Schematic and Symbol Editors
Creating a Lower-Level Schematic
Using a schematic for a lower-level module allows you to have a visual representation of your module and allows you to create custom macros. You can create a lower-level schematic that you instantiate in a top-level schematic or HDL file as follows.
Before completing this procedure, you should have created a source file, selecting Schematic as your Source File Type. Image
The new SCH file name appears in the Sources panel, and the new schematic opens in the Workspace.
To Create a Lower-Level Schematic
  1.  Add symbol instances to your schematic.
    You can add the following types of symbols:
    •  Xilinx® unified library symbols. Image
    •  Symbols you create using the Symbol Wizard. Image
    •  Symbols you create using lower-level modules, such as HDL files. Image
  2.  Add wires to connect your symbols. Image
  3.  Create buses. Image
  4.  Add I/O markers. Image
    Note  See Adding I/O Markers to an Empty Schematic for details on how to add all the I/O Markers to your schematic at once.
  5.  Check your schematic for errors. Image
  6.  Fix any errors, and save your SCH file.
The schematic is saved in your project.
Once you have created a schematic, you can perform any of the following on your design:
  •  If your top-level design is a schematic, create a schematic symbol for your lower-level schematic, and instantiate the schematic symbol in your top-level schematic. Image
  •  If your top-level design is an HDL file, create an instantiation template for your lower-level schematic, and instantiate the template in your top-level HDL file. Image
  •  View your schematic as a read-only structural Hardware Description Language (HDL) file to ensure that the HDL file generated from your schematic is as you expected. Image
  •  Store the SCH file for documentation purposes.
See Also
Creating a Top-Level Schematic

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