Why doesn't my FT232BM/FT245BM work when connected to a USB 2.0 host controller or USB 2.0 hub? Some hubs and host controllers appear to be extremely sensitive to noise. A glitch on the USB lines can causes the device to hang. This problem can be fixed by adding two 47pF capacitors to ground on the USB DP and DM lines. These should be located between the 27Ohm series resistors and the hub.