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Customize PDK library without changing it.

nosaj

Hi all,


I'm looking for a way to change the CDF default value that doesn't require user interaction and changes to the actual PDK library.

e.g.

By default, pmos A=1, and CDF value of pmos's x, y, z  depends on callback of A.

Normally when the user instantiate pmos, they will change A=2, and subsequently updating x, y, z.

What I want : When user instantiates the pmos, CDF is already set to A=2 and x, y, z already update accordingly and automatically

How can this be achieved?

 Thanks in advance.

Parents

  •  There are numerous problems with changing the defaults in the effective CDF. For a start, if the user does a File->Refresh in the CIW, and hits OK when it asks them whether they want the CDF refreshed, the effective CDF will be discarded.

    Getting all the callbacks to run on the create instance form doesn't really make sense, and isn't really doable. You could potentially do something in a formInitProc (which you could set in the effective CDF too), but formInitProcs that change values are nasty, because they will then modify the values on existing instances when you do an edit properties, which gives you misleading information when you simply do edit properties to look at the current properties. Similarly if you changed the doneProc - that's also nasty.

    The cleanest solution would probably be to not only change A=2 in the effective CDF, but also change the defaults for x, y  and z to the values the callbacks would have set them to. That way it is all consistent out of the box. After all, that's the case with the original defaults - at least if well design.

    Overall, I'd be very wary of doing this. Especially if there are pcells involved - if the pcell's defaults then become different from the CDF's defaults, then odd things can happen (workaroundable by setting storeDefault=yes; what happens is that edit props things that if the form shows the CDF's default, it doesn't store the property on the instance; during pcell evaluation, if there's no property on the instance, it uses the pcell's default - so you think you've asked for one value, but it's actually evaluated using a different value).

    Regards,

    Andrew.

Reply

  •  There are numerous problems with changing the defaults in the effective CDF. For a start, if the user does a File->Refresh in the CIW, and hits OK when it asks them whether they want the CDF refreshed, the effective CDF will be discarded.

    Getting all the callbacks to run on the create instance form doesn't really make sense, and isn't really doable. You could potentially do something in a formInitProc (which you could set in the effective CDF too), but formInitProcs that change values are nasty, because they will then modify the values on existing instances when you do an edit properties, which gives you misleading information when you simply do edit properties to look at the current properties. Similarly if you changed the doneProc - that's also nasty.

    The cleanest solution would probably be to not only change A=2 in the effective CDF, but also change the defaults for x, y  and z to the values the callbacks would have set them to. That way it is all consistent out of the box. After all, that's the case with the original defaults - at least if well design.

    Overall, I'd be very wary of doing this. Especially if there are pcells involved - if the pcell's defaults then become different from the CDF's defaults, then odd things can happen (workaroundable by setting storeDefault=yes; what happens is that edit props things that if the form shows the CDF's default, it doesn't store the property on the instance; during pcell evaluation, if there's no property on the instance, it uses the pcell's default - so you think you've asked for one value, but it's actually evaluated using a different value).

    Regards,

    Andrew.

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