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/*********************************************************

 MODULE:                Sub Level SDRAM Refresh Acknowledge

 FILE NAME:     ref_ack.v

 VERSION:       1.0

 DATE:          April 28th, 2002

 AUTHOR:                Hossein Amidi

 COMPANY:

 CODE TYPE:     Register Transfer Level

 DESCRIPTION:   This module is the sub level RTL code of SDRAM Controller ASIC verilog

 code. It is the Refresh Acknowledge block.

 Hossein Amidi

 (C) April 2002

*********************************************************/

// DEFINES

`timescale 1ns / 10ps

module ref_ack(// Input

                                        reset,

                                        clk0,

                                        do_refresh,

                                        do_reada,

                                        do_writea,

                                        do_preacharge,

                                        do_load_mod,

                                        ref_req,

                                        // Output

                                        cmack,

                                        ref_ack

                                        );

// Parameter

`include        "parameter.v"

// Input

input reset;

input clk0;

input do_refresh;

input do_reada;

input do_writea;

input do_preacharge;

input do_load_mod;

input ref_req;

// Output

output cmack;

output ref_ack;

// Internal wire and reg signals

wire reset;

wire clk0;

wire do_refresh;

wire do_reada;

wire do_writea;

wire do_preacharge;

wire do_load_mod;

wire ref_req;

reg     cmack;

reg   ref_ack;

// Assignment

// This always block generates the command acknowledge, cmack, signal.

// It also generates the acknowledge signal, ref_ack, that acknowledges

// a refresh request that was generated by the internal refresh timer circuit.

always @(posedge reset or posedge clk0)

begin

        if (reset == 1'b1)

        begin

                cmack    <= 0;

                ref_ack  <= 0;

        end

        else

        begin

                if (do_refresh == 1 & ref_req == 1)                   // Internal refresh timer refresh request

                        ref_ack <= 1;

                else if ((do_refresh == 1) | (do_reada == 1) | (do_writea == 1) | (do_preacharge == 1)   // externa  commands

                         | (do_load_mod))

                        cmack <= 1;

                else

                begin

                        ref_ack <= 0;

                        cmack   <= 0;

                end

        end

end

endmodule