Subversion Repositories pentevo

// ZX-Evo Base Configuration (c) NedoPC 2008,2009,2010,2011,2012,2013,2014

//

// mix up border and pixels, add palette and blanks

/*

    This file is part of ZX-Evo Base Configuration firmware.

    ZX-Evo Base Configuration firmware is free software:

    you can redistribute it and/or modify it under the terms of

    the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    ZX-Evo Base Configuration firmware is distributed in the hope that

    it will be useful, but WITHOUT ANY WARRANTY; without even

    the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with ZX-Evo Base Configuration firmware.

    If not, see <http://www.gnu.org/licenses/>.

*/

`include "../include/tune.v"

module video_palframe(

        input  wire        clk, // 28MHz clock

        input  wire        hpix,

        input  wire        vpix,

        input  wire        hblank,

        input  wire        vblank,

        input  wire        hsync_start,

        input  wire        vsync,

        input  wire [ 3:0] pixels,

        input  wire [ 3:0] border,

        input  wire        border_sync,

        input  wire        border_sync_ena,

        // ulaplus related

        input  wire [ 1:0] up_palsel,

        input  wire [ 2:0] up_paper,

        input  wire [ 2:0] up_ink,

        input  wire        up_pixel,

        input  wire        up_ena,

        input  wire        up_palwr,

        input  wire [ 5:0] up_paladdr,

        input  wire [ 7:0] up_paldata,

        input  wire        atm_palwr,

        input  wire [ 5:0] atm_paldata,

        output wire [ 5:0] palcolor, // just for palette readback

        output wire [ 5:0] color

);

        reg [7:0] palette_read;

        wire [ 3:0] zxcolor;

        wire [ 5:0] up_color;

        wire [ 8:0] palette_color;

        reg [3:0] synced_border;

        reg vsync_r;

        reg [1:0] ctr_14;

        reg ctr_h;

        reg ctr_v;

        always @(posedge clk)

        if( border_sync )

                synced_border <= border;

        assign zxcolor = (hpix&vpix) ? pixels : (border_sync_ena ? synced_border : border);

        assign up_color = (hpix&vpix) ? {up_palsel,~up_pixel,up_pixel?up_ink:up_paper} : {3'd0,border[2:0]};

        assign palette_color = up_ena ? {3'b100,up_color} : {5'd0,zxcolor};

        // palette

        reg [7:0] palette [0:511]; // let quartus instantiate it as RAM

        always @(posedge clk)

        begin

                if( atm_palwr || up_palwr )

                begin : palette_write

                        reg [8:0] pal_addr;

                        pal_addr = atm_palwr ? { 5'd0, zxcolor } : { 3'b100, up_paladdr };

                        palette[pal_addr] <= atm_palwr ? {atm_paldata[3:2],1'b0,atm_paldata[5:4],1'b0,atm_paldata[1:0]} : up_paldata;

                end

                palette_read <= palette[palette_color];

        end

        assign palcolor = {palette_read[4:3],palette_read[7:6], palette_read[1:0]};

        // make 3bit palette

        always @(posedge clk)

                vsync_r <= vsync;

        //

        wire vsync_start = vsync && !vsync_r;

        //

        initial ctr_14 = 2'b00;

        always @(posedge clk)

                ctr_14 <= ctr_14+2'b01;

        //

        initial ctr_h = 1'b0;

        always @(posedge clk) if( hsync_start )

                ctr_h <= ~ctr_h;

        //

        initial ctr_v = 1'b0;

        always @(posedge clk) if( vsync_start )

                ctr_v <= ~ctr_v;

        wire plus1 = ctr_14[1] ^ ctr_h ^ ctr_v;

        wire [1:0] red;

        wire [1:0] grn;

        wire [1:0] blu;

        video_palframe_mk3bit red_color

        (

                .plus1    (plus1            ),

                .color_in (palette_read[7:5]),

                .color_out(red              )

        );

        //

        video_palframe_mk3bit grn_color

        (

                .plus1    (plus1            ),

                .color_in (palette_read[4:2]),

                .color_out(grn              )

        );

        //

        assign blu = palette_read[1:0];

        assign color = (hblank | vblank) ? 6'd0 : {grn,red,blu};

endmodule

module video_palframe_mk3bit

(

        input  wire       plus1,

        input  wire [2:0] color_in,

        output reg  [1:0] color_out

);

        always @*

        case( color_in )

                3'b000:  color_out <= 2'b00;

                3'b001:  color_out <= plus1 ? 2'b01 : 2'b00;

                3'b010:  color_out <= 2'b01;

                3'b011:  color_out <= plus1 ? 2'b10 : 2'b01;

                3'b100:  color_out <= 2'b10;

                3'b101:  color_out <= plus1 ? 2'b11 : 2'b10;

                default: color_out <= 2'b11;

        endcase

endmodule