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

////                                                             ////

////  Author: Eyal Hochberg                                      ////

////          eyal@provartec.com                                 ////

////                                                             ////

////  Downloaded from: http://www.opencores.org                  ////

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

////                                                             ////

//// Copyright (C) 2010 Provartec LTD                            ////

//// www.provartec.com                                           ////

//// info@provartec.com                                          ////

////                                                             ////

//// 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.////

////                                                             ////

//// 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. http://www.gnu.org/licenses/lgpl.html              ////

////                                                             ////

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

INCLUDE def_axi2ahb.txt

OUTFILE PREFIX_axi2ahb_ctrl.v

module  PREFIX_axi2ahb_ctrl (PORTS);

   input                  clk;

   input                  reset;

   revport                GROUP_AHB;

   output                 ahb_finish;

   output                 rdata_phase;

   output                 wdata_phase;

   output                 data_last;

   input                  rdata_ready;

   input                  wdata_ready;

   input                  cmd_empty;

   input                  cmd_read;

   input [ADDR_BITS-1:0]  cmd_addr;

   input [3:0]            cmd_len;

   input [1:0]            cmd_size;

   parameter              TRANS_IDLE   = 2'b00;

   parameter              TRANS_BUSY   = 2'b01;

   parameter              TRANS_NONSEQ = 2'b10;

   parameter              TRANS_SEQ    = 2'b11;

   parameter              BURST_SINGLE = 3'b000;

   parameter              BURST_INCR4  = 3'b011;

   parameter              BURST_INCR8  = 3'b101;

   parameter              BURST_INCR16 = 3'b111;

   wire                   data_ready;

   wire                   ahb_idle;

   wire                   ahb_ack;

   wire                   ahb_ack_last;

   wire                   ahb_start;

   wire                   ahb_last;

   wire                   data_last;

   reg [4:0]              cmd_counter;

   reg                    rdata_phase;

   reg                    wdata_phase;

   wire                   data_phase;

   reg [1:0]              HTRANS;

   reg [2:0]              HBURST;

   reg [1:0]              HSIZE;

   reg                    HWRITE;

   reg [ADDR_BITS-1:0]    HADDR;

   assign                 ahb_finish   = ahb_ack_last;

   assign                 data_ready   = cmd_read ? rdata_ready : wdata_ready;

   assign                 data_phase   = wdata_phase | rdata_phase;

   assign                 ahb_idle     = HTRANS == TRANS_IDLE;

   assign                 ahb_ack      = HTRANS[1] & HREADY;

   assign                 ahb_ack_last = ahb_last & ahb_ack;

   assign                 ahb_start    = (~cmd_empty) & data_ready & ahb_idle & (HREADY | (~data_phase));

   assign                 data_last    = HREADY & (ahb_idle || (HTRANS == TRANS_NONSEQ));

   always @(posedge clk or posedge reset)

     if (reset)

       cmd_counter <= #FFD 4'd0;

     else if (ahb_ack_last)

       cmd_counter <= #FFD 4'd0;

     else if (ahb_ack)

       cmd_counter <= #FFD cmd_counter + 1'b1;

   assign             ahb_last = cmd_counter == cmd_len;

   always @(posedge clk or posedge reset)

     if (reset)

       rdata_phase <= #FFD 1'b0;

     else if (ahb_ack & (~HWRITE))

       rdata_phase <= #FFD 1'b1;

     else if (data_last)

       rdata_phase <= #FFD 1'b0;

   always @(posedge clk or posedge reset)

     if (reset)

       wdata_phase <= #FFD 1'b0;

     else if (ahb_ack & HWRITE)

       wdata_phase <= #FFD 1'b1;

     else if (data_last)

       wdata_phase <= #FFD 1'b0;

   always @(posedge clk or posedge reset)

     if (reset)

       HTRANS <= #FFD TRANS_IDLE;

     else if (ahb_start)

       HTRANS <= #FFD TRANS_NONSEQ;

     else if (ahb_ack_last)

       HTRANS <= #FFD TRANS_IDLE;

     else if (ahb_ack)

       HTRANS <= #FFD TRANS_SEQ;

   always @(posedge clk or posedge reset)

     if (reset)

       HBURST <= #FFD BURST_SINGLE;

     else if (ahb_start & (cmd_len == 4'd0))

       HBURST <= #FFD BURST_SINGLE;

     else if (ahb_start & (cmd_len == 4'd3))

       HBURST <= #FFD BURST_INCR4;

     else if (ahb_start & (cmd_len == 4'd7))

       HBURST <= #FFD BURST_INCR8;

     else if (ahb_start & (cmd_len == 4'd15))

       HBURST <= #FFD BURST_INCR16;

   always @(posedge clk or posedge reset)

     if (reset)

       HSIZE <= #FFD 2'b00;

     else if (ahb_start)

       HSIZE <= cmd_size;

   always @(posedge clk or posedge reset)

     if (reset)

       HWRITE <= #FFD 2'b00;

     else if (ahb_start)

       HWRITE <= (~cmd_read);

   always @(posedge clk or posedge reset)

     if (reset)

       HADDR <= #FFD {ADDR_BITS{1'b0}};

     else if (ahb_start)

       HADDR <= #FFD cmd_addr;

     else if (ahb_ack_last)

       HADDR <= #FFD {ADDR_BITS{1'b0}};

     else if (ahb_ack)

       HADDR <= #FFD HADDR + (

                              HSIZE == 2'b00 ? 4'd1 :

                              HSIZE == 2'b01 ? 4'd2 :

                              HSIZE == 2'b10 ? 4'd4 :

                              HSIZE == 2'b11 ? 4'd8 :

                              4'd0);

endmodule