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How to trigger call-back procedure when changing cell-name of existing instance?

Sheppy

Hello,

I am developing a PDK containing various components (p-cells with call-back procedures). The designers using it at this moment, are performing the following steps to create large test-layouts, with lots and lots of nearly identical devices:

  1. Create a layout with many instances of a PMOS transistor, varying parameters like width, length, gate-drian space, gate-source space, etc.
  2. Copy this layout to a new cell
  3. Perform a search-and-replace and changing all cell-names from PMOS to NMOS

In an other PDK, this works, all parameters that need an update (like for instance a parameter called Device Info) are updated, but others, like width and length, remain as is. Thus creating a new layout with virtually no effort. So what clearly happens is that a cell-name change triggers the p-cell to update certain parameters.

When they try to do this with my p-cells, it doesn't work. All parameter names are identical (as is in the other PDK), but after the cell-name change the value of all parameters remain teh same. An example:

The parameter called DeviceInfo contains the following for the PMOS: Standard Low Voltage P-Channel MOS Device
After changing the cell-name, it should be updated to: Standard Low Voltage N-Channel MOS Device

However, this update does not happen.

Now is my question: how do I make my devices behave identical to the other PDK?

How do I trigger the call-back procedure to update, if necessary, the parameters of the p-cell?

With kind regards,

Sjoerd

Parents
  • Sheppy

    Hi Andrew,

    Thank you for your reply.

    I understand your answer and this has always been how I have been doing schematics/layout and how I was taught to use Cadence when I started "a long time ago" at Philips Electronics (many years before it became NXP...).

    Having said that, I see the advantage of doing it "the wrong way". We're in the process of developing a new process node, and to characterize / evaluate a group of new devices, one large schematic/layout is generated manually, and then by select-all or search-replace devices are being swapped. This schematic/layout contains hundreds of devices. So my new question is:

    • Is it possible to set a trigger which calls a certain procedure once OK or APPLY has been clicked in the properties form?

    I know many triggers can be set within Cadence (i.e. upon opening a viewer), so is this possible? And as a more general question:

    • Is there a support document that lists all triggers that are available in Cadence (Virtuoso)?

    In stead of going this way, do you advice me to write custom code to automatically swap components? This would be easy to do, since a certain type of NMOS is always swapped with a similar type of PMOS: a PMOS_50 always replaces a NMOS_50, PMOS_85 replaces NMOS_85, and so on. In total there are 10 types, so the code is not difficult to write (might even be possible to use abConvertComponentParamsHier() to do the trick).

    Final question for this reply:

    • Is abInvokeCdfCallbacks/CCFinvokeCdfCallbacks the same as CCSinvokeCdfCallbacks (code I got years ago to fix an issue with instantiating p-cells from within an other p-cell)?

    Thanks in advance,


    With kind regards,

    Sjoerd

Reply
  • Sheppy

    Hi Andrew,

    Thank you for your reply.

    I understand your answer and this has always been how I have been doing schematics/layout and how I was taught to use Cadence when I started "a long time ago" at Philips Electronics (many years before it became NXP...).

    Having said that, I see the advantage of doing it "the wrong way". We're in the process of developing a new process node, and to characterize / evaluate a group of new devices, one large schematic/layout is generated manually, and then by select-all or search-replace devices are being swapped. This schematic/layout contains hundreds of devices. So my new question is:

    • Is it possible to set a trigger which calls a certain procedure once OK or APPLY has been clicked in the properties form?

    I know many triggers can be set within Cadence (i.e. upon opening a viewer), so is this possible? And as a more general question:

    • Is there a support document that lists all triggers that are available in Cadence (Virtuoso)?

    In stead of going this way, do you advice me to write custom code to automatically swap components? This would be easy to do, since a certain type of NMOS is always swapped with a similar type of PMOS: a PMOS_50 always replaces a NMOS_50, PMOS_85 replaces NMOS_85, and so on. In total there are 10 types, so the code is not difficult to write (might even be possible to use abConvertComponentParamsHier() to do the trick).

    Final question for this reply:

    • Is abInvokeCdfCallbacks/CCFinvokeCdfCallbacks the same as CCSinvokeCdfCallbacks (code I got years ago to fix an issue with instantiating p-cells from within an other p-cell)?

    Thanks in advance,


    With kind regards,

    Sjoerd

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