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'[EE] Software SPI'
2007\07\26@212712 by Rich

picon face
Has anyone created a software SPI?

2007\07\26@215403 by David VanHorn

picon face
I have on the avr, but most of the larger ones have hardware.


On 7/26/07, Rich <spam_OUTrgrazia1TakeThisOuTspamrochester.rr.com> wrote:
> Has anyone created a software SPI?
> -

2007\07\26@224533 by Jake Anderson

flavicon
face
Rich wrote:
> Has anyone created a software SPI?
>  
yes

2007\07\27@001354 by Rich

picon face
How do you do it in software?

----- Original Message -----
From: "David VanHorn" <.....microbrixKILLspamspam@spam@gmail.com>
To: "Microcontroller discussion list - Public." <piclistspamKILLspammit.edu>
Sent: Thursday, July 26, 2007 9:53 PM
Subject: Re: [EE] Software SPI


>I have on the avr, but most of the larger ones have hardware.
>
>
> On 7/26/07, Rich <.....rgrazia1KILLspamspam.....rochester.rr.com> wrote:
>> Has anyone created a software SPI?
>> --

2007\07\27@004637 by Jake Anderson

flavicon
face
Rich wrote:
> How do you do it in software?
>
>  
http://justfuckinggoogleit.com/search.pl?query=PIC+SPI+software

2007\07\27@013546 by John Chung

picon face
Use bit-banging method. It is like implementing
through the simple stuff like i/o port. Still it is
worth your time?

John


--- Rich <EraseMErgrazia1spam_OUTspamTakeThisOuTrochester.rr.com> wrote:

> How do you do it in software?
>
> {Original Message removed}

2007\07\27@030813 by Marcel Birthelmer

picon face
Rich,
here is a website I made a while ago detailing how to interface a PIC
to a MAX7221 with bit-banged SPI communication. Please see if it helps
you.

http://marcel.carrietech.com/pic/spiled.php

- Marcel

2007\07\27@031021 by Marcel Birthelmer

picon face
It looks like the script broke, so here is the direct link to the source code:
http://marcel.carrietech.com/pic/spileds.asm

On 7/27/07, Marcel Birthelmer <marcelb.listsspamspam_OUTgmail.com> wrote:
> Rich,
> here is a website I made a while ago detailing how to interface a PIC
> to a MAX7221 with bit-banged SPI communication. Please see if it helps
> you.
>
> http://marcel.carrietech.com/pic/spiled.php
>
> - Marcel
>

2007\07\27@031436 by Bob Axtell

face picon face
Rich wrote:
> Has anyone created a software SPI?
>  
Yes.

2007\07\27@032553 by wouter van ooijen

face picon face
> Has anyone created a software SPI?

Yes.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu



2007\07\27@033109 by Dario Greggio

face picon face
Jake Anderson wrote:

> Rich wrote:
>
>>Has anyone created a software SPI?
>>  
>
> yes

of course :)

--
Ciao, Dario
--
ADPM Synthesis sas - Torino
--
http://www.adpm.tk

2007\07\27@051821 by Michael Rigby-Jones

picon face


>-----Original Message-----
>From: @spam@piclist-bouncesKILLspamspammit.edu [KILLspampiclist-bouncesKILLspamspammit.edu]
>On Behalf Of Rich
>Sent: 27 July 2007 02:27
>To: Microcontroller discussion list - Public.
>Subject: [EE] Software SPI
>
>
>Has anyone created a software SPI?

SPI is trivial to bit bang compared with e.g. I2C.  However, note that there are four possible timing/polarity variations with SPI, and most peripherals only support one.  The data can be clocked on a positive or negative edge, and on a trailing or leading egde so you have to make sure you set up the data at the right point.  The PIC datasheets usualy have a diagram explaining this in the MSSP section.

For the highest possible speed, don't use a loop but clock out each 8 bits with separate instructions (i.e. unroll the loop).  This has only a small code size overhead but can give a good improvement in bit rate.

Regards

Mike

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2007\07\27@093816 by enkitec

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On 27 Jul 2007 at 9:31, Dario Greggio wrote:

> Jake Anderson wrote:
>
> > Rich wrote:
> >
> >>Has anyone created a software SPI?
> >>  
> >
> > yes
>
> of course :)
>

more than once!

Mark

2007\07\27@110652 by Rich

picon face
Did you apply it to memory or A/D?

----- Original Message -----
From: "wouter van ooijen" <RemoveMEwouterTakeThisOuTspamvoti.nl>
To: "'Microcontroller discussion list - Public.'" <spamBeGonepiclistspamBeGonespammit.edu>
Sent: Friday, July 27, 2007 3:25 AM
Subject: RE: [EE] Software SPI


{Quote hidden}

> --

2007\07\27@111154 by Rich

picon face
Maybe not.  The board is already created.  Just thinking about a peripheral.

