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[/] [gamepads/] [trunk/] [gcpad/] [rtl/] [vhdl/] [gcpad_rx.vhd] - Rev 12
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------------------------------------------------------------------------------- -- -- GCpad controller core -- -- $Id: gcpad_rx.vhd,v 1.2 2004-10-08 20:51:59 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; use work.gcpad_pack.analog_axis_t; entity gcpad_rx is generic ( reset_level_g : integer := 0; clocks_per_1us_g : integer := 2 ); port ( -- System Interface ------------------------------------------------------- clk_i : in std_logic; reset_i : in std_logic; -- Control Interface ------------------------------------------------------ rx_en_i : in boolean; rx_done_o : out boolean; rx_size_i : in std_logic_vector(3 downto 0); -- Gamepad Interface ------------------------------------------------------ pad_data_i : in std_logic; -- Buttons Interface ------------------------------------------------------ but_a_o : out std_logic; but_b_o : out std_logic; but_x_o : out std_logic; but_y_o : out std_logic; but_z_o : out std_logic; but_start_o : out std_logic; but_tl_o : out std_logic; but_tr_o : out std_logic; but_left_o : out std_logic; but_right_o : out std_logic; but_up_o : out std_logic; but_down_o : out std_logic; ana_joy_x_o : out analog_axis_t; ana_joy_y_o : out analog_axis_t; ana_c_x_o : out analog_axis_t; ana_c_y_o : out analog_axis_t; ana_l_o : out analog_axis_t; ana_r_o : out analog_axis_t ); end gcpad_rx; library ieee; use ieee.numeric_std.all; use work.gcpad_pack.all; architecture rtl of gcpad_rx is type state_t is (IDLE, DETECT_TIMEOUT, WAIT_FOR_1, WAIT_FOR_0, FINISHED); signal state_s, state_q : state_t; signal buttons_q, shift_buttons_q : buttons_t; signal save_buttons_s : boolean; signal shift_buttons_s : boolean; constant cnt_sample_high_c : natural := clocks_per_1us_g * 4 - 1; subtype cnt_sample_t is natural range 0 to cnt_sample_high_c; signal cnt_zeros_q : cnt_sample_t; signal cnt_ones_q : cnt_sample_t; signal sampled_s : boolean; signal sync_sample_s : boolean; signal wrap_sample_s : boolean; signal sample_underflow_q : boolean; signal more_ones_q : boolean; -- timeout counter counts three sample undeflows constant cnt_timeout_high_c : natural := 3; subtype cnt_timeout_t is natural range 0 to cnt_timeout_high_c; signal cnt_timeout_q : cnt_timeout_t; signal timeout_q : boolean; signal sync_timeout_s : boolean; subtype num_buttons_read_t is unsigned(6 downto 0); signal num_buttons_read_q : num_buttons_read_t; signal all_buttons_read_s : boolean; signal reset_num_buttons_s : boolean; signal pad_data_sync_q : std_logic_vector(1 downto 0); signal pad_data_s : std_logic; signal rx_done_q, set_rx_done_s : boolean; begin ----------------------------------------------------------------------------- -- Process seq -- -- Purpose: -- Implements the sequential elements of this module. -- seq: process (reset_i, clk_i) variable dec_timeout_v : boolean; variable size_v : std_logic_vector(num_buttons_read_t'range); begin if reset_i = reset_level_g then buttons_q <= (others => '0'); shift_buttons_q <= (others => '0'); state_q <= IDLE; cnt_zeros_q <= cnt_sample_high_c; cnt_ones_q <= cnt_sample_high_c; more_ones_q <= false; sample_underflow_q <= false; cnt_timeout_q <= cnt_timeout_high_c; timeout_q <= false; num_buttons_read_q <= (others => '0'); rx_done_q <= false; pad_data_sync_q <= (others => '1'); elsif clk_i'event and clk_i = '1' then -- synchronizer for pad data pad_data_sync_q(0) <= pad_data_i; pad_data_sync_q(1) <= pad_data_sync_q(0); state_q <= state_s; dec_timeout_v := false; -- sample counter if sync_sample_s then -- explicit preload cnt_zeros_q <= cnt_sample_high_c; cnt_ones_q <= cnt_sample_high_c; else if cnt_zeros_q = 0 then if wrap_sample_s then cnt_zeros_q <= cnt_sample_high_c; end if; dec_timeout_v := true; elsif pad_data_s = '0' then cnt_zeros_q <= cnt_zeros_q - 1; end if; if cnt_ones_q = 0 then if wrap_sample_s then cnt_ones_q <= cnt_sample_high_c; end if; dec_timeout_v := true; elsif pad_data_s /= '0' then cnt_ones_q <= cnt_ones_q - 1; end if; end if; if cnt_ones_q < cnt_zeros_q then more_ones_q <= true; else more_ones_q <= false; end if; -- detect sample underflow sample_underflow_q <= dec_timeout_v; -- timeout counter if sync_timeout_s then -- explicit preload cnt_timeout_q <= cnt_timeout_high_c; timeout_q <= false; elsif cnt_timeout_q = 0 then -- wrap-around cnt_timeout_q <= cnt_timeout_high_c; timeout_q <= true; elsif dec_timeout_v then -- decrement counter when sampler wraps around cnt_timeout_q <= cnt_timeout_q - 1; end if; -- count remaining number of buttons to read if shift_buttons_s then shift_buttons_q(buttons_t'high downto 1) <= shift_buttons_q(buttons_t'high-1 downto 0); if more_ones_q then shift_buttons_q(0) <= '1'; else shift_buttons_q(0) <= '0'; end if; end if; if reset_num_buttons_s then -- explicit preload size_v(num_buttons_read_t'high downto 3) := rx_size_i; size_v(2 downto 0) := (others => '0'); num_buttons_read_q <= unsigned(size_v); elsif shift_buttons_s then -- decrement counter when a button bit has been read if not all_buttons_read_s then num_buttons_read_q <= num_buttons_read_q - 1; end if; end if; -- the buttons if save_buttons_s then buttons_q <= shift_buttons_q; end if; if set_rx_done_s then rx_done_q <= true; else rx_done_q <= false; end if; end if; end process seq; -- ----------------------------------------------------------------------------- pad_data_s <= pad_data_sync_q(1); -- indicates that all buttons have been read all_buttons_read_s <= num_buttons_read_q = 0; ----------------------------------------------------------------------------- -- Process fsm -- -- Purpose: -- Models the controlling state machine. -- fsm: process (state_q, rx_en_i, pad_data_s, all_buttons_read_s, sampled_s, sample_underflow_q, timeout_q) begin sync_sample_s <= false; sync_timeout_s <= false; state_s <= IDLE; shift_buttons_s <= false; save_buttons_s <= false; set_rx_done_s <= false; reset_num_buttons_s <= false; wrap_sample_s <= false; case state_q is -- IDLE ----------------------------------------------------------------- -- The idle state. when IDLE => if rx_en_i then state_s <= DETECT_TIMEOUT; else -- keep counters synchronized when no reception is running sync_sample_s <= true; sync_timeout_s <= true; reset_num_buttons_s <= true; state_s <= IDLE; end if; when DETECT_TIMEOUT => state_s <= DETECT_TIMEOUT; if pad_data_s = '0' then sync_sample_s <= true; state_s <= WAIT_FOR_1; else -- wait for timeout wrap_sample_s <= true; if timeout_q then set_rx_done_s <= true; state_s <= IDLE; end if; end if; -- WAIT_FOR_1 ----------------------------------------------------------- -- Sample counter has expired and a 0 bit has been detected. -- We must now wait for pad_data_s to become 1. -- Or abort upon timeout. when WAIT_FOR_1 => if pad_data_s = '0' then if not sample_underflow_q then state_s <= WAIT_FOR_1; else -- timeout while reading buttons! set_rx_done_s <= true; state_s <= IDLE; end if; else state_s <= WAIT_FOR_0; end if; -- WAIT_FOR_0 ----------------------------------------------------------- -- pad_data_s is at 1 level now and no timeout occured so far. -- We wait for the next 0 level on pad_data_s or abort upon timeout. when WAIT_FOR_0 => -- wait for falling edge of pad data if pad_data_s = '0' then sync_sample_s <= true; if not all_buttons_read_s then -- loop another time if there are still some buttons to read shift_buttons_s <= true; state_s <= WAIT_FOR_1; else state_s <= WAIT_FOR_0; end if; else if sample_underflow_q then if all_buttons_read_s then -- last button was read -- so it's ok to timeout state_s <= FINISHED; else -- timeout while reading buttons! set_rx_done_s <= true; state_s <= IDLE; end if; else state_s <= WAIT_FOR_0; end if; end if; when FINISHED => -- finally save buttons save_buttons_s <= true; set_rx_done_s <= true; when others => null; end case; end process fsm; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Output Mapping ----------------------------------------------------------------------------- rx_done_o <= rx_done_q; but_a_o <= buttons_q(pos_a_c); but_b_o <= buttons_q(pos_b_c); but_x_o <= buttons_q(pos_x_c); but_y_o <= buttons_q(pos_y_c); but_z_o <= buttons_q(pos_z_c); but_start_o <= buttons_q(pos_start_c); but_tl_o <= buttons_q(pos_tl_c); but_tr_o <= buttons_q(pos_tr_c); but_left_o <= buttons_q(pos_left_c); but_right_o <= buttons_q(pos_right_c); but_up_o <= buttons_q(pos_up_c); but_down_o <= buttons_q(pos_down_c); ana_joy_x_o <= buttons_q(joy_x_high_c downto joy_x_low_c); ana_joy_y_o <= buttons_q(joy_y_high_c downto joy_y_low_c); ana_c_x_o <= buttons_q(c_x_high_c downto c_x_low_c); ana_c_y_o <= buttons_q(c_y_high_c downto c_y_low_c); ana_l_o <= buttons_q(l_high_c downto l_low_c); ana_r_o <= buttons_q(r_high_c downto r_low_c); 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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