Occurrences reference designator assignment in complex hierarchical design

Hi Bill,

 

It is good to hear your vote of confidence in hierarchical designs in Cadence.  Can you provide any insight on the 'tricks' that you mentioned?  I haven't been able to find any way to keep the software from deleting all my occurrence data every time I cut/paste a hierarchical block (even with the 'design level' option checked).  This also deletes the reference designators, and replaces them with a new ref des, which is SOMETIMES the same as the original (maybe 75% of the components?).  Losing the synchronization between schematic and PWB ref designators is not really a good recipe for a maintainable design...  Talking with Cadence support, we've identified that this is a bug with the software, but if you have a workaround I would be very curious to know what it is.  I'm at the point of needing to flatten a 150 page extremely complex hierarchical schematic, so any clues you can provide would be appreciated.

 

Thanks!

Jeff

Jeff,

I loss sync way to often and have to deal with this sometimes on a daily basis.

Note:  the annotation must be done first!

1. Try update place -> update symbol -> module

Depending on what you've done this may work.

2. Delete all symbols and routing in the modules that have errors , but not the Module subclass outline

Repeat step 1

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Sometimes I need to open the schematic for the mdd file and do the reuse creation first and the recreate the mdd file.

Then go back to the upper level design file and re-annotate.

Let me know if you don't understand or this doesn't work.

Bill

We are having the same issues with no one being very happy about hierarchy and also looking to flatten designs. This is too bad as I see it as a valuable tool if it functions correctly. Presently we use hierarchy blocks and replicate for physical duplication of the blocks. If the hierarchy worked as advertised it would be easier to use physical sections from board to board.

If you understand how the software works, you will appreciate that this behaviour is not "a bug". Complex hierarchy, repeated h-blocks, in Capture has one copy of the schematic, in reality this is the "Instances" (original) version, and "n" sets of properties for that schematic, the "Occurrences" properties, one set of properties for each h-block that references the schematic. When the schematic is copied, to paste "somewhere else", the "Instances" version is actually copied, including the original Instances properties, if any - any other implementation of "copy" would involve determining "which" set of Occurrences properties were to be retained, this wouldn't be impossible to implement but tricky to make fool proof. If another h-block that references the schematic is added, another set of properties are added to the "Occurrences" properties, no copy of the underlying schematic is made. Maybe more control of Annotation would be the way to go.

Hi oldmouldy!

Yes, I do appreciate the fact that COPYING a block and pasting would require that new occurrence properties be generated for that new occurrence, and that copying those new properties from the instance makes the most sense.  I agree that this is the desired behavior for COPY/paste.

The bug is that when you CUT and paste a hierarchical block, the occurrence properties are deleted and replaced by new occurrence properties for that block.  In a CUT/paste operation, I am simply trying to move that design component to another location or schematic page.  That block is a part of my design, that correlates to a layout via matching reference designators (or maybe occurrence ID property).  In addition, I may have occurrence properties associated with the parts within that block (ROOM assignments, etc.).  When I CUT/paste the block, I pick up my design, and when I paste it back down, it is DIFFERENT (new ID, ROOM, ref des, etc. properties).  This is 100% a bug, and makes it nearly impossible to reliably maintain a complex hierarchical design.  Please try this.  If your results are different, then I will very happy to know how, but both the AE from Cadence and myself have replicated this issue.  The major danger is that the initial hierarchical design will 'appear' to work fine, and layout and everything will be okay, but if you ever need to CUT/paste any blocks or components, you will lose the occurrence data associated with your parts, and reference designators will be changed and become out of sync with the layout.  For a complex design, this would be a nightmare, and until this bug is fixed, I can conclusively state that Cadence does not support reliable and maintainable hierarchical designs.  I would love to be proven wrong on this, but I don't have high hopes...  I'm greatly anticipating the day that this is fixed, so I can actually use hierarchy in my designs without ending up with an inflexible and/or non-maintainable design.  For now, we are stuck flattening everything...

~Jeff