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Looking for documentation about tv&vga drivers — Parallax Forums

Looking for documentation about tv&vga drivers

ManAtWorkManAtWork Posts: 2,178
edited 2010-03-28 07:47 in Propeller 1
Hello,

I find the video capabilities of the propeller really great. But I can't find much documentation about how it really works. Or actually, I don't care much about how it works but how to use all features of it. For example, I found out that·VGA_text.spin uses one tile (word) per character. vgatest2.spin from the propeller_demo uses two half-tiles per character so that it's possible to use the special characters to draw 3D-like boxes. But how does that really work? How do I select the correct mode? I also don't fully understand the use of the color tables. The demos and the propeller manual gives very little info. Before I start to reverse-engineer the code I'd like to ask the forum.

Thanks

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-03-26 13:37
    The best documentation on how the TV driver works and how the Propeller video hardware works is the Hydra Manual. It's not free, but it's worth every penny of its cost. There's some information distributed throughout the Propeller Manual and the Datasheet.
  • Steve JonesSteve Jones Posts: 4
    edited 2010-03-26 14:13
    Really?

    Hmm.. I'm an old Basic Stamp 1 guy, just getting into the Propeller, and the video hardware is what attracted my attention to the Prop, but I have no intention of writing or playing games, so I didn't buy the Hydra..

    I was assuming that like other Parallax stuff, all the technical info I'd need would be freely available..

    Is there a market for used manuals? Seems a shame to buy a $50 manual just for learning about how to use the video driver that I already bought..
  • potatoheadpotatohead Posts: 10,261
    edited 2010-03-26 15:11
    If you want, you can get the chapters that detail how the Parallax driver works for free. I'm not where I can link them up at the moment, but I will be later. Google hydra free chapters. If you don't find them, let me know. I think they are still in the Parallax Propeller downloads.

    The reference drivers; namely, the ones that ship with the Propeller tool, can actually do a lot. If you learn those, you will have a good leg up on the many other graphics options out there.

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  • ManAtWorkManAtWork Posts: 2,178
    edited 2010-03-26 15:46
    Hello Potatohead,

    Do you mean this (Downloads·& Resources at the bottom right)?
    http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/hydra/List/0/SortField/4/ProductID/474/Default.aspx
    Chapter 16·contains some useful info, but unfortunatelly, the "sneak peek" ends at the most exciting page.

    This makes me wonder a bit. Not that I think that everything has to be free. I had no problem paying Mike $10 for every question answered (what would make him a rich man if he was payed for his 14744 postssmilewinkgrin.gif ). If I really wanted to program games I'd also had no objections against buying a book or dev kit for $50 which is really affordable. I asked for a devkit for the gameboy when it was new and they told me something around $20,000. shocked.gif

    But IMHO, at least the library sources should include some documentation about their interface, how to properly use the parameters and so on. Missing that is bad programming style.

    Cheers
  • Steve JonesSteve Jones Posts: 4
    edited 2010-03-26 15:48
    Thanks! I did that google search, and found chapter 16 on the Parallax site, which seems to have a lot of great information..

    For historical purposes, This is what I found:
    http://www.parallax.com/dl/docs/prod/prop/Hydra-Ch16Sample-v1.0.pdf

    At least now I know what a "tile" is.. smile.gif This should be enough information to make sure I dont get to see the sun this weekend!!

    Thanks for the help!

    -Steve
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2010-03-26 17:06
    I went through the same sort of thing when learning how to use the Sensirion object for the SHT11 temp/humidity sensor. The "demo" code in the OBEX lacks detailed explanations of how the functions work and/or are used, so as a newbie, I had to dig deep, line by line, along side my Propeller manual to understand how to implement use of the object in my own code. To me, a demo program would have full explanations and comments throughout so you can better understand the object being published.

    I would love to see a new sister site for the OBEX created that would be an OBEX version of Wikipedia. For each object in the OBEX, there would be a page that explains things like how to use it, how it works, how to tweak it, what bugs exist if any, examples of completed projects using the object, etc, etc. As a wiki, it would be maintained by the end-users to keep it up to date.

