Merge pull request #226 from yrabbit/oser10-elvds-example

Add an example for OSER10 using ELVDS pins

examples/himbaechel/Makefile.himbaechel

@@ -54,6 +54,7 @@ all: \
 	bsram-pROM-tangnano9k.fs bsram-SDPB-tangnano9k.fs bsram-SP-tangnano9k.fs \
 	bsram-DPB-tangnano9k.fs bsram-pROMX9-tangnano9k.fs bsram-SDPX9B-tangnano9k.fs \
 	bsram-SPX9-tangnano9k.fs bsram-DPX9B-tangnano9k.fs \
+	oser10-elvds-tangnano9k.fs \
 	\
 	blinky-szfpga.fs shift-szfpga.fs blinky-tbuf-szfpga.fs blinky-oddr-szfpga.fs \
 	blinky-osc-szfpga.fs tlvds-szfpga.fs elvds-szfpga.fs oddr-tlvds-szfpga.fs \

examples/himbaechel/oser10-elvds.v

@@ -0,0 +1,83 @@
+/* Using an oscilloscope you can see on pins tlvds_p and tlvds_n the signal with changing polarity.
+* You can also use a 100 Ohm resistor and two LEDs connected in opposite directions between these pins.
+* ODDR needs 4 clock cycles to start working, so be patient:)
+*/
+module top (
+    input clk,
+	input rst_i,
+    output elvds_p,
+    output elvds_n,
+	output LED_B
+);
+
+	ELVDS_TBUF diff_buf(
+			.OEN(w_oen),
+			.O(elvds_p),
+			.OB(elvds_n),
+			.I(oser_out)
+		);
+
+	OSER10 os(
+		.D0(1'b0),
+		.D1(1'b1),
+		.D2(1'b0),
+		.D3(1'b1),
+		.D4(1'b0),
+		.D5(1'b1),
+		.D6(1'b0),
+		.D7(1'b1),
+		.D8(1'b0),
+		.D9(1'b1),
+		.FCLK(fclk_w),
+		.PCLK(pclk_w),
+		.RESET(1'b0),
+		.Q(oser_out)
+	);
+	defparam os.GSREN = "false";
+	defparam os.LSREN = "true";
+
+	wire clk_w;
+	wire pclk_w;
+	wire fclk_w;
+
+	assign pclk_o = pclk_w;
+	assign fclk_o = fclk_w;
+
+	reg [2:0] count;
+	wire clkA;
+	reg clkB;
+	always @(posedge fclk_w) begin
+		if (!rst_i) begin
+			count <= 0;
+		end else begin 
+			if (count == 3'd4) begin
+				count <= 0;
+			end else begin
+				count <= count+1;
+			end
+		end 
+	end
+	assign clkA = count[1];
+
+	always@(negedge fclk_w) begin
+		clkB <= clkA;
+	end
+	assign pclk_w = clkA | clkB;
+
+	// slow 
+	reg [24:0] ctr_q;
+	wire [24:0] ctr_d;
+	wire tick_w;
+
+	// Sequential code (flip-flop)
+	always @(posedge clk)
+		ctr_q <= ctr_d;
+
+	// Combinational code (boolean logic)
+	assign ctr_d = ctr_q + 1'b1;
+	assign tick_w = ctr_q[24];
+
+	assign fclk_w = tick_w;
+	assign LED_B = tick_w;
+endmodule
+