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 Setting "schematic" as stop view in Spectre netlister 

Last post Thu, Jul 2 2009 10:11 AM by hkutuk. 2 replies.
Started by hkutuk 01 Jul 2009 11:37 AM. Topic has 2 replies and 1980 views
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  • Wed, Jul 1 2009 11:37 AM

    • hkutuk
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    • Joined on Thu, Dec 4 2008
    • Posts 6
    • Points 60
    Setting "schematic" as stop view in Spectre netlister Reply

    Hi,
    I'm setting "schematic" in the stop view list so the netlister doesn't descend into the subckt blocks. This works if I have a single level gates such as a nand. However if I have multiple levels of hierarchy the netlister fails.

    For example for a single level hierarchy for a NAND gate and with a stop view of schematic I get what I expect even though the pins are missing! The netlister only includes the instantiation line as:

    // Library name: hkutuk_lib
    // Cell name: netlist_problem
    // View name: schematic
    g0 a9na2n size0W=0.0u size0L=0.0u size1W=0.0u size1L=0.0u


    but when I use a multilevel hierarchical block the netlister fails with a message like this:

    Netlist Error: Cannot find any info on instance "i3" in cell-view "hkutuk_lib" "netlist_problem" "schematic"


    Is there something wrong with the netlister or am I missing something?

    The CDS_Netlisting_Mode is set to Analog.

    Thanks,

    -Haydar

    • Post Points: 20
  • Thu, Jul 2 2009 3:20 AM

    Re: Setting "schematic" as stop view in Spectre netlister Reply

    That's probably because if you've told it to stop at a particular place, it needs then to have CDF simInfo for that cell to tell it how to netlist it. Normally CDF is not needed for intermediate levels of hierarchy, because provided the terminal order (etc) is consistent between the instance and the definition, all is OK. If it's become a leaf cell because it's in your stop list, then it needs something to tell it what to netlist.

    I can only imagine that the nand gate already has some CDF (although perhaps it is incomplete because of the missing pins), but the cell for i3 doesn't have any CDF.

    Setting "schematic" as your stop list is a bit of an odd thing to do, although I presume you have a good reason to do it?

    Andrew.

    • Post Points: 20
  • Thu, Jul 2 2009 10:11 AM

    • hkutuk
    • Not Ranked
    • Joined on Thu, Dec 4 2008
    • Posts 6
    • Points 60
    Re: Setting "schematic" as stop view in Spectre netlister Reply
    OK let me try to explain how this started.
    I want to replace the schematic blocks (pre-layout) with a postlayout description via my SKILL code. The cells that I want to use with postlayout information have an “extracted” view created in addition to their schematic and symbol views. I simply created the extractred view in the library manger by copying the schematic view as extracted. I tried copying symbol views as extracted view with no different outcome. Then I added “extracted” in the stop view list in ADE->setup->environment. So basically, when a block has an extracted view, the netlister should stop netlisting (as extracted is in the stop view) and instead do what the skill code instructs it to do.This did work just fine with cells with no hierarchy such as simple gates like an inverter. But when I had cells with multiple hierarchies it wouldn’t work anymore and the netlister would give error messages as: Netlist Error: Cannot find any info on instance "i3" in cell-view "hkutuk_lib" "netlist_problem" "schematic"To test this further I decided to use a native stop view name such as “schematic” and have the netlister to stop at the top level. Again it worked when I had non hierarchical cells but not when I have multiple hierarchies. For example, with “schematic” in the stop view list, a simple nand gate netlists but when I have multiple hierarchies I get the same error message as above.Since the native schematic and my extracted views behaved the same way, I thought there is a problem with the netlister. Eventually I'd like to be able to mark the cells extracted and stop the netlister here and intercept the netlisting with my own code to replace pre-layout blocks with post-layout.I hope this explanation makes sense. Thanks much for your help.-Haydar
    • Post Points: 5
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Started by hkutuk at 01 Jul 2009 11:37 AM. Topic has 2 replies.