----- Original Message -----
From: "John Chung" <TakeThisOuTkravnusEraseMEspamspam_OUTyahoo.com>
To: "Microcontroller discussion list - Public." <RemoveMEpiclistspamTakeThisOuTmit.edu>
Sent: Friday, July 27, 2007 1:35 AM
Subject: Re: [EE] Software SPI


{Quote hidden}

>

2007\07\27@111252 by Rich

picon face
Thank you, Marcel.  I appreciate it.


----- Original Message -----
From: "Marcel Birthelmer" <RemoveMEmarcelb.listsTakeThisOuTspamspamgmail.com>
To: "Microcontroller discussion list - Public." <EraseMEpiclistspamspamspamBeGonemit.edu>
Sent: Friday, July 27, 2007 3:08 AM
Subject: Re: [EE] Software SPI


> Rich,
> here is a website I made a while ago detailing how to interface a PIC
> to a MAX7221 with bit-banged SPI communication. Please see if it helps
> you.
>
> http://marcel.carrietech.com/pic/spiled.php
>
> - Marcel
> --

2007\07\27@111435 by Dario Greggio

face picon face
Rich wrote:

> Did you apply it to memory or A/D?

me, to both Memory and DAC.
Ah, and CC2420 / Nordic RF chips too.


--
Ciao, Dario

2007\07\27@112432 by Rich

picon face
Thank You again, Marcel.

----- Original Message -----
From: "Marcel Birthelmer" <RemoveMEmarcelb.listsKILLspamspamgmail.com>
To: "Microcontroller discussion list - Public." <piclistSTOPspamspamspam_OUTmit.edu>
Sent: Friday, July 27, 2007 3:10 AM
Subject: Re: [EE] Software SPI


{Quote hidden}

> --

2007\07\27@112806 by Rich

picon face
Thanks, Mike.  I appreciate your help.

----- Original Message -----
From: "Michael Rigby-Jones" <KILLspamMichael.Rigby-JonesspamBeGonespambookham.com>
To: "Microcontroller discussion list - Public." <EraseMEpiclistspamEraseMEmit.edu>
Sent: Friday, July 27, 2007 5:21 AM
Subject: RE: [EE] Software SPI


>
>
>>{Original Message removed}

2007\07\27@113650 by wouter van ooijen

face picon face
> Did you apply it to memory or A/D?

( no or yes ) == yes

Never ask such questions to the mathematically educated...

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu



2007\07\30@104457 by alan smith

picon face
ya....a way mature response.....nice Jake...

Jake Anderson <@spam@jake@spam@spamspam_OUTvapourforge.com> wrote:  Rich wrote:
> How do you do it in software?
>
>
http://justfuckinggoogleit.com/search.pl?query=PIC+SPI+software

2007\07\30@205722 by Jake Anderson

flavicon
face
alan smith wrote:
> ya....a way mature response.....nice Jake...
>  
He has been on the list for about a year (as far as I can tell) and
should know better. It does actually give the answer he was looking for
after 15 seconds(pretty much every response on the search page is an
implementation of a software SPI routine including one from microchip).
It just struck me as a particularly dumb question on that many levels I
couldn't quite get past it. I would have thought the 20 or so "yes"
responses might have tipped him to the fact that it was pretty common
and perhaps just maybe he could have a look for himself. Next time I'll
endeavour to find a similar page without the naughty word.

2007\07\30@213449 by Rich

picon face
It's OK, Alan.  I don't hold hard feeling towards rudeness.  After all, it's
not my problem.  But that you noticed attests to your dignity.


----- Original Message -----
From: "alan smith" <spamBeGonemicro_eng2spamKILLspamyahoo.com>
To: "Microcontroller discussion list - Public." <.....piclistspam_OUTspammit.edu>
Sent: Monday, July 30, 2007 10:44 AM
Subject: Re: [EE] Software SPI


> ya....a way mature response.....nice Jake...
>
> Jake Anderson <TakeThisOuTjake.....spamTakeThisOuTvapourforge.com> wrote:  Rich wrote:
>> How do you do it in software?
>>
>>
> http://justfuckinggoogleit.com/search.pl?query=PIC+SPI+software
>
> --

2007\07\30@220157 by Rich

picon face
It is apparent from the very refined diction in your response that you have
great and extensive knowledge.  I do not. I am, however, aware that software
SPI is not as likely to be utilized by many persons because it is cumbersome
and less efficient that the simple hardware connection to a SPI port.  I
have never written the code.  In fact, I am sure to be less expert in
programming than most on the list.  But in my simple ignorance I expected
that someone else perhaps might have retrofitted a PCB having no SPI port,
as I intended.  But you may be correct.  It just might have been a dumb
question that I should not have annoyed anyone on the list with.
   Nevertheless, I am always grateful to those on the list who are
courteous and genuine.  This is a fine list with magnanimous members.


