4 Replies Latest reply on Jun 27, 2013 8:14 PM by zoufadong

    extra pin on a part



           Version: MENTOR EE 7.9.4

           I met a strange situation while I build a part in library manager.

           I want to build some parts for crystals which have different package type. For a crystal, normally it has only two pins on its symbol, so I try to make one general symbol for all crystals with only two pins, and assign this symbol to different packages.





      fig.1  crystal symbol with only two pins


                                                                                                       fig.2 package with NC pins                                                                       fig.3 package with gnd pin

          for package in figure 2, I can just assign the unused pin to NC while doing the pin mapping. but for package in figure 3, things get complicated. because the third pin could be connected to a net, some engineer want to  connect it to GND while others connect it to DGND. if I just map this pin to GND in pin mapping dialog, the engineer won't have any chance to change the net name for this pin.

         the question is how to maintain only one general symbol while providing user the opportunity to assign other net name to extra pins other than the ones appeared on symbol?


        • 1. Re: extra pin on a part

          It's not a better way that all xo parts use only one type of symbol although there is a work-around to deal with your unique requirements.


          If you prefer see a only-2 pins-explicited schematics symbol for both of  2 logic-pins xo and more-than-2 logic pins xo, Just create different

          symbol names for them. for one of symbols, you assign the global signal attribute on the symbol and you can associate with your more-than-2 logic pins xo.



          • 2. Re: extra pin on a part

            If you only use integrated EE flow, you jut simply add  "supply rename" attribute on the 2 pin symbol.



            • 3. Re: extra pin on a part

              My chinese buddy,

              see below's snapshot for supply rename usage.


              1) create a symbol for 3 pin XO where you only explicitlly put 2 pin on the symbol and add attribute "supply rename" and assign a temp value, make it visible(it's useful to help deisgner get know there is another pin there)

              2) create the PDB entry for 3 pin xo, just assign the temp value to the pin in supply assignment

              3) put the symbol on schematics, change the temp value to current net name

              the example, I just changed GND to DGND, now the pin1 of xo and the pin 3 of xo get connected.





              • 4. Re: extra pin on a part


                     I got your idea, Thanks, you helped me a lot.