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--- resources:char_drawer [2019/07/11 15:18]
jgoeders created
+++ resources:char_drawer [2019/11/01 16:41] (current)
jgoeders
@@ Line 1: / Line 1: @@
 ======The CharDrawer Module======
+This module is used to draw strings of characters to the display, one pixel at a time.  The module accepts only upper case characters (A-Z), digits (0-9) and space (" ").  A null character (0) will not be drawn, and all other ASCII values are drawn as a solid rectangle.
+There are several different ways to construct strings in SystemVerilog.  For example, the following are all equivalent:
+<code SystemVerilog>
+logic [39:0] char_string;
+assign char_string = "HELLO";
+</code>
+<code SystemVerilog>
+logic [39:0] char_string;
+assign char_string = 40'h48454C4C4F;
+</code>
+<code SystemVerilog>
+logic [39:0] char_string;
+assign char_string = {"H", "E", "L", "L", "O"};
+</code>
+<code SystemVerilog>
+logic [39:0] char_string;
+assign char_string = {8'h48, 8'h45, 8'h4C, 8'h4C, 8'h4F};
+</code>
+^ Module Name = CharDrawer ^^^^
+^ Parameter ^ Default Value ^ Description ^^
+| MAX_CHARS | 16 |The length of the string that the module can display. ||
+^ Port Name ^ Direction ^ Width ^ Description ^
+| clk | Input | 1 | 100 MHz Clock |
+| reset | Input | 1 | Active-high reset |
+| enable| Input | 1 | Raise this signal to start drawing.  The drawing will continue until finished.  To draw a new string you must lower and then raise this signal. |
+| done | Output | 1 | Active-high, indicating that the string is done drawing |
+| x_in | Input | 9 | Top-left x-coordinate of drawing region |
+| y_in | Input | 8 | Top-left y-coordinate of drawing region |
+| string_in | Input | MAX_CHARS * 8 | ASCII character string to draw, most-significant byte is drawn first.  |
+| x_out | Output| 9 | x-Coordinate of pixel to draw |
+| y_out| Output | 8 | y-Coordinate of pixel to draw |
+Click the link below to download the CharDrawer.sv file.
+<file Verilog CharDrawer.sv>
+module CharDrawer # (
+    parameter MAX_CHARS = 16
+)(
+    input wire logic                            clk,        // Clock
+    input wire logic                            reset,      // Active-high reset
+    input wire logic                            enable,     // Start drawing
+    output logic                                done,       // Done drawing
+    input wire logic    [8:0]                   x_in,       // Top-left (x,y)
+    input wire logic    [7:0]                   y_in,
+    input wire logic    [(MAX_CHARS * 8) - 1:0] string_in,  // ASCII character string to draw
+                                                            // MSB is drawn first
+    output logic        [8:0]                   x_out,      // Output (x,y) of pixel to draw
+    output logic        [7:0]                   y_out,
+    output logic                                draw_en     // Active-high enable of drawing
+);
+localparam CHAR_COLS = 5;
+localparam CHAR_ROWS = 5;
+logic   [8:0]               x;                  // Track top-left (x,y) of current character to draw
+logic   [7:0]               y;
+// ROM to lookup pixel map of each character, row by row
+logic   [8:0]               pixel_rom_addr;     // { 5 bits of char_id, see table below, 3 bits for row #}
+logic   [4:0]               pixel_rom_out;      // row of pixel data, output from ROM
+logic   [4:0]               pixel_row;          // Shift register populated with row of pixel data, then shifted out as it is drawn
