Adding toggle design including testbench and Makefile to run simulation.

5 files changed, 324 insertions, 0 deletions

diff --git a/LICENSE b/LICENSE
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+Author: Joachim Strömbergson
+Copyright (c) 2014, 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.
diff --git a/README.md b/README.md
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+toggle
+======
+## Introduction ##
+
+This repo contains a simple deign that toggles an ouput pin. The toggle
+is in sync with the given sys_clk, but the toggle circuit divides down
+the clock. The divisor is build time defined.
+
+The design is used in the Cryptech FPGA design to observe internal
+clock frequencies.
+
+
+## Status ##
+Has been simulated with Icarus Verilog.
diff --git a/src/rtl/toggle.v b/src/rtl/toggle.v
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+//======================================================================
+//
+// toggle
+// ------
+// gpio pin toggler.
+//
+//
+// Author: Joachim Strombergson
+// Copyright (c) 2018, 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 toggle
+
+  (
+   input wire          sys_clk,
+   input wire          reset_n,
+   output wire [7 : 0] gpio_b
+  );
+
+  localparam TOGGLE_DELAY_CYCLES = 100;
+
+  reg [7 : 0] toggle_ctr_reg;
+  reg [7 : 0] toggle_ctr_new;
+
+  reg toggle_reg;
+  reg toggle_we;
+
+  assign gpio_b = {7'b1010101, toggle_reg};
+
+  always @(posedge sys_clk)
+    begin: sys_clk_toggle_reg_update
+      if (!reset_n)
+        begin
+          toggle_ctr_reg <= 32'h0;
+          toggle_reg     <= 1'b0;
+        end
+      else
+        begin
+          toggle_ctr_reg <= toggle_ctr_new;
+
+          if (toggle_we)
+            toggle_reg <= ~toggle_reg;
+        end
+    end
+
+  always @*
+    begin : sys_clk_toggle
+      if (toggle_ctr_reg == TOGGLE_DELAY_CYCLES)
+        begin
+          toggle_ctr_new = 32'h0;
+          toggle_we      = 1'b1;
+        end
+      else
+        begin
+          toggle_ctr_new = toggle_ctr_reg + 1'b1;
+          toggle_we      = 1'b0;
+        end
+    end
+
+endmodule // toggle
+
+//======================================================================
+// EOF toggle.v
+//======================================================================
diff --git a/src/tb/tb_toggle.v b/src/tb/tb_toggle.v
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+//======================================================================
+//
+// tb_toggle
+// ---------
+// Testbench for the gpio pin toggler.
+//
+//
+// Author: Joachim Strombergson
+// Copyright (c) 2018, 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 tb_toggle();
+
+  parameter CLK_HALF_PERIOD = 1;
+  parameter CLK_PERIOD      = 2 * CLK_HALF_PERIOD;
+
+  reg tb_sys_clk;
+  reg tb_reset_n;
+  wire [7 : 0] tb_gpio_b;
+  reg [31 : 0]  cycle_ctr;
+
+  toggle dut(
+           .sys_clk(tb_sys_clk),
+           .reset_n(tb_reset_n),
+           .gpio_b(tb_gpio_b)
+          );
+
+
+  //----------------------------------------------------------------
+  // clk_gen
+  //
+  // Always running clock generator process.
+  //----------------------------------------------------------------
+  always
+    begin : clk_gen
+      #CLK_HALF_PERIOD;
+      tb_sys_clk = !tb_sys_clk;
+    end // clk_gen
+
+
+  //----------------------------------------------------------------
+  // sys_monitor()
+  //
+  // An always running process that creates a cycle counter and
+  // conditionally displays information about the DUT.
+  //----------------------------------------------------------------
+  always
+    begin : sys_monitor
+      cycle_ctr = cycle_ctr + 1;
+
+      #(CLK_PERIOD);
+
+      $display("cycle: 0x%016x gpio_b: 0x%08x  toggle_ctr: 0x%08x  toggle_reg: 0x%01x",
+               cycle_ctr, tb_gpio_b, dut.toggle_ctr_reg, dut.toggle_reg);
+    end
+
+
+  //----------------------------------------------------------------
+  // init_sim()
+  //
+  // Initialize all counters and testbed functionality as well
+  // as setting the DUT inputs to defined values.
+  //----------------------------------------------------------------
+  initial
+    begin
+      cycle_ctr     = 0;
+      tb_sys_clk    = 0;
+      tb_reset_n    = 0;
+
+      #(CLK_PERIOD * 10);
+
+      tb_reset_n    = 1;
+
+      #(CLK_PERIOD * 10000);
+      $finish;
+    end
+
+endmodule // tb_toggle
+
+//======================================================================
+// EOF tb_toggle.v
+//======================================================================
diff --git a/toolruns/Makefile b/toolruns/Makefile
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+#===================================================================
+#
+# Makefile
+# --------
+# Makefile for building the toggle design and simulation.
+#
+#
+# Author: Joachim Strombergson
+# Copyright (c) 2018, 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.
+#
+#===================================================================
+
+TOGGLE_SRC =../src/rtl/toggle.v
+TB_TOGGLE_SRC =../src/tb/tb_toggle.v
+
+CC = iverilog
+CC_FLAGS = -Wall
+
+LINT = verilator
+LINT_FLAGS = +1364-2001ext+ --lint-only  -Wall -Wno-fatal -Wno-DECLFILENAME
+
+all: top.sim
+
+
+top.sim: $(TB_TOGGLE SRC) $(TOGGLE_SRC)
+	$(CC) $(CC_FLAGS) -o top.sim $(TB_TOGGLE_SRC) $(TOGGLE_SRC)
+
+
+sim-top: top.sim
+	./top.sim
+
+
+lint:  $(TOP_SRC)
+	$(LINT) $(LINT_FLAGS) $(TOGGLE_SRC)
+
+
+clean:
+	rm -f top.sim
+
+
+help:
+	@echo "Supported targets:"
+	@echo "------------------"
+	@echo "all:          Build all simulation targets."
+	@echo "lint:         Lint all rtl source files."
+	@echo "top.sim:      Build top level simulation target."
+	@echo "sim-top:      Run top level simulation."
+	@echo "clean:        Delete all built files."
+
+#===================================================================
+# EOF Makefile
+#===================================================================