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  • kf4ixmkf4ixm Posts: 529
    edited 2010-03-26 17:19
    WBA Consulting said...
    I would love to see a new sister site for the OBEX created that would be an OBEX version of Wikipedia. For each object in the OBEX, there would be a page that explains things like how to use it, how it works, how to tweak it, what bugs exist if any, examples of completed projects using the object, etc, etc. As a wiki, it would be maintained by the end-users to keep it up to date.

    I very much second that idea! Although most objects are documented fairly well,·i think that would make the objects much more newbie-friendly. Especially seeing examples and tweakings of such.
  • K2K2 Posts: 693
    edited 2010-03-26 17:25
    "If it was hard to write, it should be hard to read!" That's what I've been telling people for years.
  • potatoheadpotatohead Posts: 10,261
    edited 2010-03-27 02:29
    Well, on the matter of style, I think I need to defend Andre' and the HYDRA team here.

    Truth is, full, robust documentation is expensive, and the HYDRA kit isn't. The whole thing is lean. If one goes to look at the code itself, the clarity is good, and the examples give people easy and ready means to test limits and explore functions. Constants are used, comments are used, and the layout of key memory locations is reasonable. It's pay now or pay later on these things, and the clear trend right now is lean, potent products, which the Prop and many associated products are.

    I found the materials pleasing, in that there was NOT a huge amount of material to consume. The core concepts are there, leaving the rest as hands on time, which I needed (still do), and enjoyed.

    "bad" programming style isn't really applicable here, IMHO, "lean" is.

    Just by way of reference, my professional employment involves a well known, high end CAD program. The software cost on that program is well over 10K. Docs and media are $500. There are easily a quarter million seats in play, with at least half of those buying documentation. (multiple seats only require one documentation package) Do the math on that, and very quickly arrive at the sobering realities of documentation these days, particularly given 2/3 of that is an ANNUAL cost for updates, changes, revisions, etc... Most interestingly, the product can be purchased without that documentation, and perhaps 1 in 5 people do every year. All return to pick up the charge, and gladly continue with annual updates as well.

    By comparison, the volume of information associated with the HYDRA is a steal. Said information is either embodied in the code, which costs you time and food to consume, or embodied in a book, presented for easy consumption, which costs you dollars, in addition to time and food, --> perhaps less time and food [noparse]:)[/noparse]

    If you look at the HYDRA book cost, and the cost of the HYDRA, then add up components, labor markup, etc... the documentation that exists as part of the purchase is sold at a very reasonable cost, particularly when bought with the hardware. Factor all that in, and there is a strong case for the code being free. So then, a download received is exactly what was paid for, and this has little to do with style, given the goal of the project was to realize the HYDRA and documentation in the first place, and to do so in a competitive way second, or perhaps first... ask Andre' about that. I think he will say first.

    If that code were paid for, then some expectation of higher order documentation would be reasonable, again, IMHO, people have to eat. What is competitive about the HYDRA, and Parallax products, as well as it's associated vendors products, is this lean compromise. It is assumed that we all have some quantity of time to invest, and so that cost is not bundled or passed on, making the products available. Early adopters have picked them up, and here we are. Now that an economy exists, there now are enough people, WITH THE NEED, to invest more than time and food, and so we see add on materials. If those were bundled up front, the following things would have occurred, all with the potential to significantly limit the community as it stands today:

    1. Time to market opportunity costs for Parallax, or excessive development costs

    2. Significantly higher barrier to entry for potential users

    3. Somewhat diminished potential for add on, third party, type products, services and such (high barrier limits initial product user base growth).

    As it is, most people these days have very realistic choices, ranging from "just gimme the chip cheap", to "I need serious help and pre-built stuff to work from". That's a part of the secret sauce right there, and I think it's worth just a bit of consideration, before declaring "bad".

    [noparse]:)[/noparse]

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    Post Edited (potatohead) : 3/27/2010 2:52:28 AM GMT
  • Karl SmithKarl Smith Posts: 50
    edited 2010-03-27 11:32
    You can look at DeSilva's book "Programming the Parallax Propeller using Machine Language"

    it has usefull information on video generation

    http://forums.parallax.com/showthread.php?p=668559
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-03-28 07:47
    In the OBEX is a VGA Learn which has some explanations. The 1-pin TV originally done by EricBall has some explanation and I have added my understanding on the 1-pin TV & Kbd thread. I am still coming to grips with some of this.

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