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AR# 39650

Design Assistant for XST - Help applying constraints with an XCF

Description

Please refer to this answer record for help applying constraints within an XCF.

Note: This Answer Record is a part of the Xilinx Solution Center for XST (Xilinx Answer 38927). The Xilinx Solution Center for XST is available to address all questions related to XST. Whether you are starting a new design or troubleshooting a problem, use the Solution Center for XST to guide you to the right information.

Solution

Some XST constraints can be applied not only globally but also specifically to certain modules, instances or signals in the XST Constraint File (XCF). Most XST constraints that can be applied in RTL code can also be applied in XCF. Applying constraints in the XCF makes the HDL source code more portable and reusable.


Following are some examples of applying XST constraints in XCF.


BEGIN MODEL "top"
NET "signal1" fsm_style = lut;
END;


MODEL "top" keep_hierarchy = yes;


BEGIN MODEL "top"
INST"submodule1"shift_extract = no;
END;


For more information about any constraints syntax in XCF, please refer toUG627/687-XST User Guide (Xilinx Answer 38931).

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
38927 Xilinx Solution Center for XST N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
39749 Design Assistant for XST - Help with XST Options/Constraints/Attributes N/A N/A
AR# 39650
Date Created 03/14/2011
Last Updated 01/25/2013
Status Active
Type General Article