RC ; sdc ; load_of

 Hi Boris,

 problem is load_of is not an SDC command. There are a number of things you can do

(1) create a load_of procedure in TCL along the lines of

proc load_of {args} {
   set libCellPath [find / -null_ok -libpin $args]
   if {$libCellPath != {}} {
      set load [get_liberty_attribute capacitance $libCellPath]
   } else {
      set load 0
   }
   return $load
}

(2) User RC syntax

  set_attribute external_pin_cap [expr 5 * [lindex [get_attr capacitance $load_pin] 0]] [all des outs]

note that the expression  'lindex [get_attr capacitance $load_pin] 0' is needed since it provide values for rising and falling edges. Also $load_pin is the ouput of something like 'find /libraries -libpin . ...]

hope this helps,

gh-

Below statement is the equivalent of what you are looking for. 

set_load [expr 30 * [lindex [get_attribute capacitance [get_lib_pins lib_name/inv3/A]] 0] ] [all_outputs]

 P.S.: lindex 0 is being taken considering rise cap value

Great! Thanks a lot!!!

There's a problem: [get_attribute capacitance ...] only gives the capacitance in fF

rc:/> get_attribute -h capacitance libpin
  get_attribute: returns an attribute value from an object

Usage: get_attribute <string> [<object>+]

    <string>:
        attribute name
    [<object>+]:
        object of interest (must be unique)

    attribute category: lib_ui

    attribute name: capacitance
          category: lib_ui (returns Liberty attribute cell information)
       object type: libpin
       access type: read-write
         data type: capacitance rise/fall
     default value: 0.0 0.0
             units: femtofarads
              help: The rise/fall capacitance.

So you have to divide the retrieved value by 1000 as RTL compiler computes in pF.

 That would be correct. The good news is RC is consistent and always return in fF independent of library units so once you fix the proc, you should be good to go

good luck,

gh-