MM516
User's Manual
25
Revision 1.4 7-8-2011
Hardware Description Manual
5.2.6 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 100A) 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 BlueCore 5 chip. The entire circuit
must be able to enter the suspend mode. Refer to separate CSR documentation for more details on USB Suspend.
5.2.7 Detach and Wake_Up Signaling
BlueCore 5 chip can provide out-of-band signaling 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 BlueCore 5 chip 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
PSKEY_USB_PIO_DETACH and PSKEY_USB_PIO_WAKEUP to the selected PIO number.
USB_DETACH is an input which, when asserted high, causes BlueCore 5 chip 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, BlueCore 5 chip 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 BlueCore 5 chip is effectively disconnected from the bus.
Figure 9
USB_DETACH and USB_WAKE_UP Signals
5.2.8 USB Driver
A USB Bluetooth device driver is required to provide a software interface between BlueCore 5 chip and Bluetooth
software running on the host computer. Suitable drivers are available from
http://www.csrsupport.com.
