hsdaoh_core: add CRC16 checksum support

Output is identical to the implementation in
hsdaoh-rp2350.

common/hsdaoh/crc16_ccitt.v

@@ -0,0 +1,86 @@
+/* -----------------------------------------------------------------------------------
+ * Module Name  : crc16_ccitt
+ * Generated by : https://github.com/PXVI/ip_parallel_custom_crc_gerator_verilog
+ * Author       : pxvi
+ * Description  : Parallel CRC( 16-bit ) module with 16-bit data input. 
+ *                Polynomial Degrees [ 16 12 5 0 ]
+ * -----------------------------------------------------------------------------------
+ * 
+ * MIT License
+ * 
+ * Copyright (c) 2024 k-sva
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the Software), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ * 
+ * ----------------------------------------------------------------------------------- */
+module crc16_ccitt  #(  parameter   RESET_SEED = 'hffff )(
+                                                                            input wire CLK,
+                                                                            input wire RSTn,
+
+                                                                            input wire [15:0] data_in,
+                                                                            input wire enable,
+                                                                            input wire clear,
+
+                                                                            output [15:0] CRC
+                                                                        );
+
+
+     reg [16-1:0] Mout_p, Mout_n;
+
+    always@( posedge CLK )
+    begin
+        Mout_p <= Mout_n;
+
+        if( !RSTn )
+        begin
+            Mout_p <= RESET_SEED;
+        end
+    end
+
+    always@( * )
+    begin
+        Mout_n = Mout_p;
+
+        if( clear )
+        begin
+            Mout_n = RESET_SEED;
+        end
+        else if( enable )
+        begin
+            Mout_n[0] = data_in[0] ^ data_in[4] ^ data_in[8] ^ data_in[11] ^ data_in[12] ^ Mout_p[0] ^ Mout_p[4] ^ Mout_p[8] ^ Mout_p[11] ^ Mout_p[12] ;
+            Mout_n[1] = data_in[1] ^ data_in[5] ^ data_in[9] ^ data_in[12] ^ data_in[13] ^ Mout_p[1] ^ Mout_p[5] ^ Mout_p[9] ^ Mout_p[12] ^ Mout_p[13] ;
+            Mout_n[2] = data_in[2] ^ data_in[6] ^ data_in[10] ^ data_in[13] ^ data_in[14] ^ Mout_p[2] ^ Mout_p[6] ^ Mout_p[10] ^ Mout_p[13] ^ Mout_p[14] ;
+            Mout_n[3] = data_in[3] ^ data_in[7] ^ data_in[11] ^ data_in[14] ^ data_in[15] ^ Mout_p[3] ^ Mout_p[7] ^ Mout_p[11] ^ Mout_p[14] ^ Mout_p[15] ;
+            Mout_n[4] = data_in[4] ^ data_in[8] ^ data_in[12] ^ data_in[15] ^ Mout_p[4] ^ Mout_p[8] ^ Mout_p[12] ^ Mout_p[15] ;
+            Mout_n[5] = data_in[0] ^ data_in[4] ^ data_in[5] ^ data_in[8] ^ data_in[9] ^ data_in[11] ^ data_in[12] ^ data_in[13] ^ Mout_p[0] ^ Mout_p[4] ^ Mout_p[5] ^ Mout_p[8] ^ Mout_p[9] ^ Mout_p[11] ^ Mout_p[12] ^ Mout_p[13] ;
+            Mout_n[6] = data_in[1] ^ data_in[5] ^ data_in[6] ^ data_in[9] ^ data_in[10] ^ data_in[12] ^ data_in[13] ^ data_in[14] ^ Mout_p[1] ^ Mout_p[5] ^ Mout_p[6] ^ Mout_p[9] ^ Mout_p[10] ^ Mout_p[12] ^ Mout_p[13] ^ Mout_p[14] ;
+            Mout_n[7] = data_in[2] ^ data_in[6] ^ data_in[7] ^ data_in[10] ^ data_in[11] ^ data_in[13] ^ data_in[14] ^ data_in[15] ^ Mout_p[2] ^ Mout_p[6] ^ Mout_p[7] ^ Mout_p[10] ^ Mout_p[11] ^ Mout_p[13] ^ Mout_p[14] ^ Mout_p[15] ;
+            Mout_n[8] = data_in[3] ^ data_in[7] ^ data_in[8] ^ data_in[11] ^ data_in[12] ^ data_in[14] ^ data_in[15] ^ Mout_p[3] ^ Mout_p[7] ^ Mout_p[8] ^ Mout_p[11] ^ Mout_p[12] ^ Mout_p[14] ^ Mout_p[15] ;
+            Mout_n[9] = data_in[4] ^ data_in[8] ^ data_in[9] ^ data_in[12] ^ data_in[13] ^ data_in[15] ^ Mout_p[4] ^ Mout_p[8] ^ Mout_p[9] ^ Mout_p[12] ^ Mout_p[13] ^ Mout_p[15] ;
+            Mout_n[10] = data_in[5] ^ data_in[9] ^ data_in[10] ^ data_in[13] ^ data_in[14] ^ Mout_p[5] ^ Mout_p[9] ^ Mout_p[10] ^ Mout_p[13] ^ Mout_p[14] ;
+            Mout_n[11] = data_in[6] ^ data_in[10] ^ data_in[11] ^ data_in[14] ^ data_in[15] ^ Mout_p[6] ^ Mout_p[10] ^ Mout_p[11] ^ Mout_p[14] ^ Mout_p[15] ;
+            Mout_n[12] = data_in[0] ^ data_in[4] ^ data_in[7] ^ data_in[8] ^ data_in[15] ^ Mout_p[0] ^ Mout_p[4] ^ Mout_p[7] ^ Mout_p[8] ^ Mout_p[15] ;
+            Mout_n[13] = data_in[1] ^ data_in[5] ^ data_in[8] ^ data_in[9] ^ Mout_p[1] ^ Mout_p[5] ^ Mout_p[8] ^ Mout_p[9] ;
+            Mout_n[14] = data_in[2] ^ data_in[6] ^ data_in[9] ^ data_in[10] ^ Mout_p[2] ^ Mout_p[6] ^ Mout_p[9] ^ Mout_p[10] ;
+            Mout_n[15] = data_in[3] ^ data_in[7] ^ data_in[10] ^ data_in[11] ^ Mout_p[3] ^ Mout_p[7] ^ Mout_p[10] ^ Mout_p[11] ;
+        end
+    end
+
+    assign CRC = Mout_p;
+endmodule

