fiforeadgen.v

FIFO（先进先出队列）通常用于数据的缓存和用于容纳异步信号的频率或相位的差异。本FIFO的实现是利用 双口RAM 和读写地址产生模块来实现的.FIFO的接口信号包括异步的写时钟（wr_clk）和读

// --------------------------------------------------------------------
// >>>>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
// --------------------------------------------------------------------
// Copyright (c) 2005 by DTK Corporation
// --------------------------------------------------------------------
// --------------------------------------------------------------------
//
// This file is the read-generator of the fast FIFO 
//controller reference design.
//
// --------------------------------------------------------------------
//
// Revision History : 
// --------------------------------------------------------------------
//   Ver  :| Author            :| Mod. Date :| Changes Made:
//   V0.1 :| Robin Liu         :| 03/29/05  :| Pre-Release
// --------------------------------------------------------------------
`timescale 1ns / 100ps    
module FIFOReadGen(rd_page,dprdaddress,dout,rst,rd_clk,rden,empty,dpdout);
`include "FIFOPar.v"
output[`FIFOAddrDepth-1:0] dprdaddress ;
output[`FIFODataWidth-1:0] dout;
output rd_page;
input [`FIFODataWidth-1:0] dpdout;
input rst,rd_clk,rden,empty;
reg rd_page;
reg [`FIFOAddrDepth-1:0] dprdaddressTemp;
wire [`FIFODataWidth-1:0] dout;

// when rden=1, FIFO out is enable
assign #tDLY dout=rden? dpdout :`FIFODataWidth'bz;

always@(posedge rd_clk or negedge rst) 
  if (!rst) #tDLY begin 
     dprdaddressTemp=0;
     rd_page=0; end
  else if (rden & (!empty))
      case(dprdaddressTemp)
           `FIFOMaxAddressValue:#tDLY  begin  dprdaddressTemp=0; rd_page=!rd_page; end
            default             : #tDLY dprdaddressTemp=dprdaddressTemp+1;
      endcase    
assign dprdaddress=(rden & (!empty))?  ((dprdaddressTemp==`FIFOMaxAddressValue) ? `FIFOAddrDepth'b0 : (dprdaddressTemp+1)) 
                                    : dprdaddressTemp;
      
endmodule