From b4b02140677c27ebb35ec2fdea6e93006d975967 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joachim=20Stro=CC=88mbergson?= <joachim@secworks.se>
Date: Mon, 13 Apr 2015 14:45:40 +0200
Subject: Adding a test design that instantiates a single Cryptech ring
 oscillator with registered inputs and outputs. This allow us to test
 implementations in different FPGA technologies for different oscillator
 configurations.

---
 src/test/single_rosc.v | 122 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 src/test/single_rosc.v

diff --git a/src/test/single_rosc.v b/src/test/single_rosc.v
new file mode 100644
index 0000000..62ca198
--- /dev/null
+++ b/src/test/single_rosc.v
@@ -0,0 +1,122 @@
+//======================================================================
+//
+// single_rosc.v
+// -------------
+// Top level module for testing the digital ring oscillator. This
+// module basically instantiates an oscillator with registered inputs
+// and outputs to allow synthesis tools to do good placement and
+// timing of the oscillator parts.
+//
+// The module is used to test how the oscillator is mapped to
+// resources in different FPGAs, and what happens when the size
+// of the oscillator increases.
+// idea of using carry chain in adders as inverter by Bernd Paysan.
+//
+//
+//
+// Author: Joachim Strombergson
+// Copyright (c) 2015, NORDUnet A/S All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// - Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+//
+// - Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in the
+//   documentation and/or other materials provided with the distribution.
+//
+// - Neither the name of the NORDUnet nor the names of its contributors may
+//   be used to endorse or promote products derived from this software
+//   without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+//======================================================================
+
+module single_rosc
+             (
+              input wire                   clk,
+              input wire                   reset_n,
+
+              input wire                   we,
+
+              input wire [(WIDTH - 1) : 0] opa,
+              input wire [(WIDTH - 1) : 0] opb,
+
+              output wire                  dout
+             );
+
+  parameter WIDTH = 3;
+
+  //----------------------------------------------------------------
+  // Registers.
+  //----------------------------------------------------------------
+  reg [(WIDTH - 1) : 0] opa_reg;
+  reg [(WIDTH - 1) : 0] opb_reg;
+
+  reg                   we_reg;
+
+  reg                   dout_reg;
+
+  // Ugly in-line Xilinx attribute to preserve the registers.
+  (* equivalent_register_removal = "no" *)
+  wire                  dout_new;
+
+
+  //----------------------------------------------------------------
+  // Concurrent assignment.
+  //----------------------------------------------------------------
+  assign dout = dout_reg;
+
+
+  //----------------------------------------------------------------
+  // oscillator instance.
+  //----------------------------------------------------------------
+  rosc #(.WIDTH(WIDTH)) osc(
+                            .clk(clk),
+                            .we(we_reg),
+                            .reset_n(reset_n),
+                            .opa(opa_reg),
+                            .opb(opb_reg),
+                            .dout(dout_new)
+                            );
+
+
+  //----------------------------------------------------------------
+  // reg_update
+  //----------------------------------------------------------------
+     always @ (posedge clk or negedge reset_n)
+       begin
+         if (!reset_n)
+           begin
+             opa_reg  <= {WIDTH{1'b0}};
+             opb_reg  <= {WIDTH{1'b0}};
+             we_reg   <= 1'b0;
+             dout_reg <= 1'b0;
+           end
+         else
+           begin
+             we_reg   <= we;
+             opa_reg  <= opa;
+             opb_reg  <= opb;
+             dout_reg <= dout_new;
+           end
+       end
+
+endmodule // single_rosc
+
+//======================================================================
+// EOF single_rosc.v
+//======================================================================
-- 
cgit v1.2.3