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---------------------------------------------------------------------------
-- (c) 2016 mark watson
-- I am happy for anyone to use this for non-commercial use.
-- If my vhdl files are used commercially or otherwise sold,
-- please contact me for explicit permission at scrameta (gmail).
-- This applies for source and binary form and derived works.
---------------------------------------------------------------------------
LIBRARY ieee;
USE ieee.std_logic_1164.all;
use ieee.numeric_std.all;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.STD_LOGIC_MISC.all;

ENTITY scandoubler_hdmi IS
PORT
(
-- Atari clock_domain
CLK_ATARI_IN : IN STD_LOGIC; -- 56MHz approx (PAL 50Hz exactly/NTSC 59.94Hz exactly)

RESET_N : IN STD_LOGIC;

-- Audio
audio_left : in std_logic_vector(15 downto 0);
audio_right: in std_logic_vector(15 downto 0);
-- GTIA interface
pal : in std_logic;
scanlines_on : in std_logic;
csync_on : in std_logic;
colour_enable : in std_logic; -- 720 pixels/line (at least...)
colour_in : in std_logic_vector(7 downto 0);
vsync_in : in std_logic; -- high for new
hsync_in : in std_logic; -- high for new line
format : in std_logic_vector(1 downto 0); -- "00"=VGA,"01"=DVI,"10"=HDMI
--HDMI clock domain
CLK_HDMI_IN : IN STD_LOGIC; -- 135MHz exactly
CLK_PIXEL_IN : IN STD_LOGIC; -- 27 MHz exactly (aligned with HDMI)

-- VGA output - in clk pixel domain
O_hsync : out std_logic;
O_vsync : out std_logic;
O_blank : out std_logic;
O_red : out std_logic_vector(7 downto 0);
O_green : out std_logic_vector(7 downto 0);
O_blue : out std_logic_vector(7 downto 0);

-- TO TV...
O_TMDS_H : OUT STD_LOGIC_VECTOR(7 downto 0);
O_TMDS_L : OUT STD_LOGIC_VECTOR(7 downto 0)
);
END scandoubler_hdmi;

ARCHITECTURE vhdl OF scandoubler_hdmi IS

component hdmi_line_buffer IS
PORT
(
data : IN STD_LOGIC_VECTOR (7 DOWNTO 0);
rdaddress : IN STD_LOGIC_VECTOR (12 DOWNTO 0);
rdclock : IN STD_LOGIC ;
wraddress : IN STD_LOGIC_VECTOR (12 DOWNTO 0);
wrclock : IN STD_LOGIC := '1';
wren : IN STD_LOGIC := '0';
q : OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
);
END component;

signal colour_mask : std_logic_vector(7 downto 0);

-- TODO: NTSC!
-- ModeLine " 720x 480@59.94Hz" 27.00 720 736 798 858 480 489 495 525 -HSync -VSync

signal hcnt : std_logic_vector(11 downto 0) := "000000000000"; -- horizontal pixel counter
signal vcnt : std_logic_vector(11 downto 0) := "000000000000"; -- vertical line counter

signal hsync_next : std_logic;
signal vsync_next : std_logic;
signal blank_next : std_logic;
signal red_next : std_logic_vector(7 downto 0);
signal green_next : std_logic_vector(7 downto 0);
signal blue_next : std_logic_vector(7 downto 0);

signal hsync_reg : std_logic;
signal vsync_reg : std_logic;
signal blank_reg : std_logic;
signal red_reg : std_logic_vector(7 downto 0);
signal green_reg : std_logic_vector(7 downto 0);
signal blue_reg : std_logic_vector(7 downto 0);
signal hs_hsync_next : std_logic;
signal hs_vsync_next : std_logic;
signal hs_hsync_reg : std_logic;
signal hs_vsync_reg : std_logic;
signal hs_blank_reg : std_logic;
signal hs_red_reg : std_logic_vector(7 downto 0);
signal hs_green_reg : std_logic_vector(7 downto 0);
signal hs_blue_reg : std_logic_vector(7 downto 0);
signal hs_red_reg2 : std_logic_vector(7 downto 4);
signal hs_green_reg2 : std_logic_vector(7 downto 4);
signal hs_blue_reg2 : std_logic_vector(7 downto 4);

--
signal cap_vsync_shift_next : std_logic_vector(3 downto 0);
signal cap_vsync_shift_reg : std_logic_vector(3 downto 0);
signal cap_vcount_next : std_logic_vector(1 downto 0);
signal cap_vcount_reg : std_logic_vector(1 downto 0);
signal cap_hcount_next : std_logic_vector(10 downto 0);
signal cap_hcount_reg : std_logic_vector(10 downto 0);
signal cap_vsync_reg : std_logic;
signal cap_hsync_reg : std_logic;
signal cap_frame_start : std_logic;
signal cap_line_start_raw : std_logic;
signal cap_line_start : std_logic;
signal cap_format : std_logic_vector(1 downto 0);

