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library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;
use work.ppu_consts.all;
entity ppu_dispctl is port(
SYSCLK : in std_logic; -- system clock
RESET : in std_logic;
X : out std_logic_vector(PPU_POS_H_WIDTH-1 downto 0); -- tiny screen pixel x
Y : out std_logic_vector(PPU_POS_V_WIDTH-1 downto 0); -- tiny screen pixel y
RI,GI,BI : in std_logic_vector(PPU_COLOR_OUTPUT_DEPTH-1 downto 0); -- color in
PREADY : in std_logic; -- current pixel ready (pixel color is stable)
RO,GO,BO : out std_logic_vector(PPU_COLOR_OUTPUT_DEPTH-1 downto 0); -- VGA color out
NVSYNC, NHSYNC : out std_logic; -- VGA sync out
THBLANK, TVBLANK : out std_logic := '0'; -- tiny sync signals
ACTIVE : out std_logic); -- screen currently active (currently same for tiny/native, TODO: offset tiny for first scanline)
end ppu_dispctl;
architecture Behavioral of ppu_dispctl is
component ppu_dispctl_pixclk is port (
npxclk : out std_logic;
tpxclk : out std_logic;
reset : in std_logic;
sysclk : in std_logic);
end component;
component ppu_dispctl_slbuf port( -- scanline buffer
clka : in std_logic;
wea : in std_logic_vector(0 to 0);
addra : in std_logic_vector(PPU_DISPCTL_SLBUF_ADDR_WIDTH-1 downto 0);
dina : in std_logic_vector(PPU_RGB_COLOR_OUTPUT_DEPTH-1 downto 0);
clkb : in std_logic;
rstb : in std_logic;
addrb : in std_logic_vector(PPU_DISPCTL_SLBUF_ADDR_WIDTH-1 downto 0);
doutb : out std_logic_vector(PPU_RGB_COLOR_OUTPUT_DEPTH-1 downto 0);
rsta_busy : out std_logic;
rstb_busy : out std_logic);
end component;
signal NPIXCLK, TPIXCLK : std_logic;
signal NHCOUNT, NVCOUNT : unsigned(PPU_VGA_SIGNAL_PIXEL_WIDTH-1 downto 0) := (others => '0');
signal ADDR_I, ADDR_O : std_logic_vector(PPU_DISPCTL_SLBUF_ADDR_WIDTH-1 downto 0);
signal DATA_I, DATA_O : std_logic_vector(PPU_RGB_COLOR_OUTPUT_DEPTH-1 downto 0);
signal T_POS_X : unsigned(PPU_SCREEN_T_POS_X_WIDTH-1 downto 0) := (others => '0'); -- real tiny x position
signal T_POS_Y : unsigned(PPU_SCREEN_T_POS_Y_WIDTH-1 downto 0) := (others => '0'); -- real tiny y position
signal U_POS_X : unsigned(PPU_SCREEN_T_POS_X_WIDTH-1 downto 0) := (others => '0'); -- upscaled tiny x position
signal U_POS_Y : unsigned(PPU_SCREEN_T_POS_Y_WIDTH-1 downto 0) := (others => '0'); -- upscaled tiny y position
signal N_POS_X : unsigned(PPU_SCREEN_N_POS_X_WIDTH-1 downto 0) := (others => '0'); -- native x position
signal N_POS_Y : unsigned(PPU_SCREEN_N_POS_Y_WIDTH-1 downto 0) := (others => '0'); -- native y position
signal NACTIVE, NHACTIVE, NVACTIVE : std_logic := '0';
signal TACTIVE, THACTIVE, TVACTIVE : std_logic := '0';
begin
-- scanline buffer data in
DATA_I <= RI & GI & BI;
ADDR_I <= std_logic_vector(resize(T_POS_X, ADDR_I'length)) when T_POS_Y(0) = '0' else std_logic_vector(resize(T_POS_X, ADDR_I'length) + PPU_SCREEN_WIDTH);
T_POS_Y <= U_POS_Y;
X <= std_logic_vector(T_POS_X) when NACTIVE = '1' else (others => '0');
Y <= std_logic_vector(T_POS_Y) when NACTIVE = '1' else (others => '0');
U_POS_X <= resize(N_POS_X(N_POS_X'length-1 downto 1), U_POS_X'length);
U_POS_Y <= resize(N_POS_Y(N_POS_Y'length-1 downto 1), U_POS_Y'length);
-- scanline buffer data out
ADDR_O <= std_logic_vector(resize(U_POS_X, ADDR_I'length)) when U_POS_Y(0) = '1' else std_logic_vector(resize(U_POS_X, ADDR_I'length) + PPU_SCREEN_WIDTH);
