mirror
/
RGBtoHDMI
kopia lustrzana https://github.com/hoglet67/RGBtoHDMI
1
0
Forkuj 0
Kod Zgłoszenia Projekty Wydania Wiki Aktywność

Atom CPLD: Reworked for a 57.272MHz clock 

Change-Id: Ie6abd79a38fd6eecec239afa6411be383df67ed3
pull/11/head
David Banks 2018-11-23 19:01:49 +00:00
rodzic 4723366512
commit 1ae2cf9fc4
1 zmienionych plików z 27 dodań i 36 usunięć
Pokaż statystyki Ściągnij plik aktualizacji Ściągnij plik porównania Expand all files Collapse all files

63
vhdl_atom/RGBtoHDMI.vhdl
Wyświetl plik

@ -52,27 +52,25 @@ architecture Behavorial of RGBtoHDMI is
constant VERSION_NUM : std_logic_vector(11 downto 0) := x"221";
-- Default offset to sstart sampling at
constant default_offset : unsigned(10 downto 0) := to_unsigned(2048 - 640, 12);
constant default_offset : unsigned(10 downto 0) := to_unsigned(2048 - 256, 12);
-- Turn on back porch clamp
constant atom_clamp_start : unsigned(10 downto 0) := to_unsigned(2048 - 640 + 72, 12);
constant atom_clamp_start : unsigned(10 downto 0) := to_unsigned(2048 - 256 + 48, 12);
-- Turn off back port clamo
constant atom_clamp_end : unsigned(10 downto 0) := to_unsigned(2048 - 640 + 128, 12);
constant atom_clamp_end : unsigned(10 downto 0) := to_unsigned(2048 - 256 + 248, 12);
-- Sampling points
constant INIT_SAMPLING_POINTS : std_logic_vector(2 downto 0) := "010";
signal shift_R : std_logic_vector(3 downto 0);
signal shift_G : std_logic_vector(3 downto 0);
signal shift_B : std_logic_vector(3 downto 0);
-- The sampling counter runs at 12x pixel clock of 7.15909MHz = 85.909080MHz
-- A sample is taken every 6 counts
-- i.e. Each Atom pixel is sampled twice
-- It serves several purposes:
-- 1. Counts the 12us between the rising edge of nCSYNC and the first pixel
-- 2. Counts within each pixel (bits 0, 1, 2)
@ -89,7 +87,8 @@ architecture Behavorial of RGBtoHDMI is
signal offset : unsigned (2 downto 0);
-- Sample pixel on next clock; pipelined to reduce the number of product terms
signal sample : std_logic;
signal shift : std_logic;
signal sample : std_logic;
-- Decoded RGB signals
signal R : std_logic;
@ -126,11 +125,6 @@ architecture Behavorial of RGBtoHDMI is
signal HS1: std_logic;
signal HS2: std_logic;
signal fs1: std_logic;
signal fs2: std_logic;
signal fs3: std_logic;
signal fs: std_logic;
begin
offset <= unsigned(sp_reg(2 downto 0));
@ -154,23 +148,28 @@ begin
HS2 <= HS1;
-- Counter is used to find sampling point for first pixel
if HS2 = '1' and HS1 = '0' then
if HS2 = '0' and HS1 = '1' then
counter <= default_offset;
elsif counter(counter'left) = '1' then
counter <= counter + 1;
elsif counter(2 downto 0) /= 5 then
counter(5 downto 0) <= counter(5 downto 0) + 1;
else
counter(5 downto 0) <= counter(5 downto 0) + 3;
counter(5 downto 0) <= counter(5 downto 0) + 1;
end if;
-- sample/shift control
if counter(2 downto 0) = offset then
-- sample
if counter(2 downto 0) = offset(2 downto 0) then
sample <= '1';
else
sample <= '0';
end if;
-- shift
if counter(1 downto 0) = offset(1 downto 0) then
shift <= '1';
else
shift <= '0';
end if;
if sample = '1' then
-- Atom pixel processing
AL1 <= AL_I;
@ -191,11 +190,11 @@ begin
BH3 <= BH2;
L3 <= L2;
AL <= (AL1 AND AL2) OR (AL1 AND AL3) OR (AL2 AND AL3);
AH <= (AH1 AND AH2) OR (AH1 AND AH3) OR (AH2 AND AH3);
BL <= (BL1 AND BL2) OR (BL1 AND BL3) OR (BL2 AND BL3);
BH <= (BH1 AND BH2) OR (BH1 AND BH3) OR (BH2 AND BH3);
L <= ( L1 AND L2) OR ( L1 AND L3) OR ( L2 AND L3);
AL <= AL3; -- (AL1 AND AL2) OR (AL1 AND AL3) OR (AL2 AND AL3);
AH <= AH3; -- (AH1 AND AH2) OR (AH1 AND AH3) OR (AH2 AND AH3);
BL <= BL3; -- (BL1 AND BL2) OR (BL1 AND BL3) OR (BL2 AND BL3);
BH <= BH3; -- (BH1 AND BH2) OR (BH1 AND BH3) OR (BH2 AND BH3);
L <= l3; -- ( L1 AND L2) OR ( L1 AND L3) OR ( L2 AND L3);
-- AL AH BL BH L R G1 G2 B
--YELLOW 1.5 1.0 0 0 1 0 X 1 1 1 0
@ -225,7 +224,7 @@ begin
end if;
if sample = '1' and counter(counter'left) = '0' then
if shift = '1' and counter(counter'left) = '0' then
-- R Sample/shift register
shift_R <= R & shift_R(3 downto 1);
-- G Sample/shift register
@ -239,7 +238,7 @@ begin
quad <= VERSION_NUM;
psync <= '0';
elsif counter(counter'left) = '0' then
if counter(4 downto 0) = "00000" then
if counter(3 downto 0) = "0000" then
quad(11) <= shift_B(3);
quad(10) <= shift_G(3);
quad(9) <= shift_R(3);
@ -252,7 +251,7 @@ begin
quad(2) <= shift_B(0);
quad(1) <= shift_G(0);
quad(0) <= shift_R(0);
psync <= counter(5);
psync <= counter(4);
end if;
else
quad <= (others => '0');
@ -266,16 +265,8 @@ begin
clamp <= '0';
end if;
-- generate a short fs (two lines) on the rising edge of FS_N
if HS2 = '1' and HS1 = '0' then
fs1 <= FS_I;
fs2 <= fs1;
fs3 <= fs2;
fs <= fs3 or not fs1;
end if;
-- generate the csync output
csync <= HS_I and fs;
csync <= HS_I and FS_I;
end if;
end process;