mister-devel/Apple-II_MiSTer
1
0
Fork 0
mirror of https://github.com/MiSTer-devel/Apple-II_MiSTer.git synced 2026-05-17 03:01:39 +00:00
Code Issues Packages Projects Releases Wiki Activity
Files
master
Apple-II_MiSTer/rtl/vga_controller.vhd
Newsdee 876a404048 Use custom palette for monochrome text
2024-05-26 23:30:42 +08:00

443 lines
19 KiB
VHDL
Raw Permalink Blame History

-------------------------------------------------------------------------------
--
-- A VGA line-doubler for an Apple ][
--
-- Stephen A. Edwards, sedwards@cs.columbia.edu
--
--
-- The Apple ][ uses a 14.31818 MHz master clock. It outputs a new
-- horizontal line every 65 * 14 + 2 = 912 14M cycles. The extra two
-- are from the "extended cycle" used to keep the 3.579545 MHz
-- colorburst signal in sync. Of these, 40 * 14 = 560 are active video.
--
-- In graphics mode, the Apple effectively generates 140 four-bit pixels
-- output serially (i.e., with 3.579545 MHz pixel clock). In text mode,
-- it generates 280 one-bit pixels (i.e., with a 7.15909 MHz pixel clock).
--
-- We capture 140 four-bit nibbles for each line and interpret them in
-- one of the two modes. In graphics mode, each is displayed as a
-- single pixel of one of 16 colors. In text mode, each is displayed
-- as two black or white pixels.
--
-------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity vga_controller is
port (
CLK_14M : in std_logic; -- 14.31818 MHz master clock
VIDEO : in std_logic; -- from the Apple video generator
COLOR_LINE : in std_logic;
SCREEN_MODE: in std_logic_vector(1 downto 0); -- 00: Color, 01: B&W, 10: Green, 11: Amber
COLOR_PALETTE: in std_logic_vector(1 downto 0); -- 4 palette choices
HBL : in std_logic;
VBL : in std_logic;
VGA_HS : out std_logic;
VGA_VS : out std_logic;
VGA_HBL : out std_logic;
VGA_VBL : out std_logic;
VGA_R : out unsigned(7 downto 0);
VGA_G : out unsigned(7 downto 0);
VGA_B : out unsigned(7 downto 0);
-- load different palettes
ioctl_addr : in std_logic_vector(24 downto 0);
ioctl_data : in std_logic_vector(7 downto 0);
ioctl_index : in std_logic_vector(7 downto 0);
ioctl_download: in std_logic;
ioctl_wr : in std_logic;
ioctl_wait : out std_logic
);
end vga_controller;
architecture rtl of vga_controller is
-- latest color derivation based on Linards' updated approach from:
-- https://www.reddit.com/r/apple2/comments/1cido07/better_apple_ii_color_theory_and_results/
-- https://www.reddit.com/r/apple2/comments/1cisrjf/better_apple_ii_color_theory_and_results_images/
-- original RGB values from Linards Ticmanis (posted on comp.sys.apple2 on 29-Sep-2005)
-- https://groups.google.com/g/comp.sys.apple2/c/uILy74pRsrk/m/G9XDxQhWi1AJ
-- for mpre detail on how the RGB values were determined,
-- please refer to code and documents in https://github.com/Newsdee/apple2ntsc
constant WHITE: unsigned(7 downto 0) := X"FF";
constant WHITE_NTSC: unsigned(7 downto 0) := X"F1";
signal shift_reg : unsigned(5 downto 0); -- Last six pixels
signal last_hbl : std_logic;
