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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  #(parameter dwidth = 32,
                          parameter awidth = 32)
(clk, rst, adr, din, dout, cyc, stb, we, sel, ack, err, rty);
 
 
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;
 
event test_command_start;
event test_command_mid;
event test_command_end;
 
////////////////////////////////////////////////////////////////////
//
// 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)");
        end
 
////////////////////////////////////////////////////////////////////
//
// Wishbone write cycle
//
 
task wb_write;
        input   delay;
        integer delay;
 
        input   [awidth -1:0]   a;
        input   [dwidth -1:0]   d;
 
        begin
                -> test_command_start;
                // 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);
                -> test_command_mid;
 
                // wait for acknowledge from slave
                while(~ack)     @(posedge clk);
                -> test_command_mid;
 
                // 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}};
                -> test_command_end;
 
        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
                d    = din; // Grab the data on the posedge of clock
                #1;         // Delay the clearing (hold time of the control signals
                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 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 at address %h. Received %h, expected %h at time %t", a, q, d_exp, $time);
        end
endtask
 
endmodule