CBL_BinaryToGray : A combinational logic converting a binary code to a gray code

This model describes a combinational logic converting a binary code to a gray code. Gray codes are non-weighted codes, where two successive values differ only by one bit.

module CBL_BinaryToGray #(
    parameter width = 4             // bit width
)(
    input [width-1:0] in,           // input bits
    output reg [width-1:0] out      // output bits
);

int i;

always @(in) begin
    for (i=0; i<width; i++) begin
        if (i < width-1) out[i] = in[i+1] ^ in[i];
        else out[i] = in[i];
    end
end

endmodule

Input/Output Terminals

Name	I/O	Type	Description
in [width-1:0]	input	wire	input bits
out [width-1:0]	output	reg	output bits

Parameters

Name	Type	Default	Description
width	integer	4	bit width

List of Testbenches

tb_check : A testbench for checking the basic functionality of a combinational logic

This testbench checks the basic functionality of a combinational logic by enumerating all the possible input values and listing its corresponding outputs.

module tb_check ();
parameter in_width = 4;
parameter out_width = in_width;

reg [in_width-1:0] in;
wire [out_width-1:0] out;

CBL_BinaryToGray #(.width(in_width)) DUT (.in, .out);

initial begin
    in = 0;

    repeat ((1 << in_width) - 1) begin
        #(1ns);
        in = in + 1;
    end
end

always @(out) begin
    $display("IN: %b --> OUT: %b", in, out);
end

endmodule