share your opinions on autorouters?

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Jayson

Joined: 08 Oct 2001
Posts: 460
Helped: 17
Location: Brazil

20 Nov 2003 3:28 keepout spectra autorouter

can someone share their experience with autorouters, like Specctra or others.

Is an autorouter like specctra reliable for routing a whole board or does it require interactive editting, and how much interactivity is required?

- Jayson

wwwxuli

Joined: 21 Mar 2003
Posts: 9

22 Nov 2003 19:00 Re: share your opinions on autorouters?

I use PowerPCB to do placement and divided the ground and power plane, then I set the design rules for clearance, at last I convert it to specctra to route, all of wires are routed in specctra except the clock signals, becaue the arc wire in PowerPCB will be changed to acute angle.

I wonder whether it is necessary to set design rules by language in specctra.

Jayson

Joined: 08 Oct 2001
Posts: 460
Helped: 17
Location: Brazil

22 Nov 2003 19:09 Re: share your opinions on autorouters?

do you autoroute in Speccta or do you use interactive routing?

- Jayson

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AG

Joined: 17 May 2001
Posts: 33

22 Nov 2003 19:12 Re: share your opinions on autorouters?

If you want good result route manually your pcb. Wink

eltonjohn

Joined: 22 Feb 2002
Posts: 1751
Helped: 28

22 Nov 2003 20:02 Re: share your opinions on autorouters?

I Guys

I have routed boards for many years now . But just small boards .No big deal up to 6 layers .. I well know from experience that sometimes is better to route it by hand .. But it has always been a curiosity for me HOW those HI DENSITY PC MOTHERBOARDS are ROUTED? .. Doing it by hand will seem like to TAKE YEARS !

Any body knows??

eternal_nan

Joined: 10 Mar 2003
Posts: 158
Helped: 15
Location: eternity

23 Nov 2003 2:37 Re: share your opinions on autorouters?

I reccommend all of the sensitive/high speed signals on your board by hand and letting the autorouter do the rest. Also, I noticed cheap autorouters (like the ones built into protel and orcad) tend to work better on boards with <4 layers (like most hobby projects) than expensive ones (like specctra) do.

eternal_nan

binu G

Joined: 09 Jan 2003
Posts: 739
Helped: 9
Location: Bangalore

23 Nov 2003 4:26

i use power pcb for the placement and design rules
routing i preffer spectra, but not auto routing manual routing in spectra is very effective than routing the board in the power pcb, and it can be fast too .
binu

Frosty

Joined: 01 Jan 1970
Posts: 418
Helped: 666
Location: EARTH

25 Nov 2003 2:34 Re: share your opinions on autorouters?

Autorouters will only do what you tell them. These beasts are 100% rules driven. The time is in the rules definition as regardless of what it says on the box, some rules regarding grids or 'channels' will conflict with other rules such as grid settings vs trace width settings, clearance, net length matching, diff pairs, clock from toos & termination and so on.

Sometimes the time to set up the rules is more than the time to route manually especially if you have a lot of mixed analogue/digital rules to follow and use split planes.

If you use software for capture that will translate all PCB rules defined at SCH level to be followed by router then you will save time. Protel does not do this, or at least does not allow for proper rules definition in SCH yet with enough parameters to work on a dense design.

For a mid range router, well integrated into the tool suite Pads is pretty hard to beat with Blaze.

Specctra is really cool but I have not seen it work well with other tools, based on quality of rules translation and interactivity level, outside of Cadence suites. But no suprise there of course Very Happy

The Specctra interface is where most non-cadence tools fall down, but I beleive PCAD works very well with it as they used Specctra for many years anyway.

All down to time, and in some cases available CPU time & lots of RAM!

Howver most routers can help in routing some of the sh#t work like fanout, memory arrays or reptative routing and so on. Even the cheap built in ones do this OK most of the time.

As regard PC motherboards routing, the last project I was involved with long time ago was a team effort and they used Specctra, based on a Pentium Pro CPU, the time allocated for defining and optimising the rules, of which most can be obtained from most vendors or associated standrads anyway, was 6 months!

Cheaper to buy a mobo these days Razz

asit

Joined: 22 Mar 2002
Posts: 95
Helped: 3
Location: India

25 Nov 2003 7:00

What you guys suggest for single layer small PCBs with jumpers?

borisov57

Joined: 11 May 2001
Posts: 43
Helped: 2

25 Nov 2003 8:59 Re: share your opinions on autorouters?

I am in process of routing double sided 160mm x 100 mm board with usb contoroler, dsp, ram, two din96 connectors and some other chips and connectors. OrCad smartroute almost finished it with 3 conflicts. The "best" router specctra left 18 unconnects behind and even "better" autoactive leaves 35. Blaze manage to route to 5 opens after running half night long on 450Mhz computer.

jhenxl

Joined: 25 Nov 2003
Posts: 6

25 Nov 2003 18:55 Re: share your opinions on autorouters?

Despite what margeting people says, i have found autorouters behaving poorly. Especially when you are routing mixed-signal pcb. There has been couple occasion when autorouter has routed clock signal over analog groundplate. Though the problem might be in a user. But anyway i think you get better pcb when you route them by hand.

phonedrop

Joined: 18 Jul 2003
Posts: 18

25 Nov 2003 21:59 Re: share your opinions on autorouters?

Jayson wrote:

It has ben a while since I used the specctra router, V 10.0 was the last realease. I had a pcb that had .5 meg worth of high speed roule and there was no way I could finish on time with out the auto router. Sure there wee routes that I could have done better by hand, but with the auto-router we were able to tell what constraints were going to break and it forced the engineering staff to prioritize the rules.

pd

Vicent Yang

Joined: 01 Jan 1970
Posts: 111
Location: Taiwan

26 Nov 2003 19:11 Re: share your opinions on autorouters?

For single side PCB the best thing is to do the routing manually because for single side PCB you will need a lot of time to set the rules for the router.

neerajs

Joined: 21 Nov 2003
Posts: 29
Helped: 1

27 Nov 2003 6:31 Re: share your opinions on autorouters?

We have found Specctra to be a good autorouter ofcourse one need to set the rules correctly..

