//============================================================================
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//============================================================================
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// Implementation of the ZX Spectrum keyboard input generator
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// ZX Spectrum keyboard input
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// This module takes scan-codes from the PS/2 keyboard input and sets
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//
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// corresponding ZX key bitfields which are read by IN (FE) instructions.
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// This module takes scan-codes from the attached PS/2 keyboard and sets
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// corresponding ZX key bitfields which are read by the 'IN' instructions.
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//
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//
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// PS/2 | ZX Spectrum
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// PS/2 | ZX Spectrum
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// ----------+-----------------
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// ----------+-----------------
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// CTRL | CAPS SHIFT
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// CTRL | CAPS SHIFT
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// ALT | SYMBOL SHIFT
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// ALT | SYMBOL SHIFT
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//
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//
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// In addition to regular alpha-numeric keys, this code simulates many standard
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// For convenience, in addition to regular alpha-numeric keys, this code
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// symbols on the PS/2 keyboard for convenience.
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// simulates several other standard symbols on the PS/2 keyboard.
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//
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//
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// PS/2 | ZX Spectrum
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// PS/2 | ZX Spectrum
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// ----------+-----------------
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// ----------+-----------------
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// BACKSPACE | DELETE
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// BACKSPACE | DELETE
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// Arrows Left, Right, Up, Down
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// Arrows Left, Right, Up, Down
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// ESC | BREAK (CAPS+SPACE)
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// ESC | BREAK (CAPS+SPACE)
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// SHIFT => PS/2 shift for these separate additional keys: -_ += ;: "' <, >. ?/
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// SHIFT => PS/2 shift for additional keys: -_ += ;: "' <, >. ?/
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//
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//
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// Copyright (C) 2014-2016 Goran Devic
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// Copyright (C) 2014-2016 Goran Devic
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//
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//
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// This program is free software; you can redistribute it and/or modify it
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// This program is free software; you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by the Free
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// under the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 of the License, or (at your option)
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// Software Foundation; either version 2 of the License, or (at your option)
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// any later version.
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// any later version.
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//
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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// more details.
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// more details.
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//
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//
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// You should have received a copy of the GNU General Public License along
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// You should have received a copy of the GNU General Public License along
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// with this program; if not, write to the Free Software Foundation, Inc.,
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// with this program; if not, write to the Free Software Foundation, Inc.,
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// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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//============================================================================
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//============================================================================
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module zx_keyboard
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module zx_keyboard
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(
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(
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input wire clk,
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input wire clk,
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input wire reset, // Reset (negative logic)
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input wire nreset, // Active low reset
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// Output ZX-specific keyboard codes when requested by the ULA access
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// Output ZX-specific keyboard codes when requested by the ULA access
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input wire [15:0] A, // Address bus
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input wire [15:0] A, // Address bus
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output wire [4:0] key_row, // Output the state of a requested row of keys
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output wire [4:0] key_row, // Output the state of a requested row of keys
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|
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// Input key scan codes from the PS/2 keyboard
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// Input key scan codes from the PS/2 keyboard
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input wire [7:0] scan_code, // PS/2 scan-code
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input wire [7:0] scan_code, // PS/2 scan-code
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input wire scan_code_ready, // Active for 1 clock: a scan code is ready
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input wire scan_code_ready, // Active for 1 clock: a scan code is ready
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input wire scan_code_error, // Error receiving PS/2 keyboard data
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input wire scan_code_error, // Error receiving PS/2 keyboard data
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output wire pressed // Signal that a key is pressed
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output wire pressed // Signal that a key is pressed
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);
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);
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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//
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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reg [4:0] keys [0:7]; // 8 rows of 5 bits each
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reg [4:0] keys [0:7]; // 8 rows of 5 bits each
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reg released; // Tracks "released" scan code (F0)
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reg released; // Tracks "released" scan code (F0)
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reg extended; // Tracks "extended" scan code (E0)
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reg extended; // Tracks "extended" scan code (E0)
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reg shifted; // Tracks local "shifted" state
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reg shifted; // Tracks local "shifted" state
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|
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// Calculate a "key is pressed" signal
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// Calculate a "key is pressed" signal
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assign pressed = ~(&keys[7] & &keys[6] & &keys[5] & &keys[4] & &keys[3] & &keys[2] & &keys[1] & &keys[0]);
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assign pressed = ~(&keys[7] & &keys[6] & &keys[5] & &keys[4] & &keys[3] & &keys[2] & &keys[1] & &keys[0]);
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// Output requested row of keys continously
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// Output requested row of keys continously
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always @(*) // always_comb
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assign key_row =
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begin
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(~A[8] ? keys[0] : 5'b11111) &
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case (A[15:8])
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(~A[9] ? keys[1] : 5'b11111) &
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8'b11111110: key_row = keys[0];
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(~A[10] ? keys[2] : 5'b11111) &
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8'b11111101: key_row = keys[1];
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(~A[11] ? keys[3] : 5'b11111) &
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8'b11111011: key_row = keys[2];
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(~A[12] ? keys[4] : 5'b11111) &
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8'b11110111: key_row = keys[3];
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(~A[13] ? keys[5] : 5'b11111) &
