CDB to Openaccess translator

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This page describes the CDB to openaccess (OA) translation process. OA format is required for Cadence IC615.

Misc Info.

  • While converting a library into OA format, the cds.lib file that contains the path of the cdb library must also contain all the dependent library paths. (Though those dependent libraries have already been converted)
    • If you fail to do this, then it has been observed that via's are not converted properly (they are missing in the OA layout)
      Note: Via's which are of type contact (instances) in IC514 are of type 'via' in IC615 -- they are not listed in the library instance list in IC615!
  • Conversion options suggested by cadence-support (in addition to default options)
    General tab: Select -- Ignore CDB locks, Report conversion progress, Write absolute paths to OpenAccess cds.lib file
    Database tab: Select -- Preserve device masters, Ignore DM settings
    Technology tab: Select -- Detect Vias automatically, Map via parameters

Converting UMC library

Here are the steps to convert the UMC library to OA format

  1. Open IC615 after sourcing the correct cadence.cshrc and typing 'virtuoso'
  2. In CIW (Command interface window) Tools --> Conversion Tool Box..
  3. Click on 'CDB to OpenAccess Translator ...'
  4. Browse to a folder containing a cds.lib with the CDB library entry eg: 'DEFINE umc13mmrf /srv/foundry/UMC/130nm/rf_umc_111218/Designkits/Cadence/umc13mmrf'
  5. Select the library you want and click on 'Set library options'
  6. Select the options 'Ignore CDB locks' and 'Report conversion process' .. leave the other options in their default state
  • This gave the following errors: (only summary is pasted here from the log file)

Finished at:   Dec 19 20:48:07 2011

95 cells and 667 cellviews were translated from library 'umc13mmrf' in 22.6s.
Message Summary:
ERROR (CDBOA-401): Cannot open OpenAccess file <path>/<name> in <mode> mode. Check that the file exists and that you have permission to access it.
Generated 6 times. The translator is unable to access the file either because it does not exist or because you do not have permission (for example, you are rerunning the translator on a library that was translated previously by another user or the permissions for the OpenAccess version have been changed). Check that the file exists and that you have permission to access it and then run the translator again.
WARNING (CDBOA-406): Directory <path>/<name> is in a cellview. The directory and its contents will be copied to the destination database but will not be translated.
Generated 36 times. Neither CDBA nor OpenAccess supports directories in cellviews. The directory and its contents are copied to the destination library but are not translated. This could mean that you end up with CDBA data in the OpenAccess version of your library. Check the directory in question. If it contains data that needs to be translated, correct the source data so that it conforms to legal directory structure conventions and then run the translator again.
WARNING (CDBOA-605): For cellview <path>/<name> the view type implied by the file name (<viewtype>) differs from the view type held in the database (<viewtype>). Creating a view of type <viewtype> in OpenAccess.
Generated 6 times. The translator has encountered a CDBA cellview for which the view type stored in the cellview data file differs from the view type implied by the cellview file name. OpenAccess expects a cellview filename to reflect the stored view type. The translator identifies conflicting view type information and fixes it by changing the cellview filename to agree with its stored view type. For example, a CDBA cellview with the stored view type maskLayout to be called symbol.cdb. This would be translated into an OpenAccess cellview of type maskLayout called layout.oa. To prevent these warnings from being generated, modify your CDBA data to ensure that the view type implied by the filename matches the view type stored for the cellview. For example, if the filename is sch.cdb, then the view type should be schematic.
WARNING (CDBOA-633): Instance <name> of parameterized cell master <path>/<name> in cellview <path>/<name> may not be correct. The data type of parameter "<paramName>" on the instance is different from that defined for the master. The instance will be assigned the default value for this parameter.
Generated 2 times. The data type of one of the parameters on the instance is different from that on the master from which it is derived. This is not allowed in OpenAccess. The translator creates the instance in OpenAccess and assigns the default value for the parameter in question. To eliminate this warning, ensure the parameter data types are consistent in CDBA.

  • The error and warnings were discussed with cadence support and all of them have been waived/resolved
    • All solutions here are given by cadence support people (Sanjeev Kumar issue number= 42660550)
    • A remote login sesion was created using a windows software called "SpaceCruiser"
  • The error occurs (ERROR (CDBOA-401)) because the cellview directories (/srv/foundry/UMC/130nm/rf_umc_111218/Designkits/Cadence/umc13mmrf/DIONW_L130E/hspiceS) contain two .cdb files 'sch.cdb symbol.cdb'
    • The 'master.tag' file indicates that sch,cdb should be used
    • Renaming the 'symbol.cdb' to 'symbol' makes this error go away!
    • This renaming is done for 6 cells.
    • Doing this removes the 'ERROR (CDBOA-401)' and 'WARNING (CDBOA-605)'
  • WARNING (CDBOA-406) occurs because the cellview 'hspiceS' (/srv/foundry/UMC/130nm/rf_umc_111218/Designkits/Cadence/umc13mmrf/DIONW_L130E/hspiceS) further contains a directory called 'hspiceS'.
    This is mistake by UMC and is not supported by Cadence!
    This warning is harmless and is hence not fixed
  • WARNING (CDBOA-633) is also harmless (do not remember exact reason given by Cadence support) -- it says some default value is being taken for couple of MOMCAPS!