/////////////////////////////////////////////////////////////////////
////                                                             ////
////             LWB rev 1.2 -- BUS CHANGE FOR TWO SRAMS         ////
////                                                             ////
////                                                             ////
////                 Author: Liu Tao                             ////
////          liutao94@tsinghua.org.cn                           ////
////                                                             ////
////                                                             ////
////                                                             ////
/////////////////////////////////////////////////////////////////////
////                                                             ////
//// Copyright (C) 2003 Liu Tao                                  ////
////               liutao94@tsinghua.org.cn                      ////
////                                                             ////
////                                                             ////
/////////////////////////////////////////////////////////////////////


`include "timescale.v"

module LWBBUSCHANGE (EA_SRAM,CE_SRAM,OE_SRAM,WE_SRAM,ld,la,SRAM_CE_,SRAM_OE_,SRAM_WE_,SRAM_1_IN_ED,SRAM_2_IN_ED,toggle,ED_SRAM,SRAM_1_CE_,SRAM_1_OE_,SRAM_1_WE_,SRAM_1_EA,SRAM_1_O_ED,SRAM_1_OEN,SRAM_2_CE_,SRAM_2_OE_,SRAM_2_WE_,SRAM_2_EA,SRAM_2_O_ED,SRAM_2_OEN);



	//=================================================================================
	//input
	//=================================================================================
	    /*___________________________________________________ */
		//from C6711 EMIF interface,DECODE
		input [18:0] EA_SRAM;
		input CE_SRAM;
		input OE_SRAM;
		input WE_SRAM;
		
	    /*___________________________________________________ */
		//from SAA7113 interface
		input [7:0] ld;//data bus,to sram
		input [18:0] la;//address bus,to sram
		input SRAM_CE_;
		input SRAM_OE_;
		input SRAM_WE_;


	    /*___________________________________________________ */
		//from SRAM1
		input [7:0] SRAM_1_IN_ED;

	    /*___________________________________________________ */
		//FROM SRAM2
		input [7:0] SRAM_2_IN_ED;

	    /*___________________________________________________ */
		//from top logic control,toggle flag
		input toggle;




	//=================================================================================
	//output
	//=================================================================================
	    /*___________________________________________________ */
		//TO C6711 EMIF interface
		output [7:0] ED_SRAM;

	    /*___________________________________________________ */
		//to SRAM1
		output SRAM_1_CE_;//ce
		output SRAM_1_OE_;//oe
		output SRAM_1_WE_;//we

		output [18:0] SRAM_1_EA;//address bus
		output [7:0] SRAM_1_O_ED;//data bus output to sram
		output SRAM_1_OEN;//data output enable

	    /*___________________________________________________ */
		//to SRAM1
		output SRAM_2_CE_;//ce
		output SRAM_2_OE_;//oe
		output SRAM_2_WE_;//we

		output [18:0] SRAM_2_EA;//address bus
		output [7:0] SRAM_2_O_ED;//data bus output to sram
		output SRAM_2_OEN;//data output enable

	//=================================================================================
	//assinging
	//=================================================================================



		//toggle =1 ,dsp EMIF interface connect to sram1,dsp read data from sram1
		assign ED_SRAM = toggle ? SRAM_1_IN_ED : SRAM_2_IN_ED;
		assign SRAM_1_O_ED = toggle ? 8'hzz : ld;
		assign SRAM_1_OEN = toggle ? 1'b0 : 1'b1;
		assign SRAM_1_EA = toggle ? EA_SRAM : la;

		assign SRAM_1_CE_ = toggle ? CE_SRAM : SRAM_CE_;//toggle =1 ,output dsp to sram1;0,output saa7113 to sram1
		assign SRAM_1_OE_ = toggle ? OE_SRAM : SRAM_OE_;
		assign SRAM_1_WE_ = toggle ? WE_SRAM : SRAM_WE_;
		 
		//toggle =1 ,saa7113  interface connect to sram2,saa7113 write data to sram2
		assign SRAM_2_O_ED = toggle ? ld : 8'hzz;
		assign SRAM_2_OEN = toggle ? 1'b1 : 1'b0;
		assign SRAM_2_EA = toggle ? la : EA_SRAM;


		assign SRAM_2_CE_ = toggle ? SRAM_CE_: CE_SRAM ;//toggle =1 ,output SAA7113 to sram1;0,output DSP to sram1
		assign SRAM_2_OE_ = toggle ? SRAM_OE_: OE_SRAM ;
		assign SRAM_2_WE_ = toggle ? SRAM_WE_: WE_SRAM ;



endmodule