--
signal out_colour_raw : std_logic_vector(7 downto 0);
signal out_colour : std_logic_vector(7 downto 0);
signal out_pal : std_logic;
signal out_scanlines : std_logic;
signal out_csync : std_logic;
signal out_frame_start : std_logic;
signal out_format : std_logic_vector(1 downto 0);

-- Horizontal Timing
signal h_pixels_across : integer;
signal h_sync_on : integer;
signal h_sync_off : integer;
signal h_end_count : integer;
-- Vertical Timing
signal v_pixels_down : integer;
signal v_sync_on : integer;
signal v_sync_off : integer;
signal v_end_count : integer;

-- signed audio
signal audio_left_signed : std_logic_vector(15 downto 0);
signal audio_right_signed: std_logic_vector(15 downto 0);

-- audio synchronizer
signal audio_left_reg1 : std_logic_vector(15 downto 0);
signal audio_right_reg1 : std_logic_vector(15 downto 0);
signal audio_left_reg2 : std_logic_vector(15 downto 0);
signal audio_right_reg2 : std_logic_vector(15 downto 0);

-- hdmi/dvi->tmds
signal hdmi_encoded_red : std_logic_vector(9 downto 0);
signal hdmi_encoded_green : std_logic_vector(9 downto 0);
signal hdmi_encoded_blue : std_logic_vector(9 downto 0);
signal dvi_encoded_red : std_logic_vector(9 downto 0);
signal dvi_encoded_green : std_logic_vector(9 downto 0);
signal dvi_encoded_blue : std_logic_vector(9 downto 0);

signal encoded_red_next : std_logic_vector(9 downto 0);
signal encoded_green_next : std_logic_vector(9 downto 0);
signal encoded_blue_next : std_logic_vector(9 downto 0);
signal encoded_red_reg : std_logic_vector(9 downto 0);
signal encoded_green_reg : std_logic_vector(9 downto 0);
signal encoded_blue_reg : std_logic_vector(9 downto 0);

signal mod5 : std_logic_vector(2 downto 0) := "000"; -- modulus 5 counter
signal shift_r : std_logic_vector(9 downto 0) := "0000000000";
signal shift_g : std_logic_vector(9 downto 0) := "0000000000";
signal shift_b : std_logic_vector(9 downto 0) := "0000000000";
signal shift_clk : std_logic_vector(9 downto 0) := "0000000000";

BEGIN

--------------------------------------------------------
-- Capture side
-- Store 4 lines of data in dual port ram

-- register
process(CLK_ATARI_IN,reset_n)
begin
if (reset_n = '0') then
cap_hcount_reg <= (others=>'0');
cap_vcount_reg <= (others=>'0');
cap_vsync_reg <= '0';
cap_hsync_reg <= '0';
cap_vsync_shift_reg <= (others=>'0');
elsif (CLK_ATARI_IN'event and CLK_ATARI_IN='1') then
cap_hcount_reg <= cap_hcount_next;
cap_vcount_reg <= cap_vcount_next;
cap_vsync_reg <= vsync_in;
cap_hsync_reg <= hsync_in;
cap_vsync_shift_reg <= cap_vsync_shift_next;
end if;
end process;

cap_line_start_raw <= not(hsync_in) and cap_hsync_reg;
hsync_delay : entity work.delay_line
generic map (COUNT=>184)
port map(clk=>clk_atari_in,sync_reset=>'0',data_in=>cap_line_start_raw,enable=>colour_enable,reset_n=>'1',data_out=>cap_line_start);

-- our location
process(cap_hcount_reg, colour_enable, cap_line_start)
begin
colour_mask <= x"ff";

cap_hcount_next <= cap_hcount_reg;
if (colour_enable = '1') then
cap_hcount_next <= std_logic_vector(unsigned(cap_hcount_reg)+1);
end if;
if (cap_line_start = '1') then
cap_hcount_next <= (others=>'0');
end if;
if (or_reduce(cap_hcount_reg(10 downto 6))='0') then
colour_mask <= x"00";
end if;
if (cap_hcount_reg(10 downto 7) >= "1011") then --1408
colour_mask <= x"00";
end if;
end process;

process(cap_vcount_reg, cap_line_start, cap_vsync_reg, vsync_in, cap_vsync_shift_reg)
begin
cap_vcount_next <= cap_vcount_reg;
cap_vsync_shift_next <= cap_vsync_shift_reg;
if (cap_line_start = '1') then
cap_vcount_next <= std_logic_vector(unsigned(cap_vcount_reg)+1);
cap_vsync_shift_next <= cap_vsync_shift_reg(2 downto 0)&'0';
end if;
if (cap_vsync_reg = '1' and vsync_in = '0') then
cap_vcount_next <= (others=>'0');
cap_vsync_shift_next <= "0001";
end if;
end process;

