Forums

CAN J1939 Help

Started by Neil January 28, 2006
Dave Hansen wrote:
> On Sat, 28 Jan 2006 05:55:49 GMT in comp.arch.embedded, Neil > <NeilKurzm@worldnet.att.net> wrote: > >> Hi >> >> I will be doing a J1939 project soon. >> I need to : >> >> 1.pick a micro. >> 2.write or buy the stack. >> 3.figure out which doc I need to Buy from SAE. >> 4.Maybe get a Book? > > It's worth the ~US$600 to get the web subscription for J1939 from SAE. > That gets you the whole thing, plus a lot of useful supporting > documents. It'll save you a great deal of guesswork -- and guessing > wrong could be painful. > > The first thing you have to do when you connect to a J1939 bus is > claim an address. In order to claim an address, you have to have a > NAME. One field in the NAME is a manufacturer ID. If you don't have > a manufacturer ID, you need to apply for one from the committee. It's > fast, easy, and free, don't worry. Check the SAE web site. > > You'll want to see if your application is supported by existing PGNs > and SPNs. If so, you just need to format the data with the proper > SLOT, build the messages, and send them. And/or pick apart received > messages. If your application is not supported, you'll probably want > to implement some proprietary messages using PROP_A and PROP_B. > >> On the micro I found >> PICs >> 8052s >> AVRs > > Make sure whatever controller you buy supports CAN 2.0B. > >> Ulf tell me why I should go with Atmel (really!!) Does Atmel have any >> appnotes or contracts in the U.S. I have 8052 experience no AVR. >> >> I have search the web. too much general info. >> There is much better info on CANOpen. > > The SAE documents contain everything you need to know, from mechanical > to electrical to software. It really is worth going to the standard > documents themselves. They're not tutorial, but they are pretty > clear, as long as you can keep the terminology straight. > > If you can get (working!) source, it will be well worth your while. A > former employer bought Vector-Cantech source for about $19k. It's > quite good, though it could stand some sophistication in the address > claiming algorithm (it's not arbitrary-address capable). Microchip > offers free code for their chips, though I'm not sure how good it is, > or what it supports, but ISTM that, unless it's complete cr*p, it > would be better than nothing. > > FWIW, I'd look at a PIC18 and Microchip's code as a first > approximation. I like AVRs better, but I'm a software guy, and the > free code should be worth at least what you pay for it. > > HTH, > -=Dave >
$19K ?? That is a bit much for this project. I do not think the numbers are there, but I am not the one that pays the bills. Thanks for the Info about the SAE doc. I would hate to spend $600 for not much. I was wondering if I should just get what I need and not the whole set. I am a software guy too. I was hoping to not have to learn another CPU and compiler. At least not without a clear advantage. Do you know of any books that cover the subject? I would be nice to read ahead on the subject. Thank you for the Information. Neil
Heinz-J&#2013266172;rgen Oertel wrote:
> Neil wrote: > >> Heinz-J&#2013266172;rgen Oertel wrote: >>>> Neil >>> Neil wrote: >>>> 1.pick a micro. >>>> 2.write or buy the stack. >>>> 3.figure out which doc I need to Buy from SAE. >>> It's all listed at the SAE site >>> http://www.sae.org/standardsdev/groundvehicle/j1939.htm >>> and some explanation can be found there: >>> http://www.can-cia.org/j1939based/ >>>> 4.Maybe get a Book? >>>> On the micro I found >>>> PICs >>>> 8052s >>>> AVRs >>>> >>> definitely much more, from 8 to 32 bit, or any micro with external CAN >>> controller. It all depends on your application. >>> >>> Regards >>> Heinz >>> >>> >> Been there It tells about the documents. No details to make a decision >> with. I am going for 8bits with an integrated controller, unless the >> protocol needs more. > > On http://www.can-cia.org/j1939based/j1939/ > the profile content is described. According you description I would assume > that the SAE J1939/71 is what you need. > Another source of information is clearly your J1939 communication partner. > She should know what she expect from you. > > Heinz > > > > > > >
I can only hope they know what they want. It would be refreshing.
On Tue, 31 Jan 2006 05:34:58 GMT in comp.arch.embedded, Neil
<NeilKurzm@worldnet.att.net> wrote:

