1x4 demux using 1x2 demux (解多工器) gate level

1x4 demux using 1x2 demux (解多工器) gate level 

//-------------------------------------------------------------
// 1-4 DeMux using 1x2 DeMux (Gate Level)
// Filename: decoder_2x4.v
//-------------------------------------------------------------
module DeMux_1x4(Din,S,Y);
input Din;
input [1:0]S;
output [3:0]Y;

wire [1:0]w;

DeMux_1x2 U1(Din,S[1],w[1:0]);
DeMux_1x2 U2(w[0],S[0],Y[1:0]);
DeMux_1x2 U3(w[1],S[0],Y[3:2]);

endmodule
//------------------------------------
// 1-2 DeMux (Gate Level)
// Filename: DeMux_1x2.v
//------------------------------------
module DeMux_1x2(D,S,Y);
input D,S;
output [1:0]Y;

wire s_bar;
not u1(s_bar,S);

and U2(Y[0],s_bar,D);
and U3(Y[1],S,D);

endmodule

// 時間單位 100ns, 時間精確度100 ps

`timescale 100ns/100ps 

module TB;

/*

module DeMux_1x4(Din,S,Y);

input D;

input [1:0]S;

output [3:0]Y;

*/

reg Din;

reg [1:0]S;

wire [3:0] Y;

integer i;

 

DeMux_1x4 UUT(Din,S,Y);

 

initial begin  

   for ( i=0;i<=8;i=i+1) 

        begin

           {Din,S}  = i;

            #1;

        end

end

endmodule