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 Connecting symbol shapes to internal layer 

Last post Fri, Nov 30 2012 12:36 PM by ScottCad. 12 replies.
Started by TH Designs 30 Nov 2012 06:24 AM. Topic has 12 replies and 1879 views
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  • Fri, Nov 30 2012 6:24 AM

    • TH Designs
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    Connecting symbol shapes to internal layer Reply

    On the connector shown below I want to connect the shapes around the perimeter to the internal gnd layer. I have selected each shape and assigned the net "gnd" to each but I get no ratsnest showing a connection needs to be made. The status command does not show them as unconnected either.

    Previously I would have edited the copper area to assign the net, then placed a "free via" to connect to the gnd plane. I don't see a method to get a small hole into the shape.

    I tried to add pins to the library part, but that requires adding additional pins to the schematic symbol. Plus, can you even have a pin inside a shape?

    Tom

    (I sure picked the right avatar........)


    • Post Points: 20
  • Fri, Nov 30 2012 6:36 AM

    • budnoel
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    Re: Connecting symbol shapes to internal layer Reply

    It looks like your shapes may be static shapes.  You may need to change them to dynamic shapes before you can associate them with nets.  Select the shape and RMB - Change shape type

     

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  • Fri, Nov 30 2012 7:04 AM

    • TH Designs
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    Re: Connecting symbol shapes to internal layer Reply

    Tried that. When I try to change the shape type I get "A shape that is part of a symbol cannot be changed".

    When I try to edit it in the symbol editor, the option to change the shape is greyed out and only the defer dynamic fill is available. (Don't know what that does........)

    Tom

    • Post Points: 35
  • Fri, Nov 30 2012 7:25 AM

    • budnoel
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    Re: Connecting symbol shapes to internal layer Reply

    It sounds like you may have simply drawn the shapes in symbol editor.  I believe you need to create padstacks for those odd shapes if that is indeed what you want your lands to look like.  If you do a File - New  and choose "shape symbol" you will be able to create the shape in editor.  You then need to create a new padstack in padstack designer.  You can associate the shape you created by choosing under the Layers tab "Geometry - Shape" and then browse to the shape.  Let me know how you make out.

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  • Fri, Nov 30 2012 7:34 AM

    • fxffxf
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    Re: Connecting symbol shapes to internal layer Reply

     In the board editor:

    • Menu Shape->Select Shap....
    • Pick the shape you want to have a net assignment made
    • RMB Assign Net
    • Then either pick an object like a pin,via,shape or cline whose net you want to have the shape adopt or in the "Options" panel assign the net by name. 
    Shapes that are part of symbols cannot be changed to dynamic shapes.

     

    • Post Points: 20
  • Fri, Nov 30 2012 7:50 AM

    • TH Designs
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    Re: Connecting symbol shapes to internal layer Reply

    I did exactly what you suggested by selecting the shape then assigning the net from the options box where the list of nets are available. If I hover ofer the shape it tells me that the net I chose is what the shape is associated with BUT, there is no rats nest and no way to route the net to the inner layer.

    I have experimented with modifying the library symbol to have a pin in each of the shape areas. I then edited the schematic symbol to add these pins as power pins, named GND with no length so they don't show on the part.

    When I load the netlist, the symbol is updated, but it is no longer placed or routed. I then tried refreshing the symbol on the board without loading the new netlist, but it won't let me because the number of pins don't match the netlist. Thought if I could get the part loaded, then bring the netlist over everybody would be happy. No can do.........

    There has to be an easy way to connect shapes of a symbol to a net without having to reload the parts and re-route everything.

    Tom

    • Post Points: 20
  • Fri, Nov 30 2012 8:18 AM

    • fxffxf
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    Re: Connecting symbol shapes to internal layer Reply

    Ratsnest are not displayed to shapes. There is an Isolated shape report that you can acccess via the Reports or Status dialog. If the shape is isolated then you will need to tie it to the appropriate net by via routing from the shape to an object on that net. If could just mean that you need to add a via from  shape to another layer to tie it to a already connected shape. This can be done via the add connect command.

    This assumes you are using positive planes.

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  • Fri, Nov 30 2012 8:21 AM

    • TH Designs
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    Re: Connecting symbol shapes to internal layer Reply

    Maybe this is how it is done, maybe I just stumbled onto something.......

