----------------------------------------------------------------------------------
-- Company: 
-- Engineer: 
-- 
-- Create Date:    15:01:01 07/27/2011 
-- Design Name: 
-- Module Name:    I2C - Behavioral 
-- Project Name: 
-- Target Devices: 
-- Tool versions: 
-- Description: 
--
-- Dependencies: 
--
-- Revision: 
-- Revision 0.01 - File Created
-- Additional Comments: 
--
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.std_logic_misc.all;
use work.amc13_pack.all;

-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
--use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating
-- any Xilinx primitives in this code.
library UNISIM;
use UNISIM.VComponents.all;
Library UNIMACRO;
use UNIMACRO.vcomponents.all;

entity I2C is
    Port ( clk : in  STD_LOGIC; -- DRPclk 50MHz
           ipb_clk : in  STD_LOGIC;
           reset : in  STD_LOGIC;
--					 ns2500	: in  STD_LOGIC;
					 addr: in  STD_LOGIC_VECTOR(31 downto 0);
					 rdata	: out  STD_LOGIC_VECTOR(31 downto 0);
           CLK_rdy : out  STD_LOGIC;
           CLK_SCL : out  STD_LOGIC;
           CLK_SDA : inout  STD_LOGIC;
           SFP_ABS : in  STD_LOGIC_VECTOR(3 downto 0);
           SFP_LOS : in  STD_LOGIC_VECTOR(2 downto 0);
           SFP_SCL : out  STD_LOGIC_VECTOR(3 downto 0);
           SFP_SDA : inout  STD_LOGIC_VECTOR(3 downto 0));
end I2C;

architecture Behavioral of I2C is
signal clk_div : std_logic_vector(7 downto 0) := (others => '0');
signal SFP_ABSq : std_logic_vector(7 downto 0) := (others =>'0');
signal SFP : std_logic_vector(1 downto 0) := (others =>'0');
signal SFP_DATA : std_logic_vector(3 downto 0) := (others =>'0');
signal we_SFP : std_logic := '0';
signal set_we_SFP : std_logic := '0';
type state is (Idle,Debouce,S,D,A,W,P);
signal SM : state := Idle;
signal t_SDA : std_logic_vector(3 downto 0) := (others => '1');
signal Si5338Cntr : std_logic_vector(7 downto 0) := (others => '1');
signal t_CLK_SDA : std_logic := '1';
signal t_CLK_SDA_q : std_logic := '1';
signal Si5338Done : std_logic := '0';
signal ce_CLK_rdy : std_logic := '0';
signal ACK : std_logic := '0';
signal done : std_logic := '0';
signal data : std_logic := '0';
signal SFPROM_data : std_logic := '0';
signal SCL_phase : std_logic_vector(1 downto 0) := (others => '0');
signal SM_cntr : std_logic_vector(10 downto 0) := (others => '0');
signal Debouce_cntr : std_logic_vector(17 downto 0) := (others => '0');
signal SFP_ADDR : std_logic_vector(9 downto 0) := (others => '0');
signal we_rdata : std_logic := '0';
--type RAM16384X1 is array(0 to 16383) of std_logic;
--signal I2C_buf : RAM16384X1 := (others => '0');
signal rdata_ra : std_logic_vector(8 downto 0) := (others =>'1');
signal rdata_wa : std_logic_vector(13 downto 0) := (others =>'1');
signal DIBDI : std_logic_vector(0 downto 0) := (others =>'0');
signal resetSyncRegs : std_logic_vector(2 downto 0) := (others => '0');

