Subversion Repositories mem_ctrl

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

 *   Copyright 1999 Integrated Device Technology, Inc.

 *   All right reserved.

 *

 *   This program is proprietary and confidential information of

 *   IDT Corp. and may be used and disclosed only as authorized

 *   in a license agreement controlling such use and disclosure.

 *

 *   IDT reserves the right to make any changes to

 *   the product herein to improve function or design.

 *   IDT does not assume any liability arising out of

 *   the application or use of the product herein.

 *

 *   WARNING: The unlicensed shipping, mailing, or carring of this

 *   technical data outside the United States, or the unlicensed

 *   disclosure, by whatever means, through visits abroad, or the

 *   unlicensed disclosure to foreign national in the United States,

 *   may violate the United States criminal law.

 *

 *   File Name                 : idt71t67802s166.v

 *   Product                   : IDT71T67802

 *   Function                  : 512Kx18 pipeline burst Static RAM

 *   Simulation Tool/Version   : Verilog-XL 2.5

 *   Revision                  : rev00

 *   Date                      : 23/03/00

 *

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

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

 * Module Name: idt71t67802s166

 *

 * Notes                     : This model is believed to be functionally

 *                             accurate.  Please direct any inquiries to

 *                             IDT SRAM Applications at: sramhelp@idt.com

 *

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

`timescale 1ns/10ps

module  idt71t67802s166(A, D, DP, oe_, ce_, cs0, cs1_, lbo_,

                      gw_, bwe_, bw2_, bw1_, adsp_, adsc_, adv_, clk);

initial

begin

   $write("\n********************************************************\n");

   $write("   idt71t67802s166                                        \n");

   $write("   Rev: 01    July '99                                    \n");

   $write("   copyright 1997,1998,1999 by IDT, Inc.                  \n");

   $write("**********************************************************\n");

end

parameter addr_msb = 18;

parameter mem_top = 524287;

parameter regdelay = 1;

inout [15:0] D;

inout [1:0] DP;

input [addr_msb:0] A;

input oe_, ce_, cs0, cs1_, lbo_, gw_, bwe_, bw2_, bw1_,

      adsp_, adsc_, adv_, clk;

//internal registers for data, address, burst counter

reg [15:0] din, dout;

reg [1:0] dpin, dpout;

reg [addr_msb:0] reg_addr;

reg [1:0] brst_cnt;

wire[addr_msb:0] m_ad;

wire[15:0] data_out;

wire[1:0] dp_out;

reg wr_b1_, wr_b2_, deselr, deselrr;

wire check_data =  (~adsc_ & adsp_ & ~ce_ & cs0 & ~cs1_

                           & (~gw_ | ~bwe_ & (~bw1_ | ~bw2_)))

                 | (~deselr & adsc_ & (adsp_ | ce_)

                            & (~gw_ | ~bwe_ & (~bw1_ | ~bw2_)));

wire check_addr =   (~adsp_ & ~ce_ & cs0 & ~cs1_)

                  | ( adsp_ & ~adsc_ & ~ce_ & cs0 & ~cs1_);

specify

specparam

//Clock Parameters

   tCYC  = 6.0,  //clock cycle time

   tCH   = 2.4,   //clock high time

   tCL   = 2.4,   //clock low time

//Output Parameters

   tCD   = 3.5,   //clk to data

   tCDC  = 1.5, //output hold from clock

   tCLZ  = 0,   //CLK to output Low-Z

   tCHZ  = 3.5,   //CLK to output Hi-Z

   tOE   = 3.5,   //OE to output valid

   tOLZ  = 0,   //OE to output Hi-Z

   tOHZ  = 3.5,   //OE to output Hi-Z

//Set up times   

   tSA   = 1.5, //address set-up

   tSS   = 1.5, //address status set-up

   tSD   = 1.5, //data set-up

   tSW   = 1.5, //write set-up

   tSAV  = 1.5, //address advance set-up

   tSC   = 1.5, //chip enable and chip select set-up

//Hold times

   tHA   = 0.5, //Address hold

   tHS   = 0.5, //address status hold

   tHD   = 0.5, //data hold

   tHW   = 0.5, //write hold

   tHAV  = 0.5, //address advance hold

   tHC   = 0.5; //chip enable and chip select hold

   (oe_ *> D) = (tOE,tOE,tOHZ,tOLZ,tOHZ,tOLZ); //(01,10,0z,z1,1z,z0)

   (clk *> D) = (tCD,tCD,tCHZ,tCLZ,tCHZ,tCLZ); //(01,10,0z,z1,1z,z0)

   (oe_ *> DP) = (tOE,tOE,tOHZ,tOLZ,tOHZ,tOLZ); //(01,10,0z,z1,1z,z0)

   (clk *> DP) = (tCD,tCD,tCHZ,tCLZ,tCHZ,tCLZ); //(01,10,0z,z1,1z,z0)

//timing checks

   $period(posedge clk, tCYC );

   $width (posedge clk, tCH );

   $width (negedge clk, tCL );

   $setuphold(posedge clk, adsp_, tSS, tHS);

   $setuphold(posedge clk, adsc_, tSS, tHS);

   $setuphold(posedge clk, adv_, tSAV, tHAV);

   $setuphold(posedge clk, gw_, tSW, tHW);

   $setuphold(posedge clk, bwe_, tSW, tHW);

   $setuphold(posedge clk, bw1_, tSW, tHW);