cap_frame_start <= cap_vsync_shift_reg(2);

hdmi_line_buffer_inst : hdmi_line_buffer
port map
(
data => colour_in and colour_mask,
wraddress => cap_vcount_reg&cap_hcount_reg,
wrclock => CLK_ATARI_IN,
wren => colour_enable, -- 1824 times/line

rdaddress => vcnt(2 downto 1)&hcnt(9 downto 0)&'0',
rdclock => CLK_PIXEL_IN,
q => out_colour_raw
);

-- Audio should be signed

audio_left_signed <= std_logic_vector(to_signed(to_integer(unsigned(audio_left))-32768,16));
audio_right_signed <= std_logic_vector(to_signed(to_integer(unsigned(audio_right))-32768,16));

--------------------------------------------------------
-- Output side
-- Retrieve data from dual port ram, do palette lookup and send to hdmi encoder

pal_synchronizer : entity work.synchronizer
port map (clk=>clk_pixel_in, raw=>pal, sync=>out_pal);

scanline_synchronizer : entity work.synchronizer
port map (clk=>clk_pixel_in, raw=>scanlines_on, sync=>out_scanlines);

csync_synchronizer : entity work.synchronizer
port map (clk=>clk_pixel_in, raw=>csync_on, sync=>out_csync);

cap_vsync_synchronizer : entity work.synchronizer
port map (clk=>clk_pixel_in, raw=>cap_frame_start, sync=>out_frame_start);
cap_format0_synchronizer : entity work.synchronizer
port map (clk=>clk_pixel_in, raw=>format(0), sync=>out_format(0));
cap_format1_synchronizer : entity work.synchronizer
port map (clk=>clk_pixel_in, raw=>format(1), sync=>out_format(1));

out_colour(7 downto 4) <= out_colour_raw(7 downto 4);
out_colour(3 downto 0) <= out_colour_raw(3 downto 0) when (not(out_scanlines) or vcnt(0))='1' else '0'&out_colour_raw(3 downto 1);

-- colour palette
-- TODO- share!!
palette4 : entity work.gtia_palette
port map (PAL=>out_pal,ATARI_COLOUR=>out_colour, R_next=>red_next, G_next=>green_next, B_next=>blue_next);
-- extract from fifo to line buffer (720 pixels)
-- sync vsync between sides...

process (clk_pixel_in, hcnt, out_frame_start)
begin
if clk_pixel_in'event and clk_pixel_in = '1' then
if hcnt = h_end_count then
hcnt <= (others => '0');
else
hcnt <= hcnt + 1;
end if;
if hcnt = h_sync_on then
if (vcnt = v_end_count) then
vcnt <= (others => '0');
else
vcnt <= vcnt + 1;
end if;
end if;

if (out_frame_start='1' and (vcnt <= (v_sync_off-4) or vcnt >= (v_sync_off+4))) then
vcnt <= std_logic_vector(to_unsigned(v_sync_off,12));
end if;
end if;
end process;

hsync_next <= '0' when (hcnt <= h_sync_on) or (hcnt > h_sync_off) else '1';
vsync_next <= '0' when (vcnt <= v_sync_on) or (vcnt > v_sync_off) else '1';
blank_next <= '1' when (hcnt > h_pixels_across) or (vcnt > v_pixels_down) else '0';

-- TODO -- allow ZPU to write these - simple CRTC!
process(out_pal)
begin
if (out_pal = '1') then
h_pixels_across <= 720 - 1;
h_sync_on <= 732 - 1;
h_sync_off <= 795 - 1;
h_end_count <= 864 - 1;
v_pixels_down <= 576 - 1;
v_sync_on <= 581 - 1;
v_sync_off <= 586 - 1;
v_end_count <= 625 - 1;
else
h_pixels_across <= 720 - 1;
h_sync_on <= 736 -1;
h_sync_off <= 798 -1;
h_end_count <= 858 -1;
v_pixels_down <= 480 -1;
v_sync_on <= 489 -1;
v_sync_off <= 495 -1;
v_end_count <= 525 -1;
end if;
end process;

hdmiav_inst : entity work.hdmi
port map (
I_CLK_PIXEL => clk_pixel_in,
I_RESET => not(reset_n),
I_AUDIO_PCM_L => audio_left_reg2,
I_AUDIO_PCM_R => audio_right_reg2,
I_HSYNC => hsync_reg,
I_VSYNC => vsync_reg,
I_BLANK => blank_reg,
I_R => red_reg,
I_G => green_reg,
I_B => blue_reg,
O_R => hdmi_encoded_red,
O_G => hdmi_encoded_green,
O_B => hdmi_encoded_blue);
dvi_inst: entity work.dvi
port map (
I_CLK_PIXEL => clk_pixel_in,

