vga.svh

`ifndef _vga_svh_
`define _vga_svh_

// `define RGB
`ifndef RGB
    `define WHITE
`endif

// `define VGA640X480
`define VGA1280X1024

    `ifdef VGA640X480

        // VGA Signal 640 x 480 @ 60 Hz Industry standard timing
        // http://tinyvga.com/vga-timing/640x480@60Hz

        // General timing
        // Screen refresh rate  60 Hz
        // Vertical refresh     31.46875 kHz
        // Pixel freq.          25.175 MHz

        // Horizontal timing (line)
        // Polarity of horizontal sync pulse is negative.
        // Scanline part Pixels Time [µs]
        // Visible area  640    25.422045680238
        `define VISIBLE_LINE_PXLS 640

        // Front porch   16     0.63555114200596
        `define HORIZ_FRONT_PORCH_PXLS 16
        // Sync pulse start = 640 + 16 = 656

        // Sync pulse    96     3.8133068520357
        `define HORIZ_SYNC_PULSE_PXLS 96
        // Sync pulse end = 640 + 16 + 96 = 752

        // Back porch    48     1.9066534260179
        // Whole line    800    31.777557100298
        `define WHOLE_LINE_PXLS 800

        // Vertical timing (frame)
        // Polarity of vertical sync pulse is negative.
        // Frame part    Lines  Time [ms]
        // Visible area  480    15.253227408143
        `define VISIBLE_FRAME_PXLS 480

        // Front porch   10     0.31777557100298
        `define VERT_FRONT_PORCH_PXLS 10
        // Sync pulse start = 480 + 10 = 490

        // Sync pulse    2      0.063555114200596
        `define VERT_SYNC_PULSE_PXLS 2

        // Back porch    33     1.0486593843098
        // Sync pulse end = 480 + 10 + 2 = 492

        // Whole frame   525    16.683217477656
        `define VERT_FRAME_PXLS 525

        // counters dim to hold max of `WHOLE_LINE_PXLS and `VERT_FRAME_PXLS
        `define CNT_WDT 10

    `elsif VGA1280X1024

        // VESA Signal 1280 x 1024 @ 60 Hz timing
        // http://tinyvga.com/vga-timing/1280x1024@60Hz

        // General timing
        // Screen refresh rate  60 Hz
        // Vertical refresh     63.981042654028 kHz
        // Pixel freq.          108.0 MHz

        // Horizontal timing (line)
        // Polarity of horizontal sync pulse is positive.
        // Scanline part Pixels Time [µs]
        // Visible area  1280   11.851851851852
        `define VISIBLE_LINE_PXLS 1280

        // Front porch   48     0.44444444444444
        `define HORIZ_FRONT_PORCH_PXLS 48

        // Sync pulse    112        1.037037037037
        `define HORIZ_SYNC_PULSE_PXLS 112

        // Back porch    248        2.2962962962963
        // Whole line    1688   15.62962962963
        `define WHOLE_LINE_PXLS 1688

        // Vertical timing (frame)
        // Polarity of vertical sync pulse is positive.
        // Frame part    Lines  Time [ms]
        // Visible area  1024   16.004740740741
        `define VISIBLE_FRAME_PXLS 1024

        // Front porch   1      0.01562962962963
        `define VERT_FRONT_PORCH_PXLS 1

        // Sync pulse    3      0.046888888888889
        `define VERT_SYNC_PULSE_PXLS 3

        // Back porch    38     0.59392592592593

        // Whole frame   1066   16.661185185185
        `define VERT_FRAME_PXLS 1066

        `define CNT_WDT 11


    `else // defaulf - for test purposes

        `define VISIBLE_LINE_PXLS       100
        `define HORIZ_FRONT_PORCH_PXLS  2
        `define HORIZ_SYNC_PULSE_PXLS   4
        `define WHOLE_LINE_PXLS         150
        `define VISIBLE_FRAME_PXLS      50
        `define VERT_FRONT_PORCH_PXLS   3
        `define VERT_SYNC_PULSE_PXLS    2
        `define VERT_FRAME_PXLS         70

    `endif

    // Sync pulse start = Visible area + Front porch
    `define HORIZ_SYNC_PRE_PXLS (`VISIBLE_LINE_PXLS + `HORIZ_FRONT_PORCH_PXLS)

    // Sync pulse end   = Visible area + Front porch + Sync pulse
    `define HORIZ_SYNC_POST_PXLS (`VISIBLE_LINE_PXLS + `HORIZ_FRONT_PORCH_PXLS + `HORIZ_SYNC_PULSE_PXLS)

    // Sync pulse start = Visible area + Front porch
    `define VERT_SYNC_PRE_PXLS (`VISIBLE_FRAME_PXLS + `VERT_FRONT_PORCH_PXLS)

    // Sync pulse end   = Visible area + Front porch + Sync pulse
    `define VERT_SYNC_POST_PXLS (`VISIBLE_FRAME_PXLS + `VERT_FRONT_PORCH_PXLS + `VERT_SYNC_PULSE_PXLS)

    `define CNT_RNG [`CNT_WDT-1:0]

    `define FIRST_HORIZ_BORDER_PXLS  (`VISIBLE_FRAME_PXLS / 3)
    `define SECOND_HORIZ_BORDER_PXLS (`VISIBLE_FRAME_PXLS - `VISIBLE_FRAME_PXLS / 3)

`endif