Mart

Joined: 20 May 2002
Posts: 19
Location: Netherlands

08 Dec 2003 21:40 Re: share your opinions on autorouters?

I use it only (powerpcb spectra) for non critical digital lines with keep out planes.

But still, if you want a good result route manually your pcb.

Frosty

Joined: 01 Jan 1970
Posts: 418
Helped: 666
Location: EARTH

08 Dec 2003 21:53

asit wrote:

What you guys suggest for single layer small PCBs with jumpers?

You can have an auto jumper insertion feature within Pads PowerPCB.

Jumpers can be inserted 'on the fly' while routing the board.

elektryk

Joined: 25 Apr 2002
Posts: 117
Location: POLAND

09 Dec 2003 19:09 Re: share your opinions on autorouters?

eltonjohn wrote:

HOW those HI DENSITY PC MOTHERBOARDS are ROUTED? .. Doing it by hand will seem like to TAKE YEARS !

Not quite, for example, industrial computer system-on-chip+ram+flash+CF+ some minor stuff, about to 200 'wires', four layers (signal/mixed/ground_plane/signal) is calculated to be made by SIGNLE person about 50h.
Personally I use EDA soft for small project, (uP+minor stuff), and I am using Protel and Eagle. For 1 or 2 layers pcb made by eagle looks much better, Protel has tendency to route like 'dumb' Smile

rauol

Joined: 02 Oct 2002
Posts: 363
Helped: 11

01 Jan 2004 10:10 Re: share your opinions on autorouters?

Has anybody tried ULTIRoute Rolling Eyes

henrik2000

Joined: 06 Jul 2001
Posts: 109
Helped: 1

05 Jan 2004 8:28 Re: share your opinions on autorouters?

Well as far as auto router is concerned I love Specctra. specifically when different area of the board should be routed with different rules. When routing 12 to 15 BGA's with 208 to 450 pins or more I would love to see someone do that by hand! (I think someone mentionned that he (she) prefered hand routing??
I do agree with the fact that passing constraints from schematic is not always the best way to do it. Rather write a 'do' file or define with edit route various constraints..
For high speed signals, either with controlled impedance and or capacitance, I admit that Specctra does an exellent job.

Placement by another and routing by specctra, gives me best results.. But that is just my opinion.

Cheers.

year

Joined: 21 Feb 2002
Posts: 101

05 Jan 2004 10:27

I use only autorouter for making test board.
It is not bad. But production is differnt case.
Because, there are lots of limit to use autorouting.
But partialy I use...
So, I do not want you go and back for autorouting.
It is only your decision.

Iain

Joined: 09 Jan 2004
Posts: 111
Helped: 7

09 Jan 2004 20:05 Re: share your opinions on autorouters?

I reckon SPECCTRA is by *far* the best for high complexity boards, >4 layers, or densely packed SMT boards. Also ahead by a mile IMHO when it comes to minimising extraneous vias and the costing system in place works very well in allowing you to dictate strategy. Sadly, it costs a fortune..

Agree that the Blaze router is the best mid/low price range router although they seem to have the same problem as grid based routers when, for example, decoupling capacitors are placed close to IC's preventing standard fanout algotithms from working. In the brief play I've had I never managed to get it to UAE though and that gets points in my book Smile

neuralc

Joined: 06 Nov 2001
Posts: 274
Helped: 6

09 Jan 2004 20:38

Hi,

The main part of PCB's that I design are single face, and I have already tested autoroute in single face with Protel, Tango and Specctra: Specctra is by far the best in this scenario. Results are very good; it takes some time to converge to final solution, and normaly I can get only 2 to 4 unconnected nets that I connect manually.

Previously I place components not automatic, because I take care about crosstalk, current return path, max power of tracks, grounding, etc..

HH

NeuralC

HytekPro

Joined: 13 Dec 2002
Posts: 16

31 Jan 2004 1:13

For the high speed signals, I've never used the Autoroute. I prefer to route them all first then Protect all of them. After that, I will put them on Autoroute to route the rest of the board. Most of time, the Autoroute can finish up to 99%, so you have to take care the leftover.

howk

Joined: 19 Mar 2004
Posts: 12

19 Mar 2004 11:14 share your opinions on autorouters?

Do you give some experience about Mentor`s Auto Active ?

mkbs

Joined: 10 Apr 2003
Posts: 67
Helped: 1

19 Mar 2004 11:53 Re: share your opinions on autorouters?

Hi,
I design especially double face and sometime single face.
I never use autoroute on my project, because there are too many
constraint like HT on board,earth, mechanical and class to class clearance
(sometimes above 50 rule).
So I have tried to use autoroute (a very good Mentor Autoroute) but the
result are worst than manual route.

MKBS

nuderen

Joined: 14 Jan 2004
Posts: 15

31 Mar 2004 13:05 share your opinions on autorouters?

i have not use autoroute for my design!!
i thank manual route is better!!

penrico

Joined: 28 Aug 2001
Posts: 249
Helped: 13
Location: Argentina

31 Mar 2004 13:15 Re: share your opinions on autorouters?

I have experience in Protel 98, 99 an others, manual routing is the best way to do good PCB. Autoroute can help to most wires, but you always need to finish the board by manual routing, and you will need to redraw many of autorouted wires