Resolving Tang Nano 20K warnings from Gowin_V1.9.10_x64

boards/common/hid_printer.v

@@ -1,8 +1,8 @@
 
 module hid_printer (
+    output uart_tx,
     input clk,
     input resetn,
-    input uart_tx,
     input [1:0] usb_type, 
     input usb_report,
     input [7:0] key_modifiers,
@@ -11,24 +11,24 @@ module hid_printer (
     input signed [7:0] mouse_dx,
     input signed [7:0] mouse_dy,
     input game_l, game_r, game_u, game_d,
-    input game_a, game_b, game_x, game_y, game_sel, game_sta
+    input game_a, game_b, game_x, game_y, 
+    input game_sel, game_sta
+
+//  , input [63:0] hid_report
 );
 
-reg [22:0] cnt;
-always @(posedge clk) cnt <= cnt + 1;
 
 `include "print.vh"
-defparam tx.uart_freq=115200;
-defparam tx.clk_freq=12000000;
+
 assign print_clk = clk;
 assign uart_tx = uart_txp;
 
 `include "utils.vh"                 // scancode2ascii()
 
 reg [19:0] timer;
-reg signed [10:0] mouse_x, mouse_y; // 0-1023
-wire [7:0] mouse_x2 = mouse_x + mouse_dx;
-wire [7:0] mouse_y2 = mouse_y + mouse_dy;
+reg signed [10:0] mouse_x, mouse_y; // 0-1023 and negative(!) to detect overflow
+wire signed [10:0] mouse_x2 = mouse_x + mouse_dx;
+wire signed [10:0] mouse_y2 = mouse_y + mouse_dy;
 reg [7:0] last_dx, last_dy; 
 
 reg start_print;
@@ -40,21 +40,26 @@ reg [9:0] game_btns_r;
 wire [9:0] game_btns = {game_l, game_r, game_u, game_d, game_a, game_b, 
                         game_x, game_y, game_sel, game_sta};
 
+//reg [22:0] cnt; // print raw reports
+
 always @(posedge clk) begin
-    if(~resetn) begin
-        `print("usb_hid_host demo. Connect keyboard, mouse or gamepad.\n",STR);
+    if (~resetn) begin
+        `print("usb_hid_host demo. Connect keyboard, mouse or gamepad.\x0d\x0a",STR); // "\r\n" does not work
     end else begin
+        // Sequence timer for print delay
         if (timer == 20'hfffff) begin
             if (start_print) begin
                 timer <= 0;
                 start_print <= 0;
             end
         end else
-            timer <= timer + 1;
+            timer <= ((timer + 1) & 20'hfffff);
+
+        // print raw reports
+//        cnt <= ((cnt + 1) & 23'h7fffff);
 
         // Simple ways to handle HID inputs
         if (usb_report) begin
-
             case (usb_type) 
             1: begin        // keyboard
                 // just catch all keydown events. no auto-repeat. no capslock. 
@@ -82,8 +87,8 @@ always @(posedge clk) begin
                     start_print <= 1;
                 game_btns_r <= game_btns;
             end
-            endcase
-        end
+            endcase // usb_type
+        end // if usb_report
 
