module blinker(CLK, RST, LED);

    input       CLK;
    input   RST;
    output      LED;
    reg[31:0]   counter;
    reg         LEDR;

    always@(posedge CLK, posedge RST)
    begin
    if( RST )
    begin
        counter <= 32'b0;
        LEDR <= 0;
    end
    else
    begin
            if( counter == 12499999 )
            begin
                    LEDR <= 1'b1;
                counter <= 0;
            end
            else
            begin
                    counter <= counter + 1;
            if ( counter > 6249999 )
                LEDR <= 1'b0;
            end
    end
    end

    assign      LED = LEDR;

endmodule

module tb;

    reg clk, rst;
    wire    out;

    initial
    begin
        clk = 1'b0;
        rst = 1'b1;
        #5
        rst = 1'b0;
    end

    always
         #5 clk = !clk;

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

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