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Altera_Forum's avatar
Altera_Forum
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20 years ago

VGA controller AppNote 333

Has anyone ever tried the vga controller design from AN333? I have modified it from displaying 8-bit color pixels (using LUT) to 24-bit RGB pixels, by widening the bus to 32-bits, using 24-bits for RGB and wasting 8-bits. However, the output display is shifted by ~~140 pixels (horizontally) for every 100 lines (vertically).

Has anyone successfully come up with a 24-bit RGB color pixels VGA controller that uses avalon's streaming capabilities?

Thanks for any help.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    20 years ago

    Check your vertical and gorizontal timing parameters.

    For 800*600 it should be next:

    // horizontal timing parameters

    parameter hsync_end = 80;

    parameter hblank_begin = 200;

    parameter hblank_end = 1000;

    parameter hline_end = 1040;

    // vertical timing parameters

    parameter vsync_end = 4;

    parameter vblank_begin = 26;

    parameter vblank_end = 626;

    parameter vframe_end = 629;

    And when you send data by dma, dmalength must be 800*600*4.