Simple LED flashing on FPGA/CPLD

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company:          IS Enerprises
// Engineer:         Letuchiy Sergey V.
//
// Create Date:    16:55:03 10/07/2018
// Design Name:  Example of  simple counter
// Module Name:    Simple counter module
// Project Name:     Package of examples
// Target Devices: SP-6 xc6slx9
// Tool versions:  ISE - 14.7
// Description:  Package of examples  for developer board SPARTAN-6
//
// Dependencies:
//
// Revision:         0000.0001.0001
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module Counter_Ver1 #(parameter DIGITA = 24)
(
    input     clk,
    output    CARRYA,
     output    CARRYB,
     output    CARRYC,
     output    CARRYD
);

// 25 wires.
wire [DIGITA:0]add;
// Register counter.
reg  [DIGITA:0]RG = {(DIGITA){1'b0}};

assign add[DIGITA:0] = RG[DIGITA:0] + 1'b1;
assign CARRYA = RG[DIGITA];
assign CARRYB = !RG[DIGITA];
assign CARRYC = RG[DIGITA];
assign CARRYD = !RG[DIGITA];

// Ticker one second.
always@(posedge clk) begin

            RG[DIGITA:0] <= add[DIGITA:0];
end

endmodule