git.zerfleddert.de Git - raggedstone/blob - dhwk/source/COMM_FSM.vhd

   1 -- J.STELZNER
   2 -- INFORMATIK-3 LABOR
   3 -- 23.08.2006
   4 -- File: COMM_FSM.VHD
   5
   6 library ieee;
   7 use ieee.std_logic_1164.all ;
   8
   9 entity COMM_FSM is
  10         port
  11         (
  12         PCI_CLOCK               :in             std_logic;
  13         PCI_RSTn                :in             std_logic;
  14         IO_READ                 :in             std_logic;
  15         IO_WRITE                :in             std_logic;
  16         CONF_READ               :in             std_logic;
  17         CONF_WRITE      :in             std_logic;
  18         DEVSELn                 :in             std_logic;
  19
  20         IO_RD_COM       :       out     std_logic;--> MUX_SEL(0)
  21         CF_RD_COM       :out    std_logic;
  22         IO_WR_COM               :out    std_logic;
  23         CF_WR_COM               :out    std_logic
  24         );
  25 end entity COMM_FSM ;
  26
  27 architecture COMM_FSM_DESIGN of COMM_FSM is
  28
  29
  30 --**********************************************************
  31 --***            COMMAND FSM CODIERUNG                   ***
  32 --**********************************************************
  33 --
  34 --
  35 --                                                                         |--------- IO_RD_COM
  36 --                                                                         ||-------- CF_RD_COM
  37 --                                                                                     |||------- IO_WR_COM
  38 --                                                                         ||||------ CF_WR_COM
  39 --                                                                             ||||
  40         constant        ST_IDLE_COMM    :std_logic_vector (3 downto 0) := "0000" ;--
  41         constant        ST_CONF_WRITE   :std_logic_vector (3 downto 0) := "0001" ;--
  42         constant        ST_IO_WRITE             :std_logic_vector (3 downto 0) := "0010" ;--
  43         constant        ST_CONF_READ    :std_logic_vector (3 downto 0) := "0100" ;--
  44         constant        ST_IO_READ              :std_logic_vector (3 downto 0) := "1000" ;--
  45
  46         signal          COMM_STATE              :std_logic_vector (3 downto 0);
  47
  48 --************************************************************
  49 --***             FSM SPEICHER-AUTOMAT                     ***
  50 --************************************************************
  51
  52         attribute syn_state_machine : boolean;
  53         attribute syn_state_machine of COMM_STATE : signal is false;
  54
  55 begin
  56
  57 --**********************************************************
  58 --***                    COMMAND FSM                        ***
  59 --**********************************************************
  60
  61         process (PCI_CLOCK, PCI_RSTn)
  62         begin
  63                 if      PCI_RSTn = '0'  then    COMM_STATE      <= "0000";
  64
  65                 elsif (PCI_CLOCK'event and PCI_CLOCK = '1') then
  66
  67                         case COMM_STATE is
  68
  69                                 when ST_IDLE_COMM =>
  70                                         if              IO_READ                         = '1' then                                                      COMM_STATE <= ST_IO_READ;
  71
  72                                 elsif   CONF_READ               = '1' then                                                      COMM_STATE <= ST_CONF_READ;
  73
  74                                                 elsif   IO_WRITE                = '1' then                                                      COMM_STATE <= ST_IO_WRITE;
  75
  76                                 elsif   CONF_WRITE      = '1' then                                                      COMM_STATE <= ST_CONF_WRITE;
  77
  78                     else                                                                                                                                                COMM_STATE <= ST_IDLE_COMM;
  79                                         end if;
  80
  81                                 when ST_IO_READ                 => if DEVSELn = '1' then        COMM_STATE <= ST_IDLE_COMM; end if;
  82                                 when ST_CONF_READ               => if DEVSELn = '1' then        COMM_STATE <= ST_IDLE_COMM; end if;
  83                                 when ST_IO_WRITE                => if DEVSELn = '1' then        COMM_STATE <= ST_IDLE_COMM; end if;
  84                                 when ST_CONF_WRITE      => if DEVSELn = '1' then        COMM_STATE <= ST_IDLE_COMM; end if;
  85
  86                                 when others =>                                                                                                                          COMM_STATE <= ST_IDLE_COMM;
  87
  88                         end case;               -- COMM_STATE
  89                 end if;                         -- CLOCK
  90         end process;            -- PROCESS
  91
  92         IO_RD_COM       <=      COMM_STATE(3);
  93         CF_RD_COM       <=      COMM_STATE(2);
  94         IO_WR_COM       <=      COMM_STATE(1);
  95         CF_WR_COM       <=      COMM_STATE(0);
  96
  97 end architecture COMM_FSM_DESIGN ;
  98