Mike,

LOL. I ll do that just after I get Specctra to do my
job.
Are you proposing me this because you have nothing to
do with your hands and have been practicing weaving?

Mira

--- Mike Reagan <[EMAIL PROTECTED]> wrote:
> Mira
> 
> I feel for you if you choose  to basket weave
> instead of design.  I do not
> believe your friend is knowledgeable enough to use
> spectra.  4 BGAs should
> route in about 20 minutes if the placement is
> correct and the rules are set
> correctly.
> 
> Mike Reagan
> 
> 
> 
> 
> -----Original Message-----
> From: Mira [mailto:[EMAIL PROTECTED]
> Sent: Friday, May 21, 2004 12:11 PM
> To: Protel EDA Forum
> Subject: Re: [PEDA] Router comparison
> 
> 
> Hi Mike,
> 
> It's really important how experienced is a person to
> use the autorouter.
> As you said the fanout should be done manually. The
> placement is also manual work. The routing depends
> on
> how clever the placement and fanout were done.
> I have a friend who uses Specctra and had to
> autoroute
> a PCB with 4 BGAs and I don't know how many other
> components. He spent about two months autorouting
> just
> this board and even went to work at night to check
> the
> results and run another session.
> Even if I had to work at night, I'd do it manually
> much faster.
> 
> My $0.02
> 
> Mira
> 
> 
> --- edsi <[EMAIL PROTECTED]> wrote:
> > Tony
> >
> > > 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 route
> > > 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 noisey boards/
> > > etc.
> > >
> > > 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.
> >
> >
> > Mike Reagan
> > EDSI
> > ---------- 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 route
> > >by hand. They always look 'auto routed', busses
> > seem to not stay together,
> > >etc.
> > >
> > >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, I
> > >rather just route the board by hand...again. I am
> > trying different
> > >instructions in the DO file, and maybe that will
> > help.
> > >
> > >Tony
> > >
> > >
> > >-----Original Message-----
> > >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
> 
=== message truncated ===



        
                
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