Subversion Repositories usbhostslave

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

////                                                              ////

//// softransmit

////                                                              ////

//// This file is part of the usbhostslave opencores effort.

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

////                                                              ////

//// Module Description:                                          ////

//// 

////                                                              ////

//// To Do:                                                       ////

//// 

////                                                              ////

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

//// - Steve Fielding, sfielding@base2designs.com                 ////

////                                                              ////

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

////                                                              ////

//// Copyright (C) 2004 Steve Fielding 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                     ////

////                                                              ////

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

//

// $Id: softransmit.v,v 1.2 2004-12-18 14:36:11 sfielding Exp $

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

//

`timescale 1ns / 1ps

`include "usbHostControl_h.v"

module SOFTransmit (clk, rst, sendPacketArbiterGnt, sendPacketArbiterReq, sendPacketRdy, sendPacketWEn, SOFEnable, SOFSent, SOFSyncEn, SOFTimer, SOFTimerClr);

input   clk;

input   rst;

input   sendPacketArbiterGnt;

input   sendPacketRdy;

input   SOFEnable;    // After host software asserts SOFEnable, must wait TBD time before asserting SOFSyncEn

input   SOFSyncEn;

input   [15:0]SOFTimer;

output  sendPacketArbiterReq;

output  sendPacketWEn;

output  SOFSent;    // single cycle pulse

output  SOFTimerClr;    // Single cycle pulse

wire    clk;

wire    rst;

wire    sendPacketArbiterGnt;

reg     sendPacketArbiterReq, next_sendPacketArbiterReq;

wire    sendPacketRdy;

reg     sendPacketWEn, next_sendPacketWEn;

wire    SOFEnable;

reg     SOFSent, next_SOFSent;

wire    SOFSyncEn;

wire    [15:0]SOFTimer;

reg     SOFTimerClr, next_SOFTimerClr;

// BINARY ENCODED state machine: SOFTx

// State codes definitions:

`define START_STX 3'b000

`define WAIT_SOF_NEAR 3'b001

`define WAIT_SP_GNT 3'b010

`define WAIT_SOF_NOW 3'b011

`define SOF_FIN 3'b100

reg [2:0]CurrState_SOFTx, NextState_SOFTx;

// Machine: SOFTx

// NextState logic (combinatorial)

always @ (SOFTimer or SOFSyncEn or SOFEnable or sendPacketArbiterGnt or sendPacketRdy or SOFSent or SOFTimerClr or sendPacketArbiterReq or sendPacketWEn or CurrState_SOFTx)

begin

  NextState_SOFTx <= CurrState_SOFTx;

  // Set default values for outputs and signals

  next_SOFSent <= SOFSent;

  next_SOFTimerClr <= SOFTimerClr;

  next_sendPacketArbiterReq <= sendPacketArbiterReq;

  next_sendPacketWEn <= sendPacketWEn;

  case (CurrState_SOFTx)  // synopsys parallel_case full_case

    `START_STX:

    begin

      NextState_SOFTx <= `WAIT_SOF_NEAR;

    end

    `WAIT_SOF_NEAR:

    begin

      if (SOFTimer >= `SOF_TX_TIME - `SOF_TX_MARGIN ||

        (SOFSyncEn == 1'b1 &&

        SOFEnable == 1'b1))

      begin

        NextState_SOFTx <= `WAIT_SP_GNT;

        next_sendPacketArbiterReq <= 1'b1;

      end

    end

    `WAIT_SP_GNT:

    begin

      if (sendPacketArbiterGnt == 1'b1 && sendPacketRdy == 1'b1)

      begin

        NextState_SOFTx <= `WAIT_SOF_NOW;

      end

    end

    `WAIT_SOF_NOW:

    begin

      if (SOFTimer >= `SOF_TX_TIME)

      begin

        NextState_SOFTx <= `SOF_FIN;

        next_sendPacketWEn <= 1'b1;

        next_SOFTimerClr <= 1'b1;

        next_SOFSent <= 1'b1;

      end

      else if (SOFEnable == 1'b0)

      begin

        NextState_SOFTx <= `SOF_FIN;

        next_SOFTimerClr <= 1'b1;

      end

    end

    `SOF_FIN:

    begin

      next_sendPacketWEn <= 1'b0;

      next_SOFTimerClr <= 1'b0;

      next_SOFSent <= 1'b0;

      NextState_SOFTx <= `WAIT_SOF_NEAR;

      next_sendPacketArbiterReq <= 1'b0;

    end

  endcase

end

// Current State Logic (sequential)

always @ (posedge clk)

begin

  if (rst)

    CurrState_SOFTx <= `START_STX;

  else

    CurrState_SOFTx <= NextState_SOFTx;

end

// Registered outputs logic

always @ (posedge clk)

begin

  if (rst)

  begin

    SOFSent <= 1'b0;

    SOFTimerClr <= 1'b0;

    sendPacketArbiterReq <= 1'b0;

    sendPacketWEn <= 1'b0;

  end

  else

  begin

    SOFSent <= next_SOFSent;

    SOFTimerClr <= next_SOFTimerClr;

    sendPacketArbiterReq <= next_sendPacketArbiterReq;

    sendPacketWEn <= next_sendPacketWEn;

  end

end

endmodule