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AR# 16881

5.1i XST - "ERROR: HDLCompilers:87 - Could not find module/primitive 'ADD8'"


Keywords: schematic, adder, 5.x, synthesis, ECS

Urgency: Hot

General Description:
When I run synthesis on a design in which a schematic uses the ADD8 component, the following error occurs:

"ERROR:HDLCompilers:87 - <design_name>.vf line xx Could not find module/primitive 'add8'"



The ADD8 component cannot be directly instantiated in HDL. To work around this issue, you can create an ADD8 component using the example inference listed in the Libraries Guide at:

To create the ADD8, follow these steps:
1. Create a New Source and select VHDL or Verilog module.
2. Copy and paste the example inference into a VHDL or Verilog source file.
3. In the Processes window, expand Design Entry Utilities and double-click Create Schematic Symbol.
4. Open the schematic source for the project, and in the Symbols list, click the project library.
5. The ADD8 component you created should appear in the bottom window. You can place it in your schematic.


In general, this error will occur when any lower-level module is not available to XST. If the module in question is a user-created sub-module, make sure that the HDL file that contains the description of the module (even if it is just the module declaration for black box instantiation) has been added to the XST project.
AR# 16881
Date 10/20/2005
Status Archive
Type General Article