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Xilinx Constraints Guide

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RLOC_RANGE (Relative Location Range)<br />

The RLOC_RANGE (Relative Location Range) constraint:<br />

• Is a placement constraint.<br />

Architecture Support<br />

Applicable Elements<br />

Propagation Rules<br />

Constraint Syntax<br />

Chapter 4: <strong>Xilinx</strong> <strong>Constraints</strong><br />

• Is similar to RLOC_ORIGIN except that it limits the members of a set to a certain<br />

range on the die. The range or list of locations is meant to apply to all applicable<br />

elements with RLOCs, not just to the origin of the set<br />

Applies to FPGA devices. Does not apply to CPLD devices.<br />

Instances or macros that are members of sets<br />

RLOC_RANGE is a macro constraint and any attachment to a net is illegal.<br />

The bounding rectangle applies to all elements in a relationally placed macro, not just<br />

to the origin of the set.<br />

The values of the RLOC_RANGE constraint are not simply added to the RLOC values of<br />

the elements. In fact, the RLOC_RANGE constraint does not change the values of the<br />

RLOC constraints on underlying elements. It is an additional constraint that is attached<br />

automatically by the mapper to every member of a set.<br />

The RLOC_RANGE constraint is attached to design elements in exactly the same<br />

way as the RLOC_ORIGIN constraint. The values of the RLOC_RANGE constraint,<br />

like RLOC_ORIGIN values, must be non-zero positive numbers since they directly<br />

correspond to die locations.<br />

If a particular RLOC set is constrained by an RLOC_ORIGIN or an RLOC_RANGE<br />

constraint in the design netlist and is also constrained in the User <strong>Constraints</strong> File (UCF)<br />

file, the UCF constraint overrides the netlist constraint.<br />

RLOC_RANGE=Xm1 Yn1:X m2Yn2<br />

where<br />

the relative X values (m1 andm2 ) and Y values (n1 and n2) can be:<br />

– non-zero positive numbers<br />

– the wildcard (*) character<br />

This syntax allows for three kinds of range specifications:<br />

• Xm1Yn1:Xm2 Yn2<br />

A rectangular region bounded by the corners Xm1Yn1 and Xm2 Yn2<br />

• X*Yn1:X*Ym2<br />

The region on the Y-axis between n1 and n2 (any X value)<br />

• Xm1Y*:Xm2<br />

A region on the X-axis between m1 and m2 (any Y value)<br />

<strong>Constraints</strong> <strong>Guide</strong><br />

UG625 (v. 13.2) July 6, 2011 www.xilinx.com 255

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