• 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. Custom IC Design
  3. cross function deficiency

Stats

  • Locked Locked
  • Replies 2
  • Subscribers 125
  • Views 10343
  • 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

cross function deficiency

CADcasualty
CADcasualty over 4 years ago

I used to work at an IC design company that had it's own analog simulator and corresponding scripting language and I am now at another company using Cadence Spectre and Ocean scripting (I'll bite my tongue about Ocean for now). The scripting language I previously used had a find function that could locate aspects of a waveform very similar to Ocean's cross function - but with one glaring and (to my mind) fundamental missing capability i.e. the ability to specify the reference time point (or range of time) in the transient waveform for which to perform the search. 

An example of my usage of the cross function is:

cross(my_wave VDD-0.01 1 'rising nil)

where I'm trying to see when a clock waveform first crosses to within 10mV of VDD. The issue is that I'm trying to do this for the e.g. the 4th clock cycle, so I don't want to start my search from t=0 but instead some other known time that the 4th clock cycle starts. There is an arbitrary amount of wobbling of the my_wave signal around VDD at each clock cycle (due to dynamic loading) and I don't want to have to go through using the cross function to return all the crossings and then post-process them all. My Ocean script is already dauntingly complicated to look at and digest because of the sub-atomic nature of all of the commands necessary to get the job done (compared to what I was used to). Is there another function similar to cross that does what I want?

  • Cancel
  • Andrew Beckett
    Andrew Beckett over 4 years ago

    You can easily do this using the clip function:

    cross(clip(my_wave knownTIme nil) VDD-0.01 1 'rising nil)

    Rather than repeating time range arguments in every function, combining them gives you lots of flexibility.

    Andrew

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
  • CADcasualty
    CADcasualty over 4 years ago in reply to Andrew Beckett

    Thanks Andrew - I didn't know about the clip function. This should nicely fix my issue :-).

    • Cancel
    • Vote Up 0 Vote Down
    • 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