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'[PIC] canbus v2.0b extended id filtering'
2011\05\25@192118 by RussellMc

face picon face
Olin - this is a genuine attempt to understand what is happening here.
I'm NOT just trying to "wind you up".
I'm spending the time and effort in a genuine attempt to try to
improve perspectives - either yours or mine (and other list admins) or
both.

Your reasoned response would be appreciated.

> kris duff wrote:
> > I would like to know if it is possible to filter only the ID
> > partially ( something like bits [0:12] ).

Olin wrote:
> Yes.  That's why there are both masks and filters.  Both are well explained
> in the datasheet.

Olin -
           NOT wanting to be "on your case", but this looks from here like a
really non-useful comment and more liable to just make annoyance and
noise than be helpful.

ie  Kris wrote -
"  ... but in the datasheet something weird is written : there is a
note telling this register is available in mode 1 and 2 only.  But in
the description, there is only description for mode 0 ..."

He's saying that either the data sheet is strange or that he doesn't
understand it in some way.
Telling him that the answer is in the datasheet and well explained
seems very marginally useful at best (giving it the benefit of the
doubt).
..
He says he's looked in the datasheet, he's quoting material that
doesn't make sense to him, he's asking for help from people with
practical experience. He says that he's doing a paper design and can't
try it out with the actual hardware.

What more would you expect him to have done?
If you know the answer and decided to reply at all why were you not
more helpful?
If you decided not to be helpful (which is entirely your right) why
did you not just say nothing.

The student/master model "try harder, try harder, try harder, moron,
try ..." has some validity in some circles, perhaps, but doesn't seem
overly useful in this context.

It seems highly unlikely that he would consider an answer which is
effectively of the form "While you say that you have tried to
understand, the answer is in front of your eyes, try harder,
Grasshopper" is in any way useful. The more so because it's possible
that your answer is just flippant and trite and not necessarily useful
- you may effectively be misleading him due to lack of attention on
you part. Given your known skill and experience in such things, odds
are that you are not doing this, but he can't be sure.

Your reasoned and reasonable comment would be useful.
Optionally something like a 'mea culpa, sorry, didn't see it that way,
good point, ..." would be acceptable.
Or better still, a stunningly inspired and lucidly clear technical
explanation (such as you are well known to  be capable of) would be
marvellous :-)


            Russell

2011\05\25@192118 by RussellMc

face picon face
Olin - this is a genuine attempt to understand what is happening here.
I'm NOT just trying to "wind you up".
I'm spending the time and effort in a genuine attempt to try to
improve perspectives - either yours or mine (and other list admins) or
both.

Your reasoned response would be appreciated.

> kris duff wrote:
> > I would like to know if it is possible to filter only the ID
> > partially ( something like bits [0:12] ).

Olin wrote:
> Yes.  That's why there are both masks and filters.  Both are well explained
> in the datasheet.

Olin -
           NOT wanting to be "on your case", but this looks from here like a
really non-useful comment and more liable to just make annoyance and
noise than be helpful.

ie  Kris wrote -
"  ... but in the datasheet something weird is written : there is a
note telling this register is available in mode 1 and 2 only.  But in
the description, there is only description for mode 0 ..."

He's saying that either the data sheet is strange or that he doesn't
understand it in some way.
Telling him that the answer is in the datasheet and well explained
seems very marginally useful at best (giving it the benefit of the
doubt).
..
He says he's looked in the datasheet, he's quoting material that
doesn't make sense to him, he's asking for help from people with
practical experience. He says that he's doing a paper design and can't
try it out with the actual hardware.

What more would you expect him to have done?
If you know the answer and decided to reply at all why were you not
more helpful?
If you decided not to be helpful (which is entirely your right) why
did you not just say nothing.

The student/master model "try harder, try harder, try harder, moron,
try ..." has some validity in some circles, perhaps, but doesn't seem
overly useful in this context.

It seems highly unlikely that he would consider an answer which is
effectively of the form "While you say that you have tried to
understand, the answer is in front of your eyes, try harder,
Grasshopper" is in any way useful. The more so because it's possible
that your answer is just flippant and trite and not necessarily useful
- you may effectively be misleading him due to lack of attention on
you part. Given your known skill and experience in such things, odds
are that you are not doing this, but he can't be sure.

