cvs.zerfleddert.de Git - raggedstone/blob - dhwk/source/IO_RW_SEL.vhd

   1 -- J.STELZNER
   2 -- INFORMATIK-3 LABOR
   3 -- 23.08.2006
   4 -- File: CONFIG_WR_SEL.VHD
   5
   6 library IEEE;
   7 use IEEE.std_logic_1164.all;
   8
   9 entity IO_WR_SEL is
  10         port
  11         (
  12         IO_WR_COM               :in             std_logic;
  13         IRDY_REGn               :in             std_logic;
  14         TRDYn                           :in             std_logic;
  15         ADDR_REG                :in             std_logic_vector(31 downto 0);
  16         CBE_REGn                :in             std_logic_vector( 3 downto 0);
  17         WRITE_XX1_0     :out    std_logic;
  18         WRITE_XX3_2     :out    std_logic;
  19         WRITE_XX5_4     :out    std_logic;
  20         WRITE_XX7_6     :out    std_logic
  21         );
  22 end entity IO_WR_SEL;
  23
  24 --PCI Byte Enable
  25 --C/BE[3..0] gueltige Datenbits
  26 -------------------------------
  27 --      0000            AD 31..0
  28 --      1000            AD 23..0
  29 --      1100            AD 15..0
  30 --      1110            AD  7..0
  31 --      0011            AD 31..16
  32
  33 architecture IO_WR_SEL_DESIGN of IO_WR_SEL is
  34
  35         signal  WR_ENA  :std_logic;
  36         signal  ADDR            :std_logic_vector( 5 downto 0);
  37
  38 begin
  39
  40                 WR_ENA  <=      '1' when
  41                                                                                 IO_WR_COM = '1' and
  42                                                                                 IRDY_REGn       =       '0' and
  43                                                                                 TRDYn                   =       '0'     else    '0';
  44
  45
  46                 ADDR    <=       ADDR_REG(3) &  ADDR_REG(2)     &       CBE_REGn;
  47
  48
  49                 WRITE_XX1_0     <=      '1'     when    WR_ENA  =       '1'     and     ADDR    =       "001100"        else '0';
  50                 WRITE_XX3_2     <=      '1'     when    WR_ENA  =       '1'     and     ADDR    =       "000011"        else '0';
  51                 WRITE_XX5_4     <=      '1'     when    WR_ENA  =       '1'     and     ADDR    =       "011100"        else '0';
  52                 WRITE_XX7_6     <=      '1'     when    WR_ENA  =       '1'     and     ADDR    =       "010011"        else '0';
  53
  54 end architecture IO_WR_SEL_DESIGN;