create_net - 2022.1 English

Vivado Design Suite Tcl Command Reference Guide (UG835)

Document ID
Release Date
2022.1 English

Create nets in the current design


create_net [‑from <arg>] [‑to <arg>] [‑quiet] [‑verbose] <nets>...


Name Description
[-from] Starting bus index
[-to] Ending bus index
[-quiet] Ignore command errors
[-verbose] Suspend message limits during command execution
<nets> Names of nets to create




Create new nets in the current netlist of an open Synthesized or Implemented Design.
Note: You cannot add nets to library macros, or macro-primitives.

Nets can be created hierarchically from the top-level of the design, or within any level of the hierarchy by specifying the hierarchical net name.

Bus nets can be created with increasing or decreasing bus indexes, using negative and positive index values.

New nets are unconnected in the netlist at the time of creation. You must connect nets as desired using the connect_net command. Connected nets can be unconnected using the disconnect_net command, and can be removed from the netlist using the remove_net command.

Netlist editing changes the in-memory view of the netlist in the current design. It does not change the files in the source fileset, or change the persistent design on the disk. Changes made to the netlist may be saved to a design checkpoint using the write_checkpoint command, or may be exported to a netlist file such as Verilog, VHDL, or EDIF, using the appropriate write_* command.
Note: Netlist editing is not allowed on the elaborated RTL design.


-from <arg> - (Optional) The starting index of a new bus.

-to <arg> - (Optional) The ending index of a new bus.
Note: Specifying -from or -to without the other will results in a one-bit bus with index value specified by the -from or -to argument.
-quiet - (Optional) Execute the command quietly, returning no messages from the command. The command also returns TCL_OK regardless of any errors encountered during execution.
Note: Any errors encountered on the command-line, while launching the command, will be returned. Only errors occurring inside the command will be trapped.
-verbose - (Optional) Temporarily override any message limits and return all messages from this command.
Note: Message limits can be defined with the set_msg_config command.

<nets> - (Required) The names of nets to create. Net names can be specified from the top-level, as name only (net1), or can be specified within the design hierarchy by specifying the hierarchical net name (cell1/cellA/net1).


The following example creates a new 24-bit bus in the current Synthesized or Implemented Design:

create_net tempBus -from 23 -to 0