e Library =A0 =A0Source
-_3 =A0 =A0blah blah blah
path for the filename for the graphic symbol...
James
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13 years ago
Finding shorts in OrCAD Capture
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13 years ago
That's not the problem. The problem was that, somehow, the power symbol "Vcc3" /itself/ was shorting to the +5v rail.
No, I understand labels--used them extensively. OrCAD was connecting things with _different_ labels. Why? I don't know. Probably there were properties hidden somewhere that I couldn't see with the Properties editor, that's my best guess. I didn't do it, I inherited the file that way.
-- Cheers, James Arthur
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13 years ago
short(s)
The problem probably wasn't the symbol, but where it was used. If you connect a port name (and the power symbols are just that, names, they name the net that they are attached to) to an established net, then it just connects the two together. Probably one of the parts was attached to a pin or wire that was already attached to the VCC net. Capture was just trying to read the mind of the designer, and assumed he wanted these two global nets connected 'here' and so, it did!
Charlie
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13 years ago
Run the DRC check and enable as many options as you can - especially the option that says "report (or list?) all nets". Then, in the resulting .drc file, do a search for "ALIAS" in that file. It will list any nets that have been connected together and may give a clue as to where the problem is. The .drc file will also have a section called GLOBALS. This section will contain all power and ground nets. It may help, too.
Bob
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13 years ago
-- The only time I've had a problem like that is when I've inadvertently connected symbols together on the schematic. I use OrCAD SDT 386+ for DOS, so I don't know if this'll apply to you, but if you have a "find" fuction in the menu, invoke it, enter "Vcc3", and one instance of it will be identified. After that, clicking "next" over and over again will identify the other instances of it, sequentially, and you'll be able to see where it's connected to Vcc.
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13 years ago
d o
When I look at the misbehaving symbols (I'm looking at an uncorrected copy), I can't see any difference, or inappropriate connection.
Examining the properties in the property editor, the bad symbol is no different than the other non-shorting 'Vcc3' symbols on the page.
It's just a power symbol, value=3D'Vcc3', but replacing it--in the same place, with the same connection, with an identical-looking symbol of the same name--clears the short-circuit.
I found the two shorts this morning by deleting pages, then restoring the pages and deleting symbols 'til I found the bad actors.
I'm glad that's done!
-- Cheers, James Arthur
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13 years ago
t
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Tried it, for future cases. The DRC does report that the power supplies are shorted, but it doesn't indicate where.
Thanks for the idea.
-- Cheers, James Arthur
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13 years ago
-- Congratulations! I'd almost be willing to bet that the errors were symbols superimposed on each other... Like you said, maybe a going away present. :-( That's happened to me a couple of times, and if the legends don't conflict (like Vcc3 being on top of or under Vcc) it's tough to find.
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13 years ago
If it is a hierarchical schematic try Edit> Browse> Flat Netlist.
-- Boris
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13 years ago
I wouldn't expect to see anything in the properties, except perhaps more pins than it should have.
Did you look at the culprit in the library? It would be interesting to know what made it do it. Perhaps overlapping pins?
That's a tough one. Like I said, it would be good to know exactly what happened for future use.
BT