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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  Generic Single-Port Synchronous RAM                         ////
////                                                              ////
////  This file is part of memory library available from          ////
////  http://www.opencores.org/cvsweb.shtml/generic_memories/     ////
////                                                              ////
////  Description                                                 ////
////  This block is a wrapper with common single-port             ////
////  synchronous memory interface for different                  ////
////  types of ASIC and FPGA RAMs. Beside universal memory        ////
////  interface it also provides behavioral model of generic      ////
////  single-port synchronous RAM.                                ////
////  It should be used in all OPENCORES designs that want to be  ////
////  portable accross different target technologies and          ////
////  independent of target memory.                               ////
////                                                              ////
////  Supported ASIC RAMs are:                                    ////
////  - Artisan Single-Port Sync RAM                              ////
////  - Avant! Two-Port Sync RAM (*)                              ////
////  - Virage Single-Port Sync RAM                               ////
////  - Virtual Silicon Single-Port Sync RAM                      ////
////                                                              ////
////  Supported FPGA RAMs are:                                    ////
////  - Xilinx Virtex RAMB4_S16                                   ////
////                                                              ////
////  To Do:                                                      ////
////   - xilinx rams need external tri-state logic                ////
////   - fix avant! two-port ram                                  ////
////   - add additional RAMs (Altera etc)                         ////
////                                                              ////
////  Author(s):                                                  ////
////      - Damjan Lampret, lampret@opencores.org                 ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000 Authors 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                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
//
// CVS Revision History
//
// $Log: not supported by cvs2svn $
// Revision 1.1.1.1  2001/10/06 10:18:36  igorm
// no message
//
// Revision 1.1  2001/08/09 13:39:33  lampret
// Major clean-up.
//
// Revision 1.2  2001/07/30 05:38:02  lampret
// Adding empty directories required by HDL coding guidelines
//
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "defines.v"
 
module generic_spram_512x20(
	// Generic synchronous single-port RAM interface
	clk, rst, ce, we, oe, addr, di, do
);
 
//
// Default address and data buses width
//
parameter aw = 9;
parameter dw = 20;
 
//
// Generic synchronous single-port RAM interface
//
input			clk;	// Clock
input			rst;	// Reset
input			ce;	// Chip enable input
input			we;	// Write enable input
input			oe;	// Output enable input
input 	[aw-1:0]	addr;	// address bus inputs
input	[dw-1:0]	di;	// input data bus
output	[dw-1:0]	do;	// output data bus
 
//
// Internal wires and registers
//
 
 
`ifdef ARTISAN_SSP
 
//
// Instantiation of ASIC memory:
//
// Artisan Synchronous Single-Port RAM (ra1sh)
//
art_hssp_512x20 #(dw, 1<<aw, aw) artisan_ssp(
	.clk(clk),
	.cen(~ce),
	.wen(~we),
	.a(addr),
	.d(di),
	.oen(~oe),
	.q(do)
);
 
`else
 
`ifdef AVANT_ATP
 
//
// Instantiation of ASIC memory:
//
// Avant! Asynchronous Two-Port RAM
//
avant_atp avant_atp(
	.web(~we),
	.reb(),
	.oeb(~oe),
	.rcsb(),
	.wcsb(),
	.ra(addr),
	.wa(addr),
	.di(di),
	.do(do)
);
 
`else
 
`ifdef VIRAGE_SSP
 
//
// Instantiation of ASIC memory:
//
// Virage Synchronous 1-port R/W RAM
//
virage_ssp virage_ssp(
	.clk(clk),
	.adr(addr),
	.d(di),
	.we(we),
	.oe(oe),
	.me(ce),
	.q(do)
);
 
`else
 
`ifdef VIRTUALSILICON_SSP
 
//
// Instantiation of ASIC memory:
//
// Virtual Silicon Single-Port Synchronous SRAM
//
virtualsilicon_ssp #(1<<aw, aw-1, dw-1) virtualsilicon_ssp(
	.CK(clk),
	.ADR(addr),
	.DI(di),
	.WEN(~we),
	.CEN(~ce),
	.OEN(~oe),
	.DOUT(do)
);
 
`else
 
`ifdef XILINX_RAMB4
 
//
// Instantiation of FPGA memory:
//
// Virtex/Spartan2
//
 
//
// Block 0
//
RAMB4_S4 ramb4_s4_0(
	.CLK(clk),
	.RST(rst),
	.ADDR(addr),
	.DI(di[3:0]),
	.EN(ce),
	.WE(we),
	.DO(do[3:0])
);
 
//
// Block 1
//
RAMB4_S4 ramb4_s4_1(
	.CLK(clk),
	.RST(rst),
	.ADDR(addr),
	.DI(di[7:4]),
	.EN(ce),
	.WE(we),
	.DO(do[7:4])
);
 
//
// Block 2
//
RAMB4_S4 ramb4_s4_2(
	.CLK(clk),
	.RST(rst),
	.ADDR(addr),
	.DI(di[11:8]),
	.EN(ce),
	.WE(we),
	.DO(do[11:8])
);
 
//
// Block 3
//
RAMB4_S4 ramb4_s4_3(
	.CLK(clk),
	.RST(rst),
	.ADDR(addr),
	.DI(di[15:12]),
	.EN(ce),
	.WE(we),
	.DO(do[15:12])
);
 
//
// Block 4
//
RAMB4_S4 ramb4_s4_4(
	.CLK(clk),
	.RST(rst),
	.ADDR(addr),
	.DI(di[19:16]),
	.EN(ce),
	.WE(we),
	.DO(do[19:16])
);
 
`else
 
//
// Generic single-port synchronous RAM model
//
 
//
// Generic RAM's registers and wires
//
reg	[dw-1:0]	mem [(1<<aw)-1:0];	// RAM content
reg	[dw-1:0]	do_reg;			// RAM data output register
 
//
// Data output drivers
//
assign do = (oe) ? do_reg : {dw{1'bz}};
 
//
// RAM read and write
//
always @(posedge clk)
	if (ce && !we)
		do_reg <= #1 mem[addr];
	else if (ce && we)
		mem[addr] <= #1 di;
 
`endif	// !XILINX_RAMB4_S16
`endif	// !VIRTUALSILICON_SSP
`endif	// !VIRAGE_SSP
`endif  // !AVANT_ATP
`endif	// !ARTISAN_SSP
 
endmodule