signal hcount : unsigned(10 downto 0);
signal vcount : unsigned(5 downto 0);
constant VGA_HSYNC : integer := 68;
constant VGA_ACTIVE : integer := 282 * 2;
constant VGA_FRONT_PORCH : integer := 130;
constant VBL_TO_VSYNC : integer := 33;
constant VGA_VSYNC_LINES : integer := 3;
signal vbl_delayed : std_logic;
signal de_delayed : std_logic_vector(17 downto 0);
-- Palette signals
signal color_addr : unsigned(1 downto 0);
signal palette_index : unsigned(3 downto 0);
signal palette_rgb_in : unsigned(23 downto 0);
-- temporary buffer used for downloads
signal BUFFER_COL0 : unsigned(23 downto 0) := X"200820";
signal BUFFER_COL1 : unsigned(23 downto 0) := X"802222";
signal BUFFER_COL2 : unsigned(23 downto 0) := X"222280";
signal BUFFER_COL3 : unsigned(23 downto 0) := X"490080";
signal BUFFER_COL4 : unsigned(23 downto 0) := X"275412"; -- Dk Green
signal BUFFER_COL5 : unsigned(23 downto 0) := X"636363"; -- gray 1
signal BUFFER_COL6 : unsigned(23 downto 0) := X"4063ff"; -- Med Blue
signal BUFFER_COL7 : unsigned(23 downto 0) := X"4adbff"; -- light blue
signal BUFFER_COL8 : unsigned(23 downto 0) := X"7B4513";
signal BUFFER_COL9 : unsigned(23 downto 0) := X"FF8C00";
signal BUFFER_COL10 : unsigned(23 downto 0):= X"818181";
signal BUFFER_COL11 : unsigned(23 downto 0):= X"f87efc"; -- pink
signal BUFFER_COL12 : unsigned(23 downto 0):= X"22FF22";
signal BUFFER_COL13 : unsigned(23 downto 0):= X"FFFF22";
signal BUFFER_COL14 : unsigned(23 downto 0):= X"ADFFF1";
signal BUFFER_COL15 : unsigned(23 downto 0):= X"F0F0F0";
signal CURRENT_COL0 : unsigned(23 downto 0);
signal CURRENT_COL1 : unsigned(23 downto 0);
signal CURRENT_COL2 : unsigned(23 downto 0);
signal CURRENT_COL3 : unsigned(23 downto 0);
signal CURRENT_COL4 : unsigned(23 downto 0);
signal CURRENT_COL5 : unsigned(23 downto 0);
signal CURRENT_COL6 : unsigned(23 downto 0);
signal CURRENT_COL7 : unsigned(23 downto 0);
signal CURRENT_COL8 : unsigned(23 downto 0);
signal CURRENT_COL9 : unsigned(23 downto 0);
signal CURRENT_COL10 : unsigned(23 downto 0);
signal CURRENT_COL11 : unsigned(23 downto 0);
signal CURRENT_COL12 : unsigned(23 downto 0);
signal CURRENT_COL13 : unsigned(23 downto 0);
signal CURRENT_COL14 : unsigned(23 downto 0);
signal CURRENT_COL15 : unsigned(23 downto 0);
begin
-- palette processing
process (CLK_14M)
begin
if rising_edge(CLK_14M) then
-- whether to update palette RAM; ioctl_index must be consistent with declaration in MiSTer config string
if ioctl_download = '1' and ioctl_index = "00000010" then
-- palette is downloading so preserve values of registers
CURRENT_COL0 <= CURRENT_COL0;
CURRENT_COL1 <= CURRENT_COL1;
CURRENT_COL2 <= CURRENT_COL2;
CURRENT_COL3 <= CURRENT_COL3;
CURRENT_COL4 <= CURRENT_COL4;
CURRENT_COL5 <= CURRENT_COL5;
CURRENT_COL6 <= CURRENT_COL6;
CURRENT_COL7 <= CURRENT_COL7;
CURRENT_COL8 <= CURRENT_COL8;
CURRENT_COL9 <= CURRENT_COL9;
CURRENT_COL10 <= CURRENT_COL10;
CURRENT_COL11 <= CURRENT_COL11;
CURRENT_COL12 <= CURRENT_COL12;
CURRENT_COL13 <= CURRENT_COL13;
CURRENT_COL14 <= CURRENT_COL14;
