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.

EDIF 2 0 0

NCF

NGC Netlist

URF

NMC

UCF

Physical Macros

Netlist

Netlist Constraints File

(XST File)

User Rules File

User Constraints File

Referenced in Netlist

 

 

 

 

 

Netlist Reader

NGDBuild

NGO

Intermediate File

NGD

BLD

Generic Database

Build Report

X10031

Figure 6-1:NGDBuild Design Flow

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”.

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Xilinx 8.2i manual Converting a Netlist to an NGD File, 1NGDBuild Design Flow
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8.2i specifications

Xilinx 8.2i is a significant version of the Xilinx ISE (Integrated Software Environment) that emerged in the early 2000s, marking an important milestone in the world of FPGA (Field-Programmable Gate Array) development. This version introduced a slew of advanced features, technologies, and characteristics that made it an indispensable tool for engineers and developers in designing, simulating, and implementing digital circuits.

One of the standout features of Xilinx 8.2i is its enhanced design entry capabilities. This version supports multiple design entry methods, including schematic entry, VHDL, and Verilog HDL, giving engineers the flexibility to choose their preferred approach. The integrated environment provides user-friendly graphical interfaces, making it accessible for both novice and experienced users.

Xilinx 8.2i's synthesis tools have been improved to enable more efficient design compilation and optimization. The new algorithms used in this version facilitate faster synthesis times while reducing power consumption and improving performance. Furthermore, it features support for advanced FPGA architectures, which allows for the implementation of more complex designs with greater efficiency.

The implementation tools in Xilinx 8.2i include advanced place and route capabilities, utilizing state-of-the-art algorithms for optimized resource usage. These tools enable designers to make better use of FPGA resources, ensuring that designs fit within the constraints of the target device while maximizing performance.

Another key characteristic of Xilinx 8.2i is its extensive support for various Xilinx devices such as the Spartan, Virtex, and CoolRunner series. This compatibility ensures that developers can leverage the powerful features of these FPGA families, including high-speed transceivers and DSP slices.

Xilinx 8.2i also places a strong emphasis on simulation and verification. The version integrates with various simulation tools, allowing for thorough testing of the designs before implementation. This reduces the risk of errors and ensures that the final product meets specifications.

In addition, this version includes support for design constraints, enabling engineers to specify timing, area, and other critical design parameters. By accommodating constraints, Xilinx 8.2i helps in achieving reliable and efficient designs tailored to project needs.

In summary, Xilinx 8.2i is a robust software development tool that enhances the design process for FPGAs. Its comprehensive features, including multiple design entry options, advanced synthesis and implementation tools, extensive device support, and strong simulation capabilities, make it a valuable resource for engineers and developers striving for innovation in digital design.
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