BCM20705 Datasheet, PDF (32/67 Pages) Cypress Semiconductor – Single-Chip Bluetooth Transceiver and Baseband Processor

BCM20705 Data Sheet
USB Interface
USB Interface
Features
The following USB interface features are supported:
• USB Protocol, Revision 2.0, full-speed compliant including the hub
• Optional hub compound device with up to three device cores internal to device.
• Bus or self-power, dynamic configuration for the hub
• Global and selective suspend and resume with remote wakeup
• Bluetooth HCI
• HID, DFU, UHE (proprietary method to emulate an HID device at system boot)
• Integrated detach resistor
Operation
Note: The USB and HCI UART interfaces cannot be used simultaneously. For designs that do not use
the USB interface, VDD_USB, HUSB_DP and HUSB_DN must be connected to ground.
The BCM20705 can be configured to boot up as either a single USB peripheral or a USB hub with several USB
peripherals attached. As a single peripheral, the host detects a single USB Bluetooth device. In Hub mode, the
host detects a hub with one to three of the ports already connected to USB devices (see Figure 6).
Figure 6: USB Compounded Device Configuration
Host
USB Compounded Device
Hub Controller
USB Device 1
HID Keyboard
USB Device 2
HID Mouse
USB Device 3
Bluetooth
Depending on the desired hub mode configuration, the BCM20705 can boot up showing the three ports
connected to logical USB devices internal to the BCM20705—a generic Bluetooth device, a mouse, and a
keyboard. In this mode, the mouse and keyboard are emulated devices, since they connect to real HID devices
via a Bluetooth link. The Bluetooth link to these HID devices is hidden from the USB host. To the host, the mouse
and/or keyboard appear to be directly connected to the USB port. This Broadcom proprietary architecture is
called USB HID Emulation (UHE).
Broadcom®
Bluetooth Transceiver and Baseband Processor
November 13, 2014 • MCS20705-DS104-R
Page 31
BROADCOM CONFIDENTIAL