{Original Message removed}

2007\07\31@001126 by Jake Anderson

flavicon
face
No I am no guru of anything PIC related. It is however considered rude
to ask a question like that without doing any research of your own
first. I mean seriously "software SPI PIC"  2 out of the 3 words are in
the subject. Getting 20 people responding with "yes" (myself included
the first time round) might also indicate that this is something you
might want to spend 6 or 7 seconds looking up on your fave search engine
before asking 2000 people for personalised help.

If it was something along the lines of "The software SPI routines I have
seen online don't have the ability to dynamically change modes between
the 4 different variants has anybody seen or got one" then that would be
a valid question and a large number of people would probably offer to
help you for free. I'm all in favour of asking simple questions when you
don't understand the answers you have found yourself but I'm not here to
be your personal search assistant. Yes I probably should have just
ignored your question but I did infact give you an answer it was just
presented colourfully.

Rich wrote:
{Quote hidden}

> {Original Message removed}

2007\07\31@083741 by David VanHorn

picon face
I must admit, for questions in the nature of "has anyone ever...." I
am frequently tempted to respond with "yes", but obviously there's a
real question behind the question.

2007\07\31@100107 by wouter van ooijen

face picon face
> I must admit, for questions in the nature of "has anyone
> ever...." I am frequently tempted to respond with "yes", but
> obviously there's a real question behind the question.

But for the purpose of educating the questioneer to ask the real
question in the first place, the answer "yes" might still be best.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu



2007\07\31@104836 by David VanHorn

picon face
> But for the purpose of educating the questioneer to ask the real
> question in the first place, the answer "yes" might still be best.

True. :)

"be careful what you ask for, you may get it."

2007\07\31@113838 by Rich

picon face
I am sorry to have offended you by my question, which you apparently took as
an imposition on you and assumed it to be so for others, judging from the
"Yes" reply.  I have no animosity toward you, of course.  In fact I find
your response somewhat informative.  Your  personality is not for me to
judge. Perhaps it was a stupid question.  I ask very few questions of the
list and those that I do ask I have already tried to answer otherwise,
perhaps not as exhaustively as you might have.  I sometimes see questions on
the list that appear easily answered to me, like what to do about unused
pins, but I have no idea that I should think the person rude for asking it.
It is a legitimate and necessary question much like other questions that
seem easily answered.  I don't have any latent or manifest feelings of
superiority. I cannot think of what it is that would  impel me to respond
with feigned expletives.  There are lists, I am sure, for experts only.
This list only includes experts; who are expert in diverse areas besides
software.  I have talked to several members on list and off who are
genuinely tolerant and graceful persons, as I believe most are.  In my
humble opinion you might find more satisfaction to expend your energy in a
more constructive way by being helpful.  Perhaps I was remiss in not
clarifying my question well enough.  But I would be very disappointed if the
list were to fall to such a "legalistic" form of colloquy.


{Original Message removed}

2007\07\31@114439 by Rich

picon face
It is not constructive in any way.  "Search and find the answer somewhere
else" would be a more honest and less covert reply by those who would say
simply yes.


----- Original Message -----
From: "David VanHorn" <TakeThisOuTmicrobrixKILLspamspamspamgmail.com>
To: "Microcontroller discussion list - Public." <.....piclistspamRemoveMEmit.edu>
Sent: Tuesday, July 31, 2007 10:48 AM
Subject: Re: [EE] Software SPI


>> But for the purpose of educating the questioneer to ask the real
>> question in the first place, the answer "yes" might still be best.
>
> True. :)
>
> "be careful what you ask for, you may get it."
> --

2007\07\31@124241 by David VanHorn

picon face
On 7/31/07, Rich <RemoveMErgrazia1spamspamBeGonerochester.rr.com> wrote:
> It is not constructive in any way.  "Search and find the answer somewhere
> else" would be a more honest and less covert reply by those who would say
> simply yes.

I disagree. I think you have taken a step twoard learning to ask
better questions, which is a very important thing.  It might not have
been the most pleasant experience, but such things tend to stick with
you.

This is a very friendly list, but we get a lot of those sorts of "Has
anyone ever (some really common thing) " requests, and you DID get the
answer to the question you asked.

:)

2007\07\31@131245 by Gerhard Fiedler

picon face
Rich wrote:

>>> But for the purpose of educating the questioneer to ask the real
>>> question in the first place, the answer "yes" might still be best.

> It is not constructive in any way.  "Search and find the answer somewhere
> else" would be a more honest and less covert reply by those who would say
> simply yes.

