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 dft settings during DFT scan insertion 

Last post Mon, Jan 7 2013 11:15 PM by nannasin28. 4 replies.
Started by tanyacool 29 Oct 2012 05:40 AM. Topic has 4 replies and 1622 views
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  • Mon, Oct 29 2012 5:40 AM

    • tanyacool
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    dft settings during DFT scan insertion Reply

     hi,

     i am totally new to DFT and using RC tool for scan insertion. Some attributes settings needs to be done during synthesis.

    can anyone please list them out for scan insertion settings.

     

    thanks 

    tanya

    • Post Points: 35
  • Mon, Oct 29 2012 7:08 AM

    • grasshopper
    • Top 25 Contributor
    • Joined on Fri, Jul 18 2008
    • Chelmsford, MA
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    Re: dft settings during DFT scan insertion Reply

     Hi Tanya,

     I believe the DFT user guide is the best place to look into this. DFT has numerous nuances and providing you a one size fits all type of answer may do you more harm than good. I encourage you to discuss this with your local AEs and/or review the documentation to better tailor the answer to your needs

     hope this helps,

    gh-

    • Post Points: 20
  • Mon, Oct 29 2012 11:30 PM

    • tanyacool
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    Re: dft settings during DFT scan insertion Reply

     hi gh,

     let me frame the question in a different way:

    do we need testability logic to be inserted if we are only going for scan insertion. i am trying to do muxed scan style insertion and after that i checked the DFT rules, where around 43% registers were passing and after that i did connect scan chains in order to connect it, but i could not connect the scan chains as it said no chians available.

    can you help me on this.

     

    thanks

    tanya

     

    • Post Points: 20
  • Tue, Oct 30 2012 7:49 PM

    • grasshopper
    • Top 25 Contributor
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    • Chelmsford, MA
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    Re: dft settings during DFT scan insertion Reply

     Hi Tanyacool,

     I am not sure I fully understand your requirements but let me take a stab.

    By default,  RC maps seqs to scan equivalent provided they pass DFT rules (TDRCs)

    If you do not have control over RTL or do not want to address TDRCs in RTL you can

     (1) proceed with whatever % of TDRC-ready seqs you get

    (2) use the following attribute set to force_all resulting in all seqs with scan equivalent replaced

    attribute name: dft_scan_map_mode
              category: dft (controls design for test)
           object type: design
           access type: read-write
             data type: DftScanMapModeEnum
         default value: tdrc_pass
                  help: DFT scan conversion mode {tdrc_pass | preserve | force_all}.
     

    (3) use the command fix_dft_violations to address TDRCs 

     Note that TDRC status is tagged upon runing the command check_dft_rules

    Scan replacement happens during incremental synthesis

    scan connection will not happen unless your seqs have been scan replaced

    gh-

    • Post Points: 5
  • Mon, Jan 7 2013 11:15 PM

    • nannasin28
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    • <?xml version="1.0" encoding="utf-16"?><string>shenzhen, Guangdong</string>
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    Re: dft settings during DFT scan insertion Reply
    i could not connect the scan chains as it said no chians available.
    TDA7293
    http://www.hqew.net
    • Post Points: 5
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Started by tanyacool at 29 Oct 2012 05:40 AM. Topic has 4 replies.