module top;
reg [1:0] A, B;
wire[1:0] OUT;
system_clock #100 clock1(SEL);
mux2 M1(OUT, A, B, SEL);
initial
begin
A=2'd2;
B=2'd1;
end
endmodule

範例: 多工器

module top;

system_clock #400 clock1(A);

system_clock #200 clock2(B);

system_clock #100 clock3(SEL);

mux M1(OUT, A, B, SEL);

endmodule

module mux(OUT, A, B, SEL);

output OUT;

input A,B,SEL;

not I5 (sel_n, SEL) ;

and I6 (sel_a, A, SEL);

and I7 (sel_b, sel_n, B);

or I4 (OUT, sel_a, sel_b);

endmodule

module system_clock(clk);

parameter PERIOD=100;

output clk;

reg clk;

initial clk=0;

always

begin

#(PERIOD/2) clk=~clk;

end

always@(posedge clk)

if($time>1000)$stop;

endmodule