Subversion Repositories z80soc

library IEEE;

use IEEE.std_logic_1164.all;

use IEEE.std_logic_unsigned.all;

-- use IEEE.std_logic_arith.all;

use IEEE.numeric_std.all;

--use IEEE.std_logic_signed.all;

--use IEEE.math_real.all;

--use IEEE.math_complex.all;

ENTITY video_80x40 is

        PORT(   CLOCK_50                : IN STD_LOGIC;

                        VRAM_DATA               : IN STD_LOGIC_VECTOR(7 DOWNTO 0);

                        VRAM_ADDR               : OUT STD_LOGIC_VECTOR(12 DOWNTO 0);

                        VRAM_CLOCK              : OUT STD_LOGIC;

                        VRAM_WREN               : OUT STD_LOGIC;

                        VGA_R,

                        VGA_G,

                        VGA_B                   : OUT STD_LOGIC_VECTOR(3 DOWNTO 0);

                        VGA_HS,

                        VGA_VS                  : OUT STD_LOGIC);

END video_80x40;

ARCHITECTURE A OF video_80x40 IS

        -- Added for VDU support

        signal Clock_video              : std_logic;

        signal VGA_R_sig                : std_logic_vector(3 downto 0);

        signal VGA_G_sig                : std_logic_vector(3 downto 0);

        signal VGA_B_sig                : std_logic_vector(3 downto 0);

        signal pixel_row_sig    : std_logic_vector(9 downto 0);

        signal pixel_column_sig : std_logic_vector(9 downto 0);

        signal pixel_clock_sig  : std_logic;

        signal char_addr_sig    : std_logic_vector(7 downto 0);

        signal font_row_sig             : std_logic_vector(2 downto 0);

        signal font_col_sig             : std_logic_vector(2 downto 0);

        signal pixel_sig                : std_logic;

        signal video_on_sig             : std_logic;

BEGIN

        VGA_R_sig <= "0000";

        VGA_G_sig <= "0000";

        VGA_B_sig <= pixel_sig & pixel_sig & pixel_sig & pixel_sig;

        VRAM_WREN <= video_on_sig;

        VRAM_CLOCK <= pixel_clock_sig;

        VRAM_ADDR <= (pixel_row_sig(9 downto 4) * "0101000" + pixel_column_sig(9 downto 4));

        -- Fonts ROM read

        char_addr_sig <= VRAM_DATA;

        font_row_sig(2 downto 0) <= pixel_row_sig(3 downto 1);

        font_col_sig(2 downto 0) <= pixel_column_sig(3 downto 1);

        vga_sync_inst : work.vga_sync

                port map (

                        clock_50Mhz                     => CLOCK_50,

                        red                                     => VGA_R_sig,

                        green                           => VGA_G_sig,

                        blue                            => VGA_B_sig,

                        red_out                         => VGA_R,

                        green_out                       => VGA_G,

                        blue_out                        => VGA_B,

                        horiz_sync_out          => VGA_HS,

                        vert_sync_out           => VGA_VS,

                        video_on                        => video_on_sig,

                        pixel_clock                     => pixel_clock_sig,

                        pixel_row                       => pixel_row_sig,

                        pixel_column            => pixel_column_sig

        );

        char_rom_inst : work.char_rom

                port map (

                        clock                           => pixel_clock_sig,

                        character_address       => char_addr_sig,

                        font_row                        => font_row_sig,

                        font_col                        => font_col_sig,

                        rom_mux_output          => pixel_sig

        );

END A;