I don't think that this is what Wouter meant. I think he meant that behind
your original question "Has anyone created a software SPI?" is your real
question, whatever this is. That it has been created is easily verifiable
by any number of means. There is possibly some other doubt behind it, and
getting the answer for the question you asked could prompt you (or not...
depends on you :) to realize that you didn't ask about what you wanted to
know and ask a more specific question about the actual problem.

Gerhard

2007\07\31@132404 by wouter van ooijen

face picon face
(about the "yes" answer)

> It is not constructive in any way.

Maybe, but it is (or attempts to be) educational. Which can be
interpreted as "long-term constructive".

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu



2007\07\31@132849 by wouter van ooijen

face picon face
> I don't think that this is what Wouter meant.

Wouter agrees with Gerhard but has the (good? bad?) habit of using a
minimum number of words.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu



2007\07\31@144126 by Rich

picon face
I am pleased to reply that I got everything that I could not find on the
internet or in the archives.  I respectfully disagree with your position
that "yes" is either informative or educational.  If my question was
ambiguous and misleading your "Yes" is no better.  The direct response "have
you looked elsewhere... what are you trying to do... your question is stated
in an annoying way... don't ask, or others of a more direct approach, which
would have been logically better.  I would then have clarified the question
immediately.  But judging from the excellent responses I received some
persons understood well enough to provide exactly what I needed to know and
I was very grateful.  I did not need to ask them a better question.  They
were not annoyed that I am less expert than they.  Some people just need
less information than others.  But if my question was really considered
rude, I am indeed surprised.  I recall a time when there was some criticism
of the language used by those for whom English was not their principle
language.  That criticism was rude.  English was not the language I used as
a little kid but when I went to public schools it became my principle
language.  So I was somewhat disappointed by the criticisms. My position
then was to help explain rather than complain. But that is just my humble
opinion.  I am not of the opinion that the membership of this list ever will
or should be homogeneous.  Even the reaction to such a simple question by a
few attests to the list personality and dynamics.  That aspect I do believe
is of great value and finds expression in much of the OT discussions.
Unless there are some further complaints, this discussion seems to me to be
concluded.


{Original Message removed}

2007\07\31@195120 by Barry Gershenfeld

face picon face
I hesitated in responding to this, not wanting to start the inevitable
discussion myself, but happily, someone did.  I want to describe what I
took away from the exchange, and put it up possibly as a lesson to
consider.  The sequence of events, as I observed them:

OP (Rich) posts a question.

Numerous responses basically saying, "Yes".  Ranging from cute to rude.

Two helpful responses.

OP Thanks the two people, and walks away.  End of exchange.

 * * *

And so, what we learn from this, is that you may respond in a way that
makes a joke, or tries to lecture the OP, but someone genuinely wanting to
help will scoop you will post and answer.  The Original Poster can then
take the information, ignore the hecklers, and get on with the project.

Since Rich is reading this thread he may tell me it didn't really happen
that way, but maybe he'll play along for the sake of the lesson.   It's
about "mailing list dynamics", folks.  There are some things we can't
change.  Note that when this is over, everyone on the list basically knows
not to ask a question like that.  And yet, tomorrow, someone new will join
the list.  We must not treat them as though they should know better.  We
shouldn't forget this.  That he is not a newbie is secondary; the point is
still valid.  I suspect most of the replies weren't for his benefit
anyway.  I think we do it as much to impress each other.

The other factor is the bit about the two who responded with
information.  Some of us get our satisfaction out of helping others.  We
have varying amounts of patience.  It's really OK for someone to post a
vague question, which can be answered vaguely with few words, as sort of a
prompt for new information.  Since the OP doesn't get what he wants he will
be back with a better question.   (And trolls usually won't
return).  Often, someone will come back with a program ("Here, try
this")--which kind of ruins it for the patient teachers :-)  --but, as I
say, I can't regulate anyone's behavior, so, we get what we get, and it
works out.

And lest anyone think I'm trying to act superior, rest assured that I came
this close to posting my answer, "Yes, bit-banged, and at 10
bits/second!"   I'll add that I did it in spite of the built-in SPI, which
I had trouble getting to do what I wanted.  And had I participated in a
discussion, I would have explained it simply, ("You watch for the clock to
go high and then read the bit," etc) and let the OP's answer tell me if
that was enough, or where on the detail spectrum he was coming from.

Otherwise, as Yogi Berra might say, most people know me as the guy who
doesn't post much.
Barry


'[EE] Software SPI'
2007\08\02@145031 by Vasile Surducan
face picon face
Maybe this one will help you:
http://pdfserv.maxim-ic.com/en/an/AN2361.pdf
I didn't knew if you preffer asm, C or else...

Vasile

On 7/26/07, Rich <spamBeGonergrazia1@spam@spamspam_OUTrochester.rr.com> wrote:
> Has anyone created a software SPI?
> -

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