BC41B143A-DS-003PC Datasheet, PDF (62/94 Pages) List of Unclassifed Manufacturers – BlueCore 4-ROM Plug-n-Go Single Chip Bluetooth v2.0 + EDR System

Device Terminal Descriptions
10.5.6 Suspend Current
All USB devices must permit the USB controller to place them in a USB suspend mode. While in USB Suspend,
bus-powered devices must not draw more than 0.5mA from USB VBUS (self-powered devices may draw more than
0.5mA from their own supply). This current draw requirement prevents operation of the radio by bus-powered devices
during USB Suspend.
The voltage regulator circuit itself should draw only a small quiescent current (typically less than 100µA) to ensure
adherence to the suspend current requirement of the USB specification. This is not normally a problem with modern
regulators. Ensure that external LEDs and/or amplifiers can be turned off by BlueCore4-ROM Plug-n-Go. The entire
circuit must be able to enter the suspend mode. Refer to separate CSR documentation for more details on USB
Suspend.
10.5.7 Detach and Wake_Up Signalling
BlueCore4-ROM Plug-n-Go can provide out-of-band signalling to a host controller by using the control lines called
USB_DETACH and USB_WAKE_UP. These are outside the USB specification (no wires exist for them inside the USB
cable), but can be useful when embedding BlueCore4-ROM Plug-n-Go into a circuit where no external 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 which, when asserted high, causes BlueCore4-ROM Plug-n-Go to put USB_DN and
USB_DP in a high impedance state and turns off the pull-up resistor on DP. This detaches the device from the bus
and is logically equivalent to unplugging the device. When USB_DETACH is taken low, BlueCore4-ROM Plug-n-Go
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 BlueCore4-ROM Plug-n-Go is effectively disconnected from the bus.
Figure 10.15: USB_DETACH and USB_WAKE_UP Signal
10.5.8 USB Driver
A USB Bluetooth device driver is required to provide a software interface between BlueCore4-ROM Plug-n-Go and
Bluetooth software running on the host computer. Suitable drivers are available from http://www.csrsupport.com.
BC41B143A-ds-003Pc
Advance Information
© Cambridge Silicon Radio Limited 2005
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