press_button_get_light_demo.vhd

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.midi.all;


entity press_button_get_light is
	generic (
		gClockHz : integer := 1e8 -- 100 mhz
	);

	port (
		-- misc system signals
		iClock : in std_logic;
		iReset : in std_logic; -- assumed to be held high
		
		-- uart interface for midi
		iMidiRxD : in std_logic;

		-- indicator light
		oStatusLights : out std_logic_vector(3 downto 0);
		
		-- I2S DAC test
		oI2sData : out std_logic;
        oI2sBitClock : out std_logic;
        oI2sWorldClock : out std_logic;
		oI2sShutdown : out std_logic
	);
end press_button_get_light;


architecture etc of press_button_get_light is
	
	-- constant UART parameters required by midi
	constant BAUD_RATE : integer := 31250;
	constant PARITY_BIT : string := "none";

	-- uart rx signals (used for midi)
	signal MidiData : std_logic_vector(7 downto 0);
	signal MidiReady : std_logic;
	signal MidiFrameError : std_logic;

	-- uart tx signals (unused)
	signal DebugTxD : std_logic;
	signal DebugData : std_logic_vector(7 downto 0);
	signal DebugSend : std_logic := '0';
	signal DebugBusy : std_logic := '0';

	-- system reset signal
	signal Reset : std_logic;

	-- midi event signals
	signal StatusReady : std_logic := '0';
	signal Status : status_message;
	signal IgnoredByte : std_logic_vector(7 downto 0);
	signal IgnoredReady : std_logic := '0';

	signal NoteStatus : std_logic_vector(3 downto 0) := "0000";
	
	-- I2S DAC test signal
    signal Message : signed(31 downto 0) := to_signed(0, 32);
    constant SAMPLING_HZ : integer := 44100;
    constant FOUR_FORTY_HZ : integer := gClockHz / 440;
    --constant TEST_AMPLITUDE : integer := 1073741823; -- very loud (2**30-1)
    --constant TEST_AMPLITUDE : integer := 536870912; -- (2**29) doesn't play anything at all?
    constant TEST_AMPLITUDE : integer := 536870911; -- (2**29-1) still loud, but plays stuff
    
    signal LastNote : integer := 0;
    signal NoteHz : integer := FOUR_FORTY_HZ;
    signal NoteVolume : integer := 0;

    constant SHIFT_BASE : unsigned(7 downto 0) := "00000001";
    
    type volumes_array is array (0 to 9) of signed(31 downto 0);
    signal OctaveSamples : volumes_array;

begin

	Reset <= not iReset;

	oStatusLights <= not NoteStatus; -- set to ground to turn on the light
	
	oI2sShutdown <= iReset;

	midi_listener: process (iClock)
	begin
		if (rising_edge(iClock)) then
		    if (to_integer(OctaveSamples(0)) > 0) then
		        Message <= OctaveSamples(0);
		    elsif (to_integer(OctaveSamples(1)) > 0) then
		        Message <= OctaveSamples(1);
		    elsif (to_integer(OctaveSamples(2)) > 0) then
		        Message <= OctaveSamples(2);
		    elsif (to_integer(OctaveSamples(3)) > 0) then
		        Message <= OctaveSamples(3);
		    elsif (to_integer(OctaveSamples(4)) > 0) then
		        Message <= OctaveSamples(4);
		    elsif (to_integer(OctaveSamples(5)) > 0) then
		        Message <= OctaveSamples(5);
		    elsif (to_integer(OctaveSamples(6)) > 0) then
		        Message <= OctaveSamples(6);
		    elsif (to_integer(OctaveSamples(7)) > 0) then
		        Message <= OctaveSamples(7);
		    elsif (to_integer(OctaveSamples(8)) > 0) then
		        Message <= OctaveSamples(8);
		    elsif (to_integer(OctaveSamples(9)) > 0) then
		        Message <= OctaveSamples(9);
		    else
		        Message <= to_signed(0, Message'length);
		    end if;

--			if (Reset = '1') then
--				NoteStatus <= "0000";
--			elsif (StatusReady = '1') then
--				case Status.Message is
--					when STATUS_NOTE_ON =>
--					    NoteVolume <= TEST_AMPLITUDE;
--					    --NoteHz <= gClockHz / to_integer(shift_left(SHIFT_BASE, (to_integer(Status.Param1) - 33) / 12));
--					    LastNote <= to_integer(Status.Param1);
--						case to_integer(Status.Param1) is
--							when 60 =>
--							    NoteHz <= gClockHz / 261;
--								NoteStatus(0) <= '1';
--							when 62 =>
--							    NoteHz <= gClockHz / 293;
--								NoteStatus(1) <= '1';
--							when 64 =>
--							    NoteHz <= gClockHz / 329;
--								NoteStatus(2) <= '1';
--							when 65 =>
--							    NoteHz <= gClockHz / 349;
--								NoteStatus(3) <= '1';
--							when others =>
--							    NoteHz <= gClockHz / 440;
--						end case;
--					when STATUS_NOTE_OFF =>
--					    if (to_integer(Status.Param1) = LastNote) then
--					    	NoteVolume <= 0;
--					    	NoteHz <= 0;
--					    end if;
--						case to_integer(Status.Param1) is
--							when 60 =>
--								NoteStatus(0) <= '0';
--							when 62 =>
--								NoteStatus(1) <= '0';
--							when 64 =>
--								NoteStatus(2) <= '0';
--							when 65 =>
--								NoteStatus(3) <= '0';
--							when others =>
--						end case;
--					when others =>
--				end case;
--			end if;
		end if;
	end process;
	

	midi_event_builder: entity work.event_builder
	port map
	(
		iMidiByte => MidiData,
		iDataReady => MidiReady,
		iClock => iClock,
		oStatusReady => StatusReady,
		oStatus => Status,
		oIgnoredByte => IgnoredByte,
		oIgnoredReady => IgnoredReady
	);
	
	uart_interface: entity work.UART
	generic map (
		CLK_FREQ => gClockHz,
		BAUD_RATE => BAUD_RATE,
		PARITY_BIT => PARITY_BIT
	)
	port map (
		CLK => iClock,
		RST => Reset,
		UART_TXD => DebugTxD,
		UART_RXD => iMidiRxD,
		DATA_OUT => MidiData,
		DATA_VLD => MidiReady,
		FRAME_ERROR => MidiFrameError,
		DATA_IN => DebugData,
		DATA_SEND => DebugSend,
		BUSY => DebugBusy
	);
	
--	tone_generator: entity work.sqrwave
--	port map (
--	   iClock => iClock,
--	   iFrequency => NoteHz,
--	   iAmplitude => NoteVolume,
--	   oSample => Message
--	);
	
	i2s_interface: entity work.i2s
	generic map (
	   gClockHz => gClockHz,
	   gSamplingHz => SAMPLING_HZ
	)
	port map (
	   iClock => iClock,
	   iReset => iReset,
	   oBitClock => oI2sBitClock,
	   oWordClock => oI2sWorldClock,
       oDataLine => oI2sData,
       iLeftChannel => Message,
       iRightChannel => Message
	);
	
	octave_generator: for P in 0 to 9 generate
	begin
	   generated_octave: entity work.Octave
	   generic map (
	       gClockHz => gClockHz,
	       gMidiOctave => P,
	       gMaxVolume => TEST_AMPLITUDE
	   )
	   port map (
	       iClock => iClock,
           iReset => iReset,
           iStatusReady => StatusReady,
           iStatus => Status,
           oMessage => OctaveSamples(P)
	   );
	end generate;

end etc;