diff options
Diffstat (limited to 'basys3/basys3.srcs/apu_LUT_reader.vhd')
| -rw-r--r-- | basys3/basys3.srcs/apu_LUT_reader.vhd | 35 |
1 files changed, 21 insertions, 14 deletions
diff --git a/basys3/basys3.srcs/apu_LUT_reader.vhd b/basys3/basys3.srcs/apu_LUT_reader.vhd index a37cd30..e56f855 100644 --- a/basys3/basys3.srcs/apu_LUT_reader.vhd +++ b/basys3/basys3.srcs/apu_LUT_reader.vhd @@ -14,7 +14,10 @@ end entity; architecture Behavioral of apu_LUT_reader is - signal idx : std_logic_vector(7 downto 0) := (others => '0'); + constant AMPLITUDE : natural := 0; + constant SAMPLE_SIZE : natural := 256; + + signal idx : unsigned := (others => '0'); signal buf : unsigned := (others => '0'); begin @@ -25,21 +28,25 @@ begin idx <= x"00"; buf <= x"00"; elsif rising_edge(clk) then - --main code here + -- main code here - if wave = "00" then --Sawtooth - value <= idx; - elsif wave = "01" then --Square - if (signed(idx) < 128) then + if wave = "00" then -- Sawtooth + value <= std_logic_vector( idx ); + elsif wave = "01" then -- Square + if idx < (SAMPLE_SIZE/2) 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 + elsif wave = "10" then -- Triangle + if idx < (SAMPLE_SIZE/2) then + value <= std_logic_vector( idx*2 ); + else + value <= std_logic_vector( (SAMPLE_SIZE-idx)*2 ); + end if; + else-- wave = "11" then -- Noise + -- TODO: implement noise function here: + value <= x"80"; -- remove this end if; @@ -48,8 +55,8 @@ begin buf <= buf + 1; else buf <= x"00"; - if unsigned(idx) < 255 then --moves to next index value - idx <= std_logic_vector( unsigned(idx) + '1'); + if idx < (SAMPLE_SIZE-1) then -- moves to next index value + idx <= idx + 1; else idx <= x"00"; end if; @@ -58,4 +65,4 @@ begin end if; end process; -end architecture;
\ No newline at end of file +end architecture; |