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 Scan mode and scan chain control from internal registers 

Last post Wed, May 15 2013 11:23 AM by Sinjeetp. 4 replies.
Started by Sinjeetp 26 Apr 2013 06:25 PM. Topic has 4 replies and 1256 views
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  • Fri, Apr 26 2013 6:25 PM

    • Sinjeetp
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    Scan mode and scan chain control from internal registers Reply

    Hi,

      I have unique requirement that scan mode be set by internal register which would control output at PO. By default PI/PO which drives scan are set for something else. Before scan starts, I need to set register to a proper value so PI and PO controls inserted scan chain. I do know that there exist a way to have tester drive the Register interface to drive PI to set registers to desired value. What I do not now how to generate such pattern that tester understands and how to include them in initialization sequence.

     

    Thanks,

    Sinjeet

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    • Post Points: 20
  • Thu, May 9 2013 9:36 AM

    • Andy Hughes
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    Re: Scan mode and scan chain control from internal registers Reply

    Sinjeet,

     First, I am assuming that those control registers are not part of any of your normal ATPG chains, correct?  Also, from your description are you just setting internal values to change your PO's to proper outputs for your SO's?  Anything else this configuration does?

     Any type of setup sequence like this would be included in your modeinit sequence.  Do you currently have a custom modeinit sequence?  If not, then one needs to be created.  let me know where you are at with this so I can help you further.

     

    Andy Hughes

    • Post Points: 20
  • Thu, May 9 2013 9:53 AM

    • Sinjeetp
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    Re: Scan mode and scan chain control from internal registers Reply

     Hello Andy,

      Control registers are not part of ATPG cahins. Control registers need to be set to correct value to change few of the POs for SCAN mode. Do I have to convert SPI register write transaction in some form of scan sequence? If yes, how do I map them?

     

    Thanks,

    Sinjeet Parekh

    • Post Points: 20
  • Thu, May 9 2013 10:19 AM

    • Andy Hughes
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    Re: Scan mode and scan chain control from internal registers Reply

    Sinjeet,

      This gets into direct tool flow support.  What company do you work for?  Do you have a Cadence AE that you work with?

     

      In summary if you want to see what a modeinit looks like, do the following in the ET GUI:

    - Pull up the GUI for the tbdata you are working with

    - Go to Report->Sequences..

    - Load in testmode name. 

    - Change Pattern Format to node

    - Type in Outputfile name

    - Click on Advanced tab and select  "as scan load events"

    - Click OK and then click Run.  This will output a file for you that contains the current modeinit sequence that is default for that testmode.  You would nee to add your setup sequence to that modeinit and then use that to build your new testmode.

    Also.  The commandline for above would look something like this:

    report_sequences outputfile=XXX.seq format=node testmode=YYY compact=fill

     

    For further support please consult support.cadence.com.

    Andy

     

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  • Wed, May 15 2013 11:23 AM

    • Sinjeetp
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    Re: Scan mode and scan chain control from internal registers Reply

     Thanks Andy. I need to figure out how to modify sequence file for programming correct reg values to put chip in the scan mode.

     

    Thanks,

    Sinjeet

    • Post Points: 5
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Started by Sinjeetp at 26 Apr 2013 06:25 PM. Topic has 4 replies.