• Skip to main content
  • Skip to search
  • Skip to footer
Cadence Home
  • This search text may be transcribed, used, stored, or accessed by our third-party service providers per our Cookie Policy and Privacy Policy.

  1. Community Forums
  2. High-Level Synthesis
  3. set_multicycle_path using clock enable signals

Stats

  • Locked Locked
  • Replies 0
  • Subscribers 22
  • Views 17544
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

set_multicycle_path using clock enable signals

Hildebrandt
Hildebrandt over 7 years ago

Hello!

For synthesis with Genus 17.1 I want to constrain a multi-cycle path inside one single clock domain from some flipflops using one clock enable signal to some other flipflops using a different clock enable signal. There is a solution for Altera Quartus <https://www.altera.com/support/support-resources/design-examples/design-software/timinganalyzer/exm-tq-clock-enable.html>, which works fine for Quartus, but not for Genus. After adapting the syntax of the Quartus solution I tried in Genus:

set_multicycle_path 4 -from [get_fanout [get_pins my_component/my_clock_enable_1_reg/q]]  -to [get_fanout [get_pins my_component/my_clock_enable_2_reg/q]]  -setup

but the <get_fanout> command gives a list, which includes objects, which are not supported by <set_multicycle_path>. Here is the relevant part of the error message:

Error : A given object is not suitable for this exception. [SDC-211] [set_multicycle_path]
: The 'set_multicycle_path' command does not allow '-from' specifications for pins on unmapped combinational or hierachical instances ...

The used clock-enable signals are used inside clocked processes as combinational logic and together with other combinational conditions the synthesis tool recognizes this as clock-enable. Here is the pseudo-code:

elsif rising_edge(clk) then

   if (clock_enable_1='1' AND other_condition='1') then

Ralf

  • Cancel

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.

© 2025 Cadence Design Systems, Inc. All Rights Reserved.

  • Terms of Use
  • Privacy
  • Cookie Policy
  • US Trademarks
  • Do Not Sell or Share My Personal Information