Who's using autorouters for their designs?

[Henk Boonsma]

I'm wondering how many people are using autorouters for their board layouts
and in what percentage (i.e. what percentage is being routed by the
autorouter)? I've had some bad experience using autorouters and hardly use
them anymore. OTOH, Electra claims that autorouters do a very decent job
with digital circuits and that even though the layout doesn't look as
'artistic' as one done by a human, they are ussually better.

When I look at board layouts on most digital products (e.g. motherboards) it
seems to me that they've been done manually (i.e. most signal busses are
perfectly routed next to each other, something an autorouter won't ussually
do).

What do you guys think?

 

[Joerg]

Hello Henk,

If the design is noise critical such as most analog circuitry or fast digital areas I don't allow auto routing. I don't do layouts myself but sit with the layouter for critical areas.

It may be ok to autoroute parts of a circuit but most everything I ever designed had sections where it certainly would not be appropriate.


Regards, Joerg

http://www.analogconsultants.com

 

[Hal Murray]

I'm wondering how many people are using autorouters for their board layouts
and in what percentage (i.e. what percentage is being routed by the
autorouter)? ...

What sort of boards are you interested in?

For really simple boards, an autorouter is fine since the
routing is generally obvious, at least if you put the components
in sensible places.

For really complicated boards, you don't have enough time to
do it all by hand. For some sections, the routing is simple
if you get the components placed right. For other sections,
you have to check carefully to make sure the autorouter did
something sensible, perhaps tweaking the rules and letting it
try again.

For almost easy boards, I've had reasonable luck with guiding
Eagle's autorouter. Run it and see what I don't like. Fix that,
usually by moving a component a bit. Sometimes by ripping up a
few tangled signals and letting it try again. Sometimes with a
bit of manual help, say by pushing a wire or via around.

I often clean things up by hand, but I'm not sure that really
matters. It just looks "better" to my eye.

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[R.Lewis]

"Leon Heller" <leon_heller@hotmail.com> wrote in message
news:4179684a$0$10378$cc9e4d1f@news-text.dial.pipex.com...

"Henk Boonsma" <hboonsma@teranet.news> wrote in message
news:1098467030.f3RmPPwZCxMY/k7EROjkLg@teranews...
I'm wondering how many people are using autorouters for their board
layouts
and in what percentage (i.e. what percentage is being routed by the
autorouter)? I've had some bad experience using autorouters and hardly
use
them anymore. OTOH, Electra claims that autorouters do a very decent job
with digital circuits and that even though the layout doesn't look as
'artistic' as one done by a human, they are ussually better.

When I look at board layouts on most digital products (e.g.
motherboards)
it
seems to me that they've been done manually (i.e. most signal busses are
perfectly routed next to each other, something an autorouter won't
ussually
do).

What do you guys think?

There are lots of factors involved. Someone I was talking to about this
who
designs high-spec. boards for many large UK companies told me that they
wouldn't accept them if they had been autorouted. Motherboards are made in
such vast quantities that the additional costs for manual routing are
insignificant. Although I have Electra (supplied with the PCB package I
use)
I very rarely use it, although it does work better than any other
autorouter
I've tried.

Leon

You never can tell.
After too many years to mention in the business I have just encountered the
first board that I think will *best* be done by an autorouter (or at least
most of it will be).
Lots of space, not too many components, no speed or hi gain/ ground plane
problems, mega creepage and clearances considerations, not too price
critical.

 

[Leon Heller]

"Henk Boonsma" <hboonsma@teranet.news> wrote in message
news:1098467030.f3RmPPwZCxMY/k7EROjkLg@teranews...

I'm wondering how many people are using autorouters for their board
layouts
and in what percentage (i.e. what percentage is being routed by the
autorouter)? I've had some bad experience using autorouters and hardly use
them anymore. OTOH, Electra claims that autorouters do a very decent job
with digital circuits and that even though the layout doesn't look as
'artistic' as one done by a human, they are ussually better.

When I look at board layouts on most digital products (e.g. motherboards)
it
seems to me that they've been done manually (i.e. most signal busses are
perfectly routed next to each other, something an autorouter won't
ussually
do).

What do you guys think?

There are lots of factors involved. Someone I was talking to about this who
designs high-spec. boards for many large UK companies told me that they
wouldn't accept them if they had been autorouted. Motherboards are made in
such vast quantities that the additional costs for manual routing are
insignificant. Although I have Electra (supplied with the PCB package I use)
I very rarely use it, although it does work better than any other autorouter
I've tried.

Leon

 

[Mac]

On Fri, 22 Oct 2004 19:39:24 +0200, Henk Boonsma wrote:

I'm wondering how many people are using autorouters for their board layouts
and in what percentage (i.e. what percentage is being routed by the
autorouter)? I've had some bad experience using autorouters and hardly use
them anymore. OTOH, Electra claims that autorouters do a very decent job
with digital circuits and that even though the layout doesn't look as
'artistic' as one done by a human, they are ussually better.

When I look at board layouts on most digital products (e.g. motherboards) it
seems to me that they've been done manually (i.e. most signal busses are
perfectly routed next to each other, something an autorouter won't ussually
do).

What do you guys think?

I used to work for a well-known large company that designed single board
computers (using the high-end Mentor Graphics tools) for telecom
applications. We did not use an autorouter at all.

However, a friend of mine tells me that people who really know how to use
autorouters can get good results. He used to work with one of these guys.
The guy now works (on a contract basis) for a large, US-based PC company
and sets up the autorouter to do their motherboards for them. I don't know
what tools they use.

I guess the trick is finding the right balance so that you meet skew and
signal integrity guidelines, but don't over-constrain the board.

--Mac

 

[JeffM]

I don't do layouts myself but sit with the layouter for critical areas.
Joerg

or is that layer-outer?

Do you post from more than 1 computer?
Sometimes your posts line-break normally
and sometimes they run way past the page edge on the Google archive.

 

[Joerg]

Hi Jeff,

or is that layer-outer?


In some areas they might pronounce it that way ;-)

Do you post from more than 1 computer?
Sometimes your posts line-break normally
and sometimes they run way past the page edge on the Google archive.


No, all from one PC. I am using Mozilla. For reasons beyond my

understanding it messes up or forgets the line breaks once in a while.
With Netscape it was much worse, that sometimes posted blank pages. I
have pretty much given up hope that the simple task of line breaks will
ever be handled consistently by web software. I have set it to 65
characters but sometimes the software seems to ignore it. Oh well, at
least it's right about 95% of the time.

What I also don't understand is why posts with too long lines or missing
line breaks aren't formatted to fit the screen at the receiving end.

Regards, Joerg

http://www.analogconsultants.com