Verilog 우선 인코더

디자인

  
  
module pr_en ( input [7:0] a,
               input [7:0] b,
               input [7:0] c,
               input [7:0] d,
               input [1:0] sel,
               output reg [7:0] out);

   always @ (a or b or c or d or sel) begin
      if (sel == 2'b00)
         out <= a;
      else if (sel == 2'b01) 
         out <= b;
      else if (sel == 2'b10)
         out <= c;
      else 
         out <= d;
   end
endmodule

  

하드웨어 도식

테스트 벤치

  
  
module tb_4to1_mux;
   reg [7:0] a;
   reg [7:0] b;
   reg [7:0] c;
   reg [7:0] d;
   wire [7:0] out;
   reg [1:0] sel;
   integer i;
   
   pr_en    pr_en0 (   .a (a),
                           .b (b),
                           .c (c),
                           .d (d),
                           .sel (sel),
                           .out (out));

   initial begin
      sel <= 0;
      a <= $random;
      b <= $random;
      c <= $random;
      d <= $random;

      for (i = 1; i < 4; i=i+1) begin
         #5 sel <= i;
      end

      #5 $finish;
   end
endmodule