Theory 

1. Excess-3 (XS-3) is a non-weighted code used in decimal systems.

2. It is derived from BCD (Binary-Coded Decimal) by adding 3 (0011₂) to each BCD digit.

3. Each decimal digit (0–9) is represented by a 4-bit code
   
   
   Conversion Rule (BCD → Excess-3)

1. Take the 4-bit BCD input.

2. Add 0011 (3 in binary).

3. Result = Excess-3 code.

  Truth Table :                    Logic diagram:                                                                                         

DATA FLOW DESCRIPTION

Verilog Code :

module BCD_Excess03(B,E);

input [3:0] B;

output [3:0] E;

assign E[0] = B[0]^B[1] ;

assign E[1] = B[1]^B[2] ;

assign E[2] = B[2]^B[3];

assign E[3] = B[3];

endmodule

Test bench :

module TB_BCD_Excess03();

reg [3:0] B;

wire [3:0] E;

BCD_Excess03 dux(B,E);

initial 

begin

      B=4'd0;

     #10 B=4'd1;

     #10 B=4'd2;

     #10 B=4'd3;

     #10 B=4'd4;

     #10 B=4'd5;

     #10 B=4'd6;

     #10 B=4'd7;

     #10 B=4'd8;

     #10 B=4'd9;

     #10 B=4'd10;

     #10 B=4'd11;

     #10 B=4'd12;

     #10 B=4'd13;

     #10 B=4'd14;

     #10 B=4'd15;

     #20 $finish();

     end

endmodule

BEHAVIORAL DESCRIPTION:

module BCDtoEX3 (

    input  [3:0] bcd,

    output reg [3:0] ex3

);

always @(*) begin

    case (bcd)

        4'b0000: ex3 = 4'b0011;

        4'b0001: ex3 = 4'b0100;

        4'b0010: ex3 = 4'b0101;

        4'b0011: ex3 = 4'b0110;

        4'b0100: ex3 = 4'b0111;

        4'b0101: ex3 = 4'b1000;

        4'b0110: ex3 = 4'b1001;

        4'b0111: ex3 = 4'b1010;

        4'b1000: ex3 = 4'b1011;

        4'b1001: ex3 = 4'b1100;

        default: ex3 = 4'b0000;

    endcase

end

endmodule

test bench:

module tb_BCDtoEX3;

reg  [3:0] bcd;

wire [3:0] ex3;

BCDtoEX3 DUT (

    .bcd(bcd),

    .ex3(ex3)

);

integer i;

initial begin

    for (i = 0; i < 16; i = i + 1) begin

        bcd = i[3:0];

        #1;

    end

    $finish;

end

endmodule

O/P obtained

Pin Assignment

 i\p:- J15,L16,M13,R15 o\p:- H17,K15,J13,,N14  

RTL SCHEMATIC POWER 

TIME UTILIZATION REPORT