library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;

library work;
use work.sdram_util.ALL;

entity sdram is
port (
	clock_50	:	in	std_logic;	
	reset_n		:	in	std_logic;
	seven_seg	:	out 	std_logic_vector(7 downto 0);

	sdram_clk	:	out std_logic;

	sdram_cs_n	:	out std_logic;
	sdram_cas_n	:	out std_logic;
	sdram_ras_n	:	out std_logic;
	sdram_we_n	:	out std_logic;
	sdram_cke	:	out std_logic;

	sdram_addr	:	out std_logic_vector(12 downto 0);
	sdram_ba	:	out std_logic_vector(1 downto 0);

	sdram_dq	:	inout std_logic_vector(15 downto 0);
	sdram_dqm	:	out std_logic_vector(1 downto 0)
);
end entity;

architecture rtl of sdram is

component pllx2 IS
        PORT
        (
                areset          : IN STD_LOGIC  := '0';
                inclk0          : IN STD_LOGIC  := '0';
                c0              : OUT STD_LOGIC ;
                locked          : OUT STD_LOGIC
        );
end component;



component sdram_mcu is
	port (
		clk_clk		: in    std_logic                     := 'X';             -- clk
		reset_reset_n	: in    std_logic                     := 'X';             -- reset_n
--		pio_0_d_export	: out   std_logic_vector(7 downto 0);                     -- export
		ebb_0_cs_n	: out   std_logic;                                        -- cs_n
		ebb_0_rnw	: out   std_logic;                                        -- rnw
		ebb_0_wait_n	: in    std_logic                     := 'X';             -- wait_n
		ebb_0_addr	: out   std_logic_vector(15 downto 0);                    -- addr
		ebb_0_data_in	: in    std_logic_vector(7 downto 0)  := (others => 'X'); -- data_in
		ebb_0_data_out	: out   std_logic_vector(7 downto 0);                     -- data_out
		ebb_0_reset_n	: out   std_logic                                        -- reset_n
	);
end component sdram_mcu;

component sdram_ctrl is
  port
  (  
    clock_100  :  in std_logic;
    reset_n    :  in std_logic;

    bus_cs_n    :  in std_logic;
    bus_rnw    :  in std_logic;

    bus_wait_n  :  out std_logic;

    bus_addr    :  in addr_t;
    bus_data_in    :  in data_t;
    bus_data_out    :  out data_t;

    sdram_clk  :  out std_logic;
    sdram_cke  :  out std_logic;

    sdram_cs_n  :  out std_logic;

    sdram_cas_n  :  out std_logic;
    sdram_ras_n  :  out std_logic;
    sdram_we_n  :  out std_logic;

    sdram_addr  :  out std_logic_vector(12 downto 0);
    sdram_ba  :  out std_logic_vector(1 downto 0);

    sdram_dq  :  inout data_t;
    sdram_dqm  :  out dqm_t;

    debug  :  out std_logic_vector(7 downto 0)
  );
end component;

signal b_data_in8 : std_logic_vector(7 downto 0);
signal b_data_out8 : std_logic_vector(7 downto 0);
signal b_addr16: std_logic_vector(15 downto 0);

signal b_addr : addr_t;
signal b_data_in : data_t;
signal b_data_out : data_t;
signal b_cs_n : std_logic;
signal b_rnw : std_logic;
signal b_wait_n : std_logic;

signal pll_reset : std_logic;
signal mcu_clock : std_logic;
signal clock_100 : std_logic;
signal pll_locked : std_logic;
signal debug : std_logic_vector(7 downto 0);

signal global_reset_n : std_logic;
signal b_reset_n : std_logic;

signal buf8 : std_logic_vector(7 downto 0);


begin

        pll:   pllx2 port map (
                pll_reset,
                clock_50,
                clock_100,
                pll_locked );

	mcu_clock <= clock_50;

   	u0 : component sdram_mcu port map (
		clk_clk        => mcu_clock,        --     clk.clk
		reset_reset_n  => global_reset_n,  --   reset.reset_n
--		pio_0_d_export => seven_seg, -- pio_0_d.export
		ebb_0_cs_n      => b_cs_n,      --    ebb_0.cs_n
		ebb_0_rnw       => b_rnw,      --        .rnw
		ebb_0_wait_n    => b_wait_n,    --        .wait_n
		ebb_0_addr      => b_addr16,      --        .addr
		ebb_0_data_in   => b_data_in8,   --        .data
		ebb_0_data_out  => b_data_out8,   --        .data
		ebb_0_reset_n   => b_reset_n  
	);

 	-- bodge buses together

	b_data_in(7 downto 0) <= b_data_out8;
	b_data_in(15 downto 8) <= (others =>'0');


	ss_process: process (global_reset_n,b_rnw,b_cs_n,b_addr16) begin
		if l2b_al(global_reset_n) then
			buf8<=(others => '0');
		elsif falling_edge(b_cs_n) and l2b_al(b_rnw) then
			buf8 <= b_data_out8;
		end if;
	end process;

--	seven_seg <= buf8;

	seven_seg <= debug;
	--b_data_in8 <= buf8;
	--b_wait_n <= '1';
 	b_data_in8  <= b_data_out(7 downto 0);
	--seven_seg <= b_data_in8;	
  	--b_data_in8 <= "01011010";

	b_addr(15 downto 0) <= b_addr16;
	b_addr(23 downto 16) <= (others => '0');



	sdram_ctrl0: sdram_ctrl port map (
		clock_100 => clock_50,
		reset_n => b_reset_n,

		bus_cs_n => b_cs_n,
		bus_rnw => b_rnw,

		bus_wait_n => b_wait_n,

		bus_addr => b_addr,
		bus_data_in => b_data_in,
		bus_data_out => b_data_out,

		sdram_clk => sdram_clk,
		sdram_cke => sdram_cke,

		sdram_cs_n => sdram_cs_n,
		sdram_cas_n => sdram_cas_n,
		sdram_ras_n => sdram_ras_n,
		sdram_we_n => sdram_we_n,

		sdram_addr => sdram_addr,
		sdram_ba => sdram_ba,

		sdram_dq => sdram_dq,
		sdram_dqm => sdram_dqm,

		debug => debug
	);

	pll_reset <= '0';
	global_reset_n <= reset_n and pll_locked;
	
end architecture;