Chapter 2: Design Flow

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Block Placement

Block placement can be constrained to a specific location, to one of multiple locations, or to a location range. Locations can be specified in the schematic, with synthesis tools, or in the User Constraints File (UCF). Poor block placement can adversely affect both the placement and the routing of a design. Only I/O blocks require placement to meet external pin requirements.

Timing Specifications

You can specify timing requirements for paths in your design. PAR uses these timing specifications to achieve optimum performance when placing and routing your design.

Netlist Translation Programs

Two netlist translation programs allow you to read netlists into the Xilinx software tools. EDIF2NGD allows you to read an Electronic Data Interchange Format (EDIF) 2 0 0 file. The NGDBuild program automatically invokes these programs as needed to convert your EDIF file to an NGD file, the required format for the Xilinx software tools. NGC files output from the Xilinx XST synthesis tool are read in by NGDBuild directly.

You can find detailed descriptions of the EDIF2NGD, and NGDBuild programs in Chapter 6, “NGDBuild” and “Appendix B”.

Design Implementation

Design Implementation begins with the mapping or fitting of a logical design file to a specific device and is complete when the physical design is successfully routed and a bitstream is generated. You can alter constraints during implementation just as you did during the Design Entry step. See “Constraints” for information.

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Development System Reference Guide

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Xilinx 8.2i manual Design Implementation, Netlist Translation Programs, Block Placement, Timing Specifications

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.