begin
CLK_SDA <= '0' when t_CLK_SDA_q = '0' else 'Z';
SFP_SDA(3) <= '0' when t_SDA(3) = '0' else 'Z';
SFP_SDA(2) <= '0' when t_SDA(2) = '0' else 'Z';
SFP_SDA(1) <= '0' when t_SDA(1) = '0' else 'Z';
SFP_SDA(0) <= '0' when t_SDA(0) = '0' else 'Z';
i_CLK_rdy : SRLC32E
   generic map (
      INIT => X"00000000")
   port map (
      Q => CLK_rdy,        -- SRL data output
      Q31 => open,    -- SRL cascade output pin
      A => "11111",        -- 5-bit shift depth select input
      CE => ce_CLK_rdy,      -- Clock enable input
      CLK => clk,    -- Clock input
      D => Si5338Done         -- SRL data input
   );
ce_CLK_rdy <= '1' when clk_div(7) = '1' and SCL_phase = "11" else '0';
process(clk,reset)
begin
	if(reset = '1')then
		resetSyncRegs <= (others => '1');
	elsif(clk'event and clk = '1')then
		resetSyncRegs <= resetSyncRegs(1 downto 0) & '0';
	end if;
end process;
process(clk)
begin
	if(clk'event and clk = '1')then
		if(resetSyncRegs(2) = '1' or clk_div(7) = '1')then -- 400 KHz
			clk_div <= x"04";
		else
			clk_div <= clk_div + 1;
		end if;
		if(resetSyncRegs(2) = '1')then
			SCL_phase <= "00";
		elsif(clk_div(7) = '1')then
			SCL_phase <= SCL_phase + 1;
		end if;
		if(resetSyncRegs(2) = '1')then
			SFP_ABSq <= (others => '1');
			SM <= Idle;
			t_sda <= x"f";
		elsif(clk_div(7) = '1' and SCL_phase = "11")then
			case SM is
				when Idle =>
					SM_cntr <= "11111101000";
					SFP_ABSq <= SFP_ABSq(3 downto 0) & SFP_ABS;
					if(SFP_ABSq(7 downto 4) /= SFP_ABSq(3 downto 0))then
						SM <= Debouce;
					end if;
					t_SDA <= x"f";
					Debouce_cntr <= (others => '0');
				when Debouce =>
					SFP_ABSq <= SFP_ABSq(3 downto 0) & SFP_ABS;
					Debouce_cntr <= Debouce_cntr + 1;
					if(Debouce_cntr(17) = '1')then
						SM <= S;
					end if;
				when S =>
					SM <= D;
					t_SDA <= SFP_ABSq(7 downto 4);
				when D =>
					if(SM_cntr(2 downto 0) = "111")then
						SM <= A;
					end if;
					SM_cntr <= SM_cntr + 1;
					if(SM_cntr(10 downto 9) = "11" and data = '0')then
					  t_SDA <= SFP_ABSq(7 downto 4);
					else
					  t_SDA <= x"f";
					end if;
					ACK <= not SM_cntr(10);
				when A =>
					if(SM_cntr(10 downto 9) = "10" or (SM_cntr(10 downto 9) = "11" and SM_cntr(4 downto 3) = "11"))then
						SM <= W;
					else
						Sm <= D;
					end if;
					if(ACK = '1' and SM_cntr(10 downto 9) /= "10")then
						t_SDA <= SFP_ABSq(7 downto 4);
					else
						t_SDA <= x"f";
					end if;
				when W =>
					if(SM_cntr(10 downto 9) = "10")then
						SM <= P;
					else
						SM <= S;
					end if;
				when P =>
					SM <= Idle;
					t_SDA <= SFP_ABSq(7 downto 4);
				when others => SM <= Idle;
			end case;
		end if;
		t_CLK_SDA_q <= t_CLK_SDA;
		if(resetSyncRegs(2) = '1')then
			 Si5338Done <= '0';
		elsif(clk_div(7) = '1' and SCL_phase(1) = '1' and Si5338Cntr = x"72")then
			 Si5338Done <= '1';
		end if;
		if(resetSyncRegs(2) = '1' or Si5338Done = '1')then
			CLK_SCL <= '1';
		elsif(clk_div(7) = '1' and SCL_phase(0) = '1')then
			if(SCL_phase(1) = '0')then
				CLK_SCL <= '1';
			elsif(Si5338Cntr /= x"e2" and Si5338Cntr /= x"8f")then
				CLK_SCL <= '0';
			end if;
		end if;
		if(resetSyncRegs(2) = '1' or Si5338Done = '1')then
			Si5338Cntr <= (others => '1');
		elsif(clk_div(7) = '1')then
			if(SCL_phase = "00")then
				Si5338Cntr <= Si5338Cntr - 1;
			end if;
		end if;
		rdata_wa(12 downto 0) <= '0' & not SFP & SFP_ADDR;
		we_rdata <= we_SFP;
		DIBDI(0) <= SFP_DATA(3);
		if(we_SFP = '0')then
			SFP <= "00";
			SFP_DATA <= SFP_SDA and not SFP_ABSq(7 downto 4);
		else
			SFP(1) <= SFP(1) xor SFP(0);
			SFP(0) <= not SFP(0);
			SFP_DATA <= SFP_DATA(2 downto 0) & '0';
		end if;
		if(SFPROM_data = '1' and SCL_phase = "01" and clk_div(7) = '1')then
