I remember years ago an engineer getting mad at me because I wire-wrapped
his circuit trying to make it look nice and neat with all the wires bundled
together in "streets & avenues". He said it was a big cross talk problem. He
wanted point-to-point with just a little slack in the wire length.
Looks like some things never change.
From: edsi [mailto:[EMAIL PROTECTED]
Sent: Friday, May 21, 2004 7:13 AM
To: Protel EDA Forum
Subject: Re: [PEDA] Router comparison
> But do you spend 'days' each time you do a board? I rather just route the
> board by hand for 'days' and have it look the way I want it to look.
Tony, I spend day on what would otherwise might be months. You shouldnt
manually route 2000 components. Because there is no smart fannout
algorithim in Spectra or Electra, I used prefanned patterns. I have posted
this a while ago. The pattern are also rule driven to allow for routing
channels. I have tried some do file for fan out but the results are not as
good. I get close to 100 percent routing in very little CPU time
> I've tried using autorouters and after a while I just say f**k it, and
> by hand. They always look 'auto routed', busses seem to not stay together,
This is major misconception, that busses should follow each other.....
Maintaining the same topography and wire lengths are important. Routing and
Wrapping busses togehter invites crosstalk I see this all of the time...on
> I am about a week into my Electra trial, and it got a current board to
100%> with no violations, but it looks like hell.
It looks like hell because, you have to understand the how an autorouter
behaves. The shortest path for any route is a straight line, the
autorouter's algorithm is a manhattan path. If you can get the the router
to run diagonal then horizontal, then the router is working properly. If
you get all of your lines on each layer running in the same direction, you
are routing correctly. I call it my "stick" theory. Drop some sticks on
the floor, at random they occupy the most space. Placed adjacent to each
other, they occupy the least amount of space. If your routes are running in
the same direction, it should be very efficient
>I would have so much clean up,
I rarely have any clean up except for reviewing high speed and signal
integrity issues. ie mentioned last posting, I review lenghts, and via
counts. The via count also tells me if the the manhattan path was followed.
On any two nodes I expect 3 vias max. Start, turn and terminate.
> rather just route the board by hand...again. I am trying different
> instructions in the DO file, and maybe that will help.
It gets more complicated than that, you may have to place boards on a
router several times. For instance I have a design right now that I can see
very strong sets of Horiz and Vertical ratsnest. I am selecting busses to
route Horz, reviewing it then I select only Vertical routing. Rotuting
begins at placement, isuring that routing channels are always open
There is a misconception in this industry that autorouters are not up to the
task. If you want to route every thing on the top layer, specify the top
layer, with no vias. You might be surprized at the results.
---------- Original Message ----------------------------------
From: "Tony Karavidas" <[EMAIL PROTECTED]>
Reply-To: "Protel EDA Forum" <[EMAIL PROTECTED]>
Date: Thu, 20 May 2004 23:41:32 -0700
>But do you spend 'days' each time you do a board? I rather just route the
>board by hand for 'days' and have it look the way I want it to look.
>I've tried using autorouters and after a while I just say f**k it, and
>by hand. They always look 'auto routed', busses seem to not stay together,
>I am about a week into my Electra trial, and it got a current board to 100%
>with no violations, but it looks like hell. I would have so much clean up,
>rather just route the board by hand...again. I am trying different
>instructions in the DO file, and maybe that will help.
>From: edsi [mailto:[EMAIL PROTECTED]
>Sent: Wednesday, May 19, 2004 2:44 PM
>To: Protel EDA Forum
>Subject: Re: [PEDA] Router comparison
>Good question Joe
>I plan to phase out my usage with Spectra, Since I have an older version,
>with not quite all the bells and whistles. Alot of the "bells" in Spectra
>dont work any way. What I have found is ...SPECTRA like all the other
>routers were written 20 years ago. Spectra has not kept up with the latest
>footprint technology. Spectra has a difficult time keeping bundled busses
>together. Has problems fanning out ( Advantage goes to ELECTRA for fanout,
>but I use pre fanned parts) Dont get me wrong SPECTRA is ....the best
>router on the market at any price.
>ELECTRA is a newcomer. I have been using it with great success and the
>enginnering department at ELECTRA is in tune with its users. They are
>receptive to inputs and will turn a suggetion around fairly quickly. Give
>this company time, they will be a major player in the CAE market.
>You guys need to plunk 3 K down and purchase the ELECTRA router. Then
>to use it. I never like to hear "WE ALWAYS ROUTE BY HAND". That tells me
>you are designing small boards, or dont know how to use a router. or you
>are simply farming out a design that should take you about half the time.
>Dont just hit GO and expect a rotuer to work. I might spend days thinking
>about routing stategies. I spend days tuning parts to open channels. I
>might make several passes, and adjust my rules. Rules driven routing can
>control vias, number of vias, line lengths, pairing, layers line widths,
>spacing. Routers work!
>And yes I am finally becoming an expert at something....it may be auto
>---------- Original Message ----------------------------------
>From: "Joe Sapienza" <[EMAIL PROTECTED]>
>Reply-To: "Protel EDA Forum" <[EMAIL PROTECTED]>
>Date: Wed, 19 May 2004 13:05:07 -0400
>>Maybe my response came across wrong, What I was getting at why both
>>I had no problems justifying the Specctra router, but I don't see me
>>spending for the Electra. Agreed that Protel with a less than spectacular
>>router may benefit from partnering with someone else for their bundled
>>or just ommiting it altogether. Like you I'm doing this full time, but
>>the economy having been down loads have been too rollercoatery to spend
>>when I'm getting by.
>>Sounds like you have spent some time with the Electra router, care to
>>expound some virtues since I was working and my demo expired long before I
>>had any real time to spend on it.
>>----- Original Message -----
>>From: "edsi" <[EMAIL PROTECTED]>
>>To: "Protel EDA Forum" <[EMAIL PROTECTED]>
>>Sent: Wednesday, May 19, 2004 12:29 PM
>>Subject: Re: [PEDA] Router comparison
>>> If you are designing boards full time ....and not just a few boards a
>>year, a good router is a must. I keep a log. I designed over 40
>>boards for each of the past 6 years. The router costs are easy for me
>>> I also perfer having 2nd party software for routing because it doesnt
>>up my main CAD system. Hey Altium what a novel idea.....I dont want
>>integrated routers....ever. I can work on two boards at once if one is
>>routing. Wow what a concept...I can really multitask on two PCs
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