Your reasoned and reasonable comment would be useful.
Optionally something like a 'mea culpa, sorry, didn't see it that way,
good point, ..." would be acceptable.
Or better still, a stunningly inspired and lucidly clear technical
explanation (such as you are well known to  be capable of) would be
marvellous :-)


            Russell

2011\05\26@095135 by Olin Lathrop

face picon face
RussellMc wrote:
>> kris duff wrote:
>>> I would like to know if it is possible to filter only the ID
>>> partially ( something like bits [0:12] ).
>
> Olin wrote:
>> Yes. That's why there are both masks and filters. Both are well
>> explained in the datasheet.
>
> Olin -
>             NOT wanting to be "on your case", but this looks from
> here like a really non-useful comment and more liable to just make
> annoyance and noise than be helpful.

To be honest, I didn't read every word of his post.  I had a board to finish
and get off to a customer and then I wanted to get home and plant tomatoes
now that it's finally not raining for the first time in 1 1/2 weeks.  This
post was in the short window while I was running a backup.  Yes, I saw he
mentioned something about the datasheet, but what he said about it didn't
make any sense, and I didn't have time to look it up myself and see what his
confusion might be.

I have read the same datasheet section myself in great detail when I
developed our own low level CAN routines, and found it to be reasonably
clear and complete.  I got everything working by using the datasheet as my
only source of information, so I have a existance proof that all the
information is in there.

>From a quick glance, it seemed to me the big concept he was missing was that
there are things called "masks" in addition to the "filters" he mentions.
Since the masks are there for precisely what he was asking about ("filter
only the ID partially"), it seemed that merely pointing out the existance of
the masks could be the nudge he needed.

The fact that all the information IS in the datasheet can also be useful.
Some seem to assume that when they can't get it, the datasheet is at fault.

So, in the limited time I had both to read his post and respond to it, I
gave him the following information:

 1 - There are things called "masks", which are for precisely the
     purpose he seemed to be asking about.

 2 - Despite possible appearances to the contrary, the information IS
     in the datasheet.

If this information is not useful or sufficient, oh well, he can have all
his money back.  He can also come back and ask more specific and more clear
questions if confusion persists.

Note that I trimmed his post to just the part I responded to.  This was of
course for the usual reason of avoiding clutter, but also to make it clear
that I wasn't responding to the rest.

Frankly, the rest look a rather jumbled mess at first glance.  This is
another reason I deleted it without comment.  You often are the one to say
that I should simply not respond when I don't like the way something is
written, but now when I did you want me to explain why.  First I don't owe
anyone, including you, any explanation.  Since I'm not being paid, I can
chose to not respond to any message or any part of any message as I see fit,
without obligation to justify it.

However, since you asked and basically put me on the spot publicly, I feel I
need to waste the time explaining just to defend myself.  If you think this
is insulting to the OP, note that I silently ignored it and you were the one
to ask for justification.

> "  ... but in the datasheet something weird is written : there is a
> note telling this register is available in mode 1 and 2 only.  But in
> the description, there is only description for mode 0 ..."

I didn't feel like playing 20 questions guessing which "modes" he was
referring to about which part of the hardware.  I may remember modes by name
or general description.  But really, I'm supposed to remember them by their
bit field value!!?  That's so obviously not supplying meaningful context as
to be borderline rude.  Yes, that's how I really felt about it, which of
course didn't exactly make me want to spend effort elaborating on the
answer.

He should have been able to understand that others are very unlikely to have
read that section of that datasheet so recently to remember such minutia.
Besides, he was having a general CAN misconception, so this was all just the
trees getting in the way of seeing the forest anyway.

> He says he's looked in the datasheet, he's quoting material that
> doesn't make sense to him, he's asking for help from people with
> practical experience.

But his quote didn't make sense to me.  It seemed to me he was expecting
people to do excessive research just to understand what he was talking
about.  From his apparent lack of understanding of context his readers
needed, it seemed to me that getting into a discussion with this guy would
be too painful.  Yes, I judge people here by the quality of their question.
This is then used to decide how much it's worth helping them.  This guy
didn't completely flunk the test, but got a D or C-.  It's my call to make,
and I don't have to justify it to anyone.  Again, note that I just silently
ignored it as you have often advised in the past.

