module led_clk (
    input board_clk,
    input switch,
    output reg [3:0] led);

    reg [32:0] counter;

    always @ (posedge board_clk) 
    begin
        if (switch == 1'b1)
            begin
                counter <= counter + 1;
                led[0] = counter[26];
            end
    end
endmodule