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I have 2 clocks in my design. One slow External clock and one high frequency ring oscillator clock. For external clock I am using the create_clock command to specify timing. The ring oscillator block is instantiated inside my design. Now how do I specify the constraint for the ring oscillator pin? My understanding is that create_generated_clock isn't relevant in this case since ring oscillator clock is not generated from any other clock and is asynchronous to other clock.

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  • \$\begingroup\$ In what environment and what tool set? \$\endgroup\$ – Oldfart Jun 11 '18 at 10:58
  • \$\begingroup\$ I am using Encounter RTL Compiler, but later Genus will be used.. \$\endgroup\$ – Pramod Jun 11 '18 at 10:59
  • \$\begingroup\$ Is it used as a clock (routed to clock pins of flops)? And, did you perform an initial synthesis run with partial/no constraints to see if the tool recognized and extracted it as a clock? \$\endgroup\$ – CapnJJ Jun 11 '18 at 15:25
  • \$\begingroup\$ Yes it is used as clock for a set of registers. The synthesis tool of course recognizes it as clock but I want it to be constrained. \$\endgroup\$ – Pramod Jun 12 '18 at 2:20

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