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Creating and modifying blocks and schematic sheets in hierarchical designs

Question asked by alex.ballantyne on Oct 9, 2013
Latest reply on Oct 10, 2013 by robert_davies



We have completed a large hierarchical schematic but have been frustrated by some of the things that happen in DxD when creating blocks and editing the schematic sheets that lie beneath.


I'm hoping someone here can offer some help and advice so that we can use DxD more effectively for this kind of schematic.


We have had to work by manualy adding pins to frozen block symbols and hierarchical connectors to schematics individually because of the behaviour of the features that should assist with these tasks in DxD.


The design was done in 7.9.3 but I have confirmed these issues exist in 7.9.5 too.


Connecting pins on blocks that are not "frozen"


For example, suppose you have created two blocks (using Add/Block) located on a sheet that will be at the top of the schematic hierarchy.

Each block has been edited to add a pin, "OUT1" on the left block and "IN1" on the right block.

If these blocks are conneted by a net, all is well until the net is named. Suppose the net is named "SIGNAL". Now both pins will have their names changed to "SIGNAL", which is not what I want bcause the pins are intended to connect to nets called OUT1 and IN1 in the left and right blocks respectively. No warning is issued, there is no confirmation dialogue. If a signal is deleted, so are any pins attached to it.


Is this the intended behaviour of DxD? Is there some way of controlling this other that freezing/unfreezing the blocks (which has other consequences).


Traversing the hierarchy when blocks and schematics are incomplete.


Suppose the schematic is a work in progress. If you push into a block which has a missing pin, a dialogue is presented offering the option of deleting the "extra" port(s) for the schematic. No information is provided to suggest which port is un-matched to a pin. Running Verify doesn't provide any clues either. Manual checking pins to ports seems to be the only way to resolve this which is time consuming and frustrating since DxD clearly has identified the error.


Adding Missing Pins


Now suppose that on the sheet with mismatched ports we now do Generate Symbol and select the "Update It" option and check the Open in Symbol Editor option.

We are presented with a symbol with the missing pins added but now all the pins have moved to the default locations and have been changed to IN/LEFT. That's not what I've got in mind for an "Update". This isn't really any use other than for initial symbol creation since adding a single pin requires all the pins to be re-positioned.


Perhaps there is somthing we are missing here, and any help or advice would be welcome. We have the impression that DxD doesn't handle the creation and maintenance of hierarchial well and are reluctant to use it for future work of that nature as a result.