			set_we_SFP <= '1';
		else
			set_we_SFP <= '0';
		end if;
		if(set_we_SFP = '1')then
			we_SFP <= '1';
		elsif(SFP = "11")then
			we_SFP <= '0';
		end if;
		if(clk_div(7) = '1')then
			if(SM = S or SM = Idle or SM = Debouce or SCL_phase(1) = '0')then
				SFP_SCL <= x"f";
			else
				SFP_SCL <= SFP_ABSq(7 downto 4);
			end if;
			if(SCL_phase = "11")then
				SFP_ADDR <= SM_cntr(9 downto 3) & not SM_cntr(2 downto 0);
				if(SM = D and SM_cntr(10) = '0')then
					SFPROM_data <= '1';
				else
					SFPROM_data <= '0';
				end if;
			end if;
		end if;		
	end if;
end process;
i_I2C_buf : BRAM_SDP_MACRO
   generic map (
      BRAM_SIZE => "18Kb", -- Target BRAM, "18Kb" or "36Kb" 
      DEVICE => "7SERIES", -- Target device: "VIRTEX5", "VIRTEX6", "7SERIES", "SPARTAN6" 
      WRITE_WIDTH => 1,    -- Valid values are 1-72 (37-72 only valid when BRAM_SIZE="36Kb")
      READ_WIDTH => 32,     -- Valid values are 1-72 (37-72 only valid when BRAM_SIZE="36Kb")
      DO_REG => 0, -- Optional output register (0 or 1)
      SIM_COLLISION_CHECK => "NONE", -- Collision check enable "ALL", "WARNING_ONLY", 
                                    -- "GENERATE_X_ONLY" or "NONE"       
      WRITE_MODE => "WRITE_FIRST", -- Specify "READ_FIRST" for same clock or synchronous clocks
                                   --  Specify "WRITE_FIRST for asynchrononous clocks on ports
      INIT => X"000000000000000000") --  Initial values on output port
   port map (
      DO => rdata,         -- Output read data port, width defined by READ_WIDTH parameter
      DI => DIBDI,         -- Input write data port, width defined by WRITE_WIDTH parameter
      RDADDR => rdata_ra, -- Input read address, width defined by read port depth
      RDCLK => ipb_clk,   -- 1-bit input read clock
      RDEN => '1',     -- 1-bit input read port enable
      REGCE => '1',   -- 1-bit input read output register enable
      RST => '0',       -- 1-bit input reset 
      WE => "1",         -- Input write enable, width defined by write port depth
      WRADDR => rdata_wa, -- Input write address, width defined by write port depth
      WRCLK => clk,   -- 1-bit input write clock
      WREN => we_rdata      -- 1-bit input write port enable
   );
--process(clk)
--begin
--	if(clk'event and clk = '1')then
--		if(we_rdata = '1')then
--			I2C_buf(conv_integer(rdata_wa)) <= DIBDI(0);
--		end if;
--	end if;
--end process;
--process(ipb_clk)
--begin
--	if(ipb_clk'event and ipb_clk = '1')then
--		for i in 0 to 31 loop
--			rdata(i) <= I2C_buf(conv_integer(rdata_ra & conv_std_logic_vector(i,5)));
--		end loop;
--	end if;
--end process;
rdata_wa(13) <= '1';
rdata_ra(7 downto 0) <= addr(7 downto 0);
rdata_ra(8) <= '1' when addr(15 downto 8) = I2C_addr(15 downto 8) else '0';
i_data : ROM32X1
   generic map (
      INIT => X"85000500")
   port map (
      O => data,   -- ROM output
      A0 => SM_cntr(0), -- ROM address[0]
      A1 => SM_cntr(1), -- ROM address[1]
      A2 => SM_cntr(2), -- ROM address[2]
      A3 => SM_cntr(3), -- ROM address[3]
      A4 => SM_cntr(4)  -- ROM address[4]
   );
i_Si5338ROM : ROM256X1
   generic map (
--      INIT => X"b83cd08dc156a041201008040205b83cd0080000000000000000000000000000")
      INIT => X"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")
   port map (
      O => t_CLK_SDA,   -- ROM output
      A0 => Si5338Cntr(0), -- ROM address[0]
      A1 => Si5338Cntr(1), -- ROM address[1]
      A2 => Si5338Cntr(2), -- ROM address[2]
      A3 => Si5338Cntr(3), -- ROM address[3]
      A4 => Si5338Cntr(4), -- ROM address[4]
      A5 => Si5338Cntr(5), -- ROM address[5]
      A6 => Si5338Cntr(6),  -- ROM address[6]
      A7 => Si5338Cntr(7)  -- ROM address[7]
   );


end Behavioral;