dpram_altera.vhd

这是一个I2S接口的VHDL实现源代码

----------------------------------------------------------------------
----                                                              ----
---- WISHBONE SPDIF IP Core                                       ----
----                                                              ----
---- This file is part of the SPDIF project                       ----
---- http://www.opencores.org/cores/spdif_interface/              ----
----                                                              ----
---- Description                                                  ----
---- Dual port ram. This version is specific for Altera FPGA's,   ----
---- and uses Altera library to instantiate block ram.            ----
----                                                              ----
----                                                              ----
---- To Do:                                                       ----
---- -                                                            ----
----                                                              ----
---- Author(s):                                                   ----
---- - Geir Drange, [e-mail]                           ----
----                                                              ----
----------------------------------------------------------------------
----                                                              ----
---- Copyright (C) 2004 Authors and OPENCORES.ORG                 ----
----                                                              ----
---- This source file may be used and distributed without         ----
---- restriction provided that this copyright statement is not    ----
---- removed from the file and that any derivative work contains  ----
---- the original copyright notice and the associated disclaimer. ----
----                                                              ----
---- This source file is free software; you can redistribute it   ----
---- and/or modify it under the terms of the GNU Lesser General   ----
---- Public License as published by the Free Software Foundation; ----
---- either version 2.1 of the License, or (at your option) any   ----
---- later version.                                               ----
----                                                              ----
---- This source 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 Lesser General Public License for more  ----
---- details.                                                     ----
----                                                              ----
---- You should have received a copy of the GNU Lesser General    ----
---- Public License along with this source; if not, download it   ----
---- from http://www.opencores.org/lgpl.shtml                     ----
----                                                              ----
----------------------------------------------------------------------
--
-- CVS Revision History
--
-- $Log: dpram_altera.vhd,v $
-- Revision 1.3  2004/06/26 14:14:46  gedra
-- Converted to numeric_std and fixed a few bugs.
--
-- Revision 1.2  2004/06/19 09:55:19  gedra
-- Delint'ed and changed name of architecture.
--
-- Revision 1.1  2004/06/18 18:40:04  gedra
-- Alternate dual port memory implementation for Altera FPGA's.
-- 
--

library ieee;
use ieee.std_logic_1164.all; 

library lpm;
use lpm.lpm_components.all;

entity dpram is
  generic (DATA_WIDTH: positive;
           RAM_WIDTH: positive);
  port (
    clk: in std_logic;
    rst: in std_logic; -- reset is optional, not used here
    din: in std_logic_vector(DATA_WIDTH - 1 downto 0);
    wr_en: in std_logic;
    rd_en: in std_logic;
    wr_addr: in std_logic_vector(RAM_WIDTH - 1 downto 0);
    rd_addr: in std_logic_vector(RAM_WIDTH - 1 downto 0);
    dout: out std_logic_vector(DATA_WIDTH - 1 downto 0));
end dpram;    

architecture altera of dpram is
  
component lpm_ram_dp
  generic ( LPM_WIDTH: positive;
            LPM_WIDTHAD: positive;
            LPM_NUMWORDS: natural := 0;
            LPM_INDATA: string := "REGISTERED";
            LPM_OUTDATA: string := "REGISTERED";
            LPM_RDADDRESS_CONTROL: string := "REGISTERED";
            LPM_WRADDRESS_CONTROL: string := "REGISTERED";
            LPM_FILE: string := "UNUSED";
            LPM_TYPE: string := "LPM_RAM_DP";
            LPM_HINT: string := "UNUSED");
  port ( data: in std_logic_vector(LPM_WIDTH-1 downto 0); 
         rdaddress, wraddress: in std_logic_vector(LPM_WIDTHAD-1 downto 0);
         rdclock, wrclock: in std_logic := '0';
         rden, rdclken, wrclken: in std_logic := '1';
         wren: in std_logic; 
         q: out std_logic_vector(LPM_WIDTH-1 downto 0));
end component;

signal one: std_logic;

begin

  one <= '1';

  ram: lpm_ram_dp 
    generic map(LPM_WIDTH => DATA_WIDTH,
                LPM_WIDTHAD => RAM_WIDTH,
                LPM_NUMWORDS => 2**RAM_WIDTH)
    port map (data => din,
              rdaddress => rd_addr,
              wraddress => wr_addr,
              rdclock => clk,
              wrclock => clk,
              rden => rd_en,    
              rdclken => one,
              wrclken => one,
              wren => wr_en,
              q => dout);    
  
end altera;