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Interfacing to VGA card — Parallax Forums

Interfacing to VGA card

Simon_AmplemanSimon_Ampleman Posts: 7
edited 2010-03-01 17:47 in Propeller 1
Hi!

I always wanted to output to TV or Computer RGB screen with a nice resolution (640x480 +) and fast framerate (24fps+).

Since it can't be done with a propeller, I thought I could interface it with an old ISA video card ? Or is there a chip I could connect the propeller to achieve this kind of output ? Anybody done that?

Thank you,

Simon

Comments

  • GameHackerGameHacker Posts: 15
    edited 2010-03-01 15:38
    I have often wondered the same. I realise most cards require drivers to utilise the non-standard features. However, all cards should at least be able to display simple text (just like the PC's BIOS screen) Some can even do bitmaps of the company's logo. Although this could somehow be hardcoded in the card's own bios.

    I have done a lot of searching on this in the past, and have found nothing. I find it hard to believe nobody has tried to interface a microcontroller to a vga card. Anyone?

    Thanks,
    Brian
  • Mike GreenMike Green Posts: 23,101
    edited 2010-03-01 15:54
    The reason you haven't seen anything on interfacing a Propeller to a video card is simply that these video cards use memory-mapped display buffers and the Propeller would have to provide a large number of address lines to the card in addition to the 8-bit or 16-bit data bus and a few control lines. This could be done with some kind of I/O expander, but that would markedly slow things down. It's certainly doable, but it's not simple and you don't get as much benefit from doing it as you might think.

    Have a look at the video drivers and hardware that Bill Henning has developed for his Morpheus boards (mikronauts.com/products/morpheus/). He uses most of one Propeller's I/O pins for interfacing to external SRAM for use as a video buffer (among other things) and has a video driver that reads from this SRAM and produces a 4-color VGA output at high resolution.
  • Simon_AmplemanSimon_Ampleman Posts: 7
    edited 2010-03-01 17:19
    Thank you again Mike !

    In this case, I could connect to an existing product that does this task...
    Does anybody know if there is something·better than·: http://www.4dsystems.com.au/prod.php?id=15·?

    Simon
  • BeanBean Posts: 8,129
    edited 2010-03-01 17:25
    I was going to recommend the multilabs ezVid card, but I just saw that they are no longer in business. What a shame, I was interested in their retro-computer board.

    http://www.multilabs.net/

    Bean

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    Use BASIC on the Propeller with the speed of assembly language.

    PropBASIC thread http://forums.parallax.com/showthread.php?p=867134

    March 2010 Nuts and Volts article·http://www.parallax.com/Portals/0/Downloads/docs/cols/nv/prop/col/nvp5.pdf
    ·
  • Mike GreenMike Green Posts: 23,101
    edited 2010-03-01 17:36
    I'm not really familiar with a lot of VGA graphics controllers. 4D Systems makes nice stuff. They used to make a Propeller-based OLED display. If you've looked at the documentation and the commands look like they will work for your needs, by all means, give it a go.
  • Bill HenningBill Henning Posts: 6,445
    edited 2010-03-01 17:47
    Hi Simon_Ampleman,

    The µVGA-PICASO-MD1 needs a µVGA-PICASOMD1-UB (Base Board Adaptor) before it is useful.

    It looks like a great little module, and the combination only costs $94USD+s/h

    Morpheus does cost more ($119USD kit / $179USD Assembled and tested + s/h) however it does MUCH more, as it is a full dual Propeller single board computer, with a growing line of expansion cards. I invite you to compare the programmers manuals for both products so you can see which one would be a better fit for your application.

    Here is the 4d manual:

    www.4dsystems.com.au/downloads//micro-VGA/uVGA-PICASO-MD1/Docs/Pdf/uVGA-PICASO-MD1_Serial_Users_Manual_Rev1.2.pdf

    Here is the Morpheus manual:

    mikronauts.com///mnt/w0401/d27/s21/b029e046/www/mikronauts.com///wp-content/uploads/2009/08/morpheus%20system%20architecture%20and%20developers%20guide.pdf

    I invite you to compare the features of the two products yourself.

    Morpheus only offers one (256x192) 256 color per pixel mode at the moment, but I will be writing drivers for:

    320x240 256 colors per pixel
    400x300 256 colors per pixel

    Moprheus also offers 4 color per pixel (from 256 color palette, with a separate palette for each scan line) 1024x768 mode, which is not available from uVGA-PICASO.

    Only you can decide which product fits your usage better.

    Best Regards,

    Bill
    Simon_Ampleman said...
    Thank you again Mike !


    In this case, I could connect to an existing product that does this task...

    Does anybody know if there is something better than : http://www.4dsystems.com.au/prod.php?id=15 ?



    Simon
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    Post Edited (Bill Henning) : 3/1/2010 6:04:07 PM GMT
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