1 files changed, 56 insertions, 0 deletions
diff --git a/basys3/basys3.srcs/apu_LUT_reader.vhd b/basys3/basys3.srcs/apu_LUT_reader.vhd
new file mode 100644
index 0000000..2dd3b06
--- /dev/null
+++ b/basys3/basys3.srcs/apu_LUT_reader.vhd
@@ -0,0 +1,56 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity apu_LUT_reader is
+    port (
+        clk   : in std_logic;
+        rst : in std_logic;
+        freq : in std_logic_vector(11 downto 0);
+        wave : in std_logic_vector(1 downto 0);
+        value : out std_logic_vector(7 downto 0)
+    );
+end entity;
+
+architecture Behavioral of apu_LUT_reader is
+
+    signal idx : std_logic_vector(7 downto 0) := (others => '0');
+    signal buf : unsigned := (others => '0');
+    
+begin
+
+    process (clk)
+    begin
+        if rst = '1' then
+            idx <= x"00";
+            buf <= x"00";
+        elsif rising_edge(clk) then
+            --main code here
+
+            if wave = "00" then     --Sawtooth
+                value <= idx;
+            elsif wave = "01" then  --Square
+                if (signed(idx) < 128) then
+                    value <= x"00";
+                else
+                    value <= x"FF";
+                end if;
+            elsif wave = "10" then  --Triangle
+                value <= std_logic_vector( abs(signed(idx)-127)*2 );
+            else--wave = "11" then  --Noise
+                --implement noise function here:
+                value <= x"80"; --remove this
+            end if;
+
+
+
+            if unsigned(idx) < 255 then --moves to next index value
+                idx <= std_logic_vector( unsigned(idx) + '1');
+            else
+                idx <= x"00";
+            end if;
+
+        end if;
+    end process;
+
+end architecture;
+\ No newline at end of file