Overlapping Clocks Defined on the Same Clock Source - Overlapping Clocks Defined on the Same Clock Source - 2026.1 English - UG1387

The create_clock -add command defines two clocks on the same netlist object. These clocks represent the multiple modes of an application. In this case, it is safe to apply a clock groups constraint between the clocks. For example:

create_clock -name clk_mode0 -period 10 [get_ports clkin]
create_clock -name clk_mode1 -period 13.334 -add [get_ports clkin]
set_clock_groups -physically_exclusive -group clk_mode0 -group clk_mode1

If clk_mode0 and clk_mode1 generate other clocks, apply the same constraint to those generated clocks as well. You can do so as follows:

set_clock_groups -physically_exclusive \
-group [get_clocks -include_generated_clock clk_mode0] \
-group [get_clocks -include_generated_clock clk_mode1]