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//----------------------------------------------------------------------------

// Copyright (C) 2001 Authors

//

// This source file may be used and distributed without restriction provided

// that this copyright statement is not removed from the file and that any

// derivative work contains the original copyright notice and the associated

// disclaimer.

//

// This source file is free software; you can redistribute it and/or modify

// it under the terms of the GNU Lesser General Public License as published

// by the Free Software Foundation; either version 2.1 of the License, or

// (at your option) any later version.

//

// This source is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public

// License for more details.

//

// You should have received a copy of the GNU Lesser General Public License

// along with this source; if not, write to the Free Software Foundation,

// Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

//

//----------------------------------------------------------------------------

//

// *File Name: io_mux.v

// 

// *Module Description:

//                      I/O mux for port function selection.

//

// *Author(s):

//              - Olivier Girard,    olgirard@gmail.com

//

//----------------------------------------------------------------------------

// $Rev: 23 $

// $LastChangedBy: olivier.girard $

// $LastChangedDate: 2009-08-30 18:39:26 +0200 (Sun, 30 Aug 2009) $

//----------------------------------------------------------------------------

`include "timescale.v"

module  io_mux (

// Function A (typically GPIO)

    a_din,

    a_dout,

    a_dout_en,

// Function B (Timer A, ...)

    b_din,

    b_dout,

    b_dout_en,

// IO Cell

    io_din,

    io_dout,

    io_dout_en,

// Function selection (0=A, 1=B)

    sel

);

// PARAMETERs

//============

parameter          WIDTH = 8;

// Function A (typically GPIO)

//===============================

output [WIDTH-1:0] a_din;

input  [WIDTH-1:0] a_dout;

input  [WIDTH-1:0] a_dout_en;

// Function B (Timer A, ...)

//===============================

output [WIDTH-1:0] b_din;

input  [WIDTH-1:0] b_dout;

input  [WIDTH-1:0] b_dout_en;

// IO Cell

//===============================

input  [WIDTH-1:0] io_din;

output [WIDTH-1:0] io_dout;

output [WIDTH-1:0] io_dout_en;

// Function selection (0=A, 1=B)

//===============================

input  [WIDTH-1:0] sel;

//=============================================================================

// 1)  I/O FUNCTION SELECTION MUX

//=============================================================================

function [WIDTH-1:0] mux (

   input [WIDTH-1:0] A,

   input [WIDTH-1:0] B,

   input [WIDTH-1:0] SEL

);

   integer i;

   begin

      mux = {WIDTH{1'b0}};

      for (i = 0; i < WIDTH; i = i + 1)

        mux[i] = sel[i] ? B[i] : A[i];

   end

endfunction

assign a_din      = mux(       io_din, {WIDTH{1'b0}}, sel);

assign b_din      = mux({WIDTH{1'b0}},        io_din, sel);

assign io_dout    = mux(       a_dout,        b_dout, sel);

assign io_dout_en = mux(    a_dout_en,     b_dout_en, sel);

endmodule // io_mux