BC41B143A-ANN-E4 ETC, BC41B143A-ANN-E4 Datasheet - Page 65

• Manufacturer Part Number: BC41B143A-ANN-E4
• Description: Bluecore 4-rom CSP EDR Single Chip Bluetooth v2.0 + EDR System
• Manufacturer: ETC

11.5.6 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 can 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 RF power amplifiers can be turned off by BlueCore4-
ROM CSP. The entire circuit must be able to enter the suspend mode. (For more details on USB Suspend, see
BlueCore Power Saving Modes).
11.5.7 Detach and Wake-Up Signalling
BlueCore4-ROM CSP 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 CSP 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 CSP to put USB_DN and
USB_DP in a high impedance state and turn off the USB pull-up resistor. This detaches the device from the bus
and is logically equivalent to unplugging the device. When USB_DETACH is taken low, BlueCore4-ROM CSP 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 CSP is effectively disconnected from
the bus).
11.5.8 USB Driver
A USB Bluetooth device driver is required to provide a software interface between BlueCore4-ROM CSP and
Bluetooth software running on the host computer. Suitable drivers are available from www.csrsupport.com.
BC41B143A-ds-002Pd
Identifier
R
s
Figure 11.14: USB_DETACH and USB_WAKE_UP Signalling
USB_DETACH
USB_WAKE_UP
Port_Impedance
USB_DP
USB_DN
USB PULL-UP
This material is subject to CSR’s non-disclosure agreement
Table 11.7: USB Interface Component Values
© Cambridge Silicon Radio Limited 2005
10ms max
22 to 27Ω
Production Information
Value
Disconnected
10ms max
No max
Impedance matching to USB cable
10ms max
Device Terminal Descriptions
Function
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