terminal/vga.vhd

81 lines
2.3 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;
entity vga is
port(
clk: in std_logic;
x, y: out std_logic_vector(9 downto 0);
pixel_rgb: in std_logic_vector(23 downto 0);
dvi_d: out std_logic_vector(11 downto 0);
dvi_clk: out std_logic;
dvi_hsync: out std_logic;
dvi_vsync: out std_logic;
dvi_de: out std_logic
);
end vga;
architecture behavioral of vga is
signal second_batch: std_logic := '0';
signal hcount: std_logic_vector(9 downto 0) := (others => '0');
signal vcount: std_logic_vector(9 downto 0) := (others => '0');
signal data_enabled: std_logic;
begin
--dvi_clk <= clk;
dvi_clk <= second_batch;
dvi_de <= data_enabled;
data_enabled <= '1' when hcount < 640 and vcount < 480 else
'0';
dvi_hsync <= '0' when 656 <= hcount and hcount <= 720 else
'1';
dvi_vsync <= '0' when 483 <= vcount and vcount <= 487 else
'1';
x <= hcount when data_enabled = '1' and hcount < 640 else std_logic_vector(to_unsigned(639, 10));
y <= vcount when data_enabled = '1' and vcount < 480 else std_logic_vector(to_unsigned(479, 10));
data_output: process(clk)
begin
if rising_edge(clk) then
if data_enabled = '1' then
if second_batch = '0' then
dvi_d <= pixel_rgb(11 downto 0);
else
dvi_d <= pixel_rgb(23 downto 12);
end if;
else
dvi_d <= (others => '0');
end if;
second_batch <= not second_batch;
end if;
end process data_output;
hcounter: process(clk)
begin
if rising_edge(clk) and second_batch = '1' then
if hcount < 799 then
hcount <= hcount + 1;
else
hcount <= (others => '0');
end if;
end if;
end process hcounter;
vcounter: process(clk, hcount)
begin
if rising_edge(clk) and second_batch = '1' and hcount = 700 then
if vcount < 499 then
vcount <= vcount + 1;
else
vcount <= (others => '0');
end if;
end if;
end process vcounter;
end behavioral;