User's Manual

USB is visible to the user. Both control lines are shared with PIO pins and can be assigned to any PIO

pin by setting the PS Keys PSKEY_USB_PIO_DETACH and PSKEY_USB_PIO_WAKEUP to the

selected PIO number.

USB_DETACH is an input that, when asserted high, causes WT32 to put USB_D- and USB_D+ in high

impedance state and turns off the pull-up resistor on D+. This detaches the device from the bus and is

logically equivalent to unplugging the device. When USB_DETACH is taken low, WT32 will connect

back to USB and await enumeration by the USB host.

USB_WAKE_UP is an active high output (used only when USB_DETACH is active) to wake up the host

and allow USB communication to recommence. It replaces the function of the software USB WAKE_UP

message (which runs over the USB cable), and cannot be sent while WT32 is effectively disconnected

from the bus.

USB_WAKE_UP

USB_DETACH

Port_Imbedance

USB_DPUSB_DN

USB_PULL_UP

10ms max

No max

Disconnected

Figure 11: USB_DETACH and USB_WAKE_UP Signal

6.2.6 USB Driver

A USB Bluetooth device driver is required to provide a software interface between WT32 and Bluetooth

software running on the host computer. Suitable drivers are available from www.bluegiga.com/techforum/.

6.2.7 USB 1.1 Compliance

WT32 is qualified to the USB specification v1.1, details of which are available from

http://www.usb.org.

The specification contains valuable information on aspects such as PCB track impedance, supply inrush

current and product labeling.

Although WT32 meets the USB specification, Bluegiga Technologies cannot guarantee that an

application circuit designed around the module is USB compliant. The choice of application circuit,

component choice and PCB layout all affect USB signal quality and electrical characteristics. The

information in this document is intended as a guide and should be read in association with the USB

specification, with particular attention being given to Chapter 7. Independent USB qualification must be

sought before an application is deemed USB compliant and can bear the USB logo. Such qualification

can be obtained from a USB plug fest or from an independent USB test house.

Terminals USB_D+ and USB_D- adhere to the USB specification 2.0 (Chapter 7) electrical

requirements.

6.2.8 USB 2.0 Compatibility

WT32 is compatible with USB v2.0 host controllers; under these circumstances the two ends agree the

mutually acceptable rate of 12Mbits/s according to the USB v2.0 specification.