module blinker(CLK, LED);

    input       CLK;
    output      LED;
    integer     counter = 0;
    reg         LEDR;

    always@(posedge CLK)
    begin
        if( counter == 12500000 )
        begin
            LEDR <= 1'b1;
            counter <= 0;
        end
        else
        begin
            counter <= counter + 1;
            LEDR <= 0;
        end
    end

    assign      LED = LEDR;

endmodule

module tb;

    reg clk;
    wire    out;

    initial
        clk = 1'b0;

    always
         #1 clk = !clk;

    initial
        $monitor("[%d] LED = %b", $time, out);

    //initial
    //  #100 $finish;

    blinker inst0(.CLK(clk), .LED(out));
endmodule