BCM20705 datasheet(32/67 Pages) CYPRESS

32 / 67 page

USB Interface

BCM20705 Data Sheet

BROADCOM CONFIDENTIAL

Broadcom®

Bluetooth Transceiver and Baseband Processor

November 13, 2014 • MCS20705-DS104-R

Page 31

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

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

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).

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.

USB Compounded Device

Hub Controller

USB Device 1

HID Keyboard

USB Device 2

HID Mouse

USB Device 3

Bluetooth

Host

BCM20705 Datasheet(PDF) 32 Page - Cypress Semiconductor