I figured if others with more patience than I followed up and he eventually
learned how to provide better context, I might jump in and add a few things..
But as it stood now, my thought process was "this will be too much trouble,
no thanks".

> He says that he's doing a paper design and can't
> try it out with the actual hardware.

Lots of people say lots of stuff.  My first reaction to that was "that's
silly", so I ignored it.  Some things are worth helping with, others not, or
I simply don't feel like it.  That's the beauty of email.  You can pretend
anything you don't want to bother replying to just didn't happen.  Again, he
can have all his money back.

> What more would you expect him to have done?

Provided better context for what was frankly just babble that would have
taken some work to make sense of.

> If you know the answer and decided to reply at all why were you not
> more helpful?

1 - That's all I had time for that day that post.  No apologies for that.

2 - That's what I thought addressed the real problem after a quick read
   of the post.  I still think that's true.

> If you decided not to be helpful (which is entirely your right) why
> did you not just say nothing.

I did exactly that to the majority of the post.  Apparently that's not good
enough for you either.

Another time I might have explained why the rest of his post was mostly
babble to me, and you probably would have gotten upset at that.  This day
for this post I didn't, and now you want my to justify why I didn't.  You
can't have it both ways.

Russell, your second guessing of my posts is getting quite tiresome.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\05\26@095823 by Xiaofan Chen

face picon face
On Thu, May 26, 2011 at 9:52 PM, Olin Lathrop <spam_OUTolin_piclistTakeThisOuTspamembedinc.com> wrote:
> Russell, your second guessing of my posts is getting quite tiresome.
>

I have to agree with Olin here.

-- Xiaofan (not subscribing to OT or TECH for quite some time

2011\05\26@100459 by kris duff

flavicon
face
I think this discussion is not needed in public ...

I don't want to listen more... you say I'm a moron and i'm stupid...

The question was more do somebody has already see this kind of weird thing in the microchip datasheet...  I did not expect that somebody open the datasheet and look into and take a day to respond...  This is a mailing list, and I know this is for quick answers...

thank you for your help.


________________________________
From: Olin Lathrop <.....olin_piclistKILLspamspam@spam@embedinc.com>
To: Microcontroller discussion list - Public. <piclistspamKILLspammit.edu>
Sent: Thursday, May 26, 2011 9:52:12 AM
Subject: Re: [PIC] canbus v2.0b extended id filtering

RussellMc wrote:
{Quote hidden}

To be honest, I didn't read every word of his post.  I had a board to finish
and get off to a customer and then I wanted to get home and plant tomatoes
now that it's finally not raining for the first time in 1 1/2 weeks.  This
post was in the short window while I was running a backup.  Yes, I saw he
mentioned something about the datasheet, but what he said about it didn't
make any sense, and I didn't have time to look it up myself and see what his
confusion might be.

I have read the same datasheet section myself in great detail when I
developed our own low level CAN routines, and found it to be reasonably
clear and complete.  I got everything working by using the datasheet as my
only source of information, so I have a existance proof that all the
information is in there.

>From a quick glance, it seemed to me the big concept he was missing was that
there are things called "masks" in addition to the "filters" he mentions.
Since the masks are there for precisely what he was asking about ("filter
only the ID partially"), it seemed that merely pointing out the existance of
the masks could be the nudge he needed.

The fact that all the information IS in the datasheet can also be useful.
Some seem to assume that when they can't get it, the datasheet is at fault.

So, in the limited time I had both to read his post and respond to it, I
gave him the following information:

 1 - There are things called "masks", which are for precisely the
     purpose he seemed to be asking about.

 2 - Despite possible appearances to the contrary, the information IS
     in the datasheet.

If this information is not useful or sufficient, oh well, he can have all
his money back.  He can also come back and ask more specific and more clear
questions if confusion persists.

Note that I trimmed his post to just the part I responded to.  This was of
course for the usual reason of avoiding clutter, but also to make it clear
that I wasn't responding to the rest.

