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Bob, How can I constrain optDesign -hold to add buffers on end points only?

eminemshow

Bob,

Things are like this, I am now at the final stage of timing closure, since functional timing is clean and test timing is ongoing. There is not enough time to config a MMMC environment. After investigation, I found that if I can add all the hold buffers at SI pin of DFF at scan shift mode, then functional timing would be un-touched (as you know, at Q pin of DFF, things would be dangerous......). So I want to ask whether I can control optDesign to make end-point only buffer insertion when fixing hold.

Thanks.

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  • BobD

    For the min spacing to blockage issue, would you check whether there's a "USEMINSPACING OBS" parameter in your LEF file?  It's hard to say without seeing a testcase what might be causing the behavior you're seeing, but since verifyGeometry isn't seeing it, I have a hunch that something LEF-based is causing the tool to think it's OK to go minimum next to obstructions.

    Thanks,
    Bob

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  • BobD

    For the min spacing to blockage issue, would you check whether there's a "USEMINSPACING OBS" parameter in your LEF file?  It's hard to say without seeing a testcase what might be causing the behavior you're seeing, but since verifyGeometry isn't seeing it, I have a hunch that something LEF-based is causing the tool to think it's OK to go minimum next to obstructions.

    Thanks,
    Bob

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