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[/] [gamepads/] [trunk/] [gcpad/] [rtl/] [vhdl/] [gcpad_ctrl.vhd] - Rev 19
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------------------------------------------------------------------------------- -- -- GCpad controller core -- -- $Id: gcpad_ctrl.vhd,v 1.2 2004-10-09 17:04:36 arniml Exp $ -- -- Copyright (c) 2004, 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/gamepads/ -- -- The project homepage is located at: -- http://www.opencores.org/projects.cgi/web/gamepads/overview -- ------------------------------------------------------------------------------- library ieee; use ieee.std_logic_1164.all; entity gcpad_ctrl is generic ( reset_level_g : integer := 0 ); port ( -- System Interface ------------------------------------------------------- clk_i : in std_logic; reset_i : in std_logic; pad_request_i : in std_logic; pad_avail_o : out std_logic; rx_timeout_o : out std_logic; -- Control Interface ------------------------------------------------------ tx_start_o : out boolean; tx_finished_i : in boolean; rx_en_o : out boolean; rx_done_i : in boolean; rx_data_ok_i : in boolean ); end gcpad_ctrl; use work.gcpad_pack.all; architecture rtl of gcpad_ctrl is type state_t is (IDLE, TX, RX1_START, RX1_WAIT, RX2_START, RX2_WAIT, RX3_START, RX3_WAIT, RX4_START, RX4_WAIT); signal state_s, state_q : state_t; signal set_txrx_finished_s : boolean; signal enable_txrx_finished_s : boolean; signal txrx_finished_q : std_logic; signal timeout_q : std_logic; begin ----------------------------------------------------------------------------- -- Process seq -- -- Purpose: -- Implements the sequential elements. -- seq: process (reset_i, clk_i) begin if reset_i = reset_level_g then state_q <= IDLE; txrx_finished_q <= '0'; timeout_q <= '1'; elsif clk_i'event and clk_i = '1' then state_q <= state_s; -- transmit/receive finished flag if set_txrx_finished_s then txrx_finished_q <= '1'; elsif pad_request_i = '1' then txrx_finished_q <= '0'; end if; if pad_request_i = '1' then timeout_q <= '1'; elsif rx_data_ok_i then timeout_q <= '0'; end if; end if; end process seq; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Process fsm -- -- Purpose: -- Models the controlling state machine. -- fsm: process (state_q, tx_finished_i, rx_done_i, pad_request_i) begin rx_en_o <= false; state_s <= IDLE; tx_start_o <= false; set_txrx_finished_s <= false; enable_txrx_finished_s <= false; case state_q is when IDLE => -- enable output of txrx_finished flag -- the flag has to be suppressed while the FSM probes four times enable_txrx_finished_s <= true; if pad_request_i = '1' then state_s <= TX; tx_start_o <= true; else state_s <= IDLE; end if; when TX => if not tx_finished_i then state_s <= TX; else state_s <= RX1_START; end if; when RX1_START => rx_en_o <= true; state_s <= RX1_WAIT; when RX1_WAIT => if rx_done_i then state_s <= RX2_START; else state_s <= RX1_WAIT; end if; when RX2_START => rx_en_o <= true; state_s <= RX2_WAIT; when RX2_WAIT => if rx_done_i then state_s <= RX3_START; else state_s <= RX2_WAIT; end if; when RX3_START => rx_en_o <= true; state_s <= RX3_WAIT; when RX3_WAIT => if rx_done_i then state_s <= RX4_START; else state_s <= RX3_WAIT; end if; when RX4_START => rx_en_o <= true; state_s <= RX4_WAIT; when RX4_WAIT => if rx_done_i then state_s <= IDLE; set_txrx_finished_s <= true; else state_s <= RX4_WAIT; end if; when others => null; end case; end process fsm; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Output mapping ----------------------------------------------------------------------------- pad_avail_o <= txrx_finished_q when enable_txrx_finished_s else '0'; rx_timeout_o <= timeout_q when enable_txrx_finished_s else '0'; end rtl; ------------------------------------------------------------------------------- -- File History: -- -- $Log: not supported by cvs2svn $ -- Revision 1.1 2004/10/07 21:23:10 arniml -- initial check-in -- -------------------------------------------------------------------------------
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