Subversion Repositories eco32

//

// kbd.v -- PC keyboard interface

//

module kbd(clk, reset,

           en, wr, addr,

           data_in, data_out,

           wt, irq,

           ps2_clk, ps2_data);

    // internal interface

    input clk;

    input reset;

    input en;

    input wr;

    input addr;

    input [7:0] data_in;

    output [7:0] data_out;

    output wt;

    output irq;

    // external interface

    input ps2_clk;

    input ps2_data;

  wire [7:0] keyboard_data;

  wire keyboard_rdy;

  reg [7:0] data;

  reg rdy;

  reg ien;

  reg [7:2] other_bits;

  keyboard keyboard1(

    .ps2_clk(ps2_clk),

    .ps2_data(ps2_data),

    .clk(clk),

    .reset(reset),

    .keyboard_data(keyboard_data[7:0]),

    .keyboard_rdy(keyboard_rdy)

  );

  always @(posedge clk) begin

    if (reset == 1) begin

      data <= 8'h00;

      rdy <= 0;

      ien <= 0;

      other_bits <= 6'b000000;

    end else begin

      if (keyboard_rdy == 1) begin

        data <= keyboard_data;

      end

      if (keyboard_rdy == 1 ||

          (en == 1 && wr == 0 && addr == 1)) begin

        rdy <= keyboard_rdy;

      end

      if (en == 1 && wr == 1 && addr == 0) begin

        rdy <= data_in[0];

        ien <= data_in[1];

        other_bits <= data_in[7:2];

      end

    end

  end

  assign data_out =

    (addr == 0) ? { other_bits[7:2], ien, rdy } : data[7:0];

  assign wt = 1'b0;

  assign irq = ien & rdy;

endmodule