1 files changed, 75 insertions, 0 deletions
diff --git a/examples/icestick/rs232demo_tb.v b/examples/icestick/rs232demo_tb.v
new file mode 100644
index 0000000..3e95abf
--- /dev/null
+++ b/examples/icestick/rs232demo_tb.v
@@ -0,0 +1,75 @@
+module testbench;
+	localparam integer PERIOD = 12000000 / 9600;
+
+	reg clk = 1;
+	always #5 clk = ~clk;
+
+	reg RX = 1;
+	wire TX;
+	wire LED1;
+	wire LED2;
+	wire LED3;
+	wire LED4;
+	wire LED5;
+
+	top uut (
+		.clk (clk ),
+		.RX  (RX  ),
+		.TX  (TX  ),
+		.LED1(LED1),
+		.LED2(LED2),
+		.LED3(LED3),
+		.LED4(LED4),
+		.LED5(LED5)
+	);
+
+	task send_byte;
+		input [7:0] c;
+		integer i;
+		begin
+			RX <= 0;
+			repeat (PERIOD) @(posedge clk);
+
+			for (i = 0; i < 8; i = i+1) begin
+				RX <= c[i];
+				repeat (PERIOD) @(posedge clk);
+			end
+
+			RX <= 1;
+			repeat (PERIOD) @(posedge clk);
+		end
+	endtask
+
+	reg [4095:0] vcdfile;
+
+	initial begin
+		if ($value$plusargs("vcd=%s", vcdfile)) begin
+			$dumpfile(vcdfile);
+			$dumpvars(0, testbench);
+		end
+
+		// send break
+		repeat (20 * PERIOD) @(posedge clk);
+		RX <= 0;
+		repeat (20 * PERIOD) @(posedge clk);
+		RX <= 1;
+		repeat (20 * PERIOD) @(posedge clk);
+
+		// turn all LEDs on
+		send_byte("1");
+		send_byte("2");
+		send_byte("3");
+		send_byte("4");
+		send_byte("5");
+
+		// turn all LEDs off
+		send_byte("1");
+		send_byte("2");
+		send_byte("3");
+		send_byte("4");
+		send_byte("5");
+
+		repeat (10 * PERIOD) @(posedge clk);
+		$finish;
+	end
+endmodule