CURRENT_COL15 <= CURRENT_COL15;
-- write to proper index with downloading palette
-- but first check if the new data is ready
if ioctl_wr = '1' then
ioctl_wait <= '1';
case color_addr is
when "00" => palette_rgb_in <= unsigned(ioctl_data) & palette_rgb_in(15 downto 0) ;
when "01" => palette_rgb_in <= palette_rgb_in(23 downto 16) & unsigned(ioctl_data) & palette_rgb_in(7 downto 0) ;
when "10" => palette_rgb_in <= palette_rgb_in(23 downto 8) & unsigned(ioctl_data) ;
when "11" => palette_rgb_in <= palette_rgb_in(23 downto 8) & unsigned(ioctl_data) ;
end case;
case palette_index is
when "0000" => BUFFER_COL0 <= palette_rgb_in;
when "0001" => BUFFER_COL1 <= palette_rgb_in;
when "0010" => BUFFER_COL2 <= palette_rgb_in;
when "0011" => BUFFER_COL3 <= palette_rgb_in;
when "0100" => BUFFER_COL4 <= palette_rgb_in;
when "0101" => BUFFER_COL5 <= palette_rgb_in;
when "0110" => BUFFER_COL6 <= palette_rgb_in;
when "0111" => BUFFER_COL7 <= palette_rgb_in;
when "1000" => BUFFER_COL8 <= palette_rgb_in;
when "1001" => BUFFER_COL9 <= palette_rgb_in;
when "1010" => BUFFER_COL10 <= palette_rgb_in;
when "1011" => BUFFER_COL11 <= palette_rgb_in;
when "1100" => BUFFER_COL12 <= palette_rgb_in;
when "1101" => BUFFER_COL13 <= palette_rgb_in;
when "1110" => BUFFER_COL14 <= palette_rgb_in;
when "1111" => BUFFER_COL15 <= palette_rgb_in;
end case;
if color_addr < "11" then
color_addr <= color_addr + 1;
else
color_addr <= "00";
palette_index <= palette_index + 1;
end if;
ioctl_wait <= '0';
end if;
else
-- palette is ready, reset vars and update registers
palette_index <= "0000";
color_addr <= "00";
palette_rgb_in <= "000000000000000000000000";
CURRENT_COL0 <= BUFFER_COL0;
CURRENT_COL1 <= BUFFER_COL1;
CURRENT_COL2 <= BUFFER_COL2;
CURRENT_COL3 <= BUFFER_COL3;
CURRENT_COL4 <= BUFFER_COL4;
CURRENT_COL5 <= BUFFER_COL5;
CURRENT_COL6 <= BUFFER_COL6;
CURRENT_COL7 <= BUFFER_COL7;
CURRENT_COL8 <= BUFFER_COL8;
CURRENT_COL9 <= BUFFER_COL9;
CURRENT_COL10 <= BUFFER_COL10;
CURRENT_COL11 <= BUFFER_COL11;
CURRENT_COL12 <= BUFFER_COL12;
CURRENT_COL13 <= BUFFER_COL13;
CURRENT_COL14 <= BUFFER_COL14;
CURRENT_COL15 <= BUFFER_COL15;
end if;
end if;
end process;
process (CLK_14M)
begin
if rising_edge(CLK_14M) then
if last_hbl = '1' and HBL = '0' then -- Falling edge
hcount <= (others => '0');
vbl_delayed <= VBL;
if VBL = '1' then
vcount <= vcount + 1;
else
vcount <= (others => '0');
end if;
else
hcount <= hcount + 1;
end if;
last_hbl <= HBL;
end if;
end process;
process (CLK_14M)
begin
if rising_edge(CLK_14M) then
if hcount = VGA_ACTIVE + VGA_FRONT_PORCH then
VGA_HS <= '1';
if vcount = VBL_TO_VSYNC then
VGA_VS <= '1';
elsif vcount = VBL_TO_VSYNC + VGA_VSYNC_LINES then
VGA_VS <= '0';
end if;
elsif hcount = VGA_ACTIVE + VGA_FRONT_PORCH + VGA_HSYNC then
VGA_HS <= '0';
end if;
end if;
end process;
process (CLK_14M)
variable r, g, b : unsigned(7 downto 0);
variable shift_color : unsigned(3 downto 0); -- subset of shift register to determine color in LUT
begin
if rising_edge(CLK_14M) then
