USB Fundamental

7/30/2019 USB Fundamental

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USB

Intel Serial Bus (Universal Serial Bus)


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What is USB?

Universal Serial Bus, an external serial bus standard that

supports data transfer rates up to 480Mbps

Simple Interface Two wires for power

Two wires for data

Up to 127 devices can be connected to one System/Host

Hubs can expand thenumber of available ports

System Topology: Host (master) and Peripherals (slaves)


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Lets Start With The Obvious:Why USB?

Set-up takes a long time and isconfusing

Frequent PC crashes

Cable clutter with device conflicts

Inaccessible connectors

Poor hot-plug support

PC circa 1999

The USB Solution

Revolutionary Ease-Of-Use

True Plug & Play

Hot insertion and removal

Auto-detection and configuration All external to the box

No more IRQ, DIP switch, and configuration

confusion

Eliminates the need for multiple I/O standards


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Flavors of USB

USB 2.0 is the Latest Governing Specification(Replaces Classic USB 1.1 Spec)

1.5

12

480

0 100 200 300 400 500

Speed (Mbps)

Low Speed

Full Speed

High Speed

> 1 Billion USB 1.1

Devices Sold

(Most Successful InterfaceEver!)


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USB 1.1 Hardware Overview

USB HOST

ROOT HUB

USB HOST

ROOT HUB

USB

Peripheral

USB

Peripheral

USB

Peripheral

USBPeripheral

USB

Peripheral

USBPeripheral

USB

Peripheral

USB

Peripheral

USB

HUB

USB

HUB

USBHUB

USBHUB

USB

HUB

USB

HUBUSB

HUB

USB

HUB

USB

Peripheral

USB

PeripheralUSB

Peripheral

USB

PeripheralUSB

Peripheral

USB

PeripheralUSB

Peripheral

USB

PeripheralUSB

Peripheral

USB

PeripheralUSB

Peripheral

USB

Peripheral

USB

Peripheral

USB

Peripheral

Topology Tiered Star, one host, auto-detects

127 Logical connection

Bus transactions Speed: 1.5Mbps or 12Mbps

Isochronous or Asynchronous

Hub Repeater & Termination

Self-Powered or bus-poweredConfiguration

Dynamic Insertion/removal

Autoconfiguration on change

Physical layer 4 pin connector, 4 wire cable

2-wire differential signaling

+5V DC supply/Gnd


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USB 1.1 Signaling

USB 1.1

Full-speed

12Mbps signal rate, 5 meter cablesLow - Speed

1.5 Mbps signal rate, 3 meter cables

Differential data linesClock recovered from data

4 signals (VBUS, D+, D-, Ground)


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USB 2.0: An Evolution of USB

Faster signaling rate 480 Mbps (40x faster than USB 1.1)

Seamless migration for end users Fully forward and backward compatible to USB 1.1

