Autorouter generates unconnected ends

I am trying to route a very simple microcontroller board. I followed the instructions in the plugin manager for installing the recommended autorouter. (Got jre21 from adoptium.net, got freerouter 2.1.0 from github, and got the kicad plugin from the plugin manager)

However half the time there unconnected ends as shown below:

How do we get cleaner autorouter results?

This is a trivial board with plenty of space for routing. (The board is a few inches on each side and the only signals are VDD, VCORE, GND, NRST, BOOT0, SWD, and SWC. It’s literally the most trivial microcontroller board possible.)

Please no comments about how we shouldn’t use autorouters. (I have designed 100 PCBs using EAGLE’s builtin autorouter for most traces. I am not going back to 100% manual routing.)

update

After looking at individual layers, I realized that this may be just a cosmetic issue. The signals are actually connected, but there is some metal overhang. Nonetheless, it makes me wonder if this autorouter is going to be able to handle more complex boards, such as what we could do in EAGLE (before it went away).

I wonder how we should comment – routing made by an autorouter isn’t made by KiCad, so we here in a KiCad user forum can’t comment on the problems. And you didn’t even have a clear question or request.

I wonder how we should comment – routing made by an autorouter isn’t made by KiCad, so we here in a KiCad user forum can’t comment on the problems.

Regardless of who makes the autorouter, it’s a basic feature of KiCad, and therefore we can expect the same level of support as for any other basic feature. As I mentioned in the question, freerouting is – as best I can tell – the recommended autorouter. If this is not the case, then please tell me what the recommended autorouter is. (I just don’t need to hear that autorouting is not useful or not a basic feature, as my experience from EAGLE already tells me otherwise.)

And you didn’t even have a clear question or request.

The question is how to make the autorouter behave reasonably. Extra pieces of metal is not reasonable. I’m not sure how to make it clearer than already worded.

Last I knew it was mostly in triage mode. It was ported to the new java by people determined to not let the old java code languish but it was more about java evangelism than anything to do with the actual program. Other than some lipstick I don’t believe anything has happened to the ‘code that matters to routing’ since the original?

The routing happens outside of Kicad. Have you tried asking the freerouting folks where the issue is? I’d think that the plugin has some problems with the start and end points from the sounds of it. I don’t know if the track cleanup tools from inside Kicad would help as I haven’t used them in quite awhile.

No. Definitely not. KiCad only provides an interface to exchange data with an autorouter, and has no links whomever provides the autorouter. I guess this interface can even be used with different autorouters.

But KiCad does have: PCB Editor / Tools / Cleanup Tracks and Vias, and you can use it to: Delete tracks that are unconnected at one end

2 Likes

No, it’s not a basic feature of KiCad. Nothing external (i.e. a plugin) isn’t part of KiCad nor a basic feature of KiCad, and it doesn’t belong to KiCad itself. It’s a 3rd party plugin.

There’s no “recommended” autorouter. Anyone can recommend what they want, but the KiCad project doesn’t recommend any autorouter.

KiCad isn’t Eagle. I’m not sure what kind of “autorouting” you would expect. KiCad has a useful push’n’shove router, and it can autocomplete simple tracks.

Opinions about autorouters are like Dirty Harry citations, everybody has one. See Autorouting, autorouter, autoplacing for more.

You learn your whole life. I’ve been using KiCad since 2017 and had no idea I didn’t even tried one of its basic features.

Furthermore, Freerouting isn’t specifically for KiCad either. Other ECAD suites that implement the dsn-ses interface can use it. The place to report issues is Freerouting’s GitHub site.

My answer point in two direction:

1)The autorouting is made by a plugin, you need talk with plugin creators/maintainers.

2)The autorouting was abandoned by most EDA tools. This has a reason, the electronic become more complex than one NE555 with a led.
Today the MCU has more than 100MHz, require high speed traces, balanced lenght, controlled impedances. Uses crystal that must be routed with exclusion zones for EMI control. Uses 4 to 20 layers. Ground planes, power planes, stitching vias and planes coupling.

For The moment a autorouter cannot understand that a differential track at 480MHz need a continuous plane. Or why you need enclose a crystal with a gnd that is same (and different) to the rest of gnd.

It would probably be quicker for us to route your board for you than try and answer a question about a Plugin (one I have never installed) that most regulars here have never used.

1 Like

Not a KiCad issue.