KiCad PCB Layout Question - Page 1
Forum section: electronics / general

author: NanoHawk
author_rank: Contributor
timestamp: July 05, 2020, 06:54:15 pm
content: Hey gang,I'm an Eagle refugee. Was pretty disappointed when Autocrap bought Eagle and made massive changes to it before wrapping it into Fissile360.Anyhow, I'm on my 3rd PCB and beginning to really like KiCad.Because I love a challenge I'm also migrating to SMD while learning KiCad. All the cool toys seem to be SMD anyhow.I noticed that the PCB layout tool is being a little "eagle-y" with regards to where it places some components. I'm sure it's a PICNIC (Problem In Chair, Not In Computer) but I'd really appreciate it if someone could help me figure out why it will not let me place some passives where I want them.I designed a breakout board for the BQ24091DGQT Single Cell battery charger today and ran into the issue. I'm using 1206's because I need to hand place the parts and it's only my second SMD board, so I'd prefer that luck be on my side with a lower skill requirement. You'll notice that the passives aren't lining up sometimes. Yes, I'm aware that the passive location is less than optimal, but it should be workable for now. I haven't gotten my head around MSOP and other tiny tiny packages in terms of part layout. Most of my past projects have been DIP where there is ample space.FYI the pin headers will be on the bottom of the board.... I have not figured out how to tell KiCad that yet. And the routing was done by FreeRouting. I know how to route by hand in Eagle, but was spending an inordinate amount of time on it in KiCad. So I said the heck with it and just spent 10 minutes getting auto-route working for these test boards.

author: Bassman59
author_rank: Super Contributor
timestamp: July 05, 2020, 10:10:16 pm
content: Quote from: NanoHawk on July 05, 2020, 06:54:15 pmThe initial placement of parts is roughly in the order in which they appear on the schematic.You're supposed to doallof the placement yourself.(There's supposed to be an assisted placement mode but I don't see it on my macOS Catalina machine.)QuoteMouse over the footprint and hit "F" (for "flip"). Now it's on the other layer. Or you could right-click on the part to bring up the context menu, and one item there is Flip. Or you could mouse over the part and hit "E" (for edit properties) and in the dialog that pops up, look for "board side" in the lower left.QuoteRouting really isn't all that difficult. What problems were you having? Sometimes the problems can be traced to design rules not set correctly.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 05, 2020, 10:51:25 pm
content: I'm a DipTrace refugee... so also relatively new to KiCAD...After creating PCB from schematic just move the parts around by hand and observe the rats nest... rotate components to try and eliminate knots/cross-overs in the rats nest and then route. Flip to put parts on the other side.I actually like freeRouting; it does a decent job and then you can tweak by pushing/shoving.... or if you know better... just manually route.When I first started SMD I used to use 0805 but this feels much too big now... I find the best bang for the buck is at 0603 parts (although obviously sometimes size is determined by component value)There are some good tutorials out there... I liked this one...https://youtu.be/t5phi3nT8OU

author: NanoHawk
author_rank: Contributor
timestamp: July 06, 2020, 05:24:00 am
content: I'm sure I'll migrate to smaller parts eventually. My eyesight isn't as sharp as it was when I was younger, so I wanted to stack the odds in favor of a pleasant experience. At least for my first $35 break out boards... lol. By the time I order chips (I always order 5 or more), passives, boards from OSHPark ($3 ish) a stencil from OSHStencils, etc... the boards will be every bit of $35. But hey I'll have dozens of passives laying around.... maybe hundreds. lol.Back to my original question..... in Eagle there is an experience where parts won't line up because they are on different grids and Eagle is too stupid to translate inches and metric. Sigh. Yes, I know the US should have completed metrification... but here we are with a turd for President and clinging to our awful inch system that should have gone the way of the dodo bird...So why would KiCad not let me align passive components that are roughly the same size? I've tried Ctrl / ALT / Shift, etc thinking it would set me free at my own peril to move the component wherever I thought it was pretty.

author: HKJ
author_rank: Super Contributor
timestamp: July 06, 2020, 05:47:52 am
content: Quote from: NanoHawk on July 06, 2020, 05:24:00 amSelect the parts, right click and select align/distribute.

author: tox3
author_rank: Contributor
timestamp: July 06, 2020, 08:55:32 am
content: Footprints are the same size and it is possible to align them.Maybe after import some parts are not on grid - you can change position manually by selecting component and pressing E and changing position to match grid. After that you should be able to align them.

author: NanoHawk
author_rank: Contributor
timestamp: July 06, 2020, 12:04:10 pm
content: Perfect. KiCad has so many moving parts that I haven't begun to learn where they are all at. I'm just kludging my way through my first boards. On the bright side, it doesn't seem to be like Eagle or any other Autocrap product. Classic Eagle had alot going for it, but it was still capable of driving you mad in about 3 nanoseconds.

author: poeschlr
author_rank: Regular Contributor
timestamp: July 06, 2020, 07:00:06 pm
content: This might be of interesthttps://forum.kicad.info/t/i-come-from-eagle-what-should-i-know-about-kicad/22459

author: 2N3055
author_rank: Super Contributor
timestamp: July 06, 2020, 07:16:45 pm
content: Quote from: poeschlr on July 06, 2020, 07:00:06 pmThis site can’t be reachedThe webpage athttps://forum.kicad.info/t/i-come-from-eagle-what-should-i-know-about-kicad/22459might be temporarily down or it may have moved permanently to a new web address.ERR_FAILEDLOL typical for Kicad ...