   $setuphold(posedge clk, bw2_, tSW, tHW);

   $setuphold(posedge clk, ce_, tSC, tHC);

   $setuphold(posedge clk, cs0, tSC, tHC);

   $setuphold(posedge clk, cs1_, tSC, tHC);

   $setuphold(posedge clk &&& check_addr, A, tSA, tHA);

   $setuphold(posedge clk &&& check_data, D, tSD, tHD);

   $setuphold(posedge clk &&& check_data, DP, tSD, tHD);

endspecify

//////////////memory array//////////////////////////////////////////////

reg [7:0] memb1[0:mem_top], memb2[0:mem_top];

reg memb1p[0:mem_top], memb2p[0:mem_top];

wire doe, baddr1, baddr0, dsel;

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

//

//Output buffers: using a bufif1 has the same effect as...

//

//      assign D = doe ? data_out : 32'hz;

//      

//It was coded this way to support SPECIFY delays in the specparam section.

//

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

bufif1 (D[0],data_out[0],doe);

bufif1 (D[1],data_out[1],doe);

bufif1 (D[2],data_out[2],doe);

bufif1 (D[3],data_out[3],doe);

bufif1 (D[4],data_out[4],doe);

bufif1 (D[5],data_out[5],doe);

bufif1 (D[6],data_out[6],doe);

bufif1 (D[7],data_out[7],doe);

bufif1 (DP[0], dp_out[0],doe);

bufif1 (D[8],data_out[8],doe);

bufif1 (D[9],data_out[9],doe);

bufif1 (D[10],data_out[10],doe);

bufif1 (D[11],data_out[11],doe);

bufif1 (D[12],data_out[12],doe);

bufif1 (D[13],data_out[13],doe);

bufif1 (D[14],data_out[14],doe);

bufif1 (D[15],data_out[15],doe);

bufif1 (DP[1], dp_out[1],doe);

assign doe = ~deselr & ~deselrr & ~oe_ & wr_b1_ & wr_b2_ ;

assign dsel = (ce_ | ~cs0 | cs1_);

always @(posedge clk)

begin

   if ( ~adsc_ || ( ~adsp_ && ~ce_ ))

     deselr <=  dsel;

end

always @(posedge clk)

begin

   deselrr <= deselr;

end

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

//

//write enable generation

//

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

always @(posedge clk)

begin

   if (  (~adsc_ & adsp_ & ~ce_ & cs0 & ~cs1_ & (~gw_ | ~bwe_ & ~bw1_))

       | (~deselr & adsc_ & (adsp_ | ce_) & (~gw_ | ~bwe_ & ~bw1_)))

      wr_b1_ <= 0;

   else wr_b1_ <= 1;

   if (  (~adsc_ & adsp_ & ~ce_ & cs0 & ~cs1_ & (~gw_ | ~bwe_ & ~bw2_))

       | (~deselr & adsc_ & (adsp_ | ce_) & (~gw_ | ~bwe_ & ~bw2_)))

      wr_b2_ <= 0;

   else wr_b2_ <= 1;

end

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

//

//input address register

//

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

always @(posedge clk)

begin

   if (  (~adsp_ & ~ce_ & cs0 & ~cs1_)

       | ( adsp_ & ~adsc_ & ~ce_ & cs0 & ~cs1_)) reg_addr[addr_msb:0] <= A[addr_msb:0];

end

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

//

// burst counter

//

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

always @(posedge clk)

begin

   if (lbo_ & (  (~adsp_ & ~ce_ & cs0 & ~cs1_)

               | ( adsp_ & ~adsc_ & ~ce_ & cs0 & ~cs1_))) brst_cnt <= 0;

   else if (~lbo_ & (  (~adsp_ & ~ce_ & cs0 & ~cs1_)

                     | ( adsp_ & ~adsc_ & ~ce_ & cs0 & ~cs1_))) brst_cnt <= A[1:0];

   else if ((adsp_ | ce_) & adsc_ & ~adv_) brst_cnt <= brst_cnt + 1;

end

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

//

//determine the memory address

//

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

assign baddr1 = lbo_ ? (brst_cnt[1] ^ reg_addr[1]) : brst_cnt[1];

assign baddr0 = lbo_ ? (brst_cnt[0] ^ reg_addr[0]) : brst_cnt[0];

assign #regdelay m_ad[addr_msb:0] = {reg_addr[addr_msb:2], baddr1, baddr0};

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

//

//data output register

//

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

always @(posedge clk)

begin

    dout[15:8]  <= memb2[m_ad];

    dpout[1]   <= memb2p[m_ad];

    dout[7:0]   <= memb1[m_ad];

    dpout[0]   <= memb1p[m_ad];

end

assign data_out = dout;

assign dp_out = dpout;

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

//

//data input register

//

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

always @(posedge clk)

begin

   din <= #regdelay D;

   dpin <= #regdelay DP;

end

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

//

// write to ram

//

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

wire #1 wrb1 = ~wr_b1_ & ~clk;

wire #1 wrb2 = ~wr_b2_ & ~clk;

always @(clk)

begin

   if (wrb1) begin

      memb1[m_ad] = din[7:0];

      memb1p[m_ad] = dpin[0];

   end

   if (wrb2) begin

      memb2[m_ad] = din[15:8];

      memb2p[m_ad] = dpin[1];

   end

end

endmodule