diff --git a/README.md b/README.md
index 0a98bb0..06fa988 100644
--- a/README.md
+++ b/README.md
@@ -62,3 +62,7 @@ https://www.avnet.com/shop/us/products/avnet-engineering-services/aes-s6mb-lx9-g
 ### Upduino 2
 
 http://www.gnarlygrey.com/
+
+### ULX3S
+
+https://github.com/emard/ulx3s
diff --git a/bench/blinky_tb.cpp b/bench/blinky_tb.cpp
new file mode 100644
index 0000000..0fdfff2
--- /dev/null
+++ b/bench/blinky_tb.cpp
@@ -0,0 +1,40 @@
+#include <verilatedos.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include <sys/types.h>
+#include <signal.h>
+#include "verilated.h"
+#include "Vblinky.h"
+#include "testb.h"
+
+int	main(int argc, char **argv) {
+	Verilated::commandArgs(argc, argv);
+	TESTB<Vblinky>	*tb = new TESTB<Vblinky>;
+
+	// See if we have a +vcd=something command-line option.
+	// If so, create the trace.vcd file
+	const char *vcd = Verilated::commandArgsPlusMatch("vcd=");
+	if (vcd[0]) {
+	  printf("Creating trace.vcd\n");
+	  tb->opentrace("trace.vcd");
+	}
+
+	// Run the simulation for 100_000 ticks
+	int old_q=0;
+	for (int i=0; i < 100000; i++) {
+	  tb->tick();
+
+	  // Print out if the q output has changed
+	  if (tb->m_core->q != old_q) {
+	    printf("LED: %d\n", tb->m_core->q);
+
+	    // and save the old q value for later comparison
+	    old_q= tb->m_core->q;
+	  }
+	}
+
+	printf("Simulation complete\n");
+}
diff --git a/bench/testb.h b/bench/testb.h
new file mode 100644
index 0000000..ae542f5
--- /dev/null
+++ b/bench/testb.h
@@ -0,0 +1,99 @@
+////////////////////////////////////////////////////////////////////////////////
+//
+// Filename: 	testb.h
+//
+// Project:	Verilog Tutorial Example file
+//
+// Purpose:	A wrapper providing a common interface to a clocked FPGA core
+//		being exercised by Verilator.
+//
+// Creator:	Dan Gisselquist, Ph.D.
+//		Gisselquist Technology, LLC
+//
+////////////////////////////////////////////////////////////////////////////////
+//
+// Written and distributed by Gisselquist Technology, LLC
+//
+// This program is hereby granted to the public domain.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.
+//
+////////////////////////////////////////////////////////////////////////////////
+//
+//
+#ifndef	TESTB_H
+#define	TESTB_H
+
+#include <stdio.h>
+#include <stdint.h>
+#include <verilated_vcd_c.h>
+
+#define	TBASSERT(TB,A) do { if (!(A)) { (TB).closetrace(); } assert(A); } while(0);
+
+template <class VA>	class TESTB {
+public:
+	VA		*m_core;
+	VerilatedVcdC*	m_trace;
+	uint64_t	m_tickcount;
+
+	TESTB(void) : m_trace(NULL), m_tickcount(0l) {
+		m_core = new VA;
+		Verilated::traceEverOn(true);
+		m_core->clk = 0;
+		eval(); // Get our initial values set properly.
+	}
+	virtual ~TESTB(void) {
+		closetrace();
+		delete m_core;
+		m_core = NULL;
+	}
+
+	virtual	void	opentrace(const char *vcdname) {
+		if (!m_trace) {
+			m_trace = new VerilatedVcdC;
+			m_core->trace(m_trace, 99);
+			m_trace->open(vcdname);
+		}
+	}
+
+	virtual	void	closetrace(void) {
+		if (m_trace) {
+			m_trace->close();
+			delete m_trace;
+			m_trace = NULL;
+		}
+	}
+
+	virtual	void	eval(void) {
+		m_core->eval();
+	}
+
+	virtual	void	tick(void) {
+		m_tickcount++;
+
+		// Make sure we have our evaluations straight before the top
+		// of the clock.  This is necessary since some of the 
+		// connection modules may have made changes, for which some
+		// logic depends.  This forces that logic to be recalculated
+		// before the top of the clock.
+		eval();
+		if (m_trace) m_trace->dump((vluint64_t)(10*m_tickcount-2));
+		m_core->clk = 1;
+		eval();
+		if (m_trace) m_trace->dump((vluint64_t)(10*m_tickcount));
+		m_core->clk = 0;
+		eval();
+		if (m_trace) {
+			m_trace->dump((vluint64_t)(10*m_tickcount+5));
+			m_trace->flush();
+		}
+	}
+
+	unsigned long	tickcount(void) {
+		return m_tickcount;
+	}
+};
+
+#endif
diff --git a/blinky.core b/blinky.core
index 8779d6d..dc3f06e 100644
--- a/blinky.core
+++ b/blinky.core
@@ -33,6 +33,12 @@ filesets:
       - upduino2/blinky_upduino2.v : {file_type : verilogSource}
       - upduino2/pinout.pcf : {file_type : PCF}
 
+  verilator_tb:
+    files:
+      - bench/blinky_tb.cpp : {file_type : cppSource}
+      - bench/testb.h : {file_type : user}
+
+
 targets:
   default:
     filesets : [rtl]
@@ -102,6 +108,15 @@ targets:
         pnr: next
     toplevel : blinky_upduino2
 
+  verilator:
+    default_tool: verilator
+    filesets : [rtl, verilator_tb]
+    tools:
+      verilator:
+        verilator_options : [--trace]
+    parameters : [clk_freq_hz=10000]
+    toplevel : blinky
+
 parameters:
   clk_freq_hz:
     datatype    : int
diff --git a/blinky.v b/blinky.v
index 2a1c67d..96bb5f0 100644
--- a/blinky.v
+++ b/blinky.v
@@ -7,7 +7,9 @@ module blinky
 
    always @(posedge clk) begin
       count <= count + 1;
+/* verilator lint_off WIDTH */
       if (count == clk_freq_hz-1) begin
+/* verilator lint_on WIDTH */
 	 q <= !q;
 	 count <= 0;
       end