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118 www.xilinx.com Development System Reference Guide
Chapter 6: NGDBuild
R
The following figure shows a simplified version of the NGDBuild design flow. NGDBuild
invokes other programs that are not shown in the following figure.
Converting a Netlist to an NGD File
NGDBuild performs the following steps to convert a netlist to an NGD file:
1. Reads the source netlist
NGDBuild invokes the Netlist Launcher. The Netlist Launcher determines the input
netlist type and starts the appropriate netlist reader program. The netlist reader
incorporates NCF files associated with each netlist. NCF files contain timing and
layout constraints for each module. The Netlist Launcher is described in detail in the
“Netlist Launcher (Netlister)” in Appendix B.
2. Reduces all components in the design to NGD primitives
NGDBuild merges components that reference other files. NGDBuild also finds the
appropriate system library components, physical macros (NMC files), and behavioral
models.
3. Checks the design by running a Logical Design Rule Check (DRC) on the converted
design
Logical DRC is a series of tests on a logical design. It is described in Chapter 5, “Logical
Design Rule Check”.
4. Writes an NGD file as output
Note:
This procedure, the Netlist Launcher, and the netlist reader programs are described in more
detail in Appendix B, “EDIF2NGD, and NGDBuild”.
Figure 6-1: NGDBuild Design Flow
X10031
NMC
Physical Macros
Referenced in Netlist
NGDBuild
Netlist Reader
UCF
User Constraints File
URF
User Rules File
BLD
Build Report
NGD
Generic Database
NGO
Intermediate File
NCF
Netlist Constraints File
EDIF 2 0 0
Netlist
NGC Netlist
(XST File)