set_active_clocks (::quartus::sdc_ext)

The following table displays information for the set_active_clocks Tcl command:

Tcl Package and Version

Belongs to ::quartus::sdc_ext 1.0

Syntax set_active_clocks [-h | -help] [-long_help] <clocks>
Arguments -h | -help Short help
-long_help Long help with examples and possible return values
<clocks> List or collection of clocks
Sets the list of active clocks for timing
analysis. All other clocks not in the list or
collection are considered inactive.

Timing analysis is only performed on active
clocks. All clocks are active by default. Generated
clocks that are generated from inactive clocks are
considered inactive. Therefore, to make a generated
clock active, specify both the parent and generated
clock when calling set_active_clocks.

To reset all clocks to active, call "set_active_clocks
*" or "set_active_clocks [all_clocks]".

The set_active_clocks command does not affect all
reports. For example, inactive clocks are still
reported by report_clocks, report_clock_transfers, and
similar commands.
Example Usage
# Only analyze clk1
set_active_clocks [get_clocks clk1]

# Only analyze clk2
set_active_clocks [get_clocks clk2]

# Analyze all clocks
set_active_clocks [all_clocks]
Return Value Code Name Code String Return
TCL_OK 0 INFO: Operation successful
TCL_ERROR 1 ERROR: Timing netlist does not exist. Use create_timing_netlist to create a timing netlist.