+// ROM to lookup width of each character
+logic   [5:0]               width_rom_addr;     // char_id
+logic   [2:0]               width_rom_out;      // width of character
+logic   [2:0]               char_width;         // width of character, saved to register
+// char_id
+// -------
+// 0-25     = A-Z
+// 26-35    = 0-9
+// 36       = " " (space)
+// 37       = all unsported characters, except null (0) which is not printed
+logic   [7:0]               char_idx;           // Index of character being drawn, starts at MAX_CHARS-1, decrements to 0
+logic   [2:0]               col_idx;            // Current column being drawn
+logic   [2:0]               row_idx;            // Current row being drawn
+logic                       col_done;           // High when on the last column of the row
+logic                       row_done;           // High when on the last row of the character
+logic                       char_done;          // High when on the last row and col
+// State Machine
+typedef enum {S_INIT, S_NEXT_CHAR, S_READ_ROW, S_SAVE_ROW, S_DRAW_ROW, S_DONE} StateType;
+StateType cs;
+logic                       char_is_null;
+logic   [7:0]               curr_char;
+logic   [7:0]               char_select;
+////////////////////////////////// Output Logic ////////////////////////////////////
+assign x_out = x + col_idx;
+assign y_out = y + row_idx;
+assign draw_en = pixel_row[CHAR_COLS - 1];
+assign done = (char_done && char_idx == 0) || (cs == S_NEXT_CHAR && char_is_null && char_idx == 0);
+////////////////////////////////// State Machine //////////////////////////////////
+always_ff @(posedge clk) begin
+    if (reset) begin
+        cs <= S_INIT;
+    end else begin
+        case (cs)
+            S_INIT:
+                if (enable)
+                    cs <= S_NEXT_CHAR;
+            S_NEXT_CHAR:
+                if (~char_is_null)
+                    cs <= S_READ_ROW;
+                else if (char_idx == 0)
+                    cs <= S_DONE;
+            S_READ_ROW:
+                cs <= S_SAVE_ROW;
+            S_SAVE_ROW:
+                cs <= S_DRAW_ROW;
+            S_DRAW_ROW: begin
+                if (col_done) begin
+                    if (row_done) begin
+                        if (char_idx == 0) begin
+                            cs <= S_DONE;
+                        end else begin
+                            cs <= S_NEXT_CHAR;
+                        end
+                    end else begin
+                        cs <= S_READ_ROW;
+                    end
+                end
+            end
+            S_DONE:
+             if (!enable)
+                cs <= S_INIT;
+        endcase
+    end
+end
+////////////////////////////////// Row/Col/Char Counting //////////////////////////////////
+assign col_done = (cs == S_DRAW_ROW) && (col_idx == (char_width - 1));
+assign row_done = (cs == S_DRAW_ROW) && (row_idx == (CHAR_ROWS - 1));
+assign char_done = col_done && row_done;
+assign char_select = string_in[char_idx * 8 +: 8];
+assign char_is_null = (char_select == 0);
+always_ff @(posedge clk) begin
+    if (cs == S_NEXT_CHAR)
+        curr_char <= char_select;
+end
+// char_idx
+always_ff @(posedge clk) begin
+    if (cs == S_INIT)
+        char_idx <= MAX_CHARS - 1;
+    else if (char_done)
+        char_idx <= char_idx - 1;
+    else if (cs == S_NEXT_CHAR && char_is_null)
+        char_idx <= char_idx - 1;
+end
+// col_idx
+always_ff @(posedge clk) begin
+    if (cs == S_READ_ROW)
