module led(
    input clk,
    input reset,
    output led0,
    input switch0
    );

parameter count_period = 100000000;

reg switch0_l = 0;
reg led0_state = 0;
integer counter = 0;

always @(posedge clk or posedge reset)
begin

    if (reset)
    begin
        switch0_l = 0;
        led0_state = 0;
        counter = 0;
    end else begin

        #1 switch0_l = switch0;

        if (switch0_l)
        begin
            if (counter == 0)
            begin
                led0_state = !led0_state;
                counter = count_period;
            end

            counter = counter - 1;
        end
    end
end

assign led0 = led0_state;

endmodule