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 clock uncertainty 

Last post Tue, Apr 8 2014 1:54 AM by iullah. 2 replies.
Started by iullah 04 Apr 2014 08:51 PM. Topic has 2 replies and 559 views
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  • Fri, Apr 4 2014 8:51 PM

    • iullah
    • Not Ranked
    • Joined on Sun, Mar 23 2014
    • Dhaka, Bangladesh
    • Posts 6
    • Points 90
    clock uncertainty Reply
    Hello All!
    How can I define different uncertainty value for different delay corners (i. e WCL_rcworst_-40) in encounter? 
    Filed under:
    • Post Points: 20
  • Sun, Apr 6 2014 11:04 PM

    • kazad
    • Top 500 Contributor
    • Joined on Wed, Sep 16 2009
    • Posts 22
    • Points 305
    Re: clock uncertainty Reply

     Hi

    Following procedure may help. Basically, you need to provide the SDC file with the new/updated clock uncertainty.

    For examle: 

     updateSDC -view WCL_rcworst_-40 -sdc <sdc_file_with_new_clock_uncertainty>

     

    ################################################################################
    # Procedure to update MMMC constraints
    # Usage: updateSDC -view <all | view_name> -sdc <sdc_file>
    ################################################################################

    proc updateSDC {args} {
       
        # Default
        set view "all"

        # Get mode name
        if {[regexp {\-view} $args]} {
            set view [lindex $args [expr [lsearch $args -view] + 1]]
        }
       
        # Get SDC file name
        if {[regexp {\-sdc} $args]} {
            set newSdcFile [lindex $args [expr [lsearch $args -sdc] + 1]]
        }
      
        # Help
        set helpString "Usage : updateSDC -view <all | view_name> \
                                      \-sdc <sdc_file> \
                                      \-help"
       
        if {[regexp {\-help} $args] || $args == ""} {
     puts $helpString
     return 0
        }
       
        # Main code
        #########################################################################

        # Save existing setup/hold views
        set restore [get_global timing_defer_mmmc_object_updates]
        set active_setup_views [all_setup_analysis_views]
        set active_hold_views [all_hold_analysis_views]

      
        set_global timing_defer_mmmc_object_updates true

        if {$view == "all"} {

     # For all views
     foreach view [all_analysis_views] {
        
         # Check if same file exists; replace if exists
         # otherwise, append it
         set modeName [get_analysis_view $view -constraint_mode]
         set sdcFiles [get_constraint_mode $modeName -sdc_files]
        
         set loc [lsearch -exact $sdcFiles $newSdcFile]
         if {$loc >= 0} {
      set sdcFiles [lreplace $sdcFiles $loc $loc]
         } else {
      lappend sdcFiles $newSdcFile
         }

         # Update
         update_constraint_mode \
      -name $modeName \
      -sdc_files $sdcFiles
     }

        } else {
     
     # For specific view
     
     # Check if same file exists; replace if exists
     # otherwise, append it
     set modeName [get_analysis_view $view -constraint_mode]
     set sdcFiles [get_constraint_mode $modeName -sdc_files]
     
     set loc [lsearch -exact $sdcFiles $newSdcFile]
     if {$loc >= 0} {
         set sdcFiles [lreplace $sdcFiles $loc $loc]
     } else {
         lappend sdcFiles $newSdcFile
     }
     
     # Update
     update_constraint_mode \
         -name $modeName \
         -sdc_files $sdcFiles
        }

        set_analysis_view -setup $active_setup_views -hold $active_hold_views -update_timing
        set_global timing_defer_mmmc_object_updates $restore
    }
     

    • Post Points: 20
  • Tue, Apr 8 2014 1:54 AM

    • iullah
    • Not Ranked
    • Joined on Sun, Mar 23 2014
    • Dhaka, Bangladesh
    • Posts 6
    • Points 90
    Re: clock uncertainty Reply
    Thanks a lot Mr. kazad for your detailed explanation. I am going to check it. 
    • Post Points: 5
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Started by iullah at 04 Apr 2014 08:51 PM. Topic has 2 replies.