shift_reg <= VIDEO & shift_reg(5 downto 1);
r := X"00";
g := X"00";
b := X"00";
-- alternate background for monochrome modes
case SCREEN_MODE is
when "00" =>
-- color mode background
if COLOR_PALETTE = "11" then
-- use custom palette
r := CURRENT_COL0(23 downto 16); g := CURRENT_COL0(15 downto 8); b := CURRENT_COL0(7 downto 0); -- black
else
-- or black for the rest
r := X"00"; g := X"00"; b := X"00";
end if;
when "01" => r := X"00"; g := X"00"; b := X"00"; -- B&W mode background
when "10" => r := X"00"; g := X"0F"; b := X"01"; -- green mode background color
when "11" => r := X"20"; g := X"08"; b := X"01"; -- amber mode background color
end case;
if COLOR_LINE = '0' then -- Monochrome mode
if shift_reg(2) = '1' then
-- handle green/amber color modes
case SCREEN_MODE is
when "00" =>
-- white (color mode)
if COLOR_PALETTE = "00" then
-- NTSC palette
r := WHITE_NTSC; g := WHITE_NTSC; b := WHITE_NTSC;
elsif COLOR_PALETTE = "11" then
-- custom palette
r := CURRENT_COL15(23 downto 16); g := CURRENT_COL15(15 downto 8); b := CURRENT_COL15(7 downto 0); -- white
else
-- Apple IIgs and AppleWin palettes
r := WHITE; g := WHITE; b := WHITE;
end if;
when "01" => r := WHITE; g := WHITE; b := WHITE; -- white (B&W mode)
when "10" => r := X"00"; g := X"C0"; b := X"01"; -- green
when "11" => r := X"FF"; g := X"80"; b := X"01"; -- amber
end case;
end if;
elsif shift_reg(0) = shift_reg(4) and shift_reg(5) = shift_reg(1) then
-- rotate the 4-bit value based on contents of shift register
-- then apply the color mapping
shift_color := shift_reg(4 downto 1) rol to_integer(hcount);
if COLOR_PALETTE = "00" then
-- lticmanis 2024 (default)
-- 'correct' palette derived by mathematical NTSC formulas,
-- calibrated to approximate GS colors as much NTSC can
case shift_color is
when "0000" => r := X"00"; g := X"00"; b := X"00"; -- black
when "0010" => r := X"9F"; g := X"1B"; b := X"48"; -- magenta
when "0100" => r := X"48"; g := X"32"; b := X"EB"; -- dark blue
when "0110" => r := X"D6"; g := X"43"; b := X"EF"; -- purple
when "1000" => r := X"19"; g := X"75"; b := X"44"; -- dark green
when "0101" => r := X"81"; g := X"81"; b := X"81"; -- gray 1
when "1100" => r := X"36"; g := X"92"; b := X"FF"; -- med blue
when "1110" => r := X"D8"; g := X"9E"; b := X"FF"; -- light blue
when "0001" => r := X"49"; g := X"65"; b := X"00"; -- brown
when "0011" => r := X"D8"; g := X"73"; b := X"00"; -- orange
when "1010" => r := X"81"; g := X"81"; b := X"81"; -- gray 2
when "0111" => r := X"FB"; g := X"8F"; b := X"BC"; -- pink
when "1001" => r := X"3C"; g := X"CC"; b := X"00"; -- green
when "1011" => r := X"BC"; g := X"D6"; b := X"00"; -- yellow
when "1101" => r := X"6C"; g := X"E6"; b := X"B8"; -- aquamarine
when "1111" => r := WHITE_NTSC; g := WHITE_NTSC; b := WHITE_NTSC; -- white
end case;
elsif COLOR_PALETTE = "01" then
-- Apple IIgs & LC (//e mode) palette
-- see "IIGS Technical Note #63" from Apple ,
-- and the 'clut' resource "Apple IIe Colors" in the IIe card's "IIe Startup" 68K Mac executable version 2.2.1d.
