Subversion Repositories yavga

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----                                                                        ----

---- This file is part of the yaVGA project                                 ----

---- http://www.opencores.org/?do=project&who=yavga                         ----

----                                                                        ----

---- Description                                                            ----

---- Implementation of yaVGA IP core                                        ----

----                                                                        ----

---- To Do:                                                                 ----

----                                                                        ----

----                                                                        ----

---- Author(s):                                                             ----

---- Sandro Amato, sdroamt@netscape.net                                     ----

----                                                                        ----

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----                                                                        ----

---- Copyright (c) 2009, Sandro Amato                                       ----

---- All rights reserved.                                                   ----

----                                                                        ----

---- Redistribution  and  use in  source  and binary forms, with or without ----

---- modification,  are  permitted  provided that  the following conditions ----

---- are met:                                                               ----

----                                                                        ----

----     * Redistributions  of  source  code  must  retain the above        ----

----       copyright   notice,  this  list  of  conditions  and  the        ----

----       following disclaimer.                                            ----

----     * Redistributions  in  binary form must reproduce the above        ----

----       copyright   notice,  this  list  of  conditions  and  the        ----

----       following  disclaimer in  the documentation and/or  other        ----

----       materials provided with the distribution.                        ----

----     * Neither  the  name  of  SANDRO AMATO nor the names of its        ----

----       contributors may be used to  endorse or  promote products        ----

----       derived from this software without specific prior written        ----

----       permission.                                                      ----

----                                                                        ----

---- THIS SOFTWARE IS PROVIDED  BY THE COPYRIGHT  HOLDERS AND  CONTRIBUTORS ----

---- "AS IS"  AND  ANY EXPRESS OR  IMPLIED  WARRANTIES, INCLUDING,  BUT NOT ----

---- LIMITED  TO, THE  IMPLIED  WARRANTIES  OF MERCHANTABILITY  AND FITNESS ----

---- FOR  A PARTICULAR  PURPOSE  ARE  DISCLAIMED. IN  NO  EVENT  SHALL  THE ----

---- COPYRIGHT  OWNER  OR CONTRIBUTORS  BE LIABLE FOR ANY DIRECT, INDIRECT, ----

---- INCIDENTAL,  SPECIAL,  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, ----

---- BUT  NOT LIMITED  TO,  PROCUREMENT OF  SUBSTITUTE  GOODS  OR SERVICES; ----

---- LOSS  OF  USE,  DATA,  OR PROFITS;  OR  BUSINESS INTERRUPTION) HOWEVER ----

---- CAUSED  AND  ON  ANY THEORY  OF LIABILITY, WHETHER IN CONTRACT, STRICT ----

---- LIABILITY,  OR  TORT  (INCLUDING  NEGLIGENCE  OR OTHERWISE) ARISING IN ----

---- ANY  WAY OUT  OF THE  USE  OF  THIS  SOFTWARE,  EVEN IF ADVISED OF THE ----

---- POSSIBILITY OF SUCH DAMAGE.                                            ----

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library IEEE;

use IEEE.STD_LOGIC_1164.all;

use IEEE.STD_LOGIC_ARITH.all;

use IEEE.STD_LOGIC_UNSIGNED.all;

---- Uncomment the following library declaration if instantiating

---- any Xilinx primitives in this code.

--library UNISIM;

--use UNISIM.VComponents.all;

entity s3e_starter_1600k is

  port (i_clk    : in  std_logic;

         o_hsync : out std_logic;

         o_vsync : out std_logic;

         o_r     : out std_logic;

         o_g     : out std_logic;

         o_b     : out std_logic);

end s3e_starter_1600k;

architecture Behavioral of s3e_starter_1600k is

  component vga_ctrl

    port(

      i_clk          : in  std_logic;

      i_reset        : in  std_logic;

      i_background   : in  std_logic;

      i_cursor_color : in  std_logic_vector(2 downto 0);

      i_cursor_x     : in  std_logic_vector(10 downto 0);

      i_cursor_y     : in  std_logic_vector(9 downto 0);

      i_h_sync_en    : in  std_logic;

      i_v_sync_en    : in  std_logic;

      i_chr_addr     : in  std_logic_vector(10 downto 0);

      i_chr_data     : in  std_logic_vector(31 downto 0);

