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 Posted: Feb 09, 2011 - 11:54 AM |
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Joined: May 04, 2007
Posts: 3529
Location: Geelong Australia, Home of the "Cats"
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Hi Cliff,
I know what you mean. I don't believe there is a shortage of references, but there may be a shortage of AVR relevant examples.
If I do something, I would do something off the top of the head(avoiding copyright issues). In particular I had in mind dissecting avr-libc Demo projects "Using the standard IO facilities". I will mull it over a bit more before I commit.  |
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Posted: Feb 09, 2011 - 11:59 AM |
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Joined: Jul 18, 2005
Posts: 62922
Location: (using avr-gcc in) Finchingfield, Essex, England
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may be a shortage of AVR relevant examples
But surely that's the very point? Beginners confuse themselves if they try to learn both pointers and AVR concepts at the same time. Surely the learning process is 1) learn C 2) learn to use it on AVRs in particular.
The use of pointers occurs at (1) as they are surely what sets C apart from other procedural languages.
Not really understanding how an AVR works while at the same time not really understanding how to use the chosen programming language is surely a recipe for disaster? |
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Posted: Feb 09, 2011 - 12:20 PM |
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Joined: May 04, 2007
Posts: 3529
Location: Geelong Australia, Home of the "Cats"
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| Your impeccable logic has turned me around to your way of thinking. |
_________________
Charles Darwin, Lord Kelvin & Murphy are always lurking about!
Lee -.-
(If you haven't already done so, edit your PostNuke profile and let let us know where you are, what you do & what your interests are.)
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Posted: Aug 03, 2011 - 06:22 AM |
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Joined: Jul 25, 2011
Posts: 49
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| May I beg for something about tools, especially software tools? Studio 5 offers a multitude of "views" that magically appear and disappear according to context, some may be familiar to avid Visual Studio users but not to noobs, some may be AVR Studio specific. Within I/O view, there are again a milliard of layers and bits and bytes. How do all these registers relate to names in other documents/tutorials? I feel overwhelmed by the amount of information, just like I was learning to drive. Where do I look, what to look for at that particular moment? A few pointed code segments accompanied with specific pointers (not programming pointers:-) to view focus (especially those cryptic names - not all of them, just the ones that I ought to be paying attention during the current step) will be great. |
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Posted: Aug 03, 2011 - 09:15 AM |
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Joined: Jul 18, 2005
Posts: 62922
Location: (using avr-gcc in) Finchingfield, Essex, England
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I feel overwhelmed by the amount of information, just like I was learning to drive
Suggest you start by using AS4 which is so simple even I can understand it. When you are familiar with this "cut down" version of what's going on the AS5 stuff should seem more obvious (and by then they may have got it working!). |
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Posted: Sep 21, 2011 - 04:56 AM |
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Joined: Jun 26, 2011
Posts: 41
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| Please add my vote for a tutorial on adding USB to a project... perhaps combining LUFA with V-USB...? |
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Posted: Sep 21, 2011 - 09:07 AM |
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Joined: Jul 18, 2005
Posts: 62922
Location: (using avr-gcc in) Finchingfield, Essex, England
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perhaps combining LUFA with V-USB..
Do you mean combine or simply "covering both of"? I cannot envisage a reason why a project would actually use both at the same time. If you are talking about all the solutions for "how do I add a USB connection to an AVR" I'd also add the use of the FTDI (PL2303?) to the list as that's the way everyone did it in the first place. |
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Posted: Sep 21, 2011 - 03:23 PM |
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Joined: Jun 26, 2011
Posts: 41
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| Maybe my understanding is incorrect - I thought that LUFA was intended for chips that included USB support in hardware... so if you wanted to use USB *directly* on chips without, you would need to have something like V-USB operating underneath it. |
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Posted: Sep 21, 2011 - 03:39 PM |
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Joined: Jul 18, 2005
Posts: 62922
Location: (using avr-gcc in) Finchingfield, Essex, England
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Maybe my understanding is incorrect
It is incorrect. There are two possibilities:
1) AVRs with USB built in - they have registers in the IO map of the chip for USB. LUFA is a software stack you run on such an AVR that hides a lot of those register details from you and lets you do things at a much higher, easier to understand level. Dean's LUFA code makes it much easier for anyone to use AT90USB and ATmega*Un chips.
2) good old fashioned tiny and mega with no sign of USB at all. They can be connected to a USB on a PC but it's done by using 2 IO lines that are "bit banged" by the very clever V-USB software that allows you to open simple USB channels to the PC. It's downside is that with no h/w support the V-USB software uses a huge percentage of the available CPU time and only leaves time for simple jobs like LED scanning and button reading etc.
There is no overlap. LUFA won't work on top of V-USB. The outward facing layer of V-USB gives a very limited "poor man's" USB interface like a massively reduced subset of LUFA on a chip with real USB h/w.
So there could be one tutorial about using V-USB (though I'd suggest that the objdev.at site has loads to get you started already)
And there could be another one about getting started with LUFA (though again most people get by with the documentation on Dean's website). One of the best tutorials for LUFA are actually the sample projects that ship with it.
I wouldn't suggest mixing them - though there could be a higher level tutorial to help folks make the decision between V-USB on tiny/mega, LUFA on USB-AVR or FTDI attached to any AVR you choose. |
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Posted: Sep 21, 2011 - 06:19 PM |
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Joined: Jun 26, 2011
Posts: 41
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| Thanks for the correction. I've been looking at the objdev.at site as well as the code... but so far the concepts seem to escape me. (Likely because I'm not very familiar with advanced C programming...) |
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Posted: Sep 21, 2011 - 07:24 PM |
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Joined: Jul 18, 2005
Posts: 62922
Location: (using avr-gcc in) Finchingfield, Essex, England
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I'm not very familiar with advanced C programming...
Whether you use LUFA or V-USB I'd say you need a pretty strong grasp of C programming - you can't really expect an LED flashing absolute beginner to pick up the concepts in either and no end of tutorials will help that. |
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Posted: Sep 22, 2011 - 12:03 AM |
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Joined: Jun 26, 2011
Posts: 41
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| Well... I'm not an LED flashing absolute beginner - I just haven't maintained my programming skills since learning BASIC, COBOL and FORTRAN in highschool. (I'm really more of a hardware guy...) |
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