case shift_color is
when "0000" => r := X"00"; g := X"00"; b := X"00"; -- 0 - black
when "0010" => r := X"DB"; g := X"1F"; b := X"42"; -- 1 - magenta
when "0100" => r := X"0C"; g := X"11"; b := X"A4"; -- 2 - dark blue
when "0110" => r := X"DC"; g := X"43"; b := X"E1"; -- 3 - purple
when "1000" => r := X"1C"; g := X"82"; b := X"31"; -- 4 - dark green
when "0101" => r := X"B3"; g := X"B3"; b := X"B3"; -- 5 - gray 1
when "1100" => r := X"39"; g := X"3D"; b := X"FF"; -- 6 - med blue
when "1110" => r := X"7A"; g := X"B3"; b := X"FF"; -- 7 - light blue
when "0001" => r := X"91"; g := X"64"; b := X"00"; -- 8 - brown
when "0011" => r := X"FA"; g := X"77"; b := X"00"; -- 9 - orange
when "1010" => r := X"63"; g := X"63"; b := X"63"; -- 10 - gray 2
when "0111" => r := X"FB"; g := X"A5"; b := X"93"; -- 11 - pink
when "1001" => r := X"40"; g := X"DE"; b := X"00"; -- 12 - green
when "1011" => r := X"FE"; g := X"FE"; b := X"00"; -- 13 - yellow
when "1101" => r := X"67"; g := X"FC"; b := X"A4"; -- 14 - aquamarine
when "1111" => r := WHITE; g := WHITE; b := WHITE; -- 15 - white
end case;
elsif COLOR_PALETTE = "10" then
-- AppleWin palette as of 1.13.18.0
case shift_color is
when "0000" => r := X"00"; g := X"00"; b := X"00"; -- black
when "0010" => r := X"93"; g := X"0B"; b := X"7C"; -- magenta
when "0100" => r := X"1F"; g := X"35"; b := X"D3"; -- dark blue
when "0110" => r := X"BB"; g := X"36"; b := X"FF"; -- purple
when "1000" => r := X"00"; g := X"76"; b := X"0C"; -- dark green
when "0101" => r := X"7E"; g := X"7E"; b := X"7E"; -- gray 1
when "1100" => r := X"07"; g := X"A8"; b := X"E0"; -- med blue
when "1110" => r := X"9D"; g := X"AC"; b := X"FF"; -- light blue
when "0001" => r := X"62"; g := X"4C"; b := X"00"; -- brown
when "0011" => r := X"F9"; g := X"56"; b := X"1D"; -- orange
when "1010" => r := X"7E"; g := X"7E"; b := X"7E"; -- gray 2
when "0111" => r := X"FF"; g := X"81"; b := X"EC"; -- pink
when "1001" => r := X"43"; g := X"C8"; b := X"00"; -- green
when "1011" => r := X"DC"; g := X"CD"; b := X"16"; -- yellow
when "1101" => r := X"5D"; g := X"F7"; b := X"84"; -- aquamarine
when "1111" => r := WHITE; g := WHITE; b := WHITE; -- white
end case;
else
-- Use custom palette
case shift_color is
when "0000" => r := CURRENT_COL0(23 downto 16); g := CURRENT_COL0(15 downto 8); b := CURRENT_COL0(7 downto 0); --black
when "0010" => r := CURRENT_COL1(23 downto 16); g := CURRENT_COL1(15 downto 8); b := CURRENT_COL1(7 downto 0); --magenta
when "0100" => r := CURRENT_COL2(23 downto 16); g := CURRENT_COL2(15 downto 8); b := CURRENT_COL2(7 downto 0); --purple
