get_bd_nets - 2023.2 English

Vivado Design Suite Tcl Command Reference Guide (UG835)

Document ID
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2023.2 English

Get a list of nets


get_bd_nets [‑regexp] [‑hierarchical] [‑filter <arg>]
    [‑boundary_type <arg>] [‑of_objects <args>] [‑quiet] [‑verbose]


List of pin objects, "" if failed.


Name Description
[-regexp] Patterns are full regular expressions
[-hierarchical] Hierarchical cells included
[-filter] Filter list with expression
[-boundary_type] Used when source object is on a hierarchical block's pin. Valid values are 'upper', 'lower', or 'both'. If 'lower' boundary, searches from the lower level of hierarchy onwards. This option is only valid for connected_to relations.
[-of_objects] One or a list of cells or pins/ports objects. List must be of one object type.
[-quiet] Ignore command errors
[-verbose] Suspend message limits during command execution
[<patterns>] Match engine names against patterns Default: *




Gets a list of nets in the current IP integrator subsystem design that match a specified search pattern. The default command gets a list of all nets in the subsystem design.

Note: To improve memory and performance, the get_* commands return a container list of a single type of objects (e.g. cells, nets, pins, or ports). You can add new objects to the list (using lappend for instance), but you can only add the same type of object that is currently in the list. Adding a different type of object, or string, to the list is not permitted and will result in a Tcl error.


-regexp - (Optional) Specifies that the search <patterns> are written as regular expressions. Both search <patterns> and -filter expressions must be written as regular expressions when this argument is used. Xilinx® regular expression Tcl commands are always anchored to the start of the search string. You can add ".*" to the beginning or end of a search string to widen the search to include a substring. See for help with regular expression syntax.
Note: The Tcl built-in command regexp is not anchored, and works as a standard Tcl command. For more information refer to

-hierarchical - (Optional) Get nets from all levels of the IP integrator subsystem design hierarchy. Without this argument, the command will only get nets from the top of the subsystem design, or from the current subsystem instance. When using -hierarchical, the search pattern should not contain a hierarchy separator because the search pattern is applied at each level of the hierarchy, not to the full hierarchical name. For instance, searching for /bridge_1/* searches each level of the hierarchy for nets with /bridge_1/ in the name. This may not return the intended results.

Note: When used with -regexp, the specified search string is matched against the full hierarchical name, and the U1/* search pattern will work as intended.

-filter <args> - (Optional) Filter the results list with the specified expression. The -filter argument filters the list of objects returned by get_bd_nets based on property values on the block design nets. You can find the properties on an object with the report_property or list_property commands. In the case of the IP integrator subsystem nets object, "NAME" and "PATH" are two of the properties that can be used to filter results.

The filter search pattern should be quoted to avoid having to escape special characters. String matching is case-sensitive and is always anchored to the start and to the end of the search string. The wildcard “*” character can be used at the beginning or at the end of a search string to widen the search to include a substring of the property value.
Note: The filter returns an object if a specified property exists on the object, and the specified pattern matches the property value on the object. In the case of the "*" wildcard character, this will match a property with a defined value of "".
For string comparison, the specific operators that can be used in filter expressions are "equal" (==), "not-equal" (!=), "match" (=~), and "not-match" (!~). Numeric comparison operators <, >, <=, and >= can also be used. Multiple filter expressions can be joined by AND and OR (&& and ||). The following gets input pins that do NOT contain the “RESET” substring within their name:
get_pins * -filter {DIRECTION == IN && NAME !~ "*RESET*"}
Boolean (bool) type properties can be directly evaluated in filter expressions as true or not true:

-boundary_type [ upper | lower | both ] - (Optional) Gets the net at the level (upper) of a specified hierarchical pin, at the level below (lower) the pin or port, or both the level of and the level below. Valid values are upper, lower, or both. The default value is upper.

Note: This argument must be used with the -of_objects argument to specify the hierarchical pin.
-of_objects <args> - (Optional) Get a list of the nets connected to the specified cell, pin, or port objects.
Note: The -of_objects option requires objects to be specified using the get_* commands, such as get_cells or get_pins, rather than specifying objects by name. In addition, -of_objects cannot be used with a search <pattern>.
-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.

<patterns> - (Optional) Match IP subsystem nets against the specified patterns. The default pattern is the wildcard '*' which returns a list of all nets in the current IP integrator subsystem design. More than one pattern can be specified to find multiple nets based on different search criteria.

Note: You must enclose multiple search patterns in braces {} to present the list as a single element.


The following example gets the net attached to the specified pin of an IP integrator hierarchical module, and returns both the net at the level of the hierarchical module, and the net inside the hierarchical module:

get_bd_nets -boundary_type both -of_objects [get_bd_pins /newMod1/aclk]
Note: If there are no nets matching the pattern you will get a warning.

The following example returns a list of all nets at all levels of the IP integrator subsystem design hierarchy:

get_bd_nets -hierarchical