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constraining no. of metal layers in Cadence SoC encounter

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Hi all! Please let me know if there is any form in the tool Cadence SoC encounter where we can declare no. of routing layers for our design with limited no. of metals say 5. But my tool & Technology supports 8 Layer Metal. One solution what I found is during design Import we can call technolgy file(.lef) of say 5 Layer metal. Is there any other place in the entire flow where I can constrain say to 5LM in the tool? Thanks in Adv!

  • The "setMaxRouteLayer" command is intended for this. It informs all of the components in the system that although there are (for example) 8 metal layers in the technology LEF that only 1-5 are to be used for routing.

    Hope this helps,
    Bob

  • Dear Bob, Thanks for reply. Now please tell me where I have to use this command in my flow? Can I declare this command at any stage in my flow or I have to declare this after or befare some particular stage? Thanks Jit

  • Hi ,

                        1. In the place stage you will be using trialroute for nets so there you can use
                                                              setTrialRouteMode  -maxRouteLayer  <value>
                                                              setPlaceMode -maxRouteLayer <value>
                        2.In CTS(If you actual routing of CTSnets later)
                                            setTrialRouteMode -maxRouteLayer <value>
                           In CTSspecfile dont forget to include
                                             TopPreferredLayer      <value>
                                             BottomPreferredLayer   <value>
                          3.set_attribute -net <netname> -top_preferred_routing_layer <value> --bottom_preferred_routing_layer <value> 

    Hope this helps you !

    Thanks n Regards
    NAADHAN      
                                        

  •  Naadhan lists some very good specific layer controls for various parts of the flow. Sometimes, for example, you want your clocks to be on even fewer layers than the rest of the design.

     If you are just using setMaxRouteLayer for everything, just specify it at the very start of your flow. It will be followed for all steps.

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