Working with VHDL Libraries
VHDL libraries allow you to store commonly used packages and entities that you can use in your VHDL files. A VHDL package file contains common design elements that you can use in the VHDL file source files that make up your design. Use the following procedures to create VHDL libraries and package files and to move package files from one library to another.
What to Do First
Open a project in Project Navigator. Image
To Reference a VHDL Library or Package File
To reference a VHDL library or package file in your VHDL file, do the following:
  •  To reference a package file, include a use statement.
  •  To reference a library file, include a use and a library statement. When referencing a library, you must declare both the library and package name.
To Create a VHDL Library
The ISE software provides a work library. However, you can create your own libraries as described in Creating a Source File. Select VHDL Library as your source type.
After you create the VHDL library, the new library appears in the vhdl library. Click the Libraries tab to view the vhdl library.
Note The Libraries tab also contains a verilog library in which you can store Verilog files for your reference. However, if you want to store commonly used modules and components that you can use in your Verilog files, see Working with Verilog Header Files.
To Create a VHDL Package File
You can create a VHDL package file as described in Creating a Source File. Select VHDL Package as your source type.
After you create the VHDL package file, the new file appears at the top of the Sources tab. By default, the new VHDL package file is added to the work library. Click the Libraries tab to view the work library. To move the file to a different library, see the following procedure.
To Move a VHDL File to a Library
To move a VHDL file from one library to another, for example, from the default work library to a library that you created, do the following:
  1.  In the Sources window, select the VHDL file to move.
    Note You can only move files with the .vhd extension. By default, new VHDL package files display at the bottom of the work library hierarchy.
  2.  Select Source > Move to Library.
  3.  In the Choose Library dialog box, select the library to move the file to.
  4.  Click OK.
Additional Information
For information on the use and syntax of a VHDL keyword, highlight the keyword in the ISE Text Editor in the Project Navigator Workspace, and press F1. Keywords are shown in blue.

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