Theory 

1. BCD (Binary Coded Decimal) represents decimal digits (0–9) in pure 4-bit binary.

2. Excess-3 was obtained by adding 3 (0011) to BCD.

3. So , to convert back:
   BCD=Excess-3−0011

Conversion Rule (Excess-3 → BCD)

1. Take the Excess-3 input.

2. Subtract 0011 (3 in binary).

3. Result = BCD 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:

verilog code :

module EX3toBCD (

    input  [3:0] ex3,

    output reg [3:0] bcd

);

always @(*) begin

    case (ex3)

        4'b0011: bcd = 4'b0000;

        4'b0100: bcd = 4'b0001;

        4'b0101: bcd = 4'b0010;

        4'b0110: bcd = 4'b0011;

        4'b0111: bcd = 4'b0100;

        4'b1000: bcd = 4'b0101;

        4'b1001: bcd = 4'b0110;

        4'b1010: bcd = 4'b0111;

        4'b1011: bcd = 4'b1000;

        4'b1100: bcd = 4'b1001;

        default: bcd = 4'b0000;

    endcase

end

endmodule

testbench :

module tb_EX3toBCD;

reg  [3:0] ex3;

wire [3:0] bcd;

EX3toBCD DUT (

    .ex3(ex3),

    .bcd(bcd)

);

integer i;

initial begin

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

        ex3 = 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