Author Topic: Connecting off PCB net in Orcad Layout?  (Read 1402 times)

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Offline spudboy488Topic starter

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Connecting off PCB net in Orcad Layout?
« on: January 13, 2020, 02:36:53 pm »
I'm designing a daughter board using OrCad Layout (old, I know). The board has 2 40 pin connectors at opposite ends. Both connectors have VCC net connections to the main board. The main board has the power supply and supplies VCC to multiple pins on each connector. I routed the board to use the closest VCC pin on a connector.

The issue I am having is that when I check connectivity, it shows all the VCC pins on each connector not being connected to each other as they are actually connected together on the main board. Short term, I added routes to all the VCC pins between the 2 connectors so I can check to see if I'm missing any other connections. I would rather not leave the connections there.

The question: Is there a way to indicate that multiple pins are connected externally from the PCB so Layout doesn't show them as being disconnected?

 
 

Offline nctnico

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Re: Connecting off PCB net in Orcad Layout?
« Reply #1 on: January 13, 2020, 09:59:38 pm »
Not that I'm aware of. In such designs I either just left the connections open or used different names for the power supply nets.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline PKTKS

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Re: Connecting off PCB net in Orcad Layout?
« Reply #2 on: January 14, 2020, 11:23:08 am »
(..)
The question: Is there a way to indicate that multiple pins are connected externally from the PCB so Layout doesn't show them as being disconnected?

Yes there is (at least there was.. and I doubt it changed)

Last time I checked (used) OrCAD stuff the "normal" simpler
way to do such stuff was via "NET LABELS"

Once the nets were globally labeled pretty much they are the same
whatever sheet you place that label available

As I recall OrCAD is the best EDIF compatible format out there
pretty much that EDIF compatibility is tight close to naming schemas

Paul
« Last Edit: January 14, 2020, 11:25:08 am by PKTKS »
 

Offline spudboy488Topic starter

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Re: Connecting off PCB net in Orcad Layout?
« Reply #3 on: January 14, 2020, 12:41:37 pm »
Not that I'm aware of. In such designs I either just left the connections open or used different names for the power supply nets.

In this case, the power supply net (named VCC) comes in on each connector and I am routing individual pins to a group of components. The net connectivity report shows the different group VCC nets are not connected. I don't want to change the name of the power supply net as a lot of the components have hidden power pins that tie to the "VCC" net and I know I'd miss one one or more if I went through and edited the schematic symbol.

 

Offline spudboy488Topic starter

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Re: Connecting off PCB net in Orcad Layout?
« Reply #4 on: January 14, 2020, 12:47:55 pm »
(..)
The question: Is there a way to indicate that multiple pins are connected externally from the PCB so Layout doesn't show them as being disconnected?

Yes there is (at least there was.. and I doubt it changed)

Last time I checked (used) OrCAD stuff the "normal" simpler
way to do such stuff was via "NET LABELS"

Once the nets were globally labeled pretty much they are the same
whatever sheet you place that label available

As I recall OrCAD is the best EDIF compatible format out there
pretty much that EDIF compatibility is tight close to naming schemas

Paul

The VCC net is globally labeled on the schematic. Rather than running VCC all around my PCB, I'm routing to the closest VCC pin on the connector that goes to the MB. I was wondering if there was a way, for example, to indicate that J1.1, J1.2, J1.37, J1.38, J2.1, and J2.2 were connected without having to actually run a trace between them all.
 

Offline PKTKS

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Re: Connecting off PCB net in Orcad Layout?
« Reply #5 on: January 14, 2020, 02:54:41 pm »

Not sure if works for your particular case

Try putting a label on each pin with the named net.
Check if your rules still hit the "unconnected" pins...

If so.. would be a wild case to think about

Paul
 

Offline nctnico

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Re: Connecting off PCB net in Orcad Layout?
« Reply #6 on: January 14, 2020, 03:24:47 pm »
Not that I'm aware of. In such designs I either just left the connections open or used different names for the power supply nets.
In this case, the power supply net (named VCC) comes in on each connector and I am routing individual pins to a group of components. The net connectivity report shows the different group VCC nets are not connected. I don't want to change the name of the power supply net as a lot of the components have hidden power pins that tie to the "VCC" net and I know I'd miss one one or more if I went through and edited the schematic symbol.
Well... using hidden power pins was a great idea when everything was powered from 5V but nowadays I strongly recommend to convert the symbols to show the power pins and connect these individually. It prevents errors when using different voltages. Not really an answer to your question bit still  ;)
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline spudboy488Topic starter

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Re: Connecting off PCB net in Orcad Layout?
« Reply #7 on: January 15, 2020, 12:34:38 pm »
Well... using hidden power pins was a great idea when everything was powered from 5V but nowadays I strongly recommend to convert the symbols to show the power pins and connect these individually. It prevents errors when using different voltages. Not really an answer to your question bit still  ;)

When I do mixed voltage designs, I'll make the power pins visible and connect then appropriately. If it's a single supply, 5V, 3.3V, whatever, VCC is the supply net.
 


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