Frankly, the rest look a rather jumbled mess at first glance.  This is
another reason I deleted it without comment.  You often are the one to say
that I should simply not respond when I don't like the way something is
written, but now when I did you want me to explain why.  First I don't owe
anyone, including you, any explanation.  Since I'm not being paid, I can
chose to not respond to any message or any part of any message as I see fit,
without obligation to justify it.

However, since you asked and basically put me on the spot publicly, I feel I
need to waste the time explaining just to defend myself.  If you think this
is insulting to the OP, note that I silently ignored it and you were the one
to ask for justification.

> "  ... but in the datasheet something weird is written : there is a
> note telling this register is available in mode 1 and 2 only.  But in
> the description, there is only description for mode 0 ..."

I didn't feel like playing 20 questions guessing which "modes" he was
referring to about which part of the hardware.  I may remember modes by name
or general description.  But really, I'm supposed to remember them by their
bit field value!!?  That's so obviously not supplying meaningful context as
to be borderline rude.  Yes, that's how I really felt about it, which of
course didn't exactly make me want to spend effort elaborating on the
answer.

He should have been able to understand that others are very unlikely to have
read that section of that datasheet so recently to remember such minutia.
Besides, he was having a general CAN misconception, so this was all just the
trees getting in the way of seeing the forest anyway.

> He says he's looked in the datasheet, he's quoting material that
> doesn't make sense to him, he's asking for help from people with
> practical experience.

But his quote didn't make sense to me.  It seemed to me he was expecting
people to do excessive research just to understand what he was talking
about.  From his apparent lack of understanding of context his readers
needed, it seemed to me that getting into a discussion with this guy would
be too painful.  Yes, I judge people here by the quality of their question.
This is then used to decide how much it's worth helping them.  This guy
didn't completely flunk the test, but got a D or C-.  It's my call to make,
and I don't have to justify it to anyone.  Again, note that I just silently
ignored it as you have often advised in the past.

I figured if others with more patience than I followed up and he eventually
learned how to provide better context, I might jump in and add a few things..
But as it stood now, my thought process was "this will be too much trouble,
no thanks".

> He says that he's doing a paper design and can't
> try it out with the actual hardware.

Lots of people say lots of stuff.  My first reaction to that was "that's
silly", so I ignored it.  Some things are worth helping with, others not, or
I simply don't feel like it.  That's the beauty of email.  You can pretend
anything you don't want to bother replying to just didn't happen.  Again, he
can have all his money back.

> What more would you expect him to have done?

Provided better context for what was frankly just babble that would have
taken some work to make sense of.

> If you know the answer and decided to reply at all why were you not
> more helpful?

1 - That's all I had time for that day that post.  No apologies for that.

2 - That's what I thought addressed the real problem after a quick read
   of the post.  I still think that's true.

> If you decided not to be helpful (which is entirely your right) why
> did you not just say nothing.

I did exactly that to the majority of the post.  Apparently that's not good
enough for you either.

Another time I might have explained why the rest of his post was mostly
babble to me, and you probably would have gotten upset at that.  This day
for this post I didn't, and now you want my to justify why I didn't.  You
can't have it both ways.

Russell, your second guessing of my posts is getting quite tiresome.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\05\26@113353 by Olin Lathrop

face picon face
kris duff wrote:
> The question was more do somebody has already see this kind of weird
> thing in the microchip datasheet...

It's not clear what exactly "think kind of weird thing" is.  You first asked
about how to filter on only a subset of the ID.  That is done with "masks".
You set up masks to indicate which bits of the ID a possible set of filters
applies to.  They is precisely what they are for.

However I don't understand what the datasheet confusion is nor how that
relates to filtering on a subset of the ID bits.

Also, it would help to take a little more care in writing your question.  I
normally don't bother to go into this, but Russell seems to want me to
explain my thought process in detail.  Since all we know about you is what
you write here, we can only judge you by that writing.  How you are
perceived has a lot to do with the quality of the answers you will get.  At
least for me, the more I judge someone to be a clueless moron, the less I'm
inclined to spend time trying to help.

