The hierarchical sources view (HSV) feature in Vivado IDE and PlanAhead(version 13.3 and later) shows the module/instance based hierarchical relation between the source files in a project.
The "Unreferenced" file group that you see is related tothe HSVfeature.
This hierarchical source view feature supports the following three update modes:
Going back to the first mode, which is default, here is a simple example. Lets say my design hierarchy is as shown below:
top1 (top1.v) |
|-- child1 (child1.v)
|-- grandchild1 (gchild1.v)top2 (top2.v)
|-- child2 (child2.v) |
|-- grandchild2 (gchild2.v)
In this project, we essentially have two independent SETS of design sources, which two potential top candidates. If we select top1 as our "top", then top2.v, child2.v and gchild2.v becomes "unreferenced" and the only files that are used for synthesis and simulation are: gchild1.v, child1.v and top1.v, and they are sent to the compilers in this "bottom up" order.
If the above explanation does not apply, please right click the source and select the source properties to verify that the file Type has not been set to unknown.
Also verify that the module names and ports match with the instantiating source file.
In many cases, the unreferenced status is due to a syntax error in the HDL code that prevents thehierarchy from being parsed and displayed as expected. Users should use the "Messages" tab to check for parsing errors. For example, a user may look in the messages tab, under the "Analysis Messages" group, and find an explicit errors mentioning what went wrong, and allow them to directly click on the error messages to cross-probe to the HDL file directly, close to where the actual error is.