>Dave Hansen wrote:
[... a bunch of stuff about J1939 ...]
>> > >$19K ?? That is a bit much for this project. I do not think the numbers >are there, but I am not the one that pays the bills.
Well, it's fairly complete, guaranteed compliant, full source, and no royalties. If you're doing several J1939 projects, or are on a tight schedule, it's probably a bargain. But you're right -- you have to be pretty serious about J1939 to make such an investment. And you'll still have plenty of work to do, even with their code.
> >Thanks for the Info about the SAE doc. I would hate to spend $600 for >not much. I was wondering if I should just get what I need and not the > whole set. > >I am a software guy too. I was hoping to not have to learn another CPU >and compiler. At least not without a clear advantage.
My first (and very fast-track) J1939 project used an unfamiliar chip, and a somewhat familiar compiler (GCC). Everything was pretty much C, and the hardwdare was a purchased (OEM) board, so that really wasn't a problem.
> >Do you know of any books that cover the subject? I would be nice to >read ahead on the subject.
No. I suspect there's several reasons for this: 1) the marketfor such a book is pretty small, 2) thatmarket is going to want to have the SAE standard anyway, 3) SAE might have something to say about the most useful information you'd want to publish anyway, i.e., that tables of PGNs, SPNs, etc. The SAE standards aren't really tutorial, but they are far from the most opaque standards I've run into. Most of the complicated stuff is covered by the phrase "29-bit CAN." The topology, termination, and connector information is very straightforward. Address claiming is not all that complicated once you get over the number of words and pictures dedicated to describing it. And the BAM and CTS/RTS transport protocols are downright simple. It's the tables that you can't do without. And you aren't going to get them anywhere but SAE. Regards, -=Dave -- Change is inevitable, progress is not.
Dave Hansen wrote:
> On Tue, 31 Jan 2006 05:34:58 GMT in comp.arch.embedded, Neil > <NeilKurzm@worldnet.att.net> wrote: > >> Dave Hansen wrote: > [... a bunch of stuff about J1939 ...] >> $19K ?? That is a bit much for this project. I do not think the numbers >> are there, but I am not the one that pays the bills. > > Well, it's fairly complete, guaranteed compliant, full source, and no > royalties. If you're doing several J1939 projects, or are on a tight > schedule, it's probably a bargain. But you're right -- you have to be > pretty serious about J1939 to make such an investment. And you'll > still have plenty of work to do, even with their code. > >> Thanks for the Info about the SAE doc. I would hate to spend $600 for >> not much. I was wondering if I should just get what I need and not the >> whole set. >> >> I am a software guy too. I was hoping to not have to learn another CPU >> and compiler. At least not without a clear advantage. > > My first (and very fast-track) J1939 project used an unfamiliar chip, > and a somewhat familiar compiler (GCC). Everything was pretty much C, > and the hardwdare was a purchased (OEM) board, so that really wasn't a > problem. > >> Do you know of any books that cover the subject? I would be nice to >> read ahead on the subject. > > No. I suspect there's several reasons for this: 1) the marketfor such > a book is pretty small, 2) thatmarket is going to want to have the SAE > standard anyway, 3) SAE might have something to say about the most > useful information you'd want to publish anyway, i.e., that tables of > PGNs, SPNs, etc. > > The SAE standards aren't really tutorial, but they are far from the > most opaque standards I've run into. Most of the complicated stuff is > covered by the phrase "29-bit CAN." The topology, termination, and > connector information is very straightforward. Address claiming is > not all that complicated once you get over the number of words and > pictures dedicated to describing it. And the BAM and CTS/RTS > transport protocols are downright simple. > > It's the tables that you can't do without. And you aren't going to > get them anywhere but SAE. > > Regards, > -=Dave >
Dave Thank you for the information. At least I have somewhere to start now. Neil
<ver&#2013266166;ffentlicht & per Mail versendet>

Neil wrote:

> $19K ?? &#2013266080;That is a bit much for this project. I do not think the numbers > are there, but I am not the one that pays the bills.
you can check Noregon http://www.noregon.com/ The J1939 stack http://noregon.safeshopper.com/5/6.htm?802 as available for about US$ 5000. I never saw the product or the documentation, therfore I can not compare it with Vector, but you can ask for it. Best Regards Heinz
Heinz-J&#2013266172;rgen Oertel wrote:
> <ver&#2013266166;ffentlicht & per Mail versendet> > > Neil wrote: > >> $19K ?? That is a bit much for this project. I do not think the numbers >> are there, but I am not the one that pays the bills. > > you can check Noregon http://www.noregon.com/ > The J1939 stack http://noregon.safeshopper.com/5/6.htm?802 > as available for about US$ 5000. > I never saw the product or the documentation, therfore I can not compare it > with Vector, but you can ask for it. > > Best Regards > Heinz
Thanks I missed that one. Neil