common/hsdaoh/hsdaoh_core.v

@@ -18,6 +18,21 @@ module hsdaoh_core
 	input wire [15:0] data_in
 );
 
+	parameter USE_CRC = 1;
+
+	reg crc_enable = 1'b0;
+	wire [15:0] crc_out;
+	reg [15:0] last_line_crc;
+
+	crc16_ccitt crc16_ccitt (
+		.CLK(clk_pixel),
+		.RSTn(rstn),
+		.data_in({hdmi_data[15:8], hdmi_data[23:16]}),
+		.enable(crc_enable),
+		.clear(!crc_enable),
+		.CRC(crc_out)
+	);
+
 	localparam [31:0] MAGIC = 32'hda7acab1;
 
 	reg [23:0] hdmi_data = 24'h000000;
@@ -35,40 +50,56 @@ module hsdaoh_core
 
 always @(posedge clk_pixel) begin
 
-	if ((cx == screen_width-1) && (cy < screen_height)) begin
+	if (cy < screen_height) begin
-		// last word of line contains counter of words per line
+		if (USE_CRC && (cx == 0))
-		hdmi_data <= {status_nibble[3:0], line_word_cnt[11:0], 8'h00};
+			crc_enable <= 1'b1;
 
-	end else if ((cx < screen_width) && (cy < screen_height)) begin
+		if (USE_CRC && (cx == screen_width+1)) begin
-		if (fifo_read_en && !fifo_empty) begin
+			last_line_crc <= crc_out;
-			// regular output of FIFO data
+			crc_enable <= 1'b0;
-			hdmi_data <= {data_in[15:0], 8'h00};
-
-			// increment line payload counter
-			line_word_cnt <= line_word_cnt + 1'b1;
-		end else begin
-			// output idle counter
-			hdmi_data <= {idle_counter[15:8], idle_counter[7:0], 8'h00};
-
-			// increment idle counter
-			idle_counter <= idle_counter + 1'b1;
 		end
-	end else
-		line_word_cnt <= 16'h0000;
 