+        col_idx <= 0;
+    else if (cs == S_DRAW_ROW)
+        col_idx <= col_idx + 1;
+end
+// row_idx
+always_ff @(posedge clk) begin
+    if (cs == S_NEXT_CHAR)
+        row_idx <= 0;
+    if (col_done)
+        row_idx <= row_idx + 1;
+end
+// x,y
+always_ff @(posedge clk) begin
+    if (cs == S_INIT) begin
+        x <= x_in;
+        y <= y_in;
+    end else if (char_done) begin
+        x <= x + char_width + 1;
+    end
+end
+// Shift register of current row of pixels being drawn
+always_ff @(posedge clk) begin
+    if (cs == S_INIT)
+        pixel_row <= 0;
+    if (cs == S_SAVE_ROW)
+        pixel_row <= pixel_rom_out;
+    else if (cs == S_DRAW_ROW)
+        pixel_row <= {pixel_row[CHAR_COLS - 2:0], 1'b0};
+end
+////////////////////////////////// Character ROM Lookups //////////////////////////////////
+always_comb begin
+    if (curr_char >= "A" && curr_char <= "Z") begin
+        pixel_rom_addr = {curr_char - "A", row_idx};
+        width_rom_addr = {curr_char - "A"};
+    end else if (curr_char >= "0" && curr_char <= "9") begin
+        pixel_rom_addr = {curr_char - "0" + 26, row_idx};
+        width_rom_addr = {curr_char - "0" + 26};
+    end else if (curr_char == " ") begin
+        pixel_rom_addr = {8'd36, row_idx};
+        width_rom_addr = 8'd36;
+    end else begin
+        pixel_rom_addr = {8'd37, row_idx};
+        width_rom_addr = 8'd37;
+    end
+end
+always_ff @(posedge clk) begin
+    if (cs == S_SAVE_ROW)
+        char_width <= width_rom_out;
+end
+always_ff @(posedge clk) begin
+     case(pixel_rom_addr)
+        {"A" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"A" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"A" - "A", 3'd2}: pixel_rom_out = 5'b11100;
+        {"A" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"A" - "A", 3'd4}: pixel_rom_out = 5'b10100;
+        {"B" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"B" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"B" - "A", 3'd2}: pixel_rom_out = 5'b11110;
+        {"B" - "A", 3'd3}: pixel_rom_out = 5'b10010;
+        {"B" - "A", 3'd4}: pixel_rom_out = 5'b11110;
+        {"C" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"C" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"C" - "A", 3'd2}: pixel_rom_out = 5'b10000;
+        {"C" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"C" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"D" - "A", 3'd0}: pixel_rom_out = 5'b11000;
+        {"D" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"D" - "A", 3'd2}: pixel_rom_out = 5'b10100;
+        {"D" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"D" - "A", 3'd4}: pixel_rom_out = 5'b11000;
+        {"E" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"E" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"E" - "A", 3'd2}: pixel_rom_out = 5'b11000;
+        {"E" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"E" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"F" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"F" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"F" - "A", 3'd2}: pixel_rom_out = 5'b11100;
+        {"F" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"F" - "A", 3'd4}: pixel_rom_out = 5'b10000;
+        {"G" - "A", 3'd0}: pixel_rom_out = 5'b11110;
+        {"G" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"G" - "A", 3'd2}: pixel_rom_out = 5'b10110;
+        {"G" - "A", 3'd3}: pixel_rom_out = 5'b10010;
+        {"G" - "A", 3'd4}: pixel_rom_out = 5'b11110;
