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[/] [t400/] [tags/] [rel_0_1_beta/] [rtl/] [vhdl/] [t400_io_in.vhd] - Rev 70
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------------------------------------------------------------------------------- -- -- The IN port controller. -- -- $Id: t400_io_in.vhd,v 1.3 2006-05-27 19:14:18 arniml Exp $ -- -- Copyright (c) 2006 Arnim Laeuger (arniml@opencores.org) -- -- All rights reserved -- -- Redistribution and use in source and synthezised forms, with or without -- modification, are permitted provided that the following conditions are met: -- -- Redistributions of source code must retain the above copyright notice, -- this list of conditions and the following disclaimer. -- -- Redistributions in synthesized form must reproduce the above copyright -- notice, this list of conditions and the following disclaimer in the -- documentation and/or other materials provided with the distribution. -- -- Neither the name of the author nor the names of other contributors may -- be used to endorse or promote products derived from this software without -- specific prior written permission. -- -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" -- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, -- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR -- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE -- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR -- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF -- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS -- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN -- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- -- Please report bugs to the author, but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- -- The latest version of this file can be found at: -- http://www.opencores.org/cvsweb.shtml/t400/ -- ------------------------------------------------------------------------------- library ieee; use ieee.std_logic_1164.all; use work.t400_pack.all; entity t400_io_in is port ( -- System Interface ------------------------------------------------------- ck_i : in std_logic; ck_en_i : in boolean; por_i : in boolean; icyc_en_i : in boolean; in_en_i : in boolean; -- Control Interface ------------------------------------------------------ op_i : in io_in_op_t; en1_i : in std_logic; -- Port Interface --------------------------------------------------------- io_in_i : in dw_t; in_o : out dw_t; int_o : out boolean ); end t400_io_in; architecture rtl of t400_io_in is constant idx_in3_c : natural := 2; constant idx_in0_c : natural := 1; constant idx_int_c : natural := 0; type neg_edge_t is array (natural range 1 downto 0) of std_logic_vector(2 downto 0); signal neg_edge_q : neg_edge_t; signal neg_edge_s : std_logic_vector(2 downto 0); signal il_q : std_logic_vector(1 downto 0); signal int_q, int_icyc_q : boolean; begin ----------------------------------------------------------------------------- -- Process seq -- -- Purpose: -- Implements the sequential elements. -- seq: process (ck_i, por_i) variable neg_edge_v : std_logic_vector(2 downto 0); begin if por_i then neg_edge_q <= (others => (others => '0')); il_q <= (others => '0'); int_q <= false; int_icyc_q <= false; elsif ck_i'event and ck_i = '1' then -- negative edge detector filp-flops ------------------------------------ neg_edge_v(idx_in3_c) := to_X01(io_in_i(3)); neg_edge_v(idx_in0_c) := to_X01(io_in_i(0)); neg_edge_v(idx_int_c) := to_X01(io_in_i(1)); if in_en_i then neg_edge_q(0) <= neg_edge_v; neg_edge_q(1) <= neg_edge_q(0) or neg_edge_v; end if; -- IL latches ----------------------------------------------------------- if in_en_i then if neg_edge_q(1)(idx_in3_c) = '1' and ((neg_edge_q(0)(idx_in3_c) or neg_edge_v(idx_in3_c)) = '0') then il_q(1) <= '1'; end if; if neg_edge_q(1)(idx_in0_c) = '1' and ((neg_edge_q(0)(idx_in0_c) or neg_edge_v(idx_in0_c)) = '0') then il_q(0) <= '1'; end if; end if; -- Interrupt trigger ---------------------------------------------------- if in_en_i then if neg_edge_q(1)(idx_int_c) = '1' and ((neg_edge_q(0)(idx_int_c) or neg_edge_v(idx_int_c)) = '0') then int_q <= true; end if; end if; if icyc_en_i then -- delay interrupt request until end of current instruction -- this ensures that the interrupt is valid for a full instruction -- (i.e. the next one) int_icyc_q <= int_q; end if; if ck_en_i then if op_i = IOIN_INIL then il_q <= (others => '0'); end if; if op_i = IOIN_INTACK then int_q <= false; int_icyc_q <= false; end if; end if; end if; end process seq; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Output mapping ----------------------------------------------------------------------------- in_o <= il_q(1) & "00" & il_q(0) when op_i = IOIN_INIL else io_in_i; int_o <= int_icyc_q; end rtl; ------------------------------------------------------------------------------- -- File History: -- -- $Log: not supported by cvs2svn $ -- Revision 1.2 2006/05/23 01:13:28 arniml -- + reset neg_edge flip-flops to '1' -- -> after por, a 1-to-0 edge is required to trigger the latches initially -- + use to_X01 -- -- Revision 1.1 2006/05/22 00:00:55 arniml -- initial check-in -- -------------------------------------------------------------------------------
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