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Hi All,
Odd non-code based question "can anyone here (Mike, Griff et al.) recommend a web site that gives details of multilayer PCB, I need to refresh on the design principals before an interview. I just want to know when is the correct time to multilayer a board, my answer was going to be when the track width is such you can't fit any more on one layer. I'm guessing there is a better judged answer...
Glenn
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Even our simple boards are two layer. I would say its probably a cost related issue, more layers = more cost. The software can make use of as many layers as specified.
If its an RF type board or noise sensitive circuit then throw in an extra one or two for a ground plane.
Do you want me to send you the LAYOUTZ? Is it URGENTZ?
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Yep, know that, also the controlled length for RF (to balance impedance) I was just looking to see if there was a site or page anyone knew of, if memory serves TI used to have something... 
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It depends, obviously you do not want sensitive front end circuitry to be bombarded with EMI (Electromagnetic Interference) so a multi layer board that includes a ground plane would provide EMI shielding. This is true in the reverse for circuits that emit a lot of noise such as power supplies or switching circuits.
It used to be a cost factor issue but over time this is generally no longer a large cost increase. 4 layer PCBs are very common even for simpler circuits.
A couple of things to consider.
Good luck on the interview.
It was broke, so I fixed it.
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S Houghtelin wrote: It was broke, so I fixed broke it better.
Decrease the belief in God, and you increase the numbers of those who wish to play at being God by being “society’s supervisors,” who deny the existence of divine standards, but are very serious about imposing their own standards on society.-Neal A. Maxwell
You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun
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Not done any PCB design so can't be a lot of help but found this[^] that may be of some help!
New version: WinHeist Version 2.1.1 new web site.
I know the voices in my head are not real but damn they come up with some good ideas!
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Thanks I think that was the page I used before. 
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Sorry Glenn, I can't help - I leave that kind of stuff to my hardware guy who tends to use it for "expensive boards" which isn't a lot of help! 
I know it makes his life a load easier when he can use separate ground and power planes, particularly on high speed circuits when you want track lengths to be as close to the same as possible.
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Well Okay, umm darn 
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Yesterday on our local Robotics group list, someone posted a link to a free e-book on high speed circuit design. http://www.thehighspeeddesignbook.com/[^]
Hope that helps, and good luck with the job.
Ken
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High Speed Design just what the doctor asked for Cheer that dude!
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No problem, good luck at the interview.
Ken
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Or do my work for me.
Only joking, I have just been presented with a very small issue, just wondering if those of you who like this sort of thing might be able to come up with an elegant solution, just for fun.
I have a field that has a text string in it.
The text string will probably contain an error code, but might not.
The error code, so far as I can tell, will be 2 letters followed by 6 numbers or 3 letters followed by 5 numbers.
The error code, so far as I can tell, will be at the start or the end of the text string.
I need to extract the error code (should it exist) into a new field and the rest of the string into another.
Typing the question has, I believe, shown me the way to proceed.
Bonus credit; I have to do it in xsl.
I shall do it as soon as Eclipse starts working again.
Examples:
<m:StatusMessage xsi:type="xsd:string">Duplicate ContactReference supplied</m:StatusMessage>
<m:StatusMessage xsi:type="xsd:string">ss000073 Invalid value entered in PropertyRef tag</m:StatusMessage>
<m:StatusMessage xsi:type="xsd:string">Exchange Final reading cannot be less than the previous reading - xml00159</m:StatusMessage>
ps, don't you love it when companies apply no standards whatsoever to their work.
pps, if I'm honest I just wanted to complain about the lack of standards
ppps, I think it is due to developers who assume everything they create will be read by a human rather than by a computer
Some men are born mediocre, some men achieve mediocrity, and some men have mediocrity thrust upon them.
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chriselst wrote: do my work for me.
Hah! Take it to QA like the rest of 'em!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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It's easy-peasy with a Regex... 
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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It's not particularly tricky, I just don't trust them not to stick a code in the middle of the message or some such nonsense.
It's a pita having to code for all things people could do, no matter how stupid.
Some men are born mediocre, some men achieve mediocrity, and some men have mediocrity thrust upon them.
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Regex has "^" which is "start of string" to cope with that kind of rubbish!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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and '$' for "end of string" 
Decrease the belief in God, and you increase the numbers of those who wish to play at being God by being “society’s supervisors,” who deny the existence of divine standards, but are very serious about imposing their own standards on society.-Neal A. Maxwell
You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun
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chriselst wrote: as soon as Eclipse starts working
Let's make it the Monday Mission then...
veni bibi saltavi
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I turned the computer off and went out for lunch.
Some men are born mediocre, some men achieve mediocrity, and some men have mediocrity thrust upon them.
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Where should we send the codez? Could you please post your email address? It's Urgentz! 
Anything that is unrelated to elephants is irrelephant
Anonymous
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The problem with quotes on the internet is that you can never tell if they're genuine
Winston Churchill, 1944
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I'd just like a chance to prove that money can't make me happy.
Me, all the time
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"
EXSLT - Regular Expressions covers extension elements and functions that provide facilities to do with regular expressions.
For ease of implementation, the regular expressions used in this module currently use the Javascript regular expression syntax.
XSLT processors may support any number of the extension elements and functions given in this module.
Using EXSLT will only make your stylesheet portable amongst the implementations that support EXSLT. Note that there is no requirement for XSLT processors that are compliant to XSLT to support the extensions described within EXSLT.
" -- http://exslt.org/regexp/[^]
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OriginalGriff wrote: I suspect their web site was coded via QA
So you and SK did the coding then?
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No wonder then... (now I'll be nuked by SK. It was fun being part of the community, goodbye ).
Geek code v 3.12 {
GCS d--- s-/++ a- C++++ U+++ P- L- E-- W++ N++ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t++ 5? X R++ tv-- b+ DI+++ D++ G e++>+++ h--- r++>+++ y+++*
Weapons extension: ma- k++ F+2 X
}
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