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Update Reference Designators - Both Directions

melview1

I have a design using OrCAD Capture v17.2 and OrCAD PCB Designer Professional v17.2.  They are currently synced up and all is good.  There are gaps in the reference designators, so I would like to renumber the components.  There's 2 ways I can do this:


1.  Layout to Capture

From within layout, I can use Manufacture--> Auto Rename Refdes.  I can rename the components however I desire.  Then I can go to Capture and use Tools --> Back Annotate to import the changes and life is good.  The catch is that now the reference designators are fairly random when looking at a particular schematic page/block.

2.  Capture to Layout

To alleviate the issue with #1, I would like to annotate the schematic and then push it to the layout.  According to community.cadence.com/.../26840, I can probably use the batch command REFTXT to do what I want, however it looks like I have to manually create the was-is file by exporting a single line per component BOM and then keeping track of changes while I change every one of the reference designators manually for nearly 650 parts.  Is this manual method the only way to create the was-is file?  Is there a function from within Capture that will annotate and create this was-is file for me?  Is there an entirely different way to accomplish the Capture to Layout method?

Thanks.

--Mark

  • Personally I don't do forward re-annotation (schematic to layout) because of possibility of rip-up when the update is made. Typically my designs have physical references that are easy to read in the lab (book order, left to right, top to bottom). However there are exceptions to every rule...
    Here are some things that might help with either method though:
    1) Auto rename occurs on components that have the "AUTO_RENAME" property added to them. You can either select the components using various methods such as by ref des, sym type, page in OrCAD, etc... and apply that property only to those components you want to rename. No harm in doing multiple passes and just doing back annotations to the schematic when done.
    2) Use the FST_REF_DES variable to set starting reference designator for a group and then updating a group of references with this starting designator. Example FST_REF_DES = 100. Then select all parts in a given function and apply the AUTO_RENAME property. Then do a Logic->Auto Rename. Save the board and update the schematic.
    (Note: I usually follow this up with a forward annotation out the of schematic back to the board out of habit). Then set FST_REF_DES to 200 and do the next group, etc....
    3) Rename by hand. I sometimes do this when the reference designator in a local area jumps around too much. As an EE who does design, layout and debug I am forced to live with my *bad* annotations so I have found that my eye prefers a localized reference designator to be next versus a truly grid-based increment which sometimes forces a designator that lives across the board to increase before the one just below it. Complicated? Sorry. Try polishing the references by hand if needed.

    Lots of other tricks out there but hopefully these get you going in the right direction.

    B
  • Thanks for the reply. It seems to reinforce what I've been finding that layout-->schematic is quick and easy, but schematic-->layout is fairly manual and time consuming.
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