Works with existing cables and connectors

Same full/low speed signaling and functionality

Same dynamic attach/detach detection model

Same power and power management features

Supports multiple high-bandwidth peripherals

running simultaneously


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USB 2.0 Topology

USB 2.0 HOST

ROOT HUB

USB 2.0 HOST

ROOT HUB

USB 1.1

Peripheral

USB 1.1

Peripheral

USB 1.1

Peripheral

USB 1.1

PeripheralUSB 2.0

Peripheral

USB 2.0

Peripheral

USB 2.0

Peripheral

USB 2.0Peripheral

USB 2.0

HUB

USB 2.0

HUB

USB 2.0

HUB

USB 2.0

HUB

USB 1.1HUB

USB 1.1HUB

USB 2.0

HUB

USB 2.0HUB

USB 2.0

Peripheral

USB 2.0

PeripheralUSB 1.1

Peripheral

USB 1.1

PeripheralUSB 2.0

Peripheral

USB 2.0

PeripheralUSB 1.1

Peripheral

USB 1.1

PeripheralUSB 2.0

Peripheral

USB 2.0

PeripheralUSB 1.1

Peripheral

USB 1.1

Peripheral

USB 2.0

Peripheral

USB 2.0Peripheral

USB 2.0 HOST

ROOT HUB

USB 2.0 HOST

ROOT HUB

USB 1.1

Peripheral

USB 1.1

Peripheral

USB 1.1

Peripheral

USB 1.1

PeripheralUSB 2.0

Peripheral

USB 2.0

Peripheral

USB 2.0

Peripheral

USB 2.0Peripheral

USB 2.0

HUB

USB 2.0

HUB

USB 2.0

HUB

USB 2.0

HUB

USB 1.1HUB

USB 1.1HUB

USB 2.0

HUB

USB 2.0HUB

USB 2.0

Peripheral

USB 2.0

PeripheralUSB 1.1

Peripheral

USB 1.1

PeripheralUSB 2.0

Peripheral

USB 2.0

PeripheralUSB 1.1

Peripheral

USB 1.1

PeripheralUSB 2.0

Peripheral

USB 2.0

PeripheralUSB 1.1

Peripheral

USB 1.1

Peripheral

USB 2.0

Peripheral

USB 2.0Peripheral

Tier 1

Tier 2

Tier 3

Tier 4

Tier 5

USB 1.1 Traffic

USB 2.0 Traffic

USB 1.1 and USB 2.0

peripherals and hosts

WILL WORK TOGETHER


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Traditional USB Topology

One PC host per system

Host initiates all data transfers

Devices do not speak unless spoken toHubs connect multiple devices

Repeaters and Terminations

4 ports and 7 ports are popular

Power (self powered and bus)

Device and Endpoints

A device is a collection of endpoints

FullSpeed

Full

Spee

d

LowSpeed

Hub

Full

Spe

ed

Full Size USB Connectors


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Full Size USB Connectors

Connectors 4-position with shielded housing

Positive retention

Blind Mating Capabilities 2 types

Input to USB Device or HUB

Output from USB Host or HUB


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Mechanical Environment

HOSTHub

Device

Device

Series B - Plug

Series A - Plug

Series B - ReceptacleSeries A - Receptacle

Shielded cable - Maximum 5 meter

Unshielded cable - Maximum 3 meter

USB C bl


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USB Cable

Cables

28 AWG twisted pair for signaling

30-20 AWG pair for power- (IR drop limits length)

Shielding for fully rated segments

Full speed cable requires shield

Low speed cable does not requireshield

Full speed cable can be used with

low speed applications

Full speed cable is required to haveB connector

Vbus = 5Vdc

GND

Differntial

Signal Pai

Screen

Si l T i ti f LS


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Signal Termination for LSDevice

D-

D+

15KHost

or

Hub port

FS/LS USB

Transceiver

Untwisted pair, unshielded, 3 meters Max

D-

D+

Low speed function

1.5K

FS/LS USB

Transceiver

3.0~3.6V


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Signal Termination for FSDevice

Twisted pair, shielded, 5 meters Max, Z0=90 15%

D-

D+

15KHost

or

Hub port

FS/LS USB

Transceiver

D-

D+

Hub port 0

or

Full speed function

1.5K

FS/LS USB

Transceiver

3.0~3.6V

Hi h S d Si li


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High Speed SignalingChirp and Speed Detection

Device starts by attaching as Full Speed

Device then issues a Chirp K

Host response is Chirp JK sequence

Device applies High Speed termination

Idle Chirp K

ChirpJK

D+

D-

USB D t T f T


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USB Data Transfer Types

Each transfer type and protocol is best suited for particularuses.

USB Data Transfer

Types

Typical Applications

Control All Devices

Interrupt Mouse. Keyboard,Joysticks, Gaming, HID

Bulk Scanner, Printer, DSC,Modems, Networking

Isochronous Video Cameras, Audio

I h d t t f


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Isochronous data transfer

For real time application w. constant data

transfer i.e. video, audio

The need to provide data on a timely basis ismore important than verifying accurate

delivery

No error handling and correction In and Out pipes may be configured

Max 90% of bandwidth for each frame

Max FIFO length 1023 Bytes

Available at FS, HS

B lk data transfer


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Bulk data transfer

For transmission of large not time critical data

blocks, i.e. Printer, scanner, disk

Access to USB bus only if there is availablebandwidth

In and Out pipes may be configured

Max FIFO 64 BytesError detection and recovery

Available at FS, HS

Endpoints and Pipes


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Endpoints and Pipes

Endpoint Software communicates with USB device via

endpoints

Uniquely identifiable: endpoint ID

Endpoint 0: required for every device and used for

control / configuration

Non-endpoint 0: add as required by device

Pipe

Is a association between an endpoint and softwareon the host

Stream pipe and message pipe

Endpoints and pipes


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Endpoints and pipes

Central to the USB communication model is the abstract concept of transferring data using pipes between

the host and peripherals. This pipe medium can be further distributed into even smaller pipes, with

each type of data requiring a separate tiny pipe. Each tiny pipe (endpoint) carries a unique data type

that is needed between the peripheral and the host. For instance, in a multimedia USB device,

different endpoints would be required for voice (isochronous), data (bulk), and control information.

