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///////////////////////////////////////////////////////////////////////

////                                                               ////

////  WISHBONE rev.B2 Wishbone Master model                        ////

////                                                               ////

////                                                               ////

////  Author: Richard Herveille                                    ////

////          richard@asics.ws                                     ////

////          www.asics.ws                                         ////

////                                                               ////

////  Downloaded from: http://www.opencores.org/projects/mem_ctrl  ////

////                                                               ////

///////////////////////////////////////////////////////////////////////

////                                                               ////

//// Copyright (C) 2001 Richard Herveille                          ////

////                    richard@asics.ws                           ////

////                                                               ////

//// 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 SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY       ////

//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED     ////

//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS     ////

//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR        ////

//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,           ////

//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES      ////

//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE     ////

//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR          ////

//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF    ////

//// LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT    ////

//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT    ////

//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE           ////

//// POSSIBILITY OF SUCH DAMAGE.                                   ////

////                                                               ////

///////////////////////////////////////////////////////////////////////

//  CVS Log

//

//  $Id: wb_master_model.v,v 1.4 2004-02-28 15:40:42 rherveille Exp $

//

//  $Date: 2004-02-28 15:40:42 $

//  $Revision: 1.4 $

//  $Author: rherveille $

//  $Locker:  $

//  $State: Exp $

//

// Change History:

//

`include "timescale.v"

module wb_master_model(clk, rst, adr, din, dout, cyc, stb, we, sel, ack, err, rty);

parameter dwidth = 32;

parameter awidth = 32;

input                  clk, rst;

output [awidth   -1:0]   adr;

input  [dwidth   -1:0]   din;

output [dwidth   -1:0]   dout;

output                 cyc, stb;

output                          we;

output [dwidth/8 -1:0] sel;

input                           ack, err, rty;

////////////////////////////////////////////////////////////////////

//

// Local Wires

//

reg     [awidth   -1:0]  adr;

reg     [dwidth   -1:0]  dout;

reg                            cyc, stb;

reg                            we;

reg [dwidth/8 -1:0] sel;

reg [dwidth   -1:0] q;

////////////////////////////////////////////////////////////////////

//

// Memory Logic

//

initial

        begin

                //adr = 32'hxxxx_xxxx;

                //adr = 0;

                adr  = {awidth{1'bx}};

                dout = {dwidth{1'bx}};

                cyc  = 1'b0;

                stb  = 1'bx;

                we   = 1'hx;

                sel  = {dwidth/8{1'bx}};

                #1;

                $display("\nINFO: WISHBONE MASTER MODEL INSTANTIATED (%m)\n");

        end

////////////////////////////////////////////////////////////////////

//

// Wishbone write cycle

//

task wb_write;

        input   delay;

        integer delay;

        input   [awidth -1:0]    a;

        input   [dwidth -1:0]    d;

        begin

                // wait initial delay

                repeat(delay) @(posedge clk);

                // assert wishbone signal

                #1;

                adr  = a;

                dout = d;

                cyc  = 1'b1;

                stb  = 1'b1;

                we   = 1'b1;

                sel  = {dwidth/8{1'b1}};

                @(posedge clk);

                // wait for acknowledge from slave

                while(~ack)     @(posedge clk);

                // negate wishbone signals

                #1;

                cyc  = 1'b0;

                stb  = 1'bx;

                adr  = {awidth{1'bx}};

                dout = {dwidth{1'bx}};

                we   = 1'hx;

                sel  = {dwidth/8{1'bx}};

        end

endtask

////////////////////////////////////////////////////////////////////

//

// Wishbone read cycle

//

task wb_read;

        input   delay;

        integer delay;

        input    [awidth -1:0]   a;

        output  [dwidth -1:0]    d;

        begin

                // wait initial delay

                repeat(delay) @(posedge clk);

                // assert wishbone signals

                #1;

                adr  = a;

                dout = {dwidth{1'bx}};

                cyc  = 1'b1;

                stb  = 1'b1;

                we   = 1'b0;

                sel  = {dwidth/8{1'b1}};

                @(posedge clk);

                // wait for acknowledge from slave

                while(~ack)     @(posedge clk);

                // negate wishbone signals

                #1;

                cyc  = 1'b0;

                stb  = 1'bx;

                adr  = {awidth{1'bx}};

                dout = {dwidth{1'bx}};

                we   = 1'hx;

                sel  = {dwidth/8{1'bx}};

                d    = din;

        end

endtask

////////////////////////////////////////////////////////////////////

//

// Wishbone compare cycle (read data from location and compare with expected data)

//

task wb_cmp;

        input   delay;

        integer delay;

        input [awidth -1:0]      a;

        input   [dwidth -1:0]    d_exp;

        begin

                wb_read (delay, a, q);

                if (d_exp !== q)

                        $display("Data compare error. Received %h, expected %h at time %t", q, d_exp, $time);

        end

endtask

endmodule