pluto_hdl_adi/library/common/ad_dds_sine.v

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// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// Each core or library found in this collection may have its own licensing terms.
// The user should keep this in in mind while exploring these cores.
//
// Redistribution and use in source and binary forms,
// with or without modification of this file, are permitted under the terms of either
// (at the option of the user):
//
// 1. The GNU General Public License version 2 as published by the
// Free Software Foundation, which can be found in the top level directory, or at:
// https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.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/dev/LICENSE
//
// ***************************************************************************
// ***************************************************************************
// 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 reg [ 15:0] sine,
input [ DW:0] ddata_in,
output reg [ DW:0] ddata_out);
localparam DW = DELAY_DATA_WIDTH - 1;
// internal registers
reg [ 33:0] s1_data_p = 'd0;
reg [ 33:0] s1_data_n = 'd0;
reg [ 15:0] s1_angle = 'd0;
reg [ DW:0] s1_ddata = 'd0;
reg [ 18:0] s2_data_0 = 'd0;
reg [ 18:0] s2_data_1 = 'd0;
reg [ DW:0] s2_ddata = 'd0;
reg [ 18:0] s3_data = 'd0;
reg [ DW: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 [ DW: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 [ DW:0] s5_ddata = 'd0;
reg [ 16:0] s6_data2 = 'd0;
reg [ 16:0] s6_data1 = 'd0;
reg [ DW:0] s6_ddata = 'd0;
reg [ 33:0] s7_data = 'd0;
reg [ DW:0] s7_ddata = 'd0;
// internal signals
wire [ 15:0] angle_s;
wire [ 33:0] s1_data_s;
wire [ DW:0] s1_ddata_s;
wire [ 15:0] s1_angle_s;
wire [ 33:0] s4_data2_s;
wire [ DW:0] s4_ddata_s;
wire [ 16:0] s4_data1_s;
wire [ 33:0] s7_data2_s;
wire [ 33:0] s7_data1_s;
wire [ DW: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
always @(posedge clk) begin
sine <= s7_data[30:15];
ddata_out <= s7_ddata;
end
endmodule
// ***************************************************************************
// ***************************************************************************