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Where Oh Where is "number_of_routing_layers"?

Comments(0)Filed under: Logic synthesis, Logic Design, Physical timing closure, rtl compiler 8.1, ple physical global, digital design, blog logic design, Physical Synthesis Wires, Synthesis, Physical Prediction, RTL, RTL compiler, rc, apropos, FED, TeamFED, Matt Rardon

 OK, I'll just do "set_attribute number_of_routing_layers 6"...

  Error   : The attribute is read-only. [TUI-26] [set_attribute]
          : attribute: 'number_of_routing_layers', object type: 'root'
          : Cannot set or reset read-only attributes.

Hey, wait a minute!


If you are faced with this dilemma, don't worry, the solution is simple. Prior to 6.2 the number_of_routing_layers attribute existed only at the root level. In 6.2 the attribute was moved to the design level since the number of layers to be used for routing is a design specific decision. It is not uncommon for different place and route blocks from the same chip to utilize a different number of layers. When the attribute was moved to the design level the root attribute was retained for backwards compatibility, but was hidden. As of 8.1.200 the root attribute was converted to read-only and by 9.1.100 the root attribute will be removed entirely.

The design level attribute is the officially documented solution. This is the attribute to use in your scripts.

Here's another tip for you. Use the apropos command to locate attributes, commands, command options and much more.

  rc:/ > apropos
  Attributes matching search string:
   number_of_routing_layers (design)


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