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8'b11101111: key_row = keys[4];
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(~A[14] ? keys[6] : 5'b11111) &
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8'b11011111: key_row = keys[5];
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(~A[15] ? keys[7] : 5'b11111);
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8'b10111111: key_row = keys[6];
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8'b01111111: key_row = keys[7];
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default:
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key_row = 5'b11111;
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endcase
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end
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always @(posedge clk or negedge reset)
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always @(posedge clk or negedge nreset)
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begin
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begin
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if (!reset) begin
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if (!nreset) begin
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released <= 0;
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released <= 0;
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extended <= 0;
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extended <= 0;
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shifted <= 0;
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shifted <= 0;
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keys[0] <= '1;
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keys[0] <= '1;
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keys[1] <= '1;
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keys[1] <= '1;
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keys[2] <= '1;
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keys[2] <= '1;
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keys[3] <= '1;
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keys[3] <= '1;
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keys[4] <= '1;
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keys[4] <= '1;
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keys[5] <= '1;
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keys[5] <= '1;
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keys[6] <= '1;
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keys[6] <= '1;
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keys[7] <= '1;
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keys[7] <= '1;
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end else
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end else
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if (scan_code_ready) begin
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if (scan_code_ready) begin
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if (scan_code==8'hE0)
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if (scan_code==8'hE0)
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extended <= 1;
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extended <= 1;
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else if (scan_code==8'hF0)
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else if (scan_code==8'hF0)
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released <= 1;
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released <= 1;
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else begin
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else begin
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// Cancel release/extended flags for the next clock
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// Cancel release/extended flags for the next clock
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extended <= 0;
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extended <= 0;
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released <= 0;
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released <= 0;
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if (extended) begin
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if (extended) begin
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// Extended keys
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// Extended keys
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case (scan_code)
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case (scan_code)
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8'h6B: begin // LEFT
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8'h6B: begin // LEFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[3][4] <= released; // 5
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keys[3][4] <= released; // 5
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end
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end
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8'h72: begin // DOWN
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8'h72: begin // DOWN
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keys[0][0] <= released; // CAPS SHIFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[4][4] <= released; // 6
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keys[4][4] <= released; // 6
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end
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end
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8'h75: begin // UP
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8'h75: begin // UP
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keys[0][0] <= released; // CAPS SHIFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[4][3] <= released; // 7
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keys[4][3] <= released; // 7
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end
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end
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8'h74: begin // RIGHT
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8'h74: begin // RIGHT
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keys[0][0] <= released; // CAPS SHIFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[4][2] <= released; // 8
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keys[4][2] <= released; // 8
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end
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end
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endcase
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endcase
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end
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end
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else begin
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else begin
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// For each PS/2 scan-code, set the ZX keyboard matrix state
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// For each PS/2 scan-code, set the ZX keyboard matrix state
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// 'released' contains 0 when a key is pressed; 1 otherwise
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// 'released' contains 0 when a key is pressed; 1 otherwise
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case (scan_code)
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case (scan_code)
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8'h12: shifted <= !released; // Local SHIFT key (left)
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8'h12: shifted <= !released; // Local SHIFT key (left)
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8'h59: shifted <= !released; // Local SHIFT key (right)
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8'h59: shifted <= !released; // Local SHIFT key (right)
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8'h14: keys[0][0] <= released; // CAPS SHIFT = Left or right Ctrl
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8'h14: keys[0][0] <= released; // CAPS SHIFT = Left or right Ctrl
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8'h1A: keys[0][1] <= released; // Z
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8'h1A: keys[0][1] <= released; // Z
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8'h22: keys[0][2] <= released; // X
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8'h22: keys[0][2] <= released; // X
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8'h21: keys[0][3] <= released; // C
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8'h21: keys[0][3] <= released; // C
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8'h2A: keys[0][4] <= released; // V
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8'h2A: keys[0][4] <= released; // V
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8'h1C: keys[1][0] <= released; // A
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8'h1C: keys[1][0] <= released; // A
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8'h1B: keys[1][1] <= released; // S
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8'h1B: keys[1][1] <= released; // S
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8'h23: keys[1][2] <= released; // D
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8'h23: keys[1][2] <= released; // D
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8'h2B: keys[1][3] <= released; // F
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8'h2B: keys[1][3] <= released; // F
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8'h34: keys[1][4] <= released; // G
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8'h34: keys[1][4] <= released; // G
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8'h15: keys[2][0] <= released; // Q
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8'h15: keys[2][0] <= released; // Q
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8'h1D: keys[2][1] <= released; // W
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8'h1D: keys[2][1] <= released; // W
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8'h24: keys[2][2] <= released; // E
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8'h24: keys[2][2] <= released; // E
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8'h2D: keys[2][3] <= released; // R
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8'h2D: keys[2][3] <= released; // R
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8'h2C: keys[2][4] <= released; // T
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8'h2C: keys[2][4] <= released; // T
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8'h16: keys[3][0] <= released; // 1
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8'h16: keys[3][0] <= released; // 1
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8'h1E: keys[3][1] <= released; // 2
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8'h1E: keys[3][1] <= released; // 2
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8'h26: keys[3][2] <= released; // 3
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8'h26: keys[3][2] <= released; // 3