I_HSYNC => hsync_reg,
I_VSYNC => vsync_reg,
I_BLANK => blank_reg,
I_RED => red_reg,
I_GREEN => green_reg,
I_BLUE => blue_reg,
O_R => dvi_encoded_red,
O_G => dvi_encoded_green,
O_B => dvi_encoded_blue);

process (out_format,dvi_encoded_red,dvi_encoded_green,dvi_encoded_blue,hdmi_encoded_red,hdmi_encoded_green,hdmi_encoded_blue)
begin
encoded_red_next <= (others=>'0');
encoded_green_next <= (others=>'0');
encoded_blue_next <= (others=>'0');

case out_format is
when "01" =>
encoded_red_next <= dvi_encoded_red;
encoded_green_next <= dvi_encoded_green;
encoded_blue_next <= dvi_encoded_blue;
when "10" =>
encoded_red_next <= hdmi_encoded_red;
encoded_green_next <= hdmi_encoded_green;
encoded_blue_next <= hdmi_encoded_blue;
when others =>
encoded_red_next <= (others=>'0');
encoded_green_next <= (others=>'0');
encoded_blue_next <= (others=>'0');
end case;
end process;

process (CLK_HDMI_IN)
begin
if (CLK_HDMI_IN'event and CLK_HDMI_IN = '1') then
if mod5(2) = '1' then
mod5 <= "000";
shift_r <= encoded_red_reg;
shift_g <= encoded_green_reg;
shift_b <= encoded_blue_reg;
shift_clk <= "0000011111";
else
mod5 <= mod5 + "001";
shift_r <= "00" & shift_r(9 downto 2);
shift_g <= "00" & shift_g(9 downto 2);
shift_b <= "00" & shift_b(9 downto 2);
shift_clk <= "00" & shift_clk(9 downto 2);
end if;
end if;
end process;


process(clk_pixel_in)
begin
if (clk_pixel_in'event and clk_pixel_in='1') then
audio_left_reg1 <= audio_left_signed;
audio_left_reg2 <= audio_left_reg1;
audio_right_reg1 <= audio_right_signed;
audio_right_reg2 <= audio_right_reg1;

hsync_reg <= hsync_next;
vsync_reg <= vsync_next;
blank_reg <= blank_next;
red_reg <= red_next;
green_reg <= green_next;
blue_reg <= blue_next;

encoded_blue_reg <= encoded_blue_next;
encoded_green_reg <= encoded_green_next;
encoded_red_reg <= encoded_red_next;
end if;
end process;

process(clk_hdmi_in)
begin
if (clk_hdmi_in'event and clk_hdmi_in='1') then
hs_hsync_reg <= hs_hsync_next;
hs_vsync_reg <= hs_vsync_next;
hs_blank_reg <= blank_reg;
hs_red_reg <= red_reg;
hs_green_reg <= green_reg;
hs_blue_reg <= blue_reg;
hs_red_reg2(7 downto 4) <= hs_red_reg(7 downto 4);
hs_green_reg2(7 downto 4) <= hs_green_reg(7 downto 4);
hs_blue_reg2(7 downto 4) <= hs_blue_reg(7 downto 4);
end if;
end process;

process(out_csync,hsync_reg,vsync_reg)
begin
if (out_csync = '1') then
hs_hsync_next <= not(hsync_reg xor vsync_reg);
hs_vsync_next <='1';
else
hs_hsync_next <= not(hsync_reg);
hs_vsync_next <= not(vsync_reg);
end if;
end process;

-- VGA outputs - with specified timings
O_hsync <= hs_hsync_reg;
O_vsync <= hs_vsync_reg;
O_blank <= hs_blank_reg;
O_red <= hs_red_reg2(7 downto 4)&hs_red_reg(3 downto 0); -- on different ddr edges
O_green <= hs_green_reg2(7 downto 4)&hs_green_reg(3 downto 0);
O_blue <= hs_blue_reg2(7 downto 4)&hs_blue_reg(3 downto 0);

-- TMDS outputs - with specified timings
O_TMDS_H <= shift_r(0) & not(shift_r(0)) & shift_g(0) & not(shift_g(0)) & shift_b(0) & not(shift_b(0)) & shift_clk(0) & not(shift_clk(0));
O_TMDS_L <= shift_r(1) & not(shift_r(1)) & shift_g(1) & not(shift_g(1)) & shift_b(1) & not(shift_b(1)) & shift_clk(1) & not(shift_clk(1));


end vhdl;


(11-11/11)