// ***************************************************************************
// ***************************************************************************
// Copyright (C) 2014-2023 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.
//
// ***************************************************************************
// ***************************************************************************
// Transmit HDMI, RGB to CrYCb conversion
// The multiplication coefficients are in 1.4.12 format
// The addition coefficients are in 1.12.12 format
// Cr = (+112.439/256)*R + (-094.154/256)*G + (-018.285/256)*B + 128;
// Y  = (+065.738/256)*R + (+129.057/256)*G + (+025.064/256)*B +  16;
// Cb = (-037.945/256)*R + (-074.494/256)*G + (+112.439/256)*B + 128;

`timescale 1ns/100ps

module ad_csc_RGB2CrYCb #(

  parameter   DELAY_DATA_WIDTH = 16
) (

  // R-G-B inputs

  input                               clk,
  input       [DELAY_DATA_WIDTH-1:0]  RGB_sync,
  input       [23:0]                  RGB_data,

  // Cr-Y-Cb outputs

  output      [DELAY_DATA_WIDTH-1:0]  CrYCb_sync,
  output      [23:0]                  CrYCb_data
);

  localparam  DW = DELAY_DATA_WIDTH - 1;

  // Cr (red-diff)

  ad_csc #(
    .DELAY_DW(DELAY_DATA_WIDTH)
  ) j_csc_1_Cr (
    .clk (clk),
    .sync (RGB_sync),
    .data (RGB_data),
    .C1 ( 17'd28784),   //  112.439
    .C2 (-17'd24103),   // -94.154
    .C3 (-17'd4681),    // -18.285
    .C4 ( 24'd8388608), //  128
    .csc_sync (CrYCb_sync),
    .csc_data (CrYCb_data[23:16]));

  // Y (luma)

  ad_csc #(
    .DELAY_DW(0)
  ) j_csc_1_Y (
    .clk (clk),
    .sync (1'd0),
    .data (RGB_data),
    .C1 (17'd16829),   // 65.739
    .C2 (17'd33039),   // 129.057
    .C3 (17'd6416),    // 25.064
    .C4 (24'd1048576), // 16
    .csc_sync (),
    .csc_data (CrYCb_data[15:8]));

  // Cb (blue-diff)

  ad_csc #(
    .DELAY_DW(0)
  ) j_csc_1_Cb (
    .clk (clk),
    .sync (1'd0),
    .data (RGB_data),
    .C1 (-17'd9714),   // -37.945
    .C2 (-17'd19070),  // -74.494
    .C3 ( 17'd28784),  //  112.439
    .C4 (24'd8388608), //  128
    .csc_sync (),
    .csc_data (CrYCb_data[7:0]));

endmodule