Subversion Repositories sv_dir_tb

module gpio_mod (

  clk,   // input clock

  rst_n,

  addr,  // address

  datai,  // data in

  datao,  // data out

  w_n,   // Write  not

  sel,   // select input

  io_o,  // gpio  out

  io_i   // gpio  in

);

input         rst_n;

input         clk;

input         sel;

input  [31:0] addr;

input  [31:0] datai;

output [31:0] datao;

input         w_n;

input  [31:0] io_i;

output [31:0] io_o;

reg [31:0] io_mode; //  1 = output

reg [31:0] tdatao;

reg [31:0] tio_o;

assign datao = tdatao;

assign io_o  = tio_o & io_mode;

always @(posedge clk) begin

  if(rst_n == 0) begin

    tio_o   <= 32'h00000000;

    io_mode <= 32'h00000000;

  end else if (w_n == 1 && sel == 1'b1) begin

    if (addr[3:0] > 4'h0) begin

      tdatao <= io_i & ~io_mode;

    end else begin

      tdatao <= io_mode;

    end

  end else if (w_n == 0 && sel == 1'b1) begin

    if (addr[3:0] > 4'h0) begin

      tio_o <= datai;

    end else begin

      io_mode <= datai;

    end

  end else if (sel == 1'b0) begin

    tdatao <= 32'hzzzzzzzz;

  end

end

endmodule