      i_chr_clk      : in  std_logic;

      i_chr_en       : in  std_logic;

      i_chr_we       : in  std_logic_vector(3 downto 0);

      i_chr_rst      : in  std_logic;

      i_wav_d        : in  std_logic_vector(15 downto 0);

      i_wav_we       : in  std_logic;

      i_wav_addr     : in  std_logic_vector(9 downto 0);

      o_h_sync       : out std_logic;

      o_v_sync       : out std_logic;

      o_r            : out std_logic;

      o_g            : out std_logic;

      o_b            : out std_logic;

      o_chr_data     : out std_logic_vector(31 downto 0)

      );

  end component;

  signal s_hsync : std_logic;

  signal s_vsync : std_logic;

  signal s_r     : std_logic;

  signal s_g     : std_logic;

  signal s_b     : std_logic;

  signal s_vsync_count : std_logic_vector(7 downto 0) := (others => '0');

  signal s_vsync1      : std_logic;

  signal s_chr_addr : std_logic_vector(10 downto 0) := (others => '0');

  signal s_rnd      : std_logic_vector(31 downto 0) := (others => '0');

  signal s_chr_we   : std_logic_vector(3 downto 0);

  attribute U_SET                      : string;

  attribute U_SET of "u1_vga_ctrl"    : label is "u1_vga_ctrl_uset";

begin

  o_hsync <= s_hsync;

  o_vsync <= s_vsync;

  o_r     <= s_r;

  o_g     <= s_g;

  o_b     <= s_b;

  u1_vga_ctrl : vga_ctrl port map(

    i_clk          => i_clk,

    i_reset        => '0',

    i_background   => '0',

    i_cursor_color => "001",

    i_cursor_x     => "00101000000",

    i_cursor_y     => "0011000000",

    o_h_sync       => s_hsync,

    o_v_sync       => s_vsync,

    i_h_sync_en    => '1',

    i_v_sync_en    => '1',

    o_r            => s_r,

    o_g            => s_g,

    o_b            => s_b,

    i_chr_addr     => s_chr_addr,       --B"000_0000_0000",

    i_chr_data     => s_rnd,            --X"00000000",

    o_chr_data     => open,

    i_chr_clk      => i_clk,

    i_chr_en       => '1',

    i_chr_we       => s_chr_we,

    i_chr_rst      => '0',

    i_wav_d        => X"0000",  --s_rnd(15 downto 0), -- 

    i_wav_we       => '0',  --s_chr_we(0), --

    i_wav_addr     => B"00_0000_0000"  --s_chr_addr(9 downto 0) --

    );

  p_write_chars : process(i_clk)

  begin

    if rising_edge(i_clk) then

      -- during the sync time in order to avoid flickering

      -- and each 128 vsync in order to stop for a while

      -- will write random chars...

      if s_vsync_count(7) = '1' and (s_hsync = '0' or s_vsync = '0') then

        -- generate a pseudo random 32 bit number

        s_rnd <= s_rnd(30 downto 0) & (s_rnd(31) xnor s_rnd(21) xnor s_rnd(1) xnor s_rnd(0));

        -- increment the address and write enable...

        s_chr_addr <= s_chr_addr + 1;

        s_chr_we   <= "1111";

      else

        s_chr_addr <= s_chr_addr;

        s_chr_we   <= "0000";

        s_rnd      <= s_rnd;

      end if;

    end if;

  end process;

--  p_rnd_bit : process(i_clk)

--    variable v_rnd_fb : std_logic;

--    variable v_rnd : std_logic_vector(31 downto 0);

--  begin

--    if rising_edge(i_clk) then

--      s_rnd_bit <= v_rnd_fb;

--      v_rnd_fb := v_rnd(31) xnor v_rnd(21) xnor v_rnd(1) xnor v_rnd(0);

--      v_rnd    := v_rnd(30 downto 0) & v_rnd_fb;

--    end if;

--  end process;

  p_vsync_count : process(i_clk)

  begin

    if rising_edge(i_clk) then

      s_vsync1 <= s_vsync;

      if (not s_vsync and s_vsync1) = '1' then  -- pulse on vsync falling

        s_vsync_count <= s_vsync_count + 1;

      end if;

    end if;

  end process;

end Behavioral;