+        {"H" - "A", 3'd0}: pixel_rom_out = 5'b10100;
+        {"H" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"H" - "A", 3'd2}: pixel_rom_out = 5'b11100;
+        {"H" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"H" - "A", 3'd4}: pixel_rom_out = 5'b10100;
+        {"I" - "A", 3'd0}: pixel_rom_out = 5'b10000;
+        {"I" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"I" - "A", 3'd2}: pixel_rom_out = 5'b10000;
+        {"I" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"I" - "A", 3'd4}: pixel_rom_out = 5'b10000;
+        {"J" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"J" - "A", 3'd1}: pixel_rom_out = 5'b00100;
+        {"J" - "A", 3'd2}: pixel_rom_out = 5'b00100;
+        {"J" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"J" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"K" - "A", 3'd0}: pixel_rom_out = 5'b10100;
+        {"K" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"K" - "A", 3'd2}: pixel_rom_out = 5'b11000;
+        {"K" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"K" - "A", 3'd4}: pixel_rom_out = 5'b10100;
+        {"L" - "A", 3'd0}: pixel_rom_out = 5'b10000;
+        {"L" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"L" - "A", 3'd2}: pixel_rom_out = 5'b10000;
+        {"L" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"L" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"M" - "A", 3'd0}: pixel_rom_out = 5'b10001;
+        {"M" - "A", 3'd1}: pixel_rom_out = 5'b11011;
+        {"M" - "A", 3'd2}: pixel_rom_out = 5'b10101;
+        {"M" - "A", 3'd3}: pixel_rom_out = 5'b10001;
+        {"M" - "A", 3'd4}: pixel_rom_out = 5'b10001;
+        {"N" - "A", 3'd0}: pixel_rom_out = 5'b10010;
+        {"N" - "A", 3'd1}: pixel_rom_out = 5'b11010;
+        {"N" - "A", 3'd2}: pixel_rom_out = 5'b10110;
+        {"N" - "A", 3'd3}: pixel_rom_out = 5'b10010;
+        {"N" - "A", 3'd4}: pixel_rom_out = 5'b10010;
+        {"O" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"O" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"O" - "A", 3'd2}: pixel_rom_out = 5'b10100;
+        {"O" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"O" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"P" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"P" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"P" - "A", 3'd2}: pixel_rom_out = 5'b11100;
+        {"P" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"P" - "A", 3'd4}: pixel_rom_out = 5'b10000;
+        {"Q" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"Q" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"Q" - "A", 3'd2}: pixel_rom_out = 5'b10100;
+        {"Q" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"Q" - "A", 3'd4}: pixel_rom_out = 5'b11110;
+        {"R" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"R" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"R" - "A", 3'd2}: pixel_rom_out = 5'b11000;
+        {"R" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"R" - "A", 3'd4}: pixel_rom_out = 5'b10100;
+        {"S" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"S" - "A", 3'd1}: pixel_rom_out = 5'b10000;
+        {"S" - "A", 3'd2}: pixel_rom_out = 5'b11100;
+        {"S" - "A", 3'd3}: pixel_rom_out = 5'b00100;
+        {"S" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"T" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"T" - "A", 3'd1}: pixel_rom_out = 5'b01000;
+        {"T" - "A", 3'd2}: pixel_rom_out = 5'b01000;
+        {"T" - "A", 3'd3}: pixel_rom_out = 5'b01000;
