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Layout XL: "Connectivity->Update->Components and Nets" resets all my pins

PNadeau

Dear folks,

Sometimes I make a few schematic changes and then in Layout XL I use Connectivity->Update->Components And Nets to update the Layout connectivity.  I select "Update nets and Instance name mismatches only" and "Update Net Signal Type" and click OK.

When I do this, the tool moves all of the pins I have already placed to the lower left-hand corner of the layout, despite nothing really changing on most of these nets, causing me to have to place them all again.

Is there a way to prevent this behaviour?  Ideally I'd like to leave most of the pins alone if nothing has changed on those nets.

If it's relevant, the pins were initially placed using Connectivity->Generate->Selected From Source, and using the "Unplaced" and "Place Individually" mode.  The pin and label are placed on the "pin" LPP for the relevant metal.

IC6.1.6.101, RHEL 6

Thanks in advance.

Cheers,
Phil

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  • PNadeau

    Hi Colin,

    Thanks very much for your persistence.  I can report the following:

    I tried check against source, and there was only one warning about a pin direction being mismatched. I fixed this and now there are no messages in CAS, but UCN still moves all the pins.

    I looked at the physical hierarchy, soft block settings.  If I click my top cell in the middle pane (the very top line with the folder beside it), the I/O pins are not listed in the I/O tab (it is completely blank), but if I go to the "Custom" subfolder I can see all my sub-cells, and selecting one of those shows the pins for that sub-cell in the I/O tab (but the top cell does not appear in the list).   It is possible this is expected behaviour, or at least unrelated to by UCN problems since I just tried this on a small cell of mine (only 4 pins) that actually does not suffer from the UCN problem (the pins are left in place somehow), and it too does not have pins listed for the top cell in a similar way.

    I am out of ideas too. Thanks for your help!

    Phil

Reply
  • PNadeau

    Hi Colin,

    Thanks very much for your persistence.  I can report the following:

    I tried check against source, and there was only one warning about a pin direction being mismatched. I fixed this and now there are no messages in CAS, but UCN still moves all the pins.

    I looked at the physical hierarchy, soft block settings.  If I click my top cell in the middle pane (the very top line with the folder beside it), the I/O pins are not listed in the I/O tab (it is completely blank), but if I go to the "Custom" subfolder I can see all my sub-cells, and selecting one of those shows the pins for that sub-cell in the I/O tab (but the top cell does not appear in the list).   It is possible this is expected behaviour, or at least unrelated to by UCN problems since I just tried this on a small cell of mine (only 4 pins) that actually does not suffer from the UCN problem (the pins are left in place somehow), and it too does not have pins listed for the top cell in a similar way.

    I am out of ideas too. Thanks for your help!

    Phil

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