leonardo, XBLKNM, EDIF, placement.

Urgency: Standard

General Description:
The following error is reported:

"ERROR:Pack:679 - Unable to obey design constraints."

Solution

1

When NGDBuild flattens a hierarchical EDIF file containing SRL16s with XBLKNM properties that were created by Leonardo Spectrum, NGDBuild does not do anything to the XBLKNM properties in the EDIF file (such as adding an instance label to the value). The placer will then try to put more SRL16s into a single slice than is physically possible, and the error above is reported.

One way to work around this problem is to not preserve the hierarchy in Leonardo Spectrum.

2

The following Leonardo Level 3 TCL script will ensure that the XBLKNM is stripped from the EDIF file. Run this script after optimization, but before writing out the EDIF file:

==== Cut here ====

foreach sheet [dfs] {
foreach cell [list_design $sheet] {
foreach attr [list_attributes $cell] {
set tmp_attr [string toupper [lindex $attr 0]]
if {[string compare $tmp_attr XBLKNM] == 0} {
puts "Removing $tmp_attr property from $cell"
remove_attribute $cell -name XBLKNM
}
}
}
}

==== Cut here ====

Consider this a "quick and dirty" work-around for the problem. Keeping the XBLKNM properties in the EDIF file will greatly help Place and Route.
AR# 9406
Date 10/01/2008
Status Archive
Type General Article