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////  8051 wishbone interface to instruction rom                  ////

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////  This file is part of the 8051 cores project                 ////

////  http://www.opencores.org/cores/8051/                        ////

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////  Description                                                 ////

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////  To Do:                                                      ////

////    nothing                                                   ////

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////  Author(s):                                                  ////

////      - Simon Teran, simont@opencores.org                     ////

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//// Copyright (C) 2000 Authors and OPENCORES.ORG                 ////

////                                                              ////

//// 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, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

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//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

//

//

// synopsys translate_off

`include "oc8051_timescale.v"

// synopsys translate_on

module oc8051_wb_iinterface(rst, clk, adr_i, dat_o,stb_i, ack_o, cyc_i,

        dat_i, cyc_o, adr_o, ack_i, stb_o);

//

// rst           (in)  reset - pin

// clk           (in)  clock - pini

input rst, clk;

//

// interface to oc8051 cpu

//

// adr_i    (in)  address

// dat_o    (out) data output

// stb_i    (in)  strobe

// ack_o    (out) acknowledge

// cyc_i    (in)  cycle

input stb_i, cyc_i;

input [15:0] adr_i;

output ack_o;

output [31:0] dat_o;

//

// interface to instruction rom

//

// adr_o    (out) address

// dat_i    (in)  data input

// stb_o    (out) strobe

// ack_i    (in) acknowledge

// cyc_o    (out)  cycle

input ack_i;

input [31:0] dat_i;

output stb_o, cyc_o;

output [15:0] adr_o;

//

// internal bufers and wires

//

reg [15:0] adr;

reg stb;

assign ack_o = ack_i;

assign dat_o = dat_i;

assign stb_o = stb_i || ack_i;

assign cyc_o = stb_o;

assign adr_o = ack_i ? adr : adr_i;

always @(posedge clk or posedge rst)

  if (rst) begin

    stb <= #1 1'b0;

    adr <= #1 16'h0000;

  end else begin

    stb <= #1 stb_i;

    adr <= #1 adr_i;

  end

endmodule