User's Manual

Page 40 of 83

A Carrier Corp. Company

PART NUMBER T82002163

REV A

Features

• USB Revision 1.1, full-speed compliant device

• 23 programmable endpoints

— Type: bulk, isochronous, or interrupt

— Direction: in or out

— Maximum packet size

— Programmable configuration, interface and alternate interface setting numbers

• Endpoint 0 for control IN and OUT

• Four configurations:

— Three programmable configurations with up to seven interfaces with seven alternate

interface settings

— Default configuration 0 with one interface and control endpoint 0

• Configurable 4-Kbyte memory for endpoint data storage

Signal Descriptions

This section describes the signals used by the USB client controller (See Table 12-1).

Table 12-1. USB Client Controller Interface I/O Signal Descriptions

Bidirectional Signals

USBC_P and USBC_N are the differential lines of the USB cable. Using differential signaling

allows transmitting multiple states on the serial bus. These states are combined to transmit data as

well as various bus conditions, including: idle, resume, start-of-packet (SOP), end-of-packet

(EOP), disconnect, connect, and reset. Four distinct states are represented using differential data by

decoding the polarity of the USBC_P and USBC_N pins. Two of the four states are used to

represent data. A one is represented when USBC_P is high and USBC_N is low; a zero is

represented when USBC_P is low and USBC_N is high. The remaining two states and pairings of

the four encodings are decoded further to represent the current state of the USB. Table 12-2 shows

how seven different bus states as well as one and zero are represented using differential signaling.

Table 12-2. USB States Using Differential Signaling