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-- $Id: tbd_nx_cram_memctl_as.vhd 433 2011-11-27 22:04:39Z mueller $

--

-- Copyright 2010-2011 by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>

--

-- This program is free software; you may redistribute and/or modify it under

-- the terms of the GNU General Public License as published by the Free

-- Software Foundation, either version 2, or at your option any later version.

--

-- This program 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 complete details.

--

------------------------------------------------------------------------------

-- Module Name:    tbd_nx_cram_memctl_as - syn

-- Description:    Wrapper for nx_cram_memctl_as to avoid records & generics.

--                 It has a port interface which will not be modified by xst

--                 synthesis (no records, no generic port).

--

-- Dependencies:   nx_cram_memctl_as

-- To test:        nx_cram_memctl_as

--

-- Target Devices: generic

--

-- Synthesized (xst):

-- Date         Rev  ise         Target      flop lutl lutm slic t peri

-- 2010-06-03   299  11.4   L68  xc3s1200e-4   91  122    0  107 t 11.4 

-- 2010-05-30   297  11.4   L68  xc3s1200e-4   91   99    0   95 t 13.1 

--

-- Tool versions:  xst 11.4, 13.1; ghdl 0.26-0.29

-- Revision History: 

-- Date         Rev Version  Comment

-- 2011-11-26   433   1.2    renamed from tbd_n2_cram_memctl_as

-- 2011-11-23   432   1.1    remove O_FLA_CE_N port from n2_cram_memctl

-- 2010-06-03   298   1.0.1  add hack to force IOB'FFs to O_MEM_ADDR

-- 2010-05-30   297   1.0    Initial version 

------------------------------------------------------------------------------

library ieee;

use ieee.std_logic_1164.all;

use work.slvtypes.all;

use work.nxcramlib.all;

entity tbd_nx_cram_memctl_as is         -- CRAM driver (async mode) [tb design]

                                        -- generic: READ0=2;READ1=2;WRITE=3

  port (

    CLK : in slbit;                     -- clock

    RESET : in slbit;                   -- reset

    REQ   : in slbit;                   -- request

    WE    : in slbit;                   -- write enable

    BUSY : out slbit;                   -- controller busy

    ACK_R : out slbit;                  -- acknowledge read

    ACK_W : out slbit;                  -- acknowledge write

    ACT_R : out slbit;                  -- signal active read

    ACT_W : out slbit;                  -- signal active write

    ADDR : in slv22;                    -- address  (32 bit word address)

    BE : in slv4;                       -- byte enable

    DI : in slv32;                      -- data in  (memory view)

    DO : out slv32;                     -- data out (memory view)

    O_MEM_CE_N : out slbit;             -- cram: chip enable   (act.low)

    O_MEM_BE_N : out slv2;              -- cram: byte enables  (act.low)

    O_MEM_WE_N : out slbit;             -- cram: write enable  (act.low)

    O_MEM_OE_N : out slbit;             -- cram: output enable (act.low)

    O_MEM_ADV_N : out slbit;            -- cram: address valid (act.low)

    O_MEM_CLK : out slbit;              -- cram: clock

    O_MEM_CRE : out slbit;              -- cram: command register enable

    I_MEM_WAIT : in slbit;              -- cram: mem wait

    O_MEM_ADDR  : out slv23;            -- cram: address lines

    IO_MEM_DATA : inout slv16           -- cram: data lines

  );

end tbd_nx_cram_memctl_as;

architecture syn of tbd_nx_cram_memctl_as is

  signal ADDR_X : slv22 := (others=>'0');

begin

  -- Note: This is a HACk to ensure that the IOB flops are on the O_MEM_ADDR

  --   pins. Without par might choose to use IFF's on ADDR, causing varying

  --   routing delays to O_MEM_ADDR. Didn't find a better way, setting

  --   iob "false" attributes in ADDR didn't help.

  --   This logic doesn't hurt, and prevents that IFFs for ADDR compete with

  --   OFF's for O_MEM_ADDR.

  ADDR_X <= ADDR when RESET='0' else (others=>'0');

  MEMCTL : nx_cram_memctl_as

    generic map (

      READ0DELAY => 2,

      READ1DELAY => 2,

      WRITEDELAY => 3)

    port map (

      CLK    => CLK,

      RESET  => RESET,

      REQ    => REQ,

      WE     => WE,

      BUSY   => BUSY,

      ACK_R  => ACK_R,

      ACK_W  => ACK_W,

      ACT_R  => ACT_R,

      ACT_W  => ACT_W,

      ADDR   => ADDR_X,

      BE     => BE,

      DI     => DI,

      DO     => DO,

      O_MEM_CE_N  => O_MEM_CE_N,

      O_MEM_BE_N  => O_MEM_BE_N,

      O_MEM_WE_N  => O_MEM_WE_N,

      O_MEM_OE_N  => O_MEM_OE_N,

      O_MEM_ADV_N => O_MEM_ADV_N,

      O_MEM_CLK   => O_MEM_CLK,

      O_MEM_CRE   => O_MEM_CRE,

      I_MEM_WAIT  => I_MEM_WAIT,

      O_MEM_ADDR  => O_MEM_ADDR,

      IO_MEM_DATA => IO_MEM_DATA

    );

end syn;