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how can I hierarchically place the flatten top level

SatendraMaurya

Hi,

Let me explain this with some example. I have a design say top-level that instantiate 4-instance of B along with bunch of other cells. There are two ways to do the placement using layout-xl:

i) Flatten the complete layout at top-level and do manual placement of each cell. Too much repetitive work and looses consistency between different instance of B

ii) Do placement at level B then from top-level instatiate B along with other cells. Saves times roughly by 4 since only once B instance and then some other cells to be placed. All B-instances are consistent. But I see area inefficient because there are lots of empty space in B that I can put some from top-level had the placement done flat.

So my question is related to (ii), is there a way to do hierarchical placement of instances so that they are all consistent and then flatten them that way we can make use of the empty space in the instance.

Satendra

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  • Andrew Beckett

    You can place instances on top of each other, so the fact that there is space in the cells doesn't stop you from using it. Unless I've misunderstood your question.

    The other way you could do this is to use cloning. You place everything flat and then lay out the devices from one of the instances. Then use the Generate Clones command and select the instances that have been laid out (with any routing between them). Then Search for other matches (you may need to set exact parameters, and change the search scope to be the layout if the devices are already generated in the layout). This will then generate "synchronous" clones which are effectively groups which are synchronised to each other - they're like cells without the hierarchy.

    Regards,

    Andrew.

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  • Andrew Beckett

    You can place instances on top of each other, so the fact that there is space in the cells doesn't stop you from using it. Unless I've misunderstood your question.

    The other way you could do this is to use cloning. You place everything flat and then lay out the devices from one of the instances. Then use the Generate Clones command and select the instances that have been laid out (with any routing between them). Then Search for other matches (you may need to set exact parameters, and change the search scope to be the layout if the devices are already generated in the layout). This will then generate "synchronous" clones which are effectively groups which are synchronised to each other - they're like cells without the hierarchy.

    Regards,

    Andrew.

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