Altera Quartus II Scripting - Manual (Page 620)

3–490 Chapter 3: Tcl Packages & Commands
timing_assignment
Quartus II Scripting Reference Manual © July 2013 Altera Corporation
set_clock_latency
Usage
set_clock_latency [-early] [-late] [-tag <data>] -to <to> <value>
Options
-early: Early clock latency
-late: Late clock latency
-tag <data>: Option to tag data to this assignment
-to <to>: Destination clock name
<value>: Input delay value after rise of reference clock
Description
Specifies the required early or late clock latency on the clock or input assignment group as specified by the
"-to" option. The Quartus II®timing analysis propagates this latency and checks it against the actual
latency. 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.
If both "-early" and "-late" options are not used, then the assignment is set for both early and late latency.
The <value> is the latency of the reference clock. The format of <value> is "<numerical value><time
unit>", for example, "7.55ns".
The following table shows the available time units:
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.
Time Unit Description
s second(s)
ms millisecond(s)
us microsecond(s)
ns nanosecond(s)
ps picosecond(s)
fs femtosecond(s)
Hz Hertz
KHz KiloHertz
MHz MegaHertz
GHz GigaHertz