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-- Copyright (C) 2002 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs is free software; you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation; either version 2 of the License, or (at
-- your option) any later version.
-- VESTs is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- not in book
library ieee; use ieee.std_logic_1164.all;
entity DRAM is
port ( a : in std_logic_vector(0 to 10);
d : inout std_logic_vector(0 to 3);
cs, we, ras, cas : in std_logic );
end entity DRAM;
architecture empty of DRAM is
begin
d <= (others => 'Z');
end architecture empty;
library ieee; use ieee.std_logic_1164.all;
entity memory_board is
end entity memory_board;
-- end not in book
architecture chip_level of memory_board is
component DRAM is
port ( a : in std_logic_vector(0 to 10);
d : inout std_logic_vector(0 to 3);
cs, we, ras, cas : in std_logic );
end component DRAM;
signal buffered_address : std_logic_vector(0 to 10);
signal DRAM_data : std_logic_vector(0 to 31);
signal bank_select : std_logic_vector(0 to 3);
signal buffered_we, buffered_ras, buffered_cas : std_logic;
-- . . . -- other declarations
begin
bank_array : for bank_index in 0 to 3 generate
begin
nibble_array : for nibble_index in 0 to 7 generate
constant data_lo : natural := nibble_index * 4;
constant data_hi : natural := nibble_index * 4 + 3;
begin
a_DRAM : component DRAM
port map ( a => buffered_address,
d => DRAM_data(data_lo to data_hi),
cs => bank_select(bank_index),
we => buffered_we,
ras => buffered_ras,
cas => buffered_cas );
end generate nibble_array;
end generate bank_array;
-- . . . -- other component instances, etc
-- not in book
buffered_address <= "01010101010";
DRAM_data <= X"01234567";
-- end not in book
end architecture chip_level;
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