User's Manual

and PSKEY_USB_PIO_WAKEUP to the selected PIO number.

USB_DETACH is an input which, when asserted high, causes WT11 to put USB_DN and

USB_DP in high impedance state and turned 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, WT11 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 WT11 is effectively disconnected from the bus.

Figure 7: USB_DETACH and USB_WAKE_UP Signal

7.2.5 USB Driver

A USB Bluetooth device driver is required to provide a software interface between WT11

and Bluetooth software running on the host computer. Suitable drivers are available from

www.bluegiga.com/techforum/

7.2.6 USB 1.1 Compliance

WT11 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 WT11 meets the USB specification, CSR cannot guarantee that an application

circuit designed around the chip 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_DP and USB_DN adhere to the USB specification 2.0 (Chapter 7) electrical

requirements.

7.2.7 USB 2.0 Compatibility

WT11 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.

7.3 SPI Interface

The synchronous serial port interface (SPI) for interfacing with other digital devices. The

SPI port can be used for system debugging. It can also be used for programming the Flash

memory. SPI interface is connected using the MOSI, MISO, CSB and CLK pins.

7.4 I/O Parallel Ports

The Parallel Input Output (PIO) Port is a general-purpose I/O interface to WT11. The port