         // print result to UART
         case (usb_type)
@@ -92,41 +97,46 @@ always @(posedge clk) begin
             keyascii <= 0;
             start_print <= 0;
            end
-
-        2:  case (timer)                                    // print mouse position
-            20'h00000: `print("\x0dMouse: x=", STR);        // there's no \r ...
-            20'h10000: `print({6'b0, mouse_x[9:0]}, 2);
-            20'h20000: `print(", y=", STR);
-            20'h30000: `print({6'b0, mouse_y[9:0]}, 2);
-            20'h40000: `print(mouse_btn[0] ? " L" : " _", STR);
-            20'h50000: `print(mouse_btn[1] ? " R" : " _", STR);
-            20'h60000: `print(mouse_btn[2] ? " M        " : " _        ", STR);
-            endcase
+        2: case (timer)                                    // print mouse position
+           20'h00000: `print("\x0dMouse: x=", STR);        // Print CR (\r) to start at line
+           20'h10000: `print({6'b0, mouse_x[9:0]}, 2);
+           20'h20000: `print(", y=", STR);
+           20'h30000: `print({6'b0, mouse_y[9:0]}, 2);
+           20'h40000: `print(mouse_btn[0] ? " L" : " _", STR);
+           20'h50000: `print(mouse_btn[1] ? " R" : " _", STR);
+           20'h60000: `print(mouse_btn[2] ? " M" : " _", STR);
+           20'h70000: `print("\x0d\x0a", STR);             // CRLF (\r\n)
+           endcase
         3: case(timer)                                      // print gamepad status
-            20'h00000: `print("\x0dGamepad:", STR);
-            20'h10000: `print(game_l ? " L" : " _", STR);
-            20'h20000: `print(game_u ? " U" : " _", STR);
-            20'h30000: `print(game_r ? " R" : " _", STR);
-            20'h40000: `print(game_d ? " D" : " _", STR);
-            20'h50000: `print(game_a ? " A" : " _", STR);
-            20'h60000: `print(game_b ? " B" : " _", STR);
-            20'h70000: `print(game_x ? " X" : " _", STR);
-            20'h80000: `print(game_y ? " Y" : " _", STR);
-            20'h90000: `print(game_sel ? " SE" : " __", STR);
-            20'ha0000: `print(game_sta ? " ST" : " __", STR);
-            20'hb0000: `print("         ", STR);
-            endcase
-        endcase
-    end
-
-    // print raw reports
-//    case (cnt[19:0])
-//    20'h00000: `print(hid_report, 8); 
-//    20'h10000: `print(", type=", STR); 
-//    20'h20000: `print({6'b0, usb_type}, 1); 
-//    20'hf0000: `print("\n", STR); 
-//    endcase
+           20'h00000: `print("\x0dGamepad:", STR);
+           20'h10000: `print(game_l ? " L" : " _", STR);
+           20'h20000: `print(game_u ? " U" : " _", STR);
+           20'h30000: `print(game_r ? " R" : " _", STR);
+           20'h40000: `print(game_d ? " D" : " _", STR);
+           20'h50000: `print(game_a ? " A" : " _", STR);
+           20'h60000: `print(game_b ? " B" : " _", STR);
+           20'h70000: `print(game_x ? " X" : " _", STR);
+           20'h80000: `print(game_y ? " Y" : " _", STR);
+           20'h90000: `print(game_sel ? " SE" : " __", STR);
+           20'ha0000: `print(game_sta ? " ST" : " __", STR);
+           20'hb0000: `print("\x0d\x0a", STR);
+           endcase
+        endcase // usb_type
+
+        // print raw reports
+//        if (cnt[22:20] == 3'b100) begin
+//            case (cnt[19:0])
+//            20'h00000: `print("Last USB HID report: ", STR);
+//            20'h10000: `print(hid_report, 8); 
+//            20'h20000: `print(", type=", STR); 
+//            20'h30000: `print({6'b0, usb_type}, HEX); 
+//            20'h40000: `print("\x0d\x0a", STR); 
+//            endcase
+//        end
 
+    end // resetn not active
 end
 
+
+
 endmodule

boards/common/print.vh

@@ -1,5 +1,5 @@
-parameter STR = 0;
-parameter HEX = 1;
+localparam STR = 1'b0;
+localparam HEX = 1'b1;
 
 wire print_clk;
 
@@ -15,11 +15,11 @@ reg spin_state=0;
 reg[6:0] print_length;
 reg print_type;
 
-parameter PRINT_IDLE_STATE = 0;
-parameter PRINT_WAIT_STATE = 1;
-parameter PRINT_WORK_STATE = 2;
-parameter PRINT_CONV_STATE = 3;
-reg[1:0] print_state=PRINT_IDLE_STATE;
+localparam PRINT_IDLE_STATE = 2'b00;
+localparam PRINT_WAIT_STATE = 2'b01;
+localparam PRINT_WORK_STATE = 2'b10;
+localparam PRINT_CONV_STATE = 2'b11;
+reg[1:0] print_state = PRINT_IDLE_STATE;
 
 wire[7:0] hex_lib[15:0];
 assign hex_lib[4'h0] = 8'h30;
@@ -108,7 +108,7 @@ always @(posedge print_clk) begin
         seq_head <= seq_head + 8'd1;
     if (seq_head!=seq_tail && !uart_bz) begin
         uart_en <= 1'b1;
-        total <= total + 1;
+        total <= ((total + 1) & 8'hff);
     end
 end
 

boards/common/uart_tx_V2.v

@@ -3,41 +3,40 @@ module uart_tx_V2(
     input wire [7:0] din,
     input wire wr_en,
     output wire tx_busy,
-
     output reg tx_p    
 );
 
 initial begin
     tx_p = 1'b1;
 end
 
-parameter clk_freq = 12000000;
+parameter clk_freq  = 12000000;
 parameter uart_freq = 115200;
 
