11011 Sequence Detector

 

module dff(

input d,clk,rst,

output reg q,qbar

);

always @(posedge clk ,negedge rst)

begin

if(rst==0) begin q<=0;qbar<=1;end

else

begin

q<=d;

qbar<=~d;

end

end

endmodule

module dff_tb();

reg d,clk;

wire q,qbar;

dff dff_i1(d,clk,q,qbar);

initial begin

clk=0;d=0;

#10d=1;

end

always #5 clk=~clk;

endmodule

module seq_detector(

    input x,clk,rst,

    output z

);

wire d0,d1,d2;

wire q0,q1,q2;

wire q0bar,q1bar,q2bar;

wire w1,w2,w3,w4,w5,w6;

and and_i1(w1,q2bar,q0bar);//w1=q2'q0'

xor xor_i1(w2,x,q1);//w2=x^q1

and and_i2(d0,w1,w2);//d0=w1w2

dff dff_i1(d0,clk,rst,q0,q0bar);

and and_i3(w3,q2bar,q1bar,q0,x);//w3=q2'q1'q0x

and and_i4(w4,q2,q1bar,q0bar,x);//w4=q2q1'q0'x

and and_i5(w5,q2bar,q1,q0bar);//w5=q2'q1q0'

or or_i1(d1,w3,w4,w5);

dff dff_i2(d1,clk,rst,q1,q1bar);

and and_i6(d2,q2bar,q1,q0,x);

dff dff_i3(d2,clk,rst,q2,q2bar);

and and_i7(z,q2,q1bar,q0bar,x);

endmodule

module seq_detector_tb();

reg x,clk,rst;

wire z;

seq_detector seq_detector_i1(x,clk,rst,z);

initial begin

clk=0;x=0;rst=1;

#2;rst=0;

#1;rst=1;

#5;x=1;

#5;x=1;

#5;x=0;

#5;x=1;

#5;x=1;

#5;x=0;

#5;x=1;

#5;x=1;

#5;x=0;

end

always #2.5 clk=~clk;

endmodule