Connecting off PCB net in Orcad Layout? - Page 1
Forum section: electronics / general

author: spudboy488
author_rank: Regular Contributor
timestamp: January 13, 2020, 02:36:53 pm
content: 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?

author: nctnico
author_rank: Super Contributor
timestamp: January 13, 2020, 09:59:38 pm
content: 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.

author: PKTKS
author_rank: Super Contributor
timestamp: January 14, 2020, 11:23:08 am
content: Quote from: spudboy488 on January 13, 2020, 02:36:53 pmYes there is (at least there was.. and I doubt it changed)Last time I checked (used) OrCAD stuff the "normal" simplerway to do such stuff was via "NET LABELS"Once the nets were globally labeled pretty much they are the samewhatever sheet you place that label availableAs I recall OrCAD is the best EDIF compatible format out therepretty much that EDIF compatibility is tight close to naming schemasPaul

author: spudboy488
author_rank: Regular Contributor
timestamp: January 14, 2020, 12:41:37 pm
content: Quote from: nctnico on January 13, 2020, 09:59:38 pmIn 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.

author: spudboy488
author_rank: Regular Contributor
timestamp: January 14, 2020, 12:47:55 pm
content: Quote from: PKTKS on January 14, 2020, 11:23:08 amThe 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.

author: PKTKS
author_rank: Super Contributor
timestamp: January 14, 2020, 02:54:41 pm
content: Not sure if works for your particular caseTry 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 aboutPaul

author: nctnico
author_rank: Super Contributor
timestamp: January 14, 2020, 03:24:47 pm
content: Quote from: spudboy488 on January 14, 2020, 12:41:37 pmWell... 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

author: spudboy488
author_rank: Regular Contributor
timestamp: January 15, 2020, 12:34:38 pm
content: Quote from: nctnico on January 14, 2020, 03:24:47 pmWhen 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.