On Fri, 06 Jan 2006 00:11:07 +0100, Alan King <
alan@...> wrote:
>
>
> Eagle works brilliantly for single sided. Only open the second layer
>
> for the correct passes and cost it properly and it will produce
>
> excellent patterns with minimal jumpers to install where the 2nd side
>
> traces are. Easily as good as a person at smaller boards, and clearly
>
> better than a person at larger ones. Just watching it work on a medium
>
> sized complex board and the lengths it can go to to elminate or length
>
> minimize the out of main plane traces, it's very clear that it's well
>
> beyond what most people would come up with for the same board.
>
>
> Only real complaint would be not the 2nd layer traces cross, which is
>
> easy with insulated jumpers. But thinking about it now, duh just make
>
> it a 4 layer board, 1 low cost, 1 highest cost, 1 highest-1, and 1
>
> highest-2. Nothing but a breeze to do..
>
>
> Alan
Well, i just took one of my projects and deleted all traces (yes i saved
under different name).
Then i tried both autorouters that come with my software, and different
settings. The best i got was 5 signals remaining.
Mind you this is a board that was already routed completely by hand single
side with no bridges.
I ackonweledge that i have high demands on layouts, since i believe a lot
of it is art, but if the autorouter can't even manage to route all signals
of a board that is easy to route what can i think of it?
I'm just surprised that so many seem to get useable results out of it and
i want to find if maybe there are better autorouters. I'm still very
interested in pictures from various autorouter outputs without any manual
touchup done.
Leon, the top left pad, why does the trace go down between the pads and
then left at 90 degree, why doesn't it just enter the pad from the top?
You can spot a similar uglyness wherever you look.
I don't agree on the placement. I agree i can't be certain without a very
close look, but when i see "fans" of many parallel signals crisscross a
board i can't help but think there might be a way to get the many signals
closer, maybe accepting a tradeoff in getting the fewer signals longer.
Sure, if you accept more layers and more vias and don't care how it looks
you can autoroute any board, but it seems they are still not quite clever
enough for me to use.
ST