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8'h25: keys[3][3] <= released; // 4
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8'h25: keys[3][3] <= released; // 4
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8'h2E: keys[3][4] <= released; // 5
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8'h2E: keys[3][4] <= released; // 5
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8'h45: keys[4][0] <= released; // 0
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8'h45: keys[4][0] <= released; // 0
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8'h46: keys[4][1] <= released; // 9
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8'h46: keys[4][1] <= released; // 9
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8'h3E: keys[4][2] <= released; // 8
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8'h3E: keys[4][2] <= released; // 8
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8'h3D: keys[4][3] <= released; // 7
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8'h3D: keys[4][3] <= released; // 7
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8'h36: keys[4][4] <= released; // 6
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8'h36: keys[4][4] <= released; // 6
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8'h4D: keys[5][0] <= released; // P
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8'h4D: keys[5][0] <= released; // P
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8'h44: keys[5][1] <= released; // O
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8'h44: keys[5][1] <= released; // O
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8'h43: keys[5][2] <= released; // I
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8'h43: keys[5][2] <= released; // I
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8'h3C: keys[5][3] <= released; // U
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8'h3C: keys[5][3] <= released; // U
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8'h35: keys[5][4] <= released; // Y
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8'h35: keys[5][4] <= released; // Y
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8'h5A: keys[6][0] <= released; // ENTER
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8'h5A: keys[6][0] <= released; // ENTER
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8'h4B: keys[6][1] <= released; // L
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8'h4B: keys[6][1] <= released; // L
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8'h42: keys[6][2] <= released; // K
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8'h42: keys[6][2] <= released; // K
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8'h3B: keys[6][3] <= released; // J
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8'h3B: keys[6][3] <= released; // J
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8'h33: keys[6][4] <= released; // H
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8'h33: keys[6][4] <= released; // H
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8'h29: keys[7][0] <= released; // SPACE
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8'h29: keys[7][0] <= released; // SPACE
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8'h11: keys[7][1] <= released; // SYMBOL SHIFT (Red) = Left and right Alt
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8'h11: keys[7][1] <= released; // SYMBOL SHIFT (Red) = Left and right Alt
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8'h3A: keys[7][2] <= released; // M
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8'h3A: keys[7][2] <= released; // M
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8'h31: keys[7][3] <= released; // N
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8'h31: keys[7][3] <= released; // N
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8'h32: keys[7][4] <= released; // B
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8'h32: keys[7][4] <= released; // B
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8'h66: begin // BACKSPACE
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8'h66: begin // BACKSPACE
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keys[0][0] <= released;
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keys[0][0] <= released;
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keys[4][0] <= released;
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keys[4][0] <= released;
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end
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end
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8'h76: begin // ESC -> BREAK
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8'h76: begin // ESC -> BREAK
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keys[0][0] <= released; // CAPS SHIFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[7][0] <= released; // SPACE
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keys[7][0] <= released; // SPACE
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end
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end
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8'h4E: begin // - or (shifted) _
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8'h4E: begin // - or (shifted) _
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[6][3] <= released; // J
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keys[6][3] <= released; // J
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[4][0] <= released; // 0
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keys[4][0] <= released; // 0
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end
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end
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end
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end
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8'h55: begin // = or (shifted) +
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8'h55: begin // = or (shifted) +
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[6][1] <= released; // L
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keys[6][1] <= released; // L
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[6][2] <= released; // K
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keys[6][2] <= released; // K
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end
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end
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end
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end
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8'h52: begin // ' or (shifted) "
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8'h52: begin // ' or (shifted) "
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[4][3] <= released; // 7
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keys[4][3] <= released; // 7
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[5][0] <= released; // P
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keys[5][0] <= released; // P
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end
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end
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end
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end
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8'h4C: begin // ; or (shifted) :
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8'h4C: begin // ; or (shifted) :
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[5][1] <= released; // O
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keys[5][1] <= released; // O
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[0][1] <= released; // Z
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keys[0][1] <= released; // Z
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end
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end
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end
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end
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8'h41: begin // , or (shifted) <
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8'h41: begin // , or (shifted) <
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][3] <= released; // N
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keys[7][3] <= released; // N
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[2][3] <= released; // R
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keys[2][3] <= released; // R
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end
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end
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end
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end
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8'h49: begin // . or (shifted) >
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8'h49: begin // . or (shifted) >
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][2] <= released; // M
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keys[7][2] <= released; // M
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[2][4] <= released; // T
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keys[2][4] <= released; // T
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end
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end
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end
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end
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8'h4A: begin // / or (shifted) ?
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8'h4A: begin // / or (shifted) ?
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if (!shifted) begin
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[0][4] <= released; // V
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keys[0][4] <= released; // V
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end
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end
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else begin
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
|
keys[0][3] <= released; // C
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keys[0][3] <= released; // C
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end
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end
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end
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end
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endcase
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endcase
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end
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end
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end
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end
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end
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end
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end
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end
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|
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endmodule
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endmodule
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