+static USBHub hub1(&usb_host); // one hub is enough for HHKB pro2
+/* may be needed for other device with more hub
+static USBHub hub2(&usb_host);
+static USBHub hub3(&usb_host);
+static USBHub hub4(&usb_host);
+static USBHub hub5(&usb_host);
+static USBHub hub6(&usb_host);
+static USBHub hub7(&usb_host);
+*/