KiCad power net connections? - Page 1
Forum section: electronics / general

author: Jidis
author_rank: Regular Contributor
timestamp: April 05, 2015, 03:08:46 am
content: I know this is probably in here, but I couldn't find it (sorry if it is):When attaching GND,Vdd,5v components in eeschema, should KiCad automatically tie them all together for you in pcbnew? I've attached net labels as well as going around and manually linking all the different sections with wires, both of which worked, but resulted in a somewhat messy schematic. Seems a bit of a hassle.If it matters any, I don't run the latest build. Looks like my apps are from way back on 9-28 of 2013. I'm in 32bit Windows XP.Thanks!

author: c4757p
author_rank: Super Contributor
timestamp: April 05, 2015, 03:17:01 am
content: Yes. Power symbols are net connections.

author: Jidis
author_rank: Regular Contributor
timestamp: April 05, 2015, 03:45:16 am
content: Thanks c4757p!So are you saying that if I add for instance a "GND" component and wire it to some part of my schematic, that it will automatically tie itself in the PCB layout to any other places I had attached a GND component? If so, it doesn't seem to work that way here. I may look into updating my software.Take Care

author: c4757p
author_rank: Super Contributor
timestamp: April 05, 2015, 03:48:10 am
content: Yes it will, and in all versions.Have you generated a netlist in the schematic, and imported it into the PCB?

author: Jidis
author_rank: Regular Contributor
timestamp: April 05, 2015, 04:59:10 am
content: Quote from: c4757p on April 05, 2015, 03:48:10 amYeah, everything is done in the correct order (schematic,electrical check,netlist,cvpcb, then layout). It'll just leave me with a bunch of stuff like resistors with an air wire on only one side. At least now I'm starting to check for it. If there are multiple parts connected to each other which are supposed to also be tied to ground or Vdd, it's not as easy to notice as the ones with only one wire. It mangled a board the other day and I had to go around and drill holes and add jumpers.Thanks

author: Neverther
author_rank: Regular Contributor
timestamp: April 05, 2015, 07:24:10 am
content: You dont need GND "components" either, you can just add short wire to the pin on your IC/whatever and then label it (net name, global label...) and it will be connected. Like when you have multiple sheets and pass netnames between them. GND component will make it more readable if it is a big schematic.For examplehereis simple little schematic where tings are passed around with net names. DRC check gives no errors as some of the pins on tiny13 are marked noconnect. Connecting unlabeled wire to one component, which goes nowhere will give DRC error. Multiple connected components will not give error and there is your little problem.Making separate blocks/sheets for different stuff will make it easier to see the labeled and unlabeled interconnects, if you place them on the edges. Sometimes it even makes the schematic readable as it is not so messy, sometimes more unreadable if there are no clear functions for different blocks/sheets.On my image on Sense1 block the GND should be brought to the right with short wire to make it more readable, currently it might cause a problem if I were to forget labeling it as it is not obvious it is connected to something else than across the opto.

author: codeboy2k
author_rank: Super Contributor
timestamp: April 05, 2015, 12:14:27 pm
content: Quote from: Neverther on April 05, 2015, 07:24:10 amPassing things around by net names is NOT a schematic...Your schematic is really ugly. Stop doing that. You've been influenced by all the other bad schematics on the net. It's not your fault. But resist the urge now and stop doing it that way.A schematic is a flow diagram. Your schematic has no flow whatsoever, and is completely broken up to the point where the reader has to start making mental connections to figure out what the "schematic" is doing. Some of your parts only connect to one other part, yet you broke it away and labelled it with net names. That's not what net names are supposed to be used for.I fixed it for you.

author: miceuz
author_rank: Frequent Contributor
timestamp: April 05, 2015, 01:58:03 pm
content: Note that Kicad has this nasty "feature" -- when pins named VCC and GND are HIDDEN, they connected to power nets. For example for various cmos4000 devices in standard library. If you have several power rails, you get magic.To work around this you have to edit the symbol, make pins visible and connect them to proper nets.

author: c4757p
author_rank: Super Contributor
timestamp: April 05, 2015, 02:30:48 pm
content: Yeah, but I'm not sure that's so much a problem with KiCad but more a problem with hidden pins, which are evil and must be killed with fire.(Okay, the libraries that come with KiCad use them - but they're utter crap in other ways too. I've never really considered the included libs to be part of the package, though.)

author: Bassman59
author_rank: Super Contributor
timestamp: April 06, 2015, 03:48:50 am
content: Quote from: c4757p on April 05, 2015, 02:30:48 pmYes, this.