git.zerfleddert.de Git - raggedstone/blob - dhwk/source/pci/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         ADDR <= ADDR_REG(3) & ADDR_REG(2) & CBE_REGn;
  46
  47         WRITE_XX1_0 <= '1' when WR_ENA = '1' and ADDR = "001100" else '0';
  48         WRITE_XX3_2 <= '1' when WR_ENA = '1' and ADDR = "000011" else '0';
  49         WRITE_XX5_4 <= '1' when WR_ENA = '1' and ADDR = "011100" else '0';
  50         WRITE_XX7_6 <= '1' when WR_ENA = '1' and ADDR = "010011" else '0';
  51
  52 end architecture IO_WR_SEL_DESIGN;