git.zerfleddert.de Git - raggedstone/blob - dhwk/source/pci/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
  64                 COMM_STATE <= "0000";
  65
  66         elsif (rising_edge(PCI_CLOCK)) then
  67                 case COMM_STATE is
  68                 when ST_IDLE_COMM =>
  69                         if IO_READ = '1' then COMM_STATE <= ST_IO_READ;
  70
  71                         elsif CONF_READ = '1' then
  72                                 COMM_STATE <= ST_CONF_READ;
  73
  74                         elsif IO_WRITE = '1' then
  75                                 COMM_STATE <= ST_IO_WRITE;
  76
  77                         elsif CONF_WRITE = '1' then
  78                                 COMM_STATE <= ST_CONF_WRITE;
  79
  80                         else
  81                                 COMM_STATE <= ST_IDLE_COMM;
  82                         end if;
  83
  84                 when ST_IO_READ =>
  85                         if DEVSELn = '1' then
  86                                 COMM_STATE <= ST_IDLE_COMM;
  87                         end if;
  88
  89                 when ST_CONF_READ =>
  90                         if DEVSELn = '1' then
  91                                 COMM_STATE <= ST_IDLE_COMM;
  92                         end if;
  93
  94                 when ST_IO_WRITE =>
  95                         if DEVSELn = '1' then
  96                                 COMM_STATE <= ST_IDLE_COMM;
  97                         end if;
  98
  99                 when ST_CONF_WRITE =>
 100                         if DEVSELn = '1' then
 101                                 COMM_STATE <= ST_IDLE_COMM;
 102                         end if;
 103
 104                 when others =>
 105                         COMM_STATE <= ST_IDLE_COMM;
 106
 107                 end case; -- COMM_STATE
 108         end if; -- CLOCK
 109 end process; -- PROCESS
 110
 111  IO_RD_COM <= COMM_STATE(3);
 112  CF_RD_COM <= COMM_STATE(2);
 113  IO_WR_COM <= COMM_STATE(1);
 114  CF_WR_COM <= COMM_STATE(0);
 115
 116 end architecture COMM_FSM_DESIGN;