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PS/2 keyboard now has ASCII translation, but shift isn't working yet

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This commit is contained in:
Niels Moseley 2018-01-28 23:41:27 +01:00
parent fe05766894
commit 25f08eeb1d
1 changed files with 117 additions and 6 deletions
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117
rtl/ps2keyboard/ps2keyboard.v
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@ -46,6 +46,12 @@ module ps2keyboard (
reg rxflag_ff; // flip-flop state for clk domain xing reg rxflag_ff; // flip-flop state for clk domain xing
reg rx_rdy; // data ready to be read reg rx_rdy; // data ready to be read
// keyboard translation signals
reg [7:0] ascii; // ASCII code of received character
reg ascii_rdy; // new ASCII character received
reg [2:0] cur_state;
reg [2:0] next_state;
// //
// PS/2 data from a device changes when the clock // PS/2 data from a device changes when the clock
// is low, so we latch when the clock transitions // is low, so we latch when the clock transitions
@ -93,6 +99,18 @@ end
// '1' for exactly one (high-speed) clock cycle. // '1' for exactly one (high-speed) clock cycle.
// //
//
// IBM Keyboard code page translation
// state machine for US keyboard layout
//
// http://www.computer-engineering.org/ps2keyboard/scancodes2.html
//
localparam S_KEYNORMAL = 3'b000;
localparam S_KEYF0 = 3'b001; // regular key release state
localparam S_KEYE0 = 3'b010; // extended key state
localparam S_KEYE0F0 = 3'b011; // extended release state
always @(posedge clk25 or posedge reset) always @(posedge clk25 or posedge reset)
begin begin
if (reset) if (reset)
@ -100,6 +118,8 @@ begin
rxflag_ff <= 0; rxflag_ff <= 0;
rx <= 0; rx <= 0;
rx_rdy <= 0; rx_rdy <= 0;
ascii_rdy <= 0;
cur_state <= S_KEYNORMAL;
end end
else else
begin begin
@ -120,15 +140,106 @@ begin
if (address == 1'b0) if (address == 1'b0)
begin begin
// RX buffer address // RX buffer address
dout <= rx; dout <= ascii;
rx_rdy <= 1'b0; ascii_rdy <= 1'b0;
end end
else else
begin begin
// RX status register // RX status register
dout <= {rx_rdy, 7'b0}; dout <= {ascii_rdy, 7'b0};
end end
end end
// keyboard translation state machine
if (rx_rdy == 1'b1)
begin
rx_rdy <= 1'b0;
case(cur_state)
S_KEYNORMAL:
begin
if (rx == 8'hF0)
next_state = S_KEYF0;
else if (rx == 8'hE0)
next_state = S_KEYE0;
else
begin
ascii_rdy <= 1'b1; // new key has arrived!
case(rx)
8'h1C: ascii <= "A";
8'h32: ascii <= "B";
8'h21: ascii <= "C";
8'h23: ascii <= "D";
8'h24: ascii <= "E";
8'h2B: ascii <= "F";
8'h34: ascii <= "G";
8'h33: ascii <= "H";
8'h43: ascii <= "I";
8'h3B: ascii <= "J";
8'h42: ascii <= "K";
8'h4B: ascii <= "L";
8'h3A: ascii <= "M";
8'h31: ascii <= "N";
8'h44: ascii <= "O";
8'h4D: ascii <= "P";
8'h15: ascii <= "Q";
8'h2D: ascii <= "R";
8'h1B: ascii <= "S";
8'h2C: ascii <= "T";
8'h3C: ascii <= "U";
8'h2A: ascii <= "V";
8'h1D: ascii <= "W";
8'h22: ascii <= "X";
8'h35: ascii <= "Y";
8'h1A: ascii <= "Z";
8'h45: ascii <= "0";
8'h16: ascii <= "1";
8'h1E: ascii <= "2";
8'h26: ascii <= "3";
8'h25: ascii <= "4";
8'h2E: ascii <= "5";
8'h36: ascii <= "6";
8'h3D: ascii <= "7";
8'h3E: ascii <= "8";
8'h46: ascii <= "9";
8'h4E: ascii <= "-";
8'h55: ascii <= "=";
8'h5D: ascii <= "\\ ";
8'h66: ascii <= 8'd8; // backspace
8'h29: ascii <= " ";
8'h5A: ascii <= 8'd13; // enter
8'h54: ascii <= "[";
8'h5B: ascii <= "]";
8'h52: ascii <= "'";
8'h41: ascii <= ",";
8'h49: ascii <= ".";
8'h4A: ascii <= "/";
endcase
end
end
S_KEYF0:
next_state = S_KEYNORMAL;
S_KEYE0:
begin
if (rx == 8'hF0)
next_state = S_KEYE0F0;
else
next_state = S_KEYNORMAL;
end
S_KEYE0F0:
begin
next_state = S_KEYNORMAL;
end
endcase;
end
else
begin
next_state = cur_state;
end
cur_state <= next_state;
end end
end end