set_clock_uncertainty (::quartus::project)

The following table displays information for the set_clock_uncertainty Tcl command:

Tcl Package and Version

Belongs to ::quartus::project 5.0

Syntax set_clock_uncertainty [-h | -help] [-long_help] [-comment <comment> ] [-disable] [-fall] [-from <src_clock_name> ] [-hold] [-remove] [-rise] [-setup] [-tag <data> ] -to <dst_clock_name> <value>
Arguments -h | -help Short help
-long_help Long help with examples and possible return values
-comment <comment> Comment
-disable Option to disable assignment
-fall Option applies to falling edge
-from <src_clock_name> Source clock name
-hold Option to specify hold time uncertainty
-remove Option to remove assignment
-rise Option applies to rising edge
-setup Option to specify setup time uncertainty
-tag <data> Option to tag data to this assignment
-to <dst_clock_name> Destination clock name
<value> Amount of expected clock jitter
Specifies simple or interlock clock uncertainty (or clock
jitter) used during setup and/or hold time analysis. The optional
source clock <src_clock_name> is specified for interlock
uncertainty and is not specified for simple uncertainty.

You may specify the -setup option, the -hold option, or 
neither. If neither is specified, then the command applies 
to both setup and hold.

The <value> is the expected amount of clock jitter.
The format of <value> is "<numerical value><time unit>", 
for example, "0.5ns". 

The following table displays available time units:

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

Assignments created or modified by using this Tcl command are 
not saved to the Quartus Prime Settings File (.qsf) unless you
explicitly call one of the following two Tcl commands:

1) export_assignments
2) 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 Prime 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.
Example Usage
## Specify a simple setup uncertainty of .3ns
## and a simple hold uncertainty of .1ns
set_clock_uncertainty 0.3ns -to clk -setup
set_clock_uncertainty 0.1ns -to clk -hold

## Both of the following commands specify a
## simple setup and hold uncertainty of .3ns
set_clock_uncertainty 0.3ns -to clk
## or
set_clock_uncertainty 0.3ns -to clk -setup -hold

## Specify an interlock setup uncertainty of .3ns
## and an interlock hold uncertainty of .1ns
set_clock_uncertainty 0.3ns -to clk -from src_clk -setup
set_clock_uncertainty 0.1ns -to clk -from src_clk -hold
Return Value Code Name Code String Return
TCL_OK 0 INFO: Operation successful
TCL_ERROR 1 ERROR: Illegal value: <string> -- Specify a positive time value.
TCL_ERROR 1 ERROR: You must open a project before you can use this command.