To create a lower-level netlist, set up a project with that netlist as the top-level module. Before you run synthesis, set the out-of-context (OOC) mode, as shown in the following figure.
Figure 1. Settings Dialog Box
In the More Options section, you can type
-mode out_of_context to have the tool not insert any I/O buffers in
this level.
After you run synthesis, open the synthesized design and in the Tcl Console,
type the write_edif Tcl command in the Tcl Console. The
syntax is as follows:
write_edif <design_name>.edf