1 files changed, 95 insertions, 0 deletions
diff --git a/basys3/basys3.srcs/ppu_vga_native.vhd b/basys3/basys3.srcs/ppu_vga_native.vhd
new file mode 100644
index 0000000..47288e9
--- /dev/null
+++ b/basys3/basys3.srcs/ppu_vga_native.vhd
@@ -0,0 +1,95 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use work.ppu_consts.all;
+use ieee.numeric_std.all;
+use ieee.std_logic_unsigned.all;
+
+entity ppu_vga_native is port (
+	CLK: in std_logic; -- system clock
+	RESET: in std_logic;
+
+	X: in std_logic_vector(PPU_POS_H_WIDTH-1 downto 0); -- current screen pixel x
+	Y: in std_logic_vector(PPU_POS_V_WIDTH-1 downto 0); -- current screen pixel y
+	PREADY: in std_logic; -- current pixel ready (pixel color is stable)
+	RI,GI,BI: in std_logic_vector(PPU_COLOR_OUTPUT_DEPTH-1 downto 0); -- VGA color in
+
+	RO,GO,BO: out std_logic_vector(PPU_COLOR_OUTPUT_DEPTH-1 downto 0); -- VGA color out
+	VSYNC, HSYNC: out std_logic); -- VGA sync outputs
+end ppu_vga_native;
+
+architecture Behavioral of ppu_vga_native is
+	type line_buffer is array(319 downto 0) of std_logic_vector(11 downto 0);
+	signal ram_x0 : line_buffer; -- buffer 0
+	signal ram_x1: line_buffer; -- buffer 1
+	signal hcount: std_logic_vector(9 downto 0):= (others => '0');
+	signal vcount: std_logic_vector(9 downto 0):= (others => '0');
+	signal clk_counter: std_logic_vector(1 downto 0):= (others => '0');
+	signal rgb_out : std_logic_vector(11 downto 0):= (others => '0'); -- output colors
+	signal px : integer; -- conversion for hcount
+	signal py :integer; -- conversion for vcount
+	signal buffer_filled_on_buffer0 : integer;
+	signal buffer_filled_on_buffer1 : integer;
+begin
+	process (clk, x, y)
+		variable v_x : integer; -- integer to hold vector X
+	begin
+		if rising_edge(clk) then
+			clk_counter <= clk_counter + 1;
+			if clk_counter = "11" then
+				v_x := to_integer(unsigned(x) - 72);
+				if v_x >= 0 and v_x < 320 and PREADY = '1' then
+					if y(0) = '0' then
+						ram_x0(v_x) <= RI & GI & BI;
+						if v_x = 319 then
+							buffer_filled_on_buffer0 <= to_integer(unsigned(y) - 14);
+						end if;
+					else
+						ram_x1(v_x) <= RI & GI & BI;
+						if v_x = 319 then
+							buffer_filled_on_buffer1 <= to_integer(unsigned(y) - 14);
+						end if;
+					end if;
+				end if;
+				-- T display(display data)
+				if (hcount >= 144) and (hcount < 784) and (vcount >= 31) and (vcount < 511) then
+					px <= to_integer(unsigned(hcount) - 144);
+					py <= to_integer(unsigned(vcount) - 31);
+					if buffer_filled_on_buffer0 = (py/2) then
+						rgb_out <= ram_x0(px/2);
+					elsif buffer_filled_on_buffer1 = (py/2) then
+						rgb_out <= ram_x1(px/2);
+					else
+						rgb_out <= (others => '0');
+					end if;
+				end if;
+				-- pulse width
+				hsync <= '1';
+				if hcount < 97 then
+					hsync <= '0';
+				end if;
+
+				vsync <= '1';
+				if vcount < 3 then
+					vsync <= '0';
+				end if;
+
+				-- sync pulse time
+				hcount <= hcount + 1;
+
+				if hcount = 800 then
+					vcount <= vcount + 1;
+					hcount <= (others => '0');
+				end if;
+
+				if vcount = 521 then
+					vcount <= (others => '0');
+				end if;
+			end if;
+
+			-- output colors
+		RO <= rgb_out(11 downto 8);
+		GO <= rgb_out(7 downto 4);
+		BO <= rgb_out(3 downto 0);
+		end if;
+	end process;
+end Behavioral;