// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// 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
//      the repository (LICENSE_GPL2), and at: <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
//
// OR
//
//   2. An ADI specific BSD license as noted in the top level directory, or 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.
//
// ***************************************************************************
// ***************************************************************************

`timescale 1ns/100ps

module ad_dds #(

  // data path disable

  parameter   DISABLE = 0) (

  // interface

  input           clk,
  input           dds_format,
  input   [15:0]  dds_phase_0,
  input   [15:0]  dds_scale_0,
  input   [15:0]  dds_phase_1,
  input   [15:0]  dds_scale_1,
  output  [15:0]  dds_data);

  // internal registers

  reg     [15:0]  dds_data_int = 'd0;
  reg     [15:0]  dds_data_out = 'd0;
  reg     [15:0]  dds_scale_0_d = 'd0;
  reg     [15:0]  dds_scale_1_d = 'd0;

  // internal signals

  wire    [15:0]  dds_data_0_s;
  wire    [15:0]  dds_data_1_s;

  // disable

  assign dds_data = (DISABLE == 1) ? 16'd0 : dds_data_out;

  // dds channel output

  always @(posedge clk) begin
    dds_data_int <= dds_data_0_s + dds_data_1_s;
    dds_data_out[15:15] <= dds_data_int[15] ^ dds_format;
    dds_data_out[14: 0] <= dds_data_int[14:0];
  end

  always @(posedge clk) begin
    dds_scale_0_d <= dds_scale_0;
    dds_scale_1_d <= dds_scale_1;
  end
  // dds-1

  ad_dds_1 i_dds_1_0 (
    .clk (clk),
    .angle (dds_phase_0),
    .scale (dds_scale_0_d),
    .dds_data (dds_data_0_s));

  // dds-2

  ad_dds_1 i_dds_1_1 (
    .clk (clk),
    .angle (dds_phase_1),
    .scale (dds_scale_1_d),
    .dds_data (dds_data_1_s));

endmodule

// ***************************************************************************
// ***************************************************************************