+        {"T" - "A", 3'd4}: pixel_rom_out = 5'b01000;
+        {"U" - "A", 3'd0}: pixel_rom_out = 5'b10100;
+        {"U" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"U" - "A", 3'd2}: pixel_rom_out = 5'b10100;
+        {"U" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"U" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"V" - "A", 3'd0}: pixel_rom_out = 5'b10100;
+        {"V" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"V" - "A", 3'd2}: pixel_rom_out = 5'b10100;
+        {"V" - "A", 3'd3}: pixel_rom_out = 5'b11100;
+        {"V" - "A", 3'd4}: pixel_rom_out = 5'b01000;
+        {"W" - "A", 3'd0}: pixel_rom_out = 5'b10001;
+        {"W" - "A", 3'd1}: pixel_rom_out = 5'b10001;
+        {"W" - "A", 3'd2}: pixel_rom_out = 5'b10101;
+        {"W" - "A", 3'd3}: pixel_rom_out = 5'b11011;
+        {"W" - "A", 3'd4}: pixel_rom_out = 5'b10001;
+        {"X" - "A", 3'd0}: pixel_rom_out = 5'b10100;
+        {"X" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"X" - "A", 3'd2}: pixel_rom_out = 5'b01000;
+        {"X" - "A", 3'd3}: pixel_rom_out = 5'b10100;
+        {"X" - "A", 3'd4}: pixel_rom_out = 5'b10100;
+        {"Y" - "A", 3'd0}: pixel_rom_out = 5'b10100;
+        {"Y" - "A", 3'd1}: pixel_rom_out = 5'b10100;
+        {"Y" - "A", 3'd2}: pixel_rom_out = 5'b11100;
+        {"Y" - "A", 3'd3}: pixel_rom_out = 5'b01000;
+        {"Y" - "A", 3'd4}: pixel_rom_out = 5'b01000;
+        {"Z" - "A", 3'd0}: pixel_rom_out = 5'b11100;
+        {"Z" - "A", 3'd1}: pixel_rom_out = 5'b00100;
+        {"Z" - "A", 3'd2}: pixel_rom_out = 5'b01000;
+        {"Z" - "A", 3'd3}: pixel_rom_out = 5'b10000;
+        {"Z" - "A", 3'd4}: pixel_rom_out = 5'b11100;
+        {"0" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"0" - "0" + 26, 3'd1}: pixel_rom_out = 5'b10100;
+        {"0" - "0" + 26, 3'd2}: pixel_rom_out = 5'b10100;
+        {"0" - "0" + 26, 3'd3}: pixel_rom_out = 5'b10100;
+        {"0" - "0" + 26, 3'd4}: pixel_rom_out = 5'b11100;
+        {"1" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11000;
+        {"1" - "0" + 26, 3'd1}: pixel_rom_out = 5'b01000;
+        {"1" - "0" + 26, 3'd2}: pixel_rom_out = 5'b01000;
+        {"1" - "0" + 26, 3'd3}: pixel_rom_out = 5'b01000;
+        {"1" - "0" + 26, 3'd4}: pixel_rom_out = 5'b01000;
+        {"2" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"2" - "0" + 26, 3'd1}: pixel_rom_out = 5'b00100;
+        {"2" - "0" + 26, 3'd2}: pixel_rom_out = 5'b11100;
+        {"2" - "0" + 26, 3'd3}: pixel_rom_out = 5'b10000;
+        {"2" - "0" + 26, 3'd4}: pixel_rom_out = 5'b11100;
+        {"3" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"3" - "0" + 26, 3'd1}: pixel_rom_out = 5'b00100;
+        {"3" - "0" + 26, 3'd2}: pixel_rom_out = 5'b01100;
+        {"3" - "0" + 26, 3'd3}: pixel_rom_out = 5'b00100;
+        {"3" - "0" + 26, 3'd4}: pixel_rom_out = 5'b11100;
+        {"4" - "0" + 26, 3'd0}: pixel_rom_out = 5'b10100;
+        {"4" - "0" + 26, 3'd1}: pixel_rom_out = 5'b10100;
+        {"4" - "0" + 26, 3'd2}: pixel_rom_out = 5'b11100;
+        {"4" - "0" + 26, 3'd3}: pixel_rom_out = 5'b00100;
+        {"4" - "0" + 26, 3'd4}: pixel_rom_out = 5'b00100;
+        {"5" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"5" - "0" + 26, 3'd1}: pixel_rom_out = 5'b10000;
+        {"5" - "0" + 26, 3'd2}: pixel_rom_out = 5'b11100;
+        {"5" - "0" + 26, 3'd3}: pixel_rom_out = 5'b00100;
+        {"5" - "0" + 26, 3'd4}: pixel_rom_out = 5'b11100;
