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Looking for Single Cog Tile Driver for P8X32A (prop 1) — Parallax Forums

Looking for Single Cog Tile Driver for P8X32A (prop 1)

Hi All,

Finally got some more free time to look into the propeller micro-controller.
Just to recap (lets say) I have very limited electronics knowledge, because it s a fair description.

So I'm back at square one, trying to build a very basic/simple no frills SBC, as a way of learning.
That's my hope anyway....

And since I've forgotten everything I learned before, I'm starting from the beginning again.

_And I would like to find a single cog Vga scanline driver (is that the right wording? scanline driver?)
Or maybe its called Vga Text driver?
Or maybe its tile driver?

Basically I want the screen area to be in my main program

Long _laScreen[SCREEN_SIZE]

Where screen size is vga 640x480 pixels
so that is 40 columns and 30 rows with a tile size of 16x16
(I chose 16x16 as I saw lots of other members using this size)
So would hope there is code already available to do this.

I want to store each character as only a BYTE, as I only need the character itself, no color nothing else.
So that gives me 1200 byte or 300 longs

It doesn't matter tome if its only black and white

Which vga driver should I use to accommodate this?

At some point, hopefully in the future, I would like to use 10x10 (pixels) tiles instead of 16x16 (pixels)

I'm still learning spin and find it easy to understand like basic.... I don't know any assembly, can understand some C, dont know other languages and don't wish to learn other languages since I have a hard time remembering things.

Thank you for looking...


  • Propeller Tool comes with a bunch of VGA drivers included, take a look at them. VGA.spin runs in a single cog, but tops out at 32 columns. I don't think full 40 columns is possible in a single cog VGA driver at 80MHz. If you want that, look into TV output, which needs less resources and gives a more pleasant color palette.

  • @Wuerfel_21 , Thank you for your response,

    I had read in the shop section ( that the 6.25mhz crystal was being used quite reliably, so i'd planned on using that and running at 100mhz

    I wonder if its even possible at 100mhz?
    Or maybe i'm jumping the gun and its better for a beginner to run at stock 80mhz first.

    I can always use the Vga.spin driver you mentioned, and come back to the display issue later i guess...
    Anyway Thank You for your input during the time when everyone is concentrated on the P2...

  • RaymanRayman Posts: 12,372

    @JaanDoh 100 MHz might let you get VGA with real 25 MHz dot clock.

    All the examples I can find for 640x480 so far use a 20 MHz dot clock that stretches the 512 horizontal pixels out to 640.
    So, a VGA monitor thinks it's 640x480.

  • @Rayman, thank you , I think that is the same example that is in the library section of proptool ,as @Wuerfel_21 mentioned above.

    That is the one i'm using (while coding - I still haven't got a working a device to test it on yet) and I have seen other tile drivers, but I'm not sure if I can spare a cog for a two cog vga driver until I finish all the learning/coding.

    The attachment is the files from the library that I'm using for now.

  • RaymanRayman Posts: 12,372

    Yes, there's also the "VGA_text_demo.spin" that uses those.

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