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Illegal output or inout port connection for port 'Aout'
von Michael (Guest)

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I have been trying to get this to work for quite sometime and I dont 
know why I cant simulate. It says error with port 'Aout'. Below is each 
of my modules that I have created. Please let me know. Thank you very 
much

1
// ALU TestBench

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`timescale 1ns/1ps

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module ALU_tb();

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reg [3:0] A, B, OPCODE;

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wire [3:0] ALU_out;

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wire Cout, OF;

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reg Cin;

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ALU A1 (A, B, Cin, OPCODE, ALU_out, Cout, OF);

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initial begin

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//OPCODE 0000 and 0001, A=0101, B=0010;

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A = 4'b0101; B = 4'b0010; Cin = 'b0; OPCODE = 4'b0000; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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OPCODE = 4'b0001; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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//OPCODE 0000, 0001, and 0010, A=0011, B=0001;

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A = 4'b0011; B = 4'b0001; Cin = 'b0; OPCODE = 4'b0000; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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OPCODE = 4'b0001; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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OPCODE = 4'b0010; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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//OPCODE 0000 and 0001, A=0100, B=0011;

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A = 4'b0100; B = 4'b0011; Cin = 'b0; OPCODE = 4'b0000; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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OPCODE = 4'b0001; #5;

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$display("OPCODE = %b, A = %b, B = %b, ALU_out = %b, Cout = %b, OF = %b", OPCODE, A, B, ALU_out, Cout, OF);

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end

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endmodule

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// ALU

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module ALU(input [3:0] A, B, input Cin, input [3:0] OPCODE, output [3:0] ALU_out, output Cout, OF);

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reg [3:0] Ain, Bin, Bn;

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wire [3:0] Sum;

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wire CoutFA, OFFA;

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reg [3:0] ALU_out_;

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reg Cout_, OF_;

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comp2s C1 (B,Bn);

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fulladder4 FA4 (Ain, Bin, Cin, Sum, CoutFA, OFFA);

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assign ALU_out = ALU_out_;

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assign Cout = Cout_;

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assign OF = OF_;

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always @ (*) begin

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Ain = 4'b0000; Bin = 4'b0000; ALU_out_ = 4'b0000; Cout_ = 1'b0; OF_ = 1'b0;

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case(OPCODE)

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4'b0000 : begin

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Ain = A;

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Bin = B;

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ALU_out_ = Sum;

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Cout_ = CoutFA;

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OF_ = OFFA;

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end

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4'b0001 : begin

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Ain = A;

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Bin = Bn;

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ALU_out_ = Sum;

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Cout_ = CoutFA;

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OF_ = OFFA;

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end

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4'b0010 : begin

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ALU_out_ = A&B;

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Cout_ = 4'd0;

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OF_ = 4'd0;

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end

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default : begin Ain = 4'b0000; Bin = 4'b0000; ALU_out_ = 4'b0000; Cout_ = 1'b0; OF_ = 1'b0;

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end

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endcase

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end

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endmodule

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// 2's compliment

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module comp2s(input [3:0] A, output [3:0] Aout);

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wire Cout, OF;

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wire [3:0] An;

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assign An=~A;

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fulladder4 FA4 (An, 4'd0, 1'b1, Aout, Cout, OF);

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endmodule

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// ripple adder

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module fulladder4(input [3:0] A, B, input Cin, output [3:0] Sum, output Cout, OF);

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wire Cout1, Cout2, Cout3;

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fulladder FA1 (A[0], B[0], Cin, Sum[0], Cout1);

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fulladder FA2 (A[1], B[1], Cout1, Sum[1], Cout2);

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fulladder FA3 (A[2], B[2], Cout2, Sum[2], Cout3);

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fulladder FA4 (A[3], B[3], Cout3, Sum[3], Cout);

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xor X1 (OF, Cout3, Cout);

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endmodule

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//Full adder

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module fulladder(input A, B, Cin, output Sum, Cout);

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halfadder HA1 (A,B,Sum1, Cout1);

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halfadder HA2 (Sum1,Cin,Sum,Cout2);

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or O1 (Cout, Cout1, Cout2);

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endmodule

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//half adder

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module halfadder(input A, B, output Sum, Cout);

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assign Sum=A^B;

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assign Cout=A&B;

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endmodule


  


  



  

  
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    Re: Illegal output or inout port connection for port 'Aout'
  


  

    

      von
      
        Lothar M.
            (Company: Titel)
        (lkmiller)
        (Moderator)
      
      


      
    


    

      
    

    

    

  
  


  

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Michael wrote:
> It says error with port 'Aout'.
What error?
I don't see any definition of Aout...


BTW: why don't you read and follow that few lines of "manual" above each 
edit box here?

  


  



  

  
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    Re: Illegal output or inout port connection for port 'Aout'
  


  

    

      von
      
        ElKo (Guest)
      
      


      
    


    

      
    

    

    

  
  


  

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Try to use a wire for signal "Bn" instead of reg.

  


  




  

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    Re: Illegal output or inout port connection for port 'Aout'
  


  

    

      von
      
        Ale (Guest)
      
      


      
    


    

      
    

    

    

  
  


  

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1
Line 43: wire [3:0] Bn;


OPCODE = 0000, A = 0101, B = 0010, ALU_out = 0111, Cout = 0, OF = 0
OPCODE = 0001, A = 0101, B = 0010, ALU_out = 0011, Cout = 1, OF = 0
OPCODE = 0000, A = 0011, B = 0001, ALU_out = 0100, Cout = 0, OF = 0
OPCODE = 0001, A = 0011, B = 0001, ALU_out = 0010, Cout = 1, OF = 0
OPCODE = 0010, A = 0011, B = 0001, ALU_out = 0001, Cout = 0, OF = 0
OPCODE = 0000, A = 0100, B = 0011, ALU_out = 0111, Cout = 0, OF = 0
OPCODE = 0001, A = 0100, B = 0011, ALU_out = 0001, Cout = 1, OF = 0

  


  




  

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