Xilinx 8.2i manual Design Entry and Synthesis, Hierarchical Design

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Design Entry and Synthesis

Design Entry and Synthesis

You can enter a design with a schematic editor or a text-based tool. Design entry begins with a design concept, expressed as a drawing or functional description. From the original design, a netlist is created, then synthesized and translated into a native generic object (NGO) file. This file is fed into the Xilinx software program called NGDBuild, which produces a logical native generic database (NGD) file.

The following figure shows the design entry and synthesis process.

Schematic

Libraries

CORE Generator

Synthesis

LibrariesHDL

Schematic Capture

Synthesis

UCF	EDIF 2 0 0 &	NGC
	Constraints/NCF	(XST Netlist)

NGDBuild

X10295

Figure 2-4:Design Entry Flow

Hierarchical Design

Design hierarchy is important in both schematic and HDL entry for the following reasons:

•Helps you conceptualize your design

•Adds structure to your design

•Promotes easier design debugging

•Makes it easier to combine different design entry methods (schematic, HDL, or state editor) for different parts of your design

•Makes it easier to design incrementally, which consists of designing, implementing, and verifying individual parts of a design in stages

•Reduces optimization time

•Facilitates concurrent design, which is the process of dividing a design among a number of people who develop different parts of the design in parallel.

Development System Reference Guide www.xilinx.com 33