    After I assign the 10 shapes around the connector to the "GND" net, I was expecting to see a ratsnest that I could clikc on and route from. Didn't have one. Since I have spent close to three hour on this, my frustration level is climbing so I just tried Route - Connect, clicked on the shape and made a short trace, double clicked to insert a via and the connection was made to the GND plane!

    I tried the same thing on a shape that did not have any net associated with it. It allowed me to route a trace and place a via, but no connection was made to either plane (which I would expect).

    So it looks like assigning the shape to a net and the MANUALLY putting in a trace from the shape to a via will connect it to the gnd plane. (I would really like the via in the shape, I'll try that also)

    I don't know if this will remain when a new netlist is loaded, but I'm hoping it stays.

    Tom

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  • Fri, Nov 30 2012 8:23 AM

    • TH Designs
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    Re: Connecting symbol shapes to internal layer Reply
    fxffxf:

    Ratsnest are not displayed to shapes. There is an Isolated shape report that you can acccess via the Reports or Status dialog. If the shape is isolated then you will need to tie it to the appropriate net by via routing from the shape to an object on that net. If could just mean that you need to add a via from  shape to another layer to tie it to a already connected shape. This can be done via the add connect command.

    This assumes you are using positive planes.

    Looks like we were typing at the same time................ You stated what I think I figured out.  Thanks!

    • Post Points: 5
  • Fri, Nov 30 2012 8:23 AM

    • TH Designs
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    • Joined on Fri, Apr 13 2012
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    Re: Connecting symbol shapes to internal layer Reply
    fxffxf:

    Ratsnest are not displayed to shapes. There is an Isolated shape report that you can acccess via the Reports or Status dialog. If the shape is isolated then you will need to tie it to the appropriate net by via routing from the shape to an object on that net. If could just mean that you need to add a via from  shape to another layer to tie it to a already connected shape. This can be done via the add connect command.

    This assumes you are using positive planes.

    Looks like we were typing at the same time................ You stated what I think I figured out.  Thanks!

    • Post Points: 20
  • Fri, Nov 30 2012 11:21 AM

    • ScottCad
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    Re: Connecting symbol shapes to internal layer Reply

    Tom on those connectors that have mounts, you might want to think about making the pads as an actual padstack, i.e adding a pin for each one. On the schematic side you can either hide those pins or re-draw the symbol to include them.

    My preference is one from electrical/drc checking. Thing is the symbol might not look ideal on the schematic but doing those mounting pads as pins has the added advantage that your schematic will exactly match that board, plus you will also get a net.

    I think having floating pads in a footprint can lead to errors on the board, sometimes costly ones.

    Anyway just a suggestion.

    Thanks Scott

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  • Fri, Nov 30 2012 11:54 AM

    • TH Designs
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    Re: Connecting symbol shapes to internal layer Reply

    Scott,

    In the future I will do that. I made a new symbol already. I would have done it on this board, but every way I tried, when I brought the netlist in it blew away my routing / placement. I didn't want to have to re-route 8 connectors again so for now I am editing the shape in Editor and assigning it to the gnd net, then manually placing a trace/via to gnd. It works pretty well with no DRC's. I even reloaded the netlist a few times and it didn't impact what I did.

    I'm probably jinxing myself here, but I think I'm getting the hang of this monster. This board was a pretty simple 4 layer debug board for a video controller. I start a job next week which will be the real test of what I have learned (or haven't learned). 12 circuits of high current DC, processors and MOSFETS. Not to mention the heat dissipation issues that go along with such circuits. I expect it will take about 30% longer then I estimated due to the learning curve I'm still on. I'm looking forward to it, in a sort of demented way..........

     Have a great weekend!

    Tom

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  • Fri, Nov 30 2012 12:36 PM

    • ScottCad
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    Re: Connecting symbol shapes to internal layer Reply

    Tom, not sure if you spotted it but there is an option in capture and also in Import Logic to leave existing etch alone when doing a forward annotation. That sucker is handy if you have routes routed in and you dont want them to be blown away.

    When you netlist in capture you could un-check "Allow etch removal during eco"

    Best of luck on that new board, sounds like you are ready to take the Bull by the Horns : )

    Have a nice weekend too

    Scott

    • Post Points: 5
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Started by TH Designs at 30 Nov 2012 06:24 AM. Topic has 12 replies.