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 Internal error with topology.c 

Last post Fri, Jun 3 2011 9:20 AM by Andrew Beckett. 5 replies.
Started by CPete 02 Jun 2011 12:15 PM. Topic has 5 replies and 2543 views
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  • Thu, Jun 2 2011 12:15 PM

    • CPete
    • Not Ranked
    • Joined on Mon, Apr 11 2011
    • Posts 6
    • Points 105
    Internal error with topology.c Reply

    Hi,

     When I try to run a Spectre dc and trans simulation with my 8-bit-adder circuit, have an internal error stopping the simulation.  I get the following messages in the spectre log window:

    1) the usual "unable to compile ahdlcmi module library" message (which has not stopped my simulations in the past),

    2) a warning from spectre during initial setup about having PMOS and NMOS from the driver circuit running at 1 A/exceeding imelt = 10 mA (the test driver/load circuit provided by our course instructor)

    3) "Internal error found in spectre during topology check, during initial setup." --> "Assertion failed in file 'topology.c' at line 1008"

     

    Any ideas how to interpret error #3??  I've done the Virtuoso save and check with no error for the 8-bit-adder or any of the lower schematics in the hierarchy.

    To explain how I'm implementing an 8-bit-adder:  The design is four 2-bit-adders linked together.  Each 2-bit-adder is made of 2 individual adders.  Individual adders have Carry Out implemented with CMOS and Sum implemented with pass-logic transistor gates.

     

    Thank you for your time.

    • Post Points: 20
  • Thu, Jun 2 2011 12:22 PM

    Re: Internal error with topology.c Reply
    What version of spectre are you using? It should say in the output file, near the top.

    Andrew
    • Post Points: 20
  • Thu, Jun 2 2011 1:21 PM

    • CPete
    • Not Ranked
    • Joined on Mon, Apr 11 2011
    • Posts 6
    • Points 105
    Re: Internal error with topology.c Reply

    Spectre 5.1.41 USR1 it says.

    • Post Points: 20
  • Fri, Jun 3 2011 1:37 AM

    Re: Internal error with topology.c Reply

    You're using a version of spectre built 6.5 years ago. That doesn't make sense, given that there have been 7 major releases of the analog simulators since then. In 2004 we split off the simulators from the IC stream, and have released MMSIM60, MMSIM61, MMSIM62, MMSIM70, MMSIM71, MMSIM72 and most recently MMSIM101. The version of spectre in the IC5141 has not been maintained for some time (although since you're using USR1 which is from December 2004, that's irrelevant).

    I would suggest you try installing a recent MMSIM version; I would expect the problem to go away as there have been many advances in the last 7 years.

    Andrew.

    • Post Points: 20
  • Fri, Jun 3 2011 9:14 AM

    • CPete
    • Not Ranked
    • Joined on Mon, Apr 11 2011
    • Posts 6
    • Points 105
    Re: Internal error with topology.c Reply

    Much agreed.  However, this version is provided by our university, who I imagine have no incentive to update unfortunately.

    I did solve my internal failure issue by taking my wires which were previously sharing common names, but not connected, and hard-wired them together in the schematic.  I'm sure the circuit logic is correct, but somehow the provided driver circuit and my adder circuit were not simulating well together.  Thanks again for the help.

    - CPete

    • Post Points: 20
  • Fri, Jun 3 2011 9:20 AM

    Re: Internal error with topology.c Reply

    I can't really see how that would help, since presumably the resulting netlist would be the same - spectre has no visibility of the schematic. I can only assume that something subtle changed which allowed it to proceed.

    Most universities would be using more recent versions than that - even if the IC version is old. But I agree, things may be more constrained there.

    Andrew.

    • Post Points: 5
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Started by CPete at 02 Jun 2011 12:15 PM. Topic has 5 replies.