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-- Copyright (c) 2017 Nuand LLC
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU Affero General Public License as
-- published by the Free Software Foundation, either version 3 of the
-- License, 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 Affero General Public License for more details.
--
-- You should have received a copy of the GNU Affero General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity edge_detector is
generic (
EDGE_RISE : std_logic ;
EDGE_FALL : std_logic ;
NUM_PULSES : positive range 1 to 1023 := 2
) ;
port (
clock : in std_logic ;
reset : in std_logic ;
sync_in : in std_logic ;
pulse_out : out std_logic
) ;
end entity ;
architecture arch of edge_detector is
signal pulses : std_logic_vector( NUM_PULSES - 1 downto 0 ) ;
begin
process( clock, reset )
begin
if( reset = '1' ) then
pulses <= ( others => sync_in ) ;
pulse_out <= '0' ;
elsif( rising_edge( clock ) ) then
pulses <= sync_in & pulses( NUM_PULSES - 1 downto 1 ) ;
if( EDGE_RISE = '1' and pulses(1 downto 0) = "10" ) then
pulse_out <= '1' ;
elsif ( EDGE_FALL = '1' and pulses(1 downto 0) = "01" ) then
pulse_out <= '1' ;
else
pulse_out <= '0' ;
end if ;
end if ;
end process ;
end architecture ;
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