author: poeschlr
author_rank: Regular Contributor
timestamp: July 06, 2020, 08:59:01 pm
content: The forum is currently in the process of being transferred to a new server so there might be times when it is not reachable.https://lists.launchpad.net/kicad-developers/msg44127.html---Also be aware that the forum is an independent thing. It is managed by Chris Gammell and his company contextual electronics. The community is very thankful for individuals like him who take their own money and time into their hand to provide a great platform for us to help each other make awesome things.

author: 2N3055
author_rank: Super Contributor
timestamp: July 06, 2020, 09:15:47 pm
content: Quote from: poeschlr on July 06, 2020, 08:59:01 pmIt was meant to be slightly humorous..But that is the nature of such distributed projects, there is no guaranteed service level. All you can expect is best effort.And we SHOULD be grateful for the effort anyways..Best regards,Sinisa

author: poeschlr
author_rank: Regular Contributor
timestamp: July 06, 2020, 09:31:04 pm
content: The forum is not down often. I remember only one time before the current outage and that was years ago (I basically visit daily so i would have noticed). And the quality level of support one gets there is extremely high. Some paid competitors will struggle to reach the responsiveness and quality offered by the community for free. (And well if the forum is down then there is still the bugtracker, other forums like the eevblog forum, stackexchange and reddit)---And if you are prepared to pay then you can get guaranteed service for KiCad as seth (one of the lead devs) started a service company for exactly this reason. That same company also has wayne on the payrol (the project leader) since his last employment fell through.-https://www.kipro-pcb.com/- And the announcement on the mailing listhttps://lists.launchpad.net/kicad-developers/msg42123.html- And the announcement that wayne joined themhttps://kicad-pcb.org/blog/2019/12/Project-Leader-Joins-KiCad-Services-Corporation/

author: 2N3055
author_rank: Super Contributor
timestamp: July 06, 2020, 09:36:26 pm
content: Quote from: poeschlr on July 06, 2020, 09:31:04 pmThat is actually very interesting info. Thank you !!Take care,

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 07, 2020, 01:55:29 pm
content: Initial post seems to be a long monologue with no obvious question (Or is it just me?)The question seems to be how to line up the 1206 components.One way is to select a row of those components by dragging a box around them, Right click the mouse and : "Align/Distribute" / "Align to Top".While moving single components, "some" point gets "attached" to the cursor, and will be placed on a grid point. That can be the center of the component, the center of a pad or numerous other items. If you move all the components by the same attachment point, then they will all line up on the grid after movement.

author: NanoHawk
author_rank: Contributor
timestamp: July 07, 2020, 04:49:51 pm
content: Perhaps I wasn't specific in the OP. It was very late in the day...I was posting to find out how to align components in Pcbnew.I noticed that 1206 Capacitors and Resistors don't want to line up and figured it had to be something simple I was doing.In the original post I felt like it was important to explain that I had an Eagle background and that it wasn't my first go-round with PCB design/layout.Sure enough, selecting and clicking align/to-top works.I do appreciate the explanation about the component points though. That makes sense from a programming standpoint.*****In case anyone is thinking this is a messy board:This is a break out board to test a chip as part of a project I'm working on. I did not spend time on optimization of the layout other than the input and output pin headers.Routing was autorouted via freerouting.When I get to where I have a prototype of a project I'll spend more time on component layout and trace optimization.

author: Twoflower
author_rank: Frequent Contributor
timestamp: July 07, 2020, 05:04:06 pm
content: Just some ideas:* Rotate D1 about 180°* C2 is shorted (do a Design-Rule-Check! Enable the routing rules KiCad has build in)* Shifting the C1-J1 connection north would probably allow to run the trace R1-IC1 without vias (swap R1 and C1 might help).

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 08, 2020, 09:30:45 am
content: I guessed your schematic and had a go...I added fill for IN, OUT and GND(Also needs BCu GND fill and a few vias in U1 thermal pad)[I did not verify anything about the circuit; just had a play)

author: NanoHawk
author_rank: Contributor
timestamp: July 08, 2020, 12:58:18 pm
content: Thanks. It's just a test board. Looks like you used smaller components as well.When I get closer to a prototype I'll start dialing in layout and optimization.What do the via's do under the thermal pad?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 08, 2020, 01:15:33 pm
content: Quote from: NanoHawk on July 08, 2020, 12:58:18 pmAll components were 1206_3216Metric apart from the chip which is whatever it is.Vias spread heat to a ground plane on the BCu. Fill on the back and put a via pattern on the thermal pad (which is VSS according to datasheet)On reflection I don't think this is a good candidate for autorouting as there are some layout rules... e.g big tracks to IN and OUT so optimising for minimum vias doesn't make sense here.Something like this...I'll stop interfering now and leave you in peace. Have fun!

author: spudboy488
author_rank: Regular Contributor
timestamp: July 09, 2020, 11:43:03 am
content: The only thing I might add is the orientation of J1 might be confusing depending on the actual connector being placed and the desired cable routing. I use MTA-100 connectors and, if placed per the layout and keeping with the MTA-100 numbering scheme, the cable would exit to the right, across the PCB. It's just a nit but something to consider.I only say this because the company I work for has some old designs where the engineer numbered the connector from left to right (with respect to the board edge) no matter what connector was being placed. I got burned a few times when having cables made as the vendor went by the standard for the specified mating connector.