BC352239A Datasheet, PDF (69/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Device Terminal Descriptions
8.6.6 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
BlueCore3-Multimedia External. The entire circuit must be able to enter the suspend mode. (For more details on
USB Suspend, see separate CSR documentation).
8.6.7 Detach and Wake_Up Signalling
BlueCore3-Multimedia External 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 BlueCore3-Multimedia External 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 BlueCore3-Multimedia External to put USB_DN
and USB_DP in a high impedance state and turned 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,
BlueCore3-Multimedia External 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 BlueCore3-Multimedia External is effectively
disconnected from the bus.
10ms max
10ms max
USB_DETACH
10ms max
No max
USB_WAKE_UP
Port_Impedance
USB_DP
USB_DN
USB_PULL_UP
Disconnected
Figure 8.25: USB_DETACH and USB_WAKE_UP Signal
8.6.8 USB Driver
A USB Bluetooth device driver is required to provide a software interface between
BlueCore3-Multimedia External and Bluetooth software running on the host computer. Suitable drivers are
available from http://www.csrsupport.com.
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
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