-localparam STATE_IDLE	= 2'b00;
-localparam STATE_START	= 2'b01;
-localparam STATE_DATA	= 2'b10;
-localparam STATE_STOP	= 2'b11;
+localparam TX_CLK_MAX = (clk_freq / uart_freq) - 1;
+localparam TX_CLK_WID = $clog2(TX_CLK_MAX);
+
+localparam STATE_IDLE	= 2'd0;
+localparam STATE_START	= 2'd1;
+localparam STATE_DATA	= 2'd2;
+localparam STATE_STOP	= 2'd3;
 
 reg[7:0] localdin;
 reg localwr_en;
 
-//always@(posedge clk)begin
-always@(*)begin	
+//always @(*) begin	
+always @(posedge clk) begin
     localdin<=din;
     localwr_en<=wr_en;
 end
 
-reg [7:0] data= 8'h00;
-reg [2:0] bitpos= 3'h0;
-reg [1:0] state= STATE_IDLE;
+reg [7:0] data   = 8'h00;
+reg [2:0] bitpos = 3'h0;
+reg [1:0] state  = STATE_IDLE;
 
-wire tx_clk;
-
-localparam TX_CLK_MAX = (clk_freq / uart_freq)-1;
-
-reg[$clog2(TX_CLK_MAX+1)+1:0] tx_clkcnt;
+reg[TX_CLK_WID-1:0] tx_clkcnt; // 7 bits is enough for 12000000/115200=104.1666 -> 105
 
+wire tx_clk;
 assign tx_clk = (tx_clkcnt == 0);
 
 initial tx_clkcnt=0;
@@ -46,7 +45,7 @@ always @(posedge clk) begin
     if (tx_clkcnt >= TX_CLK_MAX)
         tx_clkcnt <= 0;
     else
-        tx_clkcnt <= tx_clkcnt + 1;
+        tx_clkcnt <= ((tx_clkcnt + 1) & {TX_CLK_WID{1'b1}});
 end
 
 

boards/common/utils.vh

@@ -1,12 +1,18 @@
 
-localparam [7:0] SHIFT_MASK = 8'b00100010;
+// Bits in modifier byte:
+// 0=LEFT  CTRL, 1=LEFT  SHIFT, 2=LEFT  ALT, 3=LEFT  GUI
+// 4=RIGHT CTRL, 5=RIGHT SHIFT, 6=RIGHT ALT, 7=RIGHT GUI
+localparam [7:0] SHIFT_MASK = 8'b00100010; // right and left SHIFT
+localparam [7:0] CTRL_MASK  = 8'b00010001; // richt and left CTRL
 function [7:0] scancode2char(input [7:0] scancode, input [7:0] modifiers); 
     reg [7:0] a;
     if (scancode >= 4 && scancode <= 29) begin   // a-z
         if (modifiers == 0)
-            a = scancode - 4 + 97;             // a: 97, A: 65
+            a = ((scancode - 4 + 97) & 8'hff);   // a: 97
         else if ((modifiers & SHIFT_MASK) && (modifiers & ~SHIFT_MASK) == 0)
-            a = scancode - 4 + 65;
+            a = ((scancode - 4 + 65) & 8'hff);   // A: 65
+        else if ((modifiers & CTRL_MASK) && (modifiers & ~CTRL_MASK) == 0)
+            a = ((scancode - 4 +  1) & 8'hff); // CTRL-A until CTRL-Z
     end else if (modifiers == 0) begin
         case (scancode)
             30: a = "1";
@@ -19,10 +25,10 @@ function [7:0] scancode2char(input [7:0] scancode, input [7:0] modifiers);
             37: a = "8";
             38: a = "9";
             39: a = "0";
-            40: a = "\n";       // enter
+            40: a = 13;         // enter     (CR, CTRL-M)
             41: a = 27;         // esc
-            42: a = 8;          // backspace
-            43: a = 9;          // tab
+            42: a = 8;          // backspace (CTRL-H)
+            43: a = 9;          // tab       (CTRL-I)
             44: a = 32;         // space
             45: a = "-";        // -
             46: a = "=";        // =
@@ -51,11 +57,10 @@ function [7:0] scancode2char(input [7:0] scancode, input [7:0] modifiers);
             37: a = "*";
             38: a = "(";
             39: a = ")";
-            40: a = "\n";
-            40: a = "\n";       // enter
+            40: a = 10;         // shift-enter (LF, CTRL-J)
             41: a = 27;         // esc
-            42: a = 8;          // backspace
-            43: a = 9;          // tab
+            42: a = 8;          // backspace (CTRL-H)
+            43: a = 9;          // tab       (CTRL-I)
             44: a = 32;         // space
             45: a = "_";
             46: a = "+";

boards/tang-nano20k-primer25k/.gitignore

@@ -0,0 +1,4 @@
+# GOWIN Generated sythesis files
+/impl/
+# GOWIN Report files
+*.gprj.user