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jlechner |
-----------------------------------------------------------------------
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-- This file is part of SCARTS.
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--
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-- SCARTS is free software: you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation, either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- SCARTS is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with SCARTS. If not, see <http://www.gnu.org/licenses/>.
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-----------------------------------------------------------------------
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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use work.debounce_pkg.all;
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architecture beh of key_matrix is
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constant CLK_PERIOD : time := 1E9 / CLK_FREQ * 1 ns;
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constant CNT_MAX : integer := SCAN_TIME_INTERVAL / CLK_PERIOD;
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signal rows_debounced : std_logic_vector(ROW_COUNT - 1 downto 0);
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type debounce_signal_array is array(0 to COLUMN_COUNT - 1, ROW_COUNT - 1 downto 0) of std_logic;
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signal rows_debounced_old, rows_debounced_old_next : debounce_signal_array;
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signal debouncer_reinit : std_logic;
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signal debouncer_reinit_value : std_logic_vector(ROW_COUNT - 1 downto 0);
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type KEY_MATRIX_STATE_TYPE is (STATE_FIRST_COLUMN, STATE_NEXT_COLUMN, STATE_REINIT_DEBOUNCER, STATE_EXECUTE);
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signal key_matrix_state, key_matrix_state_next : KEY_MATRIX_STATE_TYPE;
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signal interval, interval_next : integer range 0 to CNT_MAX;
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signal current_column, current_column_next : integer range 0 to COLUMN_COUNT - 1;
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signal key_next : std_logic_vector(log2c(ROW_COUNT * COLUMN_COUNT) - 1 downto 0);
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signal decode_data : std_logic;
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begin
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process(current_column)
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begin
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columns <= (others => '0');
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columns(current_column) <= '1';
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end process;
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debouncer_gen : for i in 0 to ROW_COUNT - 1 generate
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debouncer_inst : debounce
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generic map
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(
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CLK_FREQ => CLK_FREQ,
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SYNC_STAGES => SYNC_STAGES,
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TIMEOUT => DEBOUNCE_TIMEOUT
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)
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port map
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(
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sys_clk => sys_clk,
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sys_res_n => sys_res_n,
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data_in => rows(i),
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data_out => rows_debounced(i),
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reinit => debouncer_reinit,
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reinit_value => debouncer_reinit_value(i)
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);
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end generate debouncer_gen;
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process(key_matrix_state, interval, current_column)
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begin
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key_matrix_state_next <= key_matrix_state;
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case key_matrix_state is
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when STATE_FIRST_COLUMN =>
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key_matrix_state_next <= STATE_REINIT_DEBOUNCER;
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when STATE_NEXT_COLUMN =>
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key_matrix_state_next <= STATE_REINIT_DEBOUNCER;
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when STATE_REINIT_DEBOUNCER =>
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key_matrix_state_next <= STATE_EXECUTE;
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when STATE_EXECUTE =>
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if interval = CNT_MAX - 1 then
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if current_column = COLUMN_COUNT - 1 then
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key_matrix_state_next <= STATE_FIRST_COLUMN;
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else
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key_matrix_state_next <= STATE_NEXT_COLUMN;
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end if;
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end if;
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end case;
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end process;
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process(key_matrix_state, interval, current_column, rows_debounced, rows_debounced_old)
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begin
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current_column_next <= current_column;
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debouncer_reinit <= '0';
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debouncer_reinit_value <= (others => '0');
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rows_debounced_old_next <= rows_debounced_old;
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interval_next <= 0;
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decode_data <= '0';
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case key_matrix_state is
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when STATE_FIRST_COLUMN =>
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current_column_next <= 0;
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when STATE_NEXT_COLUMN =>
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current_column_next <= current_column + 1;
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when STATE_REINIT_DEBOUNCER =>
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debouncer_reinit <= '1';
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for i in 0 to ROW_COUNT - 1 loop
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debouncer_reinit_value(i) <= rows_debounced_old(current_column, i);
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end loop;
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when STATE_EXECUTE =>
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interval_next <= interval + 1;
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for i in 0 to ROW_COUNT - 1 loop
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rows_debounced_old_next(current_column, i) <= rows_debounced(i);
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end loop;
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decode_data <= '1';
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end case;
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end process;
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process(sys_clk, sys_res_n)
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begin
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if sys_res_n = '0' then
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current_column <= 0;
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rows_debounced_old <= (others => (others => '0'));
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interval <= 0;
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key_matrix_state <= STATE_FIRST_COLUMN;
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key <= (others => '0');
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elsif rising_edge(sys_clk) then
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current_column <= current_column_next;
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interval <= interval_next;
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rows_debounced_old <= rows_debounced_old_next;
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key_matrix_state <= key_matrix_state_next;
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key <= key_next;
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end if;
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end process;
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process(decode_data, rows_debounced, rows_debounced_old, current_column)
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variable key_int : integer range 0 to ROW_COUNT * COLUMN_COUNT;
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variable found, valid : boolean;
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begin
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key_next <= (others => '0');
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if decode_data = '1' then
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key_int := 0;
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found := false;
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valid := true;
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for i in 0 to ROW_COUNT - 1 loop
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if rows_debounced(i) = '1' then
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if found = true then -- Only one key may be pressed at once
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valid := false;
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end if;
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if rows_debounced_old(current_column, i) = '1' then -- Only valid the first time the key is pressed
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valid := false;
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end if;
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found := true;
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end if;
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-- Calculate the key number (i * COLUMN_COUNT)
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-- = Addition of column count until the key is found
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if not found then
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key_int := key_int + COLUMN_COUNT;
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end if;
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end loop;
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if valid and found then
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-- If a valid key was found, correct the key number to the correct column
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key_int := key_int + current_column + 1;
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else
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key_int := 0;
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end if;
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key_next <= std_logic_vector(to_unsigned(key_int, log2c(ROW_COUNT * COLUMN_COUNT)));
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end if;
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end process;
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end architecture beh;
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