Altera Quartus II Scripting - Manual (Page 630)

3–500 Chapter 3: Tcl Packages & Commands
timing_assignment
Quartus II Scripting Reference Manual © July 2013 Altera Corporation
set_timing_cut_assignment
Usage
set_timing_cut_assignment [-comment <comment>] [-disable] [-from <from_pin_list>]
[-remove] [-tag <data>] [-to <to_pin_list>]
Options
-comment <comment>: Comment
-disable: Option to disable assignment
-from <from_pin_list>: List of start or source node names and/or assignment group names
for timing path, for example, {node1 node2 ...}
-remove: Option to remove timing cut assignment
-tag <data>: Option to tag data to this assignment
-to <to_pin_list>: List of end node names and/or assignment group names for timing path,
for example, {node1 node2 ...}
Description
Specifies that the timing paths that start from the designated <from_pin_list> and end in the designated
<to_pin_list> are false paths.
Nodes for the <from_pin_list> can be input pins, internal nodes, clock pins, or assignment groups. Nodes
for the <to_pin_list> can be output pins, internal nodes, clock pins, or assignment groups.
You must use either the "-from <from_pin_list>" or the "-to <to_pin_list>" option.
Note that Quartus®II timing analysis is optimized to use assignment groups for timing constraints instead
of a list of nodes. Of the following two methods to make timing cut assignments, method (1) is the optimal
method.
(1) assignment_group "src_group" -add_member "s1"
assignment_group "src_group" -add_member "s2"
assignment_group "src_group" -add_member "s3"
assignment_group "dst_group" -add_member "d1"
assignment_group "dst_group" -add_member "d2"
set_timing_cut_assignment -from "src_group" -to "dst_group"
(2) set_timing_cut_assignment -from {s1 s2 s3} -to {d1 d2}
For more information about assignment groups, type "assignment_group -h".
The "assignment_group" command replaces the deprecated "timegroup" command in ::quartus::project,
version 5.0.
Assignments created or modified by using this Tcl command are not saved to the Quartus II Settings File
(.qsf) unless you explicitly call one of the following two Tcl commands:
■ export_assignments
■ project_close (unless "-dont_export_assignments" is specified)
These two Tcl commands reside in the ::quartus::project Tcl package. You must save assignment changes
before you run Quartus®II command-line executables. Note, however, that the Tcl commands
"execute_flow" and "execute_module" (part of the ::quartus::flow Tcl package) automatically call
"export_assignments" before they run command-line executables.