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

   1 -- J.STELZNER
   2 -- INFORMATIK-3 LABOR
   3 -- 23.08.2006
   4 -- File: COMM_DEC.VHD
   5
   6 library ieee;
   7 use ieee.std_logic_1164.all ;
   8
   9 entity COMM_DEC is
  10         port
  11         (
  12                 PCI_CLOCK :in std_logic;
  13                 PCI_RSTn :in std_logic;
  14                 MY_ADDR :in std_logic;
  15                 IDSEL_REG :in std_logic;
  16                 FRAME_REGn :in std_logic;
  17                 IO_SPACE :in std_logic;
  18                 AD_REG :in std_logic_vector(31 downto 0);
  19                 CBE_REGn :in std_logic_vector( 3 downto 0);
  20                 LAR :out std_logic; --LOAD_ADDR_REG
  21                 IO_READ :out std_logic;
  22                 IO_WRITE :out std_logic;
  23                 CONF_READ :out std_logic;
  24                 CONF_WRITE :out std_logic;
  25                 SERR_CHECK :out std_logic
  26         );
  27 end entity COMM_DEC ;
  28
  29 architecture COMM_DEC_DESIGN of COMM_DEC is
  30
  31
  32  --PCI Bus Commands
  33  --C/BE[3..0] Command Type
  34  --------------------------------------
  35  -- 0000 Interrupt Acknowledge
  36  -- 0001 Special Cycle
  37  -- 0010 I/O Read
  38  -- 0011 I/O Write
  39  -- 0100 Reserved
  40  -- 0101 Reserved
  41  -- 0110 Memory Read
  42  -- 0111 Memory Write
  43  --
  44  -- 1000 Reserved
  45  -- 1001 Reserved
  46  -- 1010 Configuration Read
  47  -- 1011 Configuration Write
  48  -- 1100 Memory Read Multiple
  49  -- 1101 Dual Address Cycle
  50  -- 1110 Memory Read Line
  51  -- 1111 Memory Write and Invalidate
  52
  53
  54  --PCI Byte Enable
  55  --C/BE[3..0] gueltige Datenbits
  56  -------------------------------
  57  -- 0000 AD 31..0
  58  -- 1000 AD 23..0
  59  -- 1100 AD 15..0
  60  -- 1110 AD 7..0
  61
  62         constant cmd_int_ack :std_logic_vector(3 downto 0) := "0000";
  63         constant cmd_sp_cyc :std_logic_vector(3 downto 0) := "0001";
  64         constant cmd_io_read :std_logic_vector(3 downto 0) := "0010";
  65         constant cmd_io_write :std_logic_vector(3 downto 0) := "0011";
  66         constant cmd_res_4 :std_logic_vector(3 downto 0) := "0100";
  67         constant cmd_res_5 :std_logic_vector(3 downto 0) := "0101";
  68         constant cmd_mem_read :std_logic_vector(3 downto 0) := "0110";
  69         constant cmd_mem_write :std_logic_vector(3 downto 0) := "0111";
  70         constant cmd_res_8 :std_logic_vector(3 downto 0) := "1000";
  71         constant cmd_res_9 :std_logic_vector(3 downto 0) := "1001";
  72         constant cmd_conf_read :std_logic_vector(3 downto 0) := "1010";
  73         constant cmd_conf_write :std_logic_vector(3 downto 0) := "1011";
  74         constant cmd_mem_read_m :std_logic_vector(3 downto 0) := "1100";
  75         constant cmd_du_adr_cyc :std_logic_vector(3 downto 0) := "1101";
  76         constant cmd_mem_read_l :std_logic_vector(3 downto 0) := "1110";
  77         constant cmd_mem_write_i :std_logic_vector(3 downto 0) := "1111";
  78
  79         signal START :std_logic;
  80         signal FRAME_REG_REGn :std_logic;
  81
  82         signal SIG_IO_READ :std_logic;
  83         signal SIG_IO_WRITE :std_logic;
  84         signal SIG_CONF_READ :std_logic;
  85         signal SIG_CONF_WRITE :std_logic;
  86
  87 begin
  88
  89         process (PCI_CLOCK, PCI_RSTn)
  90         begin
  91                 if PCI_RSTn = '0' then FRAME_REG_REGn <= '1';
  92         elsif (rising_edge(PCI_CLOCK)) then
  93
  94                 FRAME_REG_REGn <= FRAME_REGn;
  95
  96         end if;
  97 end process;
  98
  99
 100 START <= (not FRAME_REGn) and FRAME_REG_REGn;
 101
 102
 103
 104 SIG_IO_READ <= '1' when START = '1'
 105                and IO_SPACE = '1'
 106                and CBE_REGn = cmd_io_read
 107                and MY_ADDR = '1'
 108        else '0';
 109
 110
 111 SIG_IO_WRITE <= '1' when START = '1'
 112                 and IO_SPACE = '1'
 113                 and CBE_REGn = cmd_io_write
 114                 and MY_ADDR = '1'
 115         else '0';
 116
 117
 118 SIG_CONF_READ <= '1' when START = '1'
 119                 and AD_REG(1 downto 0) = "00"
 120                 and CBE_REGn = cmd_conf_read
 121                 and IDSEL_REG = '1'
 122
 123         else '0';
 124
 125
 126 SIG_CONF_WRITE <= '1' when START = '1'
 127                 and AD_REG(1 downto 0) = "00"
 128                 and CBE_REGn = cmd_conf_write
 129                 and IDSEL_REG = '1'
 130         else '0';
 131
 132 LAR <= START;
 133
 134 SERR_CHECK <= SIG_IO_READ or SIG_IO_WRITE or SIG_CONF_READ or SIG_CONF_WRITE;
 135
 136 IO_READ <= SIG_IO_READ;
 137 IO_WRITE <= SIG_IO_WRITE;
 138 CONF_READ <= SIG_CONF_READ;
 139 CONF_WRITE <= SIG_CONF_WRITE;
 140
 141 end architecture COMM_DEC_DESIGN;