83 lines
2.6 KiB
Verilog
83 lines
2.6 KiB
Verilog
// ***************************************************************************
|
|
// ***************************************************************************
|
|
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
|
|
//
|
|
// In this HDL repository, there are many different and unique modules, consisting
|
|
// of various HDL (Verilog or VHDL) components. The individual modules are
|
|
// developed independently, and may be accompanied by separate and unique license
|
|
// terms.
|
|
//
|
|
// The user should read each of these license terms, and understand the
|
|
// freedoms and responsibilities that he or she has by using this source/core.
|
|
//
|
|
// This core 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.
|
|
//
|
|
// Redistribution and use of source or resulting binaries, with or without modification
|
|
// of this file, are permitted under one of the following two license terms:
|
|
//
|
|
// 1. The GNU General Public License version 2 as published by the
|
|
// Free Software Foundation, which can be found in the top level directory
|
|
// of this repository (LICENSE_GPL2), and also online at:
|
|
// <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
|
|
//
|
|
// OR
|
|
//
|
|
// 2. An ADI specific BSD license, which can be found in the top level directory
|
|
// of this repository (LICENSE_ADIBSD), and also on-line at:
|
|
// https://github.com/analogdevicesinc/hdl/blob/master/LICENSE_ADIBSD
|
|
// This will allow to generate bit files and not release the source code,
|
|
// as long as it attaches to an ADI device.
|
|
//
|
|
// ***************************************************************************
|
|
// ***************************************************************************
|
|
|
|
// A simple edge detector circuit
|
|
|
|
`timescale 1ns/100ps
|
|
|
|
module ad_edge_detect #(
|
|
|
|
parameter EDGE = 0
|
|
) (
|
|
input clk,
|
|
input rst,
|
|
|
|
input signal_in,
|
|
output reg signal_out
|
|
);
|
|
|
|
localparam POS_EDGE = 0;
|
|
localparam NEG_EDGE = 1;
|
|
localparam ANY_EDGE = 2;
|
|
|
|
reg ff_m1 = 0;
|
|
reg ff_m2 = 0;
|
|
|
|
always @(posedge clk) begin
|
|
if (rst == 1) begin
|
|
ff_m1 <= 0;
|
|
ff_m2 <= 0;
|
|
end else begin
|
|
ff_m1 <= signal_in;
|
|
ff_m2 <= ff_m1;
|
|
end
|
|
end
|
|
|
|
always @(posedge clk) begin
|
|
if (rst == 1) begin
|
|
signal_out <= 1'b0;
|
|
end else begin
|
|
if (EDGE == POS_EDGE) begin
|
|
signal_out <= ff_m1 & ~ff_m2;
|
|
end else if (EDGE == NEG_EDGE) begin
|
|
signal_out <= ~ff_m1 & ff_m2;
|
|
end else begin
|
|
signal_out <= ff_m1 ^ ff_m2;
|
|
end
|
|
end
|
|
end
|
|
|
|
endmodule
|