12 Replies Latest reply on Sep 4, 2018 1:05 PM by jleine

    Pin properties for power and ground

    jleine

      I have a question and I have not been able to get a consistent answer from Mentor support. How do you define your component power and ground pins and why do you do it that way.

       

      The library material says we should assign ground pins ground and power pins power, but if you search for it online and look at mentor examples they are defined as inputs.

       

      Many Thanks,

       

      Jeff

        • 1. Re: Pin properties for power and ground
          liviu_craciun

          Hi Jeff,

           

          is the question about a symbol and a cell in the Central Library?

           

          About what Mentor tools - schematic, layout, simulation - refer the question ?

           

          Best regards, Liviu Craciun

          1 of 1 people found this helpful
          • 2. Re: Pin properties for power and ground
            jleine

            Hi Liviu,

             

            Good questions, sorry I was down in the details and forgot to include the basics.

             

            We are using DxDesigner for schematic entry with Xpedition for layout. We use hyperlynx drc and hyperlynx for Signal integrity and DC drop analysis.

             

            Thanks,

             

            Jeff

            • 3. Re: Pin properties for power and ground
              Community_Admin

              Hi Jeff - thanks for your post. I am going to move it to the product-specific  community where it will receive greater visibility by subject matter experts. The Mentor Ideas communities are where customers can submit enhancement requests to be voted on by others and are reviewed by the product teams for possible inclusion in future releases.

              • 4. Re: Pin properties for power and ground
                Jack

                I am not an expert on library work, and I am new to expedition, but since no one else has replied...

                 

                I believe Mentor uses this capability to assign power nets to components when the symbols don't provide PWR/GND pins.

                If your symbols have the PWR/GND pins, the nets you assign to them will drive the connectivity.

                (All of our symbols show PWR/GND pins, so I have never tried any other way)

                • 5. Re: Pin properties for power and ground
                  phiet

                  Mentor use that property for verification as well.. all  depend on how much you rely on that verification. There's some rule regarding power/ground net

                  • 6. Re: Pin properties for power and ground
                    phiet

                    recently, we try to define power / ground pin as POWER/GROUND pin type for fractured part (multi symbols)...it appears to be bad idea because the tool move all power/ground pin type to a common gate, which will be common to every other symbol ...and choke at packaging!!! so we have to change pins back to somtthing else (we chose bidir)

                    • 7. Re: Pin properties for power and ground
                      jleine

                      Hi phiet,

                       

                      This is exactly the type of thing I am trying to avoid, although we have symbols with power/ground pin types and we could package it OK.

                      • 8. Re: Pin properties for power and ground
                        robert_davies

                        This is a known issue with the PDB import. You can change the pins back to power and ground in the Part Editor after importing the gates successfully as layout does not use them.

                        • 9. Re: Pin properties for power and ground
                          phiet

                          Hi Robert,

                          is there any plan to fix those known issue one day ? are those known issue highlited anywhere in documentation ? up to now,it's sad that it's up to each user to discover those issue pretty much by themselve in their learning curve ..

                          • 10. Re: Pin properties for power and ground
                            jleine

                            Hi Robert,

                             

                            I understand it is a DR that is not scheduled to be fixed.

                             

                            I would like understand this better so we know what to do. Can you point me to more documentation on the problem and the work around?

                             

                            Thanks,

                             

                            Jeff

                            • 11. Re: Pin properties for power and ground
                              robert_davies

                              To get around the PDB import issue change the pins to analog before doing the import. This will assign them to the correct gate instead of creating a separate gate for power and ground in the PDB. Then change them to whatever you require be that power/ground or leave them as analog. I cannot elaborate any more than that.

                              1 of 1 people found this helpful
                              • 12. Re: Pin properties for power and ground
                                jleine

                                Robert_Davies has correct answer, but I did not understand it because I did not understand part creation.

                                 

                                If One creates a symbol and uses the power and ground pin type properties the pins will be swappable. with each other. This is because they are placed in gates under different s slots when the pin types are imported. See below:

                                .

                                One can work around this problem by first setting the power and ground pin types to be analog for the pin property import.

                                and AFTER that is finished we go back to the symbol and change the power and ground pin properties to be power and ground.

                                 

                                Now we have power and ground pin types for schematic DRC, but and the power and ground pins are not swappable.

                                 

                                Thanks,

                                 

                                Jeff