when "0110" => r := CURRENT_COL3(23 downto 16); g := CURRENT_COL3(15 downto 8); b := CURRENT_COL3(7 downto 0); -- purple
when "1000" => r := CURRENT_COL4(23 downto 16); g := CURRENT_COL4(15 downto 8); b := CURRENT_COL4(7 downto 0); -- dark green
when "1010" => r := CURRENT_COL5(23 downto 16); g := CURRENT_COL5(15 downto 8); b := CURRENT_COL5(7 downto 0); -- gray 1
when "1100" => r := CURRENT_COL6(23 downto 16); g := CURRENT_COL6(15 downto 8); b := CURRENT_COL6(7 downto 0); -- med blue
when "1110" => r := CURRENT_COL7(23 downto 16); g := CURRENT_COL7(15 downto 8); b := CURRENT_COL7(7 downto 0); -- light blue
when "0001" => r := CURRENT_COL8(23 downto 16); g := CURRENT_COL8(15 downto 8); b := CURRENT_COL8(7 downto 0); -- brown
when "0011" => r := CURRENT_COL9(23 downto 16); g := CURRENT_COL9(15 downto 8); b := CURRENT_COL9(7 downto 0); -- orange
when "0101" => r := CURRENT_COL10(23 downto 16); g := CURRENT_COL10(15 downto 8); b := CURRENT_COL10(7 downto 0); -- gray 2
when "0111" => r := CURRENT_COL11(23 downto 16); g := CURRENT_COL11(15 downto 8); b := CURRENT_COL11(7 downto 0); -- pink
when "1001" => r := CURRENT_COL12(23 downto 16); g := CURRENT_COL12(15 downto 8); b := CURRENT_COL12(7 downto 0); -- green
when "1011" => r := CURRENT_COL13(23 downto 16); g := CURRENT_COL13(15 downto 8); b := CURRENT_COL13(7 downto 0); -- yellow
when "1101" => r := CURRENT_COL14(23 downto 16); g := CURRENT_COL14(15 downto 8); b := CURRENT_COL14(7 downto 0); -- aquamarine
when "1111" => r := CURRENT_COL15(23 downto 16); g := CURRENT_COL15(15 downto 8); b := CURRENT_COL15(7 downto 0); -- white
end case;
end if;
else
-- Tint is changing: display only black, gray, or white
case shift_reg(3 downto 2) is
when "11" =>
-- white
if COLOR_PALETTE = "00" then
r := WHITE_NTSC; g := WHITE_NTSC; b := WHITE_NTSC;
elsif COLOR_PALETTE = "11" then
-- custom palette
r := CURRENT_COL15(23 downto 16); g := CURRENT_COL15(15 downto 8); b := CURRENT_COL15(7 downto 0); -- white
else
r := WHITE; g := WHITE; b := WHITE;
end if;
-- gray - we use the darkest gray of all the palettes to avoid it being too prominent
when "01" | "10" =>
if COLOR_PALETTE = "11" then
r := CURRENT_COL5(23 downto 16); g := CURRENT_COL5(15 downto 8); b := CURRENT_COL5(7 downto 0); -- gray 1 (darker)
else
r := X"63"; g := X"63"; b := X"63";
end if;
-- black
when others => r := X"00"; g := X"00"; b := X"00";
end case;
end if;
VGA_R <= r;
VGA_G <= g;
VGA_B <= b;
de_delayed <= de_delayed(16 downto 0) & last_hbl;
end if;
end process pixel_generator;
VGA_VBL <= vbl_delayed;
VGA_HBL <= de_delayed(9) and de_delayed(17);
end rtl;
Reference in New Issue View Git Blame Copy Permalink