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pluto_hdl_adi/library/common/ad_dds_sine.v

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// ***************************************************************************
// ***************************************************************************
// 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/main/LICENSE_ADIBSD
// This will allow to generate bit files and not release the source code,
// as long as it attaches to an ADI device.
//
// ***************************************************************************
// ***************************************************************************
// this is a sine function (approximate), the basic idea is to approximate sine as a
// polynomial function (there are a lot of stuff about this on the web)
`timescale 1ns/100ps
module ad_dds_sine #(
parameter DELAY_DATA_WIDTH = 16
) (
// sine = sin(angle)
input clk,
input [15:0] angle,
output [15:0] sine,
input [(DELAY_DATA_WIDTH-1):0] ddata_in,
output [(DELAY_DATA_WIDTH-1):0] ddata_out
);
// internal registers
reg [33:0] s1_data_p = 'd0;
reg [33:0] s1_data_n = 'd0;
reg [15:0] s1_angle = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s1_ddata = 'd0;
reg [18:0] s2_data_0 = 'd0;
reg [18:0] s2_data_1 = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s2_ddata = 'd0;
reg [18:0] s3_data = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s3_ddata = 'd0;
reg [33:0] s4_data2_p = 'd0;
reg [33:0] s4_data2_n = 'd0;
reg [16:0] s4_data1_p = 'd0;
reg [16:0] s4_data1_n = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s4_ddata = 'd0;
reg [16:0] s5_data2_0 = 'd0;
reg [16:0] s5_data2_1 = 'd0;
reg [16:0] s5_data1 = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s5_ddata = 'd0;
reg [16:0] s6_data2 = 'd0;
reg [16:0] s6_data1 = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s6_ddata = 'd0;
reg [33:0] s7_data = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] s7_ddata = 'd0;
reg [15:0] sine_int = 'd0;
reg [(DELAY_DATA_WIDTH-1):0] ddata_out_int = 'd0;
// internal signals
wire [15:0] angle_s;
wire [33:0] s1_data_s;
wire [(DELAY_DATA_WIDTH-1):0] s1_ddata_s;
wire [15:0] s1_angle_s;
wire [33:0] s4_data2_s;
wire [(DELAY_DATA_WIDTH-1):0] s4_ddata_s;
wire [16:0] s4_data1_s;
wire [33:0] s7_data2_s;
wire [33:0] s7_data1_s;
wire [(DELAY_DATA_WIDTH-1):0] s7_ddata_s;
// make angle 2's complement
assign angle_s = {~angle[15], angle[14:0]};
// level 1 - intermediate
ad_mul #(
.DELAY_DATA_WIDTH(DELAY_DATA_WIDTH+16)
) i_mul_s1 (
.clk (clk),
.data_a ({angle_s[15], angle_s}),
.data_b ({angle_s[15], angle_s}),
.data_p (s1_data_s),
.ddata_in ({ddata_in, angle_s}),
.ddata_out ({s1_ddata_s, s1_angle_s}));
// 2's complement versions
always @(posedge clk) begin
s1_data_p <= s1_data_s;
s1_data_n <= ~s1_data_s + 1'b1;
s1_angle <= s1_angle_s;
s1_ddata <= s1_ddata_s;
end
// select partial products
always @(posedge clk) begin
s2_data_0 <= (s1_angle[15] == 1'b0) ? s1_data_n[31:13] : s1_data_p[31:13];
s2_data_1 <= {s1_angle[15], s1_angle[15:0], 2'b00};
s2_ddata <= s1_ddata;
end
// unit-sine
always @(posedge clk) begin
s3_data <= s2_data_0 + s2_data_1;
s3_ddata <= s2_ddata;
end
// level 2 - final
ad_mul #(
.DELAY_DATA_WIDTH(DELAY_DATA_WIDTH+17)
) i_mul_s2 (
.clk (clk),
.data_a (s3_data[16:0]),
.data_b (s3_data[16:0]),
.data_p (s4_data2_s),
.ddata_in ({s3_ddata, s3_data[16:0]}),
.ddata_out ({s4_ddata_s, s4_data1_s}));
// 2's complement versions
always @(posedge clk) begin
s4_data2_p <= s4_data2_s;
s4_data2_n <= ~s4_data2_s + 1'b1;
s4_data1_p <= s4_data1_s;
s4_data1_n <= ~s4_data1_s + 1'b1;
s4_ddata <= s4_ddata_s;
end
// select partial products
always @(posedge clk) begin
s5_data2_0 <= (s4_data1_p[16] == 1'b1) ? s4_data2_n[31:15] : s4_data2_p[31:15];
s5_data2_1 <= s4_data1_n;
s5_data1 <= s4_data1_p;
s5_ddata <= s4_ddata;
end
// corrected-sine
always @(posedge clk) begin
s6_data2 <= s5_data2_0 + s5_data2_1;
s6_data1 <= s5_data1;
s6_ddata <= s5_ddata;
end
// full-scale
ad_mul #(
.DELAY_DATA_WIDTH(1)
) i_mul_s3_2 (
.clk (clk),
.data_a (s6_data2),
.data_b (17'h1d08),
.data_p (s7_data2_s),
.ddata_in (1'b0),
.ddata_out ());
ad_mul #(
.DELAY_DATA_WIDTH(DELAY_DATA_WIDTH)
) i_mul_s3_1 (
.clk (clk),
.data_a (s6_data1),
.data_b (17'h7fff),
.data_p (s7_data1_s),
.ddata_in (s6_ddata),
.ddata_out (s7_ddata_s));
// corrected sum
always @(posedge clk) begin
s7_data <= s7_data2_s + s7_data1_s;
s7_ddata <= s7_ddata_s;
end
// output registers
assign sine = sine_int;
assign ddata_out = ddata_out_int;
always @(posedge clk) begin
sine_int <= s7_data[30:15];
ddata_out_int <= s7_ddata;
end
endmodule
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