Your sentence above unfortunately doesn't speak well about you.  "do
somebody has already see" should be "has somebody already seen".  The
meaning is still clear enough in this case, but this sort of poorly written
english is annoying to read.  It basically says "I'm so imporant and you're
so inconsequential that I don't give a crap how easy it is to read my post.
Sure, I could spend 200 more milliseconds and a few extra brain cycles to
get it right, but you're not worth it, peon".  Like it or not, you are
constantly judged by what you write and the quality of that writing.  That's
not meant as a offense, simply a statement of how the world works, whether
the world tells you this or not.

I understand this may not be your fault since you may not be a native
english speaker.  Note that this doesn't change the annoyance level in
reading your post, but would give you considerable slack if it were known to
be true.  "Sorry, I'm doing the best I can" is quite forgivable and very
different from "I don't give a crap".  However to get this slack, it has to
be known you really are a non-native english speaker, not just a lazy
ingrate.  Sometimes that's clear from other grammar, choice of words, and
spellings in the rest of the post.  In this case it's not.  Having a foreign
sounding name helps.  I understand names are little guarantee of anything,
but in the abscence of other information do tip the scales.  Unfortunately
"kris duff" is no help.  If anything, it makes it more likely you should
know english well.  The fact that K and D aren't capitalized as they should
be is another strike against you.  If you really are foreign to english and
a beginner, it helps immensely to say so.  Your sentence above would be no
issue at all if I knew you were foreign to english.

All this is just to point out the internal thought process that goes into
deciding how to judge how much effort to spend in replying to a post.  This
goes on all the time.  The only difference is that this one time I described
the process in detail so you can understand how you are preceived (since I
expect you wish to receive good replies) and to get Russell off my back.

Yes, this is rather harsh.  However that's the way the world works.  The
only difference is that I'm describing the process instead of applying it
silently.  Don't shoot the messenger (that goes for you too, Russell).


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\05\26@115350 by Bob Blick

face
flavicon
face
Olin,

Admin message: STOP.

You'll be hearing from us.

Bob

-- http://www.fastmail.fm - The professional email service

2011\05\26@122329 by kris duff

flavicon
face
I do agree.  

Thank you.


________________________________
From: Bob Blick <.....bobblickKILLspamspam.....ftml.net>
To: Microcontroller discussion list - Public. <EraseMEpiclistspam_OUTspamTakeThisOuTmit.edu>
Sent: Thursday, May 26, 2011 11:53:49 AM
Subject: Re: [PIC] canbus v2.0b extended id filtering

Olin,

Admin message: STOP.

You'll be hearing from us.

Bob

-- http://www.fastmail.fm - The professional email service

2011\05\27@105235 by Gerhard Fiedler

picon face
RussellMc wrote:

> Olin - this is a genuine attempt to understand what is happening here.

FWIW, I think Olin's response was succinct, clear and adequate. He
picked a core question and answered it, even though not in great detail.
("I'd like to know whether A is possible." - "It is possible using B and
C." - Looks ok to me as first attempt at a helpful answer.)

If I had received it in a similar context, I'd have looked closer into
filters and masks, and if I still had doubts, I'd have extracted the
relevant parts from the datasheet and asked a more focussed question
about the use of filters and masks, explaining how I think they should
work and what exactly makes me doubt that they do in fact work like
this. (This recommendation is my addition to Olin's post for the OP; so
far this is "on topic", so to speak :)

The answer seemed perfectly normal to me, even though I see your point
that one could have gone into more detail with an answer. But as Olin
says, nobody is obliged to do so (even though some could get the
impression that Olin is from the depth of information he generally
provides). In any case, I didn't see anything "rude" in this response,
and I would classify it as a helpful response (if I had received it) --
much better than none, in that an experienced developer confirmed that
what I want is possible.
Also FWIW, it seems that so far Olin's response was the most useful of
all.

Gerhar

2011\05\27@202022 by cdb

flavicon
face


:: Also FWIW, it seems that so far Olin's response was the most
:: useful of all.

The point brought up by the OP doesn't seem to have been addressed - he stated that he couldn't understand (paraphrased by me) that the datasheet seemd to be at best contradictory and at worst lacking in explanation at all about what could and couldn't be done with the various modes.

Perhaps I'm in some Twiglet zone and missed some one addressing that concern.
--
cdb, colinspamspam_OUTbtech-online.co.uk on 28/05/2011
Web presence: http://www.btech-online.co.uk   Hosted by:  http://www.justhost.com.au

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