ISE
HDL Overview
You can use a hardware description language (HDL), such as VHDL, Verilog, or ABEL (for CPLDs), for your top-level or lower-level design files. HDL files describe the behavior and structure of system and circuit designs. Using HDLs to design high-density devices allows you to do the following:
  •  Use a top-down approach
    You can use HDLs to create complex designs that require many designers to work together. After an overall plan is determined, each designer works on a separate section of the design.
  •  Run functional simulation early in the design cycle
    You can verify your design functionality early in the flow by simulating the HDL description. Testing your design decisions at the register transfer level (RTL) or gate level before the design is implemented allows you to make changes early in the design process.
  •  Use a synthesis engine to translate your design to gates
    Synthesis decreases design time by eliminating the need to define every gate. Synthesis to gates reduces the number of errors that may occur during a manual translation of the hardware description to a schematic design. Also, the synthesis tool can apply automation, such as machine encoding styles or automatic I/O insertion during optimization, resulting in greater efficiency.
  •  Retarget your code to different architectures
    You can use the same HDL design for new architectures with a minimum of recoding. This works especially well if you inferred, rather than instantiated, components. For details, see Instantiation and Inference.
Additional Resources
Additional details on the advantages of using HDLs are available in the following Xilinx® documentation:
DocumentationTopics Covered
Synthesis and Simulation Design GuideHigh-density design flow and recommended coding styles
Review this documentation and consult any of the many HDL textbooks available. In addition, you can enroll in any of the Xilinx® training classes available from the Xilinx website. Click Training Courses to view the available classes and to sign up.
See Also

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