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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

  • Hi,

    I think one way that you might be able to do this without changing the PDK library would be to change the CDF in virtual memory, in other words create/edit the "User" level cell CDF so that the "Effective" CDF now contains your desired defaults. You might need to load such code after the library had been accessed, in case a libInit.il file makes changes that stomp on your changes. If there is no libInit.il file then you might put your code in a libInit.il file inside the library structure so that it is automatically read when the library is accessed. The idea behind this approach is that the "effective" CDF is what exists in Virtual Memory and it is the summation of the Base CDF and any User CDF, the latter potentially overriding values coming from the Base settings.

    There might be another option which would mess with the Create Instance form, but I think this would involve changing the CDF anyway, so just changing the parameter directly may be the way to go with this.  Also, I am not sure that just changing "A" to 2 would force any of the CDF callbacks to run, so you could end up with a mess where the device is not self-consistent.  There is a great solution written by Andrew for forcing the callbacks to run procedurally, look for it in COS.

    Are you familiar with programming what I have described above?

    Regards,

    Lawrence.

Reply

  • Hi,

    I think one way that you might be able to do this without changing the PDK library would be to change the CDF in virtual memory, in other words create/edit the "User" level cell CDF so that the "Effective" CDF now contains your desired defaults. You might need to load such code after the library had been accessed, in case a libInit.il file makes changes that stomp on your changes. If there is no libInit.il file then you might put your code in a libInit.il file inside the library structure so that it is automatically read when the library is accessed. The idea behind this approach is that the "effective" CDF is what exists in Virtual Memory and it is the summation of the Base CDF and any User CDF, the latter potentially overriding values coming from the Base settings.

    There might be another option which would mess with the Create Instance form, but I think this would involve changing the CDF anyway, so just changing the parameter directly may be the way to go with this.  Also, I am not sure that just changing "A" to 2 would force any of the CDF callbacks to run, so you could end up with a mess where the device is not self-consistent.  There is a great solution written by Andrew for forcing the callbacks to run procedurally, look for it in COS.

    Are you familiar with programming what I have described above?

    Regards,

    Lawrence.

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