tmeissner
/
libvhdl


								library ieee;

								  use ieee.std_logic_1164.all;

								  use ieee.numeric_std.all;


								entity WishBoneSlaveE is

								  generic (

								    G_ADR_WIDTH  : positive := 8;  --* address bus width

								    G_DATA_WIDTH : positive := 8   --* data bus width

								  );

								  port (

								    --+ wishbone system if

								    WbRst_i       : in  std_logic;

								    WbClk_i       : in  std_logic;

								    --+ wishbone inputs

								    WbCyc_i       : in  std_logic;

								    WbStb_i       : in  std_logic;

								    WbWe_i        : in  std_logic;

								    WbAdr_i       : in  std_logic_vector(G_ADR_WIDTH-1 downto 0);

								    WbDat_i       : in  std_logic_vector(G_DATA_WIDTH-1 downto 0);

								    --+ wishbone outputs

								    WbDat_o       : out std_logic_vector(G_DATA_WIDTH-1 downto 0);

								    WbAck_o       : out std_logic;

								    WbErr_o       : out std_logic;

								    --+ local register if

								    LocalWen_o    : out std_logic;

								    LocalRen_o    : out std_logic;

								    LocalAdress_o : out std_logic_vector(G_ADR_WIDTH-1 downto 0);

								    LocalData_o   : out std_logic_vector(G_DATA_WIDTH-1 downto 0);

								    LocalData_i   : in  std_logic_vector(G_DATA_WIDTH-1 downto 0)

								  );

								end entity WishBoneSlaveE;


								architecture rtl of WishBoneSlaveE is


								  type t_wb_slave_fsm is (IDLE, ADDRESS, DATA);

								  signal s_wb_slave_fsm : t_wb_slave_fsm;


								  signal s_wb_active : boolean;


								begin


								  WbSlaveControlP : process (WbClk_i) is

								  begin

								    if (rising_edge(WbClk_i)) then

								      if (WbRst_i = '1') then

								        s_wb_slave_fsm <= IDLE;

								      else

								        WbReadC : case s_wb_slave_fsm is


								          when IDLE =>

								            s_wb_slave_fsm <= ADDRESS;


								          when ADDRESS =>

								            if (s_wb_active and WbWe_i = '0') then

								              s_wb_slave_fsm <= DATA;

								            end if;


								          when DATA =>

								              s_wb_slave_fsm <= ADDRESS;


								          when others  =>

								            s_wb_slave_fsm <= IDLE;


								        end case;

								      end if;

								    end if;

								  end process WbSlaveControlP;


								  s_wb_active <= true when s_wb_slave_fsm /= IDLE and WbCyc_i = '1' and WbStb_i = '1' else false;


								  --+ local register if outputs

								  LocalWen_o     <= WbWe_i      when s_wb_slave_fsm  = ADDRESS and s_wb_active else '0';

								  LocalRen_o     <= not(WbWe_i) when s_wb_slave_fsm  = ADDRESS and s_wb_active else '0';

								  LocalAdress_o  <= WbAdr_i     when s_wb_slave_fsm /= IDLE    and s_wb_active else (others => '0');

								  LocalData_o    <= WbDat_i     when s_wb_slave_fsm  = ADDRESS and s_wb_active and WbWe_i = '1' else (others => '0');


								  --+ wishbone if outputs

								  WbDat_o <= LocalData_i when s_wb_slave_fsm = DATA and WbWe_i = '0' else (others => '0');

								  WbAck_o <= '1'         when s_wb_slave_fsm = DATA or (s_wb_slave_fsm = ADDRESS and s_wb_active and WbWe_i = '1') else '0';

								  WbErr_o <= '0';


								  -- psl default clock is rising_edge(WbClk_i);

								  --

								  -- psl LOCAL_WRITE : assert always

								  --   ((WbCyc_i and WbStb_i and WbWe_i) ->

								  --    (LocalWen_o = '1' and WbAck_o = '1' and LocalAdress_o = WbAdr_i and LocalData_o = WbDat_i)) abort WbRst_i

								  --   report "PSL ERROR: Local write error";

								  --

								  -- psl LOCAL_READ : assert always

								  --   ({not(WbCyc_i) and not(WbStb_i); WbCyc_i and WbStb_i and not(WbWe_i)} |->

								  --    {LocalRen_o = '1' and LocalAdress_o = WbAdr_i and WbAck_o = '0'; LocalRen_o = '0' and WbDat_o = LocalData_i and WbAck_o = '1'}) abort WbRst_i

								  --   report "PSL ERROR: Local read error";

								  --

								  -- psl WB_ACK : assert always

								  --   WbAck_o ->

								  --   (WbCyc_i and WbStb_i)

								  --   report "PSL ERROR: WbAck invalid";

								  --

								  --  psl WB_ERR : assert always

								  --   WbErr_o ->

								  --   (WbCyc_i and WbStb_i)

								  --   report "PSL ERROR: WbErr invalid";

								  --

								  -- psl LOCAL_WE : assert always

								  --   LocalWen_o ->

								  --   (WbCyc_i and WbStb_i and WbWe_i and not(LocalRen_o)) and

								  --   (next not(LocalWen_o))

								  --   report "PSL ERROR: LocalWen invalid";

								  --

								  --  psl LOCAL_RE : assert always

								  --   LocalRen_o ->

								  --   (WbCyc_i and WbStb_i and not(WbWe_i) and not(LocalWen_o)) and

								  --   (next not(LocalRen_o))

								  --   report "PSL ERROR: LocalRen invalid";

								  --

								  -- psl RESET : assert always

								  --   WbRst_i ->

								  --   (to_integer(unsigned(WbDat_o)) = 0 and WbAck_o = '0' and WbErr_o = '0' and

								  --    LocalWen_o = '0' and LocalRen_o = '0' and to_integer(unsigned(LocalAdress_o)) = 0 and to_integer(unsigned(LocalData_o)) = 0)

								  --   report "PSL ERROR: Reset error";


								end architecture rtl;