diff options
Diffstat (limited to 'basys3')
| -rw-r--r-- | basys3/basys3.srcs/apu_consts.vhd | 8 | ||||
| -rw-r--r-- | basys3/basys3.srcs/apu_lut_reader.vhd | 16 | ||||
| -rw-r--r-- | basys3/basys3.srcs/apu_note_to_frequency.vhd | 10 |
3 files changed, 24 insertions, 10 deletions
diff --git a/basys3/basys3.srcs/apu_consts.vhd b/basys3/basys3.srcs/apu_consts.vhd new file mode 100644 index 0000000..5c4edcf --- /dev/null +++ b/basys3/basys3.srcs/apu_consts.vhd @@ -0,0 +1,8 @@ + + + +package apu_consts is + constant SAMPLE_SIZE_WIDTH : natural := 8; -- data width for sample size + constant SAMPLE_SIZE : natural := 256; -- max value in sample size + +end package apu_consts;
\ No newline at end of file diff --git a/basys3/basys3.srcs/apu_lut_reader.vhd b/basys3/basys3.srcs/apu_lut_reader.vhd index 2f92eca..b3b0ca4 100644 --- a/basys3/basys3.srcs/apu_lut_reader.vhd +++ b/basys3/basys3.srcs/apu_lut_reader.vhd @@ -2,20 +2,23 @@ library ieee; use ieee.std_logic_1164.all; use ieee.numeric_std.all; +library work; +use work.apu_consts.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) + value : out std_logic_vector(SAMPLE_SIZE_WIDTH-1 downto 0) ); end entity; architecture behavioral of apu_lut_reader is - constant AMPLITUDE : natural := 0; - constant SAMPLE_SIZE : natural := 256; + -- amplitude (currently) only applies to square waves + constant AMPLITUDE : natural := SAMPLE_SIZE/2; -- less or equals SAMPLE_SIZE/2 (Amplitude around SAMPLE_SIZE/2) signal idx : unsigned := (others => '0'); signal buf : unsigned := (others => '0'); @@ -23,6 +26,9 @@ architecture behavioral of apu_lut_reader is begin process (clk) + variable val_min : unsigned := to_unsigned(SAMPLE_SIZE/2 - integer(AMPLITUDE),SAMPLE_SIZE_WIDTH-1); + variable val_max : unsigned := to_unsigned(SAMPLE_SIZE/2 + integer(AMPLITUDE),SAMPLE_SIZE_WIDTH-1); + begin if rst = '1' then idx <= x"00"; @@ -35,9 +41,9 @@ begin value <= std_logic_vector( idx ); elsif wave = "01" then -- Square if idx < (SAMPLE_SIZE/2) then - value <= x"00"; --std_logic_vector( SAMPLE_SIZE-AMPLITUDE ); -- TODO: make so that this work with a changable amplitude (for square wave) + value <= std_logic_vector(val_min); --std_logic_vector( SAMPLE_SIZE-AMPLITUDE ); -- TODO: make so that this work with a changable amplitude (for square wave) else - value <= x"FF"; + value <= std_logic_vector(val_max); end if; elsif wave = "10" then -- Triangle if idx < (SAMPLE_SIZE/2) then diff --git a/basys3/basys3.srcs/apu_note_to_frequency.vhd b/basys3/basys3.srcs/apu_note_to_frequency.vhd index 810cef9..48defa3 100644 --- a/basys3/basys3.srcs/apu_note_to_frequency.vhd +++ b/basys3/basys3.srcs/apu_note_to_frequency.vhd @@ -2,6 +2,9 @@ library ieee; use ieee.std_logic_1164.all; use ieee.numeric_std.all; +library work; +use work.apu_consts.all; + entity apu_note_to_frequency is port ( -- clk : in std_logic; -- rst : in std_logic; @@ -10,7 +13,6 @@ entity apu_note_to_frequency is port ( end entity; architecture Behavioral of apu_note_to_frequency is - signal buff_small : std_logic_vector(7 downto 0) := (others => '0'); signal buff : std_logic_vector(15 downto 0) := (others => '0'); signal shift : integer; begin @@ -18,7 +20,7 @@ begin shift <= to_integer(unsigned( data(2 downto 0) )); buff <= - x"1F0" when data(6 downto 3) = (x"1") else -- C 496 + x"1F0" when data(6 downto 3) = (x"1") else -- C 496 --values are calculated for 8kHz sample rate x"1D0" when data(6 downto 3) = (x"2") else -- C#/Db 464 x"1B0" when data(6 downto 3) = (x"3") else -- D 432 x"1A0" when data(6 downto 3) = (x"4") else -- D#/Eb 416 @@ -32,8 +34,6 @@ begin x"100" when data(6 downto 3) = (x"C") else -- B 256 x"000"; - -- buff <= x"1" & buff_small; - freq <= std_logic_vector( shift_right(unsigned(buff), shift) ); - -- freq <= (others => '0') & buff(11 downto shift); -- bitshift values out (or div by powers of 2) -- TODO: NO WORKY!!! (concat (others => '0');) + freq <= std_logic_vector( shift_right(unsigned(buff), natural(shift)) ); -- TODO: MAYBE WORKY??? end architecture; |