Stats

  • Locked Locked
  • Replies 4
  • Subscribers 125
  • Views 16731
  • 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

Layout offgrid problem

Senan

Hello,

In the middle of my layout design I started to receive a new error of "OFFGRID". I have read some advices from net about changing the minor and major spaces from Option > Display, however it is not working.

If I go to the former layout cells which has no DRC problem, by just inserting a new layout element and then It will as well start to complain about the OFFGRID.

Here is the DRC I have

Thanks

Parents

  • First of all, the grid spacing is not controlled by the minor and major spaces - that's just for the visual grid (i.e. the dots/lines shown on the display). The snap spacing is what controls the snap grid - that's probably what's wrong. Without knowing what the allowed grid is for your technology, I can't tell you what to change it to...

    Andrew

  • in reply to Andrew Beckett

    Dear Andrew,

    Thank you for your reply

    You are absolutely right, it is about the snap spacing as also recently read.

    I kept this value as default as it was since the start of my layout work and was no problem for several cells I have finished, I don't understand why Cadence suddenly recognized that I must change it to fit the used technology.

    I tried to find some notes about the grid setting from the technology files but there was nothing about it, hence I think I will contact the foundry support.

    Generally, I am using the 0.35 µm CMOS technology from XFAB

    Regards

  • in reply to Senan

    A good way to solve such issues is to go for a somewhat bigger, but round number for the snap spacing, go for 0.1u for example, not 0.037u (just examples). Then your new placements should be fine.

    As for the already placed devices, try to round their coordinates with the same logic. This way they snap back the grid.

  • in reply to Tamsay

    I found the information from the foundry of my technology. it is 0.25 µm or recommended 0.5 µm. and this fixed my issue

Reply Children
No Data

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.