-	// Enable reading before beginning of next line
+		if (cx == screen_width-1) begin
-	if ((cx == frame_width-1) && (cy < screen_height-1) && !fifo_empty)
+			// last word of line contains counter of words per line
-		fifo_read_en = 1'b1;
+			hdmi_data <= {status_nibble[3:0], line_word_cnt[11:0], 8'h00};
+
+		end else if (USE_CRC && (cx == screen_width-2)) begin
+			// second last word contains CRC
+			hdmi_data <= {last_line_crc, 8'h00};
+
+		end else if (cx < screen_width) begin
+			if (fifo_read_en && !fifo_empty) begin
+				// regular output of FIFO data
+				hdmi_data <= {data_in[15:0], 8'h00};
+
+				// increment line payload counter
+				line_word_cnt <= line_word_cnt + 1'b1;
+			end else begin
+				// output idle counter
+				hdmi_data <= {idle_counter[15:8], idle_counter[7:0], 8'h00};
+
+				// increment idle counter
+				idle_counter <= idle_counter + 1'b1;
+			end
+		end else
+			line_word_cnt <= 16'h0000;
+
+		// Enable reading before beginning of next line
+		if ((cx == frame_width-1) && (cy != screen_height-1)) begin
+			if (!fifo_empty)
+				fifo_read_en = 1'b1;
+		end
+
+		// switch read off at end of line before sending the word counter
+		// -2 because the last word is reserved (line_word_cnt and metadata)
+		if (cx == screen_width-2-USE_CRC)
+			fifo_read_en = 1'b0;
+	end
 
 	// switch read off during blanking
 	if (cy > screen_height)
 		fifo_read_en = 1'b0;
 
-	// switch read off at end of line before sending the word counter
-	// -2 because the last word is reserved (line_word_cnt and metadata)
-	if ((cx == screen_width-2) && (cy < screen_height))
-		fifo_read_en = 1'b0;
-
 	// switch read off when FIFO has only one word remaining
 	if (fifo_aempty)
 		fifo_read_en = 1'b0;
@@ -97,10 +128,10 @@ always @(posedge clk_pixel) begin
 			9  : status_nibble <= frame_cnt[7:4];
 			10 : status_nibble <= frame_cnt[11:8];
 			11 : status_nibble <= frame_cnt[15:12];
+			14 : status_nibble <= { 3'b000, USE_CRC };
 			default : status_nibble <= 4'h0;
 		endcase
 	end
-
 end
 
 	wire tmds_clock;

hsdaoh_nano20k_test.gprj

@@ -17,6 +17,7 @@
         <File path="common/hdmi/packet_picker.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/serializer.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/tmds_channel.v" type="file.verilog" enable="1"/>
+        <File path="common/hsdaoh/crc16_ccitt.v" type="file.verilog" enable="1"/>
         <File path="common/hsdaoh/hsdaoh_core.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_nano20k_test/top.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_nano20k_test/hsdaoh_nano20k_test.cst" type="file.cst" enable="1"/>

hsdaoh_nano4k_test.gprj

@@ -17,6 +17,7 @@
         <File path="common/hdmi/packet_picker.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/serializer.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/tmds_channel.v" type="file.verilog" enable="1"/>
+        <File path="common/hsdaoh/crc16_ccitt.v" type="file.verilog" enable="1"/>
         <File path="common/hsdaoh/hsdaoh_core.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_nano4k_test/fifo_hs/fifo_hs.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_nano4k_test/top.v" type="file.verilog" enable="1"/>

hsdaoh_nano9k_test.gprj

@@ -17,6 +17,7 @@
         <File path="common/hdmi/packet_picker.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/serializer.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/tmds_channel.v" type="file.verilog" enable="1"/>
+        <File path="common/hsdaoh/crc16_ccitt.v" type="file.verilog" enable="1"/>
         <File path="common/hsdaoh/hsdaoh_core.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_nano9k_test/fifo_hs/fifo_hs.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_nano9k_test/top.v" type="file.verilog" enable="1"/>

hsdaoh_primer20k_test.gprj

@@ -17,6 +17,7 @@
         <File path="common/hdmi/packet_picker.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/serializer.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/tmds_channel.v" type="file.verilog" enable="1"/>
+        <File path="common/hsdaoh/crc16_ccitt.v" type="file.verilog" enable="1"/>
         <File path="common/hsdaoh/hsdaoh_core.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_primer20k_test/top.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_primer20k_test/hsdaoh_primer20k_test.cst" type="file.cst" enable="1"/>

hsdaoh_primer25k_test.gprj

@@ -17,6 +17,7 @@
         <File path="common/hdmi/packet_picker.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/serializer.v" type="file.verilog" enable="1"/>
         <File path="common/hdmi/tmds_channel.v" type="file.verilog" enable="1"/>
+        <File path="common/hsdaoh/crc16_ccitt.v" type="file.verilog" enable="1"/>
         <File path="common/hsdaoh/hsdaoh_core.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_primer25k_test/top.v" type="file.verilog" enable="1"/>
         <File path="hsdaoh_primer25k_test/hsdaoh_primer25k_test.cst" type="file.cst" enable="1"/>