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

   1 -- $Id: fifo_io_control.vhd,v 1.2 2007-03-11 08:04:56 sithglan Exp $
   2
   3 library IEEE;
   4 use IEEE.std_logic_1164.all;
   5
   6 entity FIFO_IO_CONTROL is
   7         port
   8         (
   9         PCI_CLOCK                               :in     std_logic;
  10         WRITE_XX1_0                             :in     std_logic; -- PCI Write
  11         FIFO_RDn                                :in     std_logic; -- FIFO Read (low active)
  12         RESET                                   :in     std_logic;
  13         SYNC_FLAG_1                             :in     std_logic; -- Recv FIFO Empty (low active)
  14         SYNC_FLAG_7                             :in     std_logic; -- Send FIFO Full (low active)
  15         S_FIFO_RESETn                           :out    std_logic; -- Send FIFO Reset (low active)
  16         R_FIFO_RESETn                           :out    std_logic; -- Recv FIFO Reset (low active)
  17         S_FIFO_WRITEn                           :out    std_logic; -- Send FIFO Write (low active)
  18         R_FIFO_READn                            :out    std_logic; -- Recv FIFO Read (low active)
  19         S_FIFO_RETRANSMITn                      :out    std_logic; -- Send FIFO Retransmit (low active)
  20         R_FIFO_RETRANSMITn                      :out    std_logic; -- Recv FIFO Retransmit (low active)
  21         S_ERROR                                 :out    std_logic; -- Send ERROR
  22         R_ERROR                                 :out    std_logic; -- Recv ERROR
  23         SR_ERROR                                :out    std_logic  -- Send / Recv Error
  24         );
  25 end entity FIFO_IO_CONTROL;
  26
  27 architecture FIFO_IO_CONTROL_DESIGN of FIFO_IO_CONTROL is
  28
  29 signal  SIG_S_ERROR     :std_logic; -- Send Error
  30 signal  SIG_R_ERROR     :std_logic; -- Recv Error
  31
  32 begin
  33
  34 -- FIFO Write
  35
  36         process (PCI_CLOCK)
  37         begin
  38                 if (PCI_CLOCK'event and PCI_CLOCK = '1')  then
  39                         if (RESET = '1') then
  40                                 S_FIFO_WRITEn <= '1';
  41                                 SIG_S_ERROR   <= '0';
  42
  43                         elsif (WRITE_XX1_0 = '0') then
  44                                 S_FIFO_WRITEn <= '1';
  45
  46                         elsif (WRITE_XX1_0 = '1') then
  47                                 if (SYNC_FLAG_7 = '0') then
  48                                         SIG_S_ERROR <= '1';
  49
  50                                 elsif (SYNC_FLAG_7 = '1') then
  51                                         S_FIFO_WRITEn <= '0';
  52                                         SIG_S_ERROR <= '0';
  53                                 end if;
  54                                                                                                 end if;
  55                 end if;
  56         end process;
  57
  58         S_ERROR <= SIG_S_ERROR;
  59
  60 -- FIFO Read
  61
  62         R_FIFO_READn <= FIFO_RDn;
  63
  64 -- Receive Error
  65
  66 process (PCI_CLOCK)
  67 begin
  68         if (PCI_CLOCK'event and PCI_CLOCK ='1')  then
  69                 if (RESET = '1') then
  70                         SIG_R_ERROR <= '0';
  71
  72                 elsif (FIFO_RDn = '0' and SYNC_FLAG_1 = '0') then
  73                         SIG_R_ERROR <= '1';
  74                 end if;
  75         end if;
  76 end process;
  77
  78         R_ERROR <=      SIG_R_ERROR;
  79
  80 -- Send or Receive Error
  81
  82 process (PCI_CLOCK)
  83 begin
  84         if (PCI_CLOCK'event and PCI_CLOCK ='1') then
  85                 SR_ERROR        <= SIG_S_ERROR or SIG_R_ERROR;
  86         end if;
  87 end process;
  88
  89 -- FIFO Reset
  90
  91 process (PCI_CLOCK)
  92 begin
  93         if (PCI_CLOCK'event and PCI_CLOCK ='1') then
  94                 S_FIFO_RESETn <= not RESET;
  95                 R_FIFO_RESETn <= not RESET;
  96         end if;
  97 end process;
  98
  99
 100 -- FIFO Retransmit
 101
 102 process (PCI_CLOCK)
 103 begin
 104         if (PCI_CLOCK'event and PCI_CLOCK ='1') then
 105                 S_FIFO_RETRANSMITn <= '1';
 106                 R_FIFO_RETRANSMITn <= '1';
 107         end if;
 108 end process;
 109
 110 end architecture FIFO_IO_CONTROL_DESIGN;