7
Serial Interfaces
7.1
USB Interface
CSR8640 BGA has a full-speed (12Mbps) USB interface for communicating with other compatible digital devices.
The USB interface on CSR8640 BGA acts as a USB peripheral, responding to requests from a master host controller.
CSR8640 BGA contains internal USB termination resistors and requires no external resistor matching.
CSR8640 BGA supports the
Universal Serial Bus Specification, Revision v2.0 (USB v2.0 Specification)
, supports
USB standard charger detection and fully supports the
USB Battery Charging Specification
, available from
. For more information on how to integrate the USB interface on CSR8640 BGA see the
Bluetooth and
USB Design Considerations Application Note
.
As well as describing USB basics and architecture, the application note describes:
■
Power distribution for high and low bus-powered configurations
■
Power distribution for self-powered configuration, which includes USB VBUS monitoring
■
USB enumeration
■
Electrical design guidelines for the power supply and data lines, as well as PCB tracks and the effects of
ferrite beads
■
USB suspend modes and Bluetooth low-power modes:
■
Global suspend
■
Selective suspend, includes remote wake
■
Wake on Bluetooth, includes permitted devices and set-up prior to selective suspend
■
Suspend mode current draw
■
PIO status in suspend mode
■
Resume, detach and wake PIOs
■
Battery charging from USB, which describes dead battery provision, charge currents, charging in suspend
modes and USB VBUS voltage consideration
■
USB termination when interface is not in use
■
Internal modules, certification and non-specification compliant operation
7.2
UART Interface
CSR8640 BGA has an optional standard UART serial interface that provides a simple mechanism for communicating
with other serial devices using the RS232 protocol, including for test and debug. The UART interface is multiplexed
with PIOs and other functions.
Figure 7.1 shows the 4 signals that implement the UART function.
G-TW
-000
8555.1.1
PIO[15]/UART_TX
PIO[14]/UART_RX
PIO[16]/UART_RTS
PIO[17]/UART_CTS
Figure 7.1: Universal Asynchronous Receiver
Advance Information
This material is subject to CSR's non-disclosure agreement
© Cambridge Silicon Radio Limited 2011
Page 30 of 110
CS-209182-DSP1
CSR8640 BGA
Data Sheet