DS-FND-BSX-PC Xilinx Inc, DS-FND-BSX-PC Datasheet - Page 276

• Manufacturer Part Number: DS-FND-BSX-PC
• Description: FOUNDATION BASE SYS W/SYN EXPRES
• Manufacturer: Xilinx Inc
• Type: Foundation Systemr

Specifications of DS-FND-BSX-PC

• For Use With/related Products: Xilinx Programmable Logic Devices
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 122-1185

Foundation Series 2.1i User Guide
The Xilinx Constraints Editor
Constraints File Overview
B-4
Netlist Constraints File (NCF)
User Constraints File (UCF)
All design files are translated from industry standard netlists into
intermediate NGO files by one of two netlist translation programs
XNF2NGD or EDIF2NGD. The exception to this rule is logic, which is
created through the use of LogiBLOX components. LogiBLOX
components may be compiled directly in memory, and are, therefore
never written to disk as a separate intermediate NGO file.
The Xilinx Constraints Editor is a Graphical User Interface (GUI) that
provides a convenient way for you to create certain new constraints.
Constraints created with the Constraints Editor are written to the
UCF (User Constraints File). See the “User Constraints File (UCF)”
section.
For more information on the Constraints Editor, see the Constraints
Editor Guide, an online book.
The following subsections describe the Netlist Constraints File, User
Constraints File, and the Physical Constraints File.
The Netlist Constraints File (NCF) is an ASCII file generated by the
synthesis program. It contains the logical contraints entered in the
design.
The User Constraint File was developed to provide a convenient
mechanism for constraining a logical design without returning to the
design entry tools. UCF constraints intentionally overwrite
constraints that are present in the netlist.
UCF constraints override any constraints contained within the netlist
created by the schematic or synthesis tools. A constraint that is being
applied via the UCF file must specify the complete hierarchical path
name for the instance or net being constrained.
In the Foundation, UCF constraints are considered more significant
because they appear later in the design flow and provide a mecha-
Xilinx Development System