+        {"6" - "0" + 26, 3'd0}: pixel_rom_out = 5'b10000;
+        {"6" - "0" + 26, 3'd1}: pixel_rom_out = 5'b10000;
+        {"6" - "0" + 26, 3'd2}: pixel_rom_out = 5'b11100;
+        {"6" - "0" + 26, 3'd3}: pixel_rom_out = 5'b10100;
+        {"6" - "0" + 26, 3'd4}: pixel_rom_out = 5'b11100;
+        {"7" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"7" - "0" + 26, 3'd1}: pixel_rom_out = 5'b00100;
+        {"7" - "0" + 26, 3'd2}: pixel_rom_out = 5'b00100;
+        {"7" - "0" + 26, 3'd3}: pixel_rom_out = 5'b00100;
+        {"7" - "0" + 26, 3'd4}: pixel_rom_out = 5'b00100;
+        {"8" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"8" - "0" + 26, 3'd1}: pixel_rom_out = 5'b10100;
+        {"8" - "0" + 26, 3'd2}: pixel_rom_out = 5'b11100;
+        {"8" - "0" + 26, 3'd3}: pixel_rom_out = 5'b10100;
+        {"8" - "0" + 26, 3'd4}: pixel_rom_out = 5'b11100;
+        {"9" - "0" + 26, 3'd0}: pixel_rom_out = 5'b11100;
+        {"9" - "0" + 26, 3'd1}: pixel_rom_out = 5'b10100;
+        {"9" - "0" + 26, 3'd2}: pixel_rom_out = 5'b11100;
+        {"9" - "0" + 26, 3'd3}: pixel_rom_out = 5'b00100;
+        {"9" - "0" + 26, 3'd4}: pixel_rom_out = 5'b00100;
+        {8'd36, 3'd0}: pixel_rom_out = 5'b00000;
+        {8'd36, 3'd1}: pixel_rom_out = 5'b00000;
+        {8'd36, 3'd2}: pixel_rom_out = 5'b00000;
+        {8'd36, 3'd3}: pixel_rom_out = 5'b00000;
+        {8'd36, 3'd4}: pixel_rom_out = 5'b00000;
+        {8'd37, 3'd0}: pixel_rom_out = 5'b11110;
+        {8'd37, 3'd1}: pixel_rom_out = 5'b11110;
+        {8'd37, 3'd2}: pixel_rom_out = 5'b11110;
+        {8'd37, 3'd3}: pixel_rom_out = 5'b11110;
+        {8'd37, 3'd4}: pixel_rom_out = 5'b11110;
+    endcase
+end
+always_ff @(posedge clk) begin
+    case(width_rom_addr)
+        // A-Z
+        {"A" - "A"}: width_rom_out = 3;
+        {"B" - "A"}: width_rom_out = 4;
+        {"C" - "A"}: width_rom_out = 3;
+        {"D" - "A"}: width_rom_out = 3;
+        {"E" - "A"}: width_rom_out = 3;
+        {"F" - "A"}: width_rom_out = 3;
+        {"G" - "A"}: width_rom_out = 4;
+        {"H" - "A"}: width_rom_out = 3;
+        {"I" - "A"}: width_rom_out = 1;
+        {"J" - "A"}: width_rom_out = 3;
+        {"K" - "A"}: width_rom_out = 3;
+        {"L" - "A"}: width_rom_out = 3;
+        {"M" - "A"}: width_rom_out = 5;
+        {"N" - "A"}: width_rom_out = 4;
+        {"O" - "A"}: width_rom_out = 3;
+        {"P" - "A"}: width_rom_out = 3;
+        {"Q" - "A"}: width_rom_out = 4;
+        {"R" - "A"}: width_rom_out = 3;
+        {"S" - "A"}: width_rom_out = 3;
+        {"T" - "A"}: width_rom_out = 3;
+        {"U" - "A"}: width_rom_out = 3;
+        {"V" - "A"}: width_rom_out = 3;
+        {"W" - "A"}: width_rom_out = 5;
+        {"X" - "A"}: width_rom_out = 3;
+        {"Y" - "A"}: width_rom_out = 3;
+        {"Z" - "A"}: width_rom_out = 3;
+        // 0-9
+        {"0" - "0" + 26}: width_rom_out = 3;
+        {"1" - "0" + 26}: width_rom_out = 2;
+        {"2" - "0" + 26}: width_rom_out = 3;
+        {"3" - "0" + 26}: width_rom_out = 3;
+        {"4" - "0" + 26}: width_rom_out = 3;
+        {"5" - "0" + 26}: width_rom_out = 3;
+        {"6" - "0" + 26}: width_rom_out = 3;
+        {"7" - "0" + 26}: width_rom_out = 3;
+        {"8" - "0" + 26}: width_rom_out = 3;
+        {"9" - "0" + 26}: width_rom_out = 3;
+        // Space
+: width_rom_out = 4;
+        // non-supported, non-null
+: width_rom_out = 4;
+    endcase
+end
+endmodule
+</file>

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