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////  8051 uart test                                              ////

////                                                              ////

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

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

////                                                              ////

////  Description                                                 ////

////   submodul of oc8051_tb, used to comunicate with 8051        ////

////   serial potr                                                ////

////                                                              ////

////  To Do:                                                      ////

////   nothing                                                    ////

////                                                              ////

////  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                     ////

////                                                              ////

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

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

// Revision 1.1  2003/04/02 11:38:40  simont

// initial inport

//

// Revision 1.4  2002/09/30 17:34:01  simont

// prepared header

//

//

// synopsys translate_off

`include "oc8051_timescale.v"

// synopsys translate_on

module oc8051_uart_test (clk, rst, addr, wr, wr_bit, data_in, data_out, bit_out, rxd, txd, ow, intr, ack, stb);

//

// serial interface simulation. part of oc8051_tb

//

// clk          (in)  clock

// rst          (in)  reset

// addr         (in)  addres [oc8051.ext_addr]

// wr           (in)  write [oc8051.write]

// wr_bit       (in) write bit addresable [oc8051.p3_out.0]

// data_in      (out) data input [oc8051.data_out]

// data_out     (in)  data output [oc8051.data_in]

// rxd          (in)  receive data [oc8051.txd]

// txd          (out) transmit data [oc8051.rxd]

// ow           (in)  owerflov (used in mode 1 and 3) [oc8051.p3_out.1]

// intr         (out) interrupt request [oc8051.p3_in.0]

//

input clk, rst, wr, wr_bit, rxd, ow, stb;

input [7:0] addr, data_in;

output txd, intr, bit_out, ack;

output [7:0] data_out;

reg [7:0] data_out;

wire syn;

reg wr_r, ack;

reg [7:0] addr_r, data_in_r;

wire tclk, rclk, brate2;

assign tclk   = 0;

assign rclk   = 0;

assign brate2 = 0;

reg       pres_ow;

reg [3:0] prescaler;

wire [7:0] scon, pcon, sbuf;

oc8051_uart oc8051_uart_test(.rst(rst), .clk(clk), .bit_in(data_in[0]),

             .data_in(data_in_r), .wr(wr_r), .wr_bit(wr_bit), .wr_addr(addr_r),

             .rxd(rxd), .txd(txd), .intr(intr), .t1_ow(ow),

             .rclk(rclk), .tclk(tclk),

             .pres_ow(pres_ow), .brate2(brate2),

             .scon(scon), .pcon(pcon), .sbuf(sbuf));

always @(posedge clk)

begin

  if (ack) ack <= #1 1'b0;

  else

    ack <= #1 stb;

end

always @(posedge clk)

begin

  wr_r <= #1 wr;

  addr_r <= #1 addr;

  data_in_r <= #1 data_in;

end

always @(posedge clk or posedge rst)

begin

  if (rst) begin

    prescaler <= #1 4'h5;

    pres_ow <= #1 1'b0;

  end else if (prescaler==4'b1011) begin

    prescaler <= #1 4'h0;

    pres_ow <= #1 1'b1;

  end else begin

    prescaler <= #1 prescaler + 4'h1;

    pres_ow <= #1 1'b0;

  end

end

always @(addr or

// serial interface

         scon or pcon or sbuf)

begin

    case (addr)

      `OC8051_SFR_SCON:         data_out = scon;

      `OC8051_SFR_SBUF:         data_out = sbuf;

      `OC8051_SFR_PCON:         data_out = pcon;

      default:                  data_out = 8'h00;

    endcase

end

assign bit_out = scon[addr[2:0]];

endmodule