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Working with Scratch Cellview

Yaosan

As most of you probably know, dbOpenCellViewByType() has a mode known as scratch mode. In this mode, the cellview opened cannot be saved to disk. However, I have some question regarding this mode. First of all, what is the master and context cellview related to the "sc" and "sd" mode? In what kind of situation should I use one of these two modes?

I would also like to know the proper way of working in this scratch view mode. Should I create a new view in scratch mode and copy over the object one by one before I start doing the modification I need? This seems to be quite troublesome IC61x with all the new blockages, vias and other OA objects listed under different property of cellviews.

I tried opening an existing, opened cellview in scratch mode, hoping it will return a new copy i.e. with new dbID that exists only in memory, but somehow it shares the same cellview ID as the original opened cellview. I also tried to use dbCopyCellView() but it won't let me copy to the scratch view unless I specify the overwrite flag, which will write the scratch view to disk, defeating the purpose of having one in the first place.

Lawrence mention scratch mode is handled differently in IC61x and IC51, can someone please explain the differences? Thanks in advance for any feedback.

Parents

  • Hi Andrew,

    Thanks for taking the time to respond with such a detailed explanation, I learned a lot from your response.

    I do notice I can now change stuff even though the cellview is in read only mode in IC61. I'm thinking I can skip scratch cellview altogether, make the changes I want directly in an opened, read only cellview, stream out from virtual memory in IC614, then do a dbRefreshCellView() to discard the edit. I hope that works.

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  • Hi Andrew,

    Thanks for taking the time to respond with such a detailed explanation, I learned a lot from your response.

    I do notice I can now change stuff even though the cellview is in read only mode in IC61. I'm thinking I can skip scratch cellview altogether, make the changes I want directly in an opened, read only cellview, stream out from virtual memory in IC614, then do a dbRefreshCellView() to discard the edit. I hope that works.

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