The primary clock
clkin has a period of 10 ns. It is divided by 2 by
the register REGA which drives other registers clock pin. The corresponding
generated clock is called clkdiv2.
Two equivalent constraints are provided below:
create_clock -name clkin -period 10 [get_ports clkin] # Option 1: master clock source is the primary clock source point create_generated_clock -name clkdiv2 -source [get_ports clkin] -divide_by 2 \ [get_pins REGA/Q] # Option 2: master clock source is the REGA clock pin create_generated_clock -name clkdiv2 -source [get_pins REGA/C] -divide_by 2 \ [get_pins REGA/Q]
Figure 1. Generated Clock Example One