apu note 2 freq

1 files changed, 40 insertions, 0 deletions

diff --git a/basys3/basys3.srcs/apu_note_to_frequency.vhd b/basys3/basys3.srcs/apu_note_to_frequency.vhd
new file mode 100644
index 0000000..878da30
--- /dev/null
+++ b/basys3/basys3.srcs/apu_note_to_frequency.vhd
@@ -0,0 +1,40 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity apu_note_to_frequency is
+    port (
+        -- clk : in std_logic;
+        -- rst : in std_logic;
+        data : in std_logic_vector(7 downto 0);
+        freq : out std_logic_vector(11 downto 0) --frequency
+    );
+end entity;
+
+architecture Behavioral of apu_note_to_frequency is
+signal buffSmall : std_logic_vector(7 downto 0) := (others => '0');
+signal buff : std_logic_vector(15 downto 0) := (others => '0');
+signal shift : integer;
+begin
+
+    shift <= to_integer(unsigned( data(2 downto 0) ));
+
+    buffSmall <= 
+        x"F0" when data(7 downto 3) = (x"C" & '0') else -- C  496
+        x"D0" when data(7 downto 3) = (x"C" & '1') else -- C# 464
+        x"B0" when data(7 downto 3) = (x"D" & '0') else -- D  432
+        x"A0" when data(7 downto 3) = (x"D" & '1') else -- D# 416
+        x"80" when data(7 downto 3) = (x"E" & '0') else -- E  384
+        x"70" when data(7 downto 3) = (x"F" & '0') else -- F  368
+        x"58" when data(7 downto 3) = (x"F" & '1') else -- F# 344
+        x"40" when data(7 downto 3) = (x"8" & '0') else -- G  320
+        x"30" when data(7 downto 3) = (x"8" & '1') else -- G# 304
+        x"20" when data(7 downto 3) = (x"A" & '0') else -- A  288
+        x"10" when data(7 downto 3) = (x"A" & '1') else -- A# 272
+        x"00" when data(7 downto 3) = (x"B" & '0') else -- B  256
+        x"01";
+
+    buff <= x"1" & buffSmall;
+    freq <= (others => '0') & buff(15 downto shift); -- bitshift values out (or div by powers of 2)
+
+end architecture;
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