RO <= DATA_O(11 downto 8) when NACTIVE = '1' else (others => '0');
GO <= DATA_O(7 downto 4) when NACTIVE = '1' else (others => '0');
BO <= DATA_O(3 downto 0) when NACTIVE = '1' else (others => '0');
-- tiny VCOUNT and HCOUNT
process(TPIXCLK, NPIXCLK, RESET)
variable TMP_T_POS_X : unsigned(PPU_SCREEN_T_POS_X_WIDTH-1 downto 0) := (others => '0');
variable TMP_NHCOUNT, TMP_NVCOUNT : unsigned(PPU_VGA_SIGNAL_PIXEL_WIDTH-1 downto 0) := (others => '0');
variable TMP_NHACTIVE, TMP_NVACTIVE : std_logic := '0';
variable TMP_NHSYNC, TMP_NVSYNC : std_logic := '0';
variable TMP_NACTIVE : std_logic := '0';
begin
if RESET = '1' then
TMP_NHCOUNT := (others => '0');
TMP_NVCOUNT := (others => '0');
TMP_NHACTIVE := '0';
TMP_NVACTIVE := '0';
TMP_NVSYNC := '0';
TMP_NHSYNC := '0';
end if;
-- native (+upscaled) VCOUNT and HCOUNT
if rising_edge(NPIXCLK) then
-- sync write (needs to be here to happen on rising edge)
NVCOUNT <= TMP_NVCOUNT;
NHCOUNT <= TMP_NHCOUNT;
NHACTIVE <= TMP_NHACTIVE;
NVACTIVE <= TMP_NVACTIVE;
NACTIVE <= TMP_NACTIVE;
NVSYNC <= TMP_NVSYNC;
NHSYNC <= TMP_NHSYNC;
N_POS_X <= resize(TMP_NHCOUNT - PPU_VGA_H_PORCH_BACK, N_POS_X'length) when TMP_NHACTIVE = '1' else (others => '0');
N_POS_Y <= resize(TMP_NVCOUNT - PPU_VGA_V_PORCH_BACK, N_POS_Y'length) when TMP_NVACTIVE = '1' else (others => '0');
-- horizontal count (pixel)
TMP_NHCOUNT := TMP_NHCOUNT + 1;
if TMP_NHCOUNT >= PPU_VGA_H_TOTAL then
TMP_NHCOUNT := (others => '0');
-- vertical count (scanline)
TMP_NVCOUNT := TMP_NVCOUNT + 1;
if TMP_NVCOUNT >= PPU_VGA_V_TOTAL then
TMP_NVCOUNT := (others => '0');
end if;
-- vertical display area (active)
if TMP_NVCOUNT = PPU_VGA_V_PORCH_BACK then TMP_NVACTIVE := '1'; end if;
if TMP_NVCOUNT = PPU_VGA_V_PORCH_BACK + PPU_VGA_V_ACTIVE then TMP_NVACTIVE := '0'; end if;
-- vertical sync period
if TMP_NVCOUNT = PPU_VGA_V_PORCH_BACK + PPU_VGA_V_ACTIVE then TMP_NVSYNC := '1'; end if;
if TMP_NVCOUNT = PPU_VGA_V_PORCH_BACK + PPU_VGA_V_ACTIVE + PPU_VGA_V_SYNC then TMP_NVSYNC := '0'; end if;
end if;
-- horizontal display area (active)
if TMP_NHCOUNT = PPU_VGA_H_PORCH_BACK then TMP_NHACTIVE := '1'; end if;
if TMP_NHCOUNT = PPU_VGA_H_PORCH_BACK + PPU_VGA_H_ACTIVE then TMP_NHACTIVE := '0'; end if;
TMP_NACTIVE := TMP_NHACTIVE and TMP_NVACTIVE;
-- horizontal sync period
if TMP_NHCOUNT = PPU_VGA_H_PORCH_BACK + PPU_VGA_H_ACTIVE then TMP_NHSYNC := '1'; end if;
if TMP_NHCOUNT = PPU_VGA_H_PORCH_BACK + PPU_VGA_H_ACTIVE + PPU_VGA_H_SYNC then TMP_NHSYNC := '0'; end if;
end if;
if falling_edge(TPIXCLK) then -- NOTE: falling edge used because of clock offset of 90 (should be 270)
T_POS_X <= TMP_T_POS_X;
if TMP_NACTIVE = '1' then
TMP_T_POS_X := TMP_T_POS_X + 1;
if TMP_T_POS_X >= PPU_SCREEN_WIDTH then
TMP_T_POS_X := (others => '0');
end if;
end if;
end if;
end process;
ACTIVE <= NACTIVE;
scanline_buffer : component ppu_dispctl_slbuf port map(
clka => SYSCLK,
wea => (others => PREADY),
addra => ADDR_I,
dina => DATA_I,
clkb => SYSCLK,
rstb => RESET,
addrb => ADDR_O,
doutb => DATA_O,
rsta_busy => open,
rstb_busy => open);
pixel_clock: component ppu_dispctl_pixclk port map(
sysclk => SYSCLK,
reset => RESET,
npxclk => NPIXCLK,
tpxclk => TPIXCLK);
THBLANK <= (not NHACTIVE) and NVACTIVE and nor(T_POS_X);
TVBLANK <= not NVACTIVE;
--THBLANK <= '0';
--TVBLANK <= '0';
end Behavioral;
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