Thus a total of 5 endpoints are required, since two endpoints are needed for bidirectional data (see

Figure 4). All these data types must be treated differently and The Cypress EZ-USB family has the

most endpoints available in the market, supporting the maximum number of 31 endpoints allowed in

the USB specification. With the vast number of endpoints, users have the flexibility to assign different

buffers for each individual data stream, instead of consolidating various data streams into a single

data type to be used for transmission. In addition, these endpoints can be programmed to be double-buffered, which improves transfer bandwidth in some applications.

Some of the USB DevicesAvailable


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Some of the USB DevicesAvailable

EZ USB Common


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EZ-USB CommonArchitecture

Enhanced 8051

SmartSIE

8Kbytes

of RAMD+D-

5 - 10X faster than standard 8051

Uses industry standard tools

Download firmware from PC

Easy & fast code development

Update customers via website

Up and running in minutes

More efficient code

Quick learning curve

Compliance guaranteed

Full Integration

What makes it EZ?


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What makes it EZ?

Protocol & Enumeration done by Smart SIE instead of micro F/W

Outside intelligence

handles all USB

requests

Unrecognized

requests answered

with stall

USB

Host

Request

Dumb SIE

(SERDES)

DSP,

uP,ASIC,

etc.Device

Response

Stall

DSP,

uP,

ASIC,

etc. Only unrecognizedrequests pass to micro

Outside intelligence

handles only custom

requests

SIE automatically

handles basic USB

requests (enumeration)

USB

Host

RequestSmart

SIE

Device

Response

Stall

EZ-USB FX


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EZ-USB FX

Address (16)8051 Core48 MHz,

4 clocks/cycle

CYSmartUSB

Engine

12 MHz

XTAL

I/O Ports (40)

4 KBor

8 KBRAM

2 KBFIFO

Address(16)/Data

Bus(8)

X4PLL

I2C

Four

64 bytes

FIFO

8/16

bits

Data(8)

DMA EngineEZ-USBFX

USBXCVR

High Performance MicroUsing Standard Tools

MemoryExpansion

orData Buffer

Ports

PeripheralI/O Flexibility

1K Double-BufferIsochronous Support

"Soft Configuration"

Easy Firmware Changes

Enhanced USB Core

Simplifies 8051 Code

Master orSlave

Operation

Abundant I/OIncluding 2 UARTS

Up to 48 MBytes/sBurst Rates

GPIF

GeneralProgrammable I/F toany ASIC/DSP or bus

standards such asATAPI, EPP, etc.

Uses Low-Cost Crystal

D+

D-

EZ-USB TX2


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EZ-USB TX2

Cypress

USB 2.0

Transceiver

SIE

Interface

NRZI &Bit Stuffing

Encoder

NRZI &

Bit Unstuffing

Decoder

PL

L 1616-bit

Bi-directional

Data

D+

D-

24 MHz Xtal

TX/RXData & System

Control

Cypress Designed High-Speed Transceiver

Cypress

USB 2.0

Transceiver

PL

L

UTMI compliant USB 2.0 transceiver

16-bit bi-directional 30Mhz interface

Bus-powered capability with suspend mode

EZ-USB SX2:


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EZ-USB SX2:USB 2.0 Serial Interface Engine

D+D-

PLL

CY Smart USBSerial Interface

Engine

4 Kbyte

FIFO

USB 2.0Xcvr

FIFO

Data

Bus

EZ-USB SX2

Internal Control Logic

Fixed Logic for

Control Function

EZ-USB SX2

Internal Control Logic

Intelligent SIEReduces USB Learning Curve

CY Smart USBSerial Interface

Engine

USB 2.0Xcvr

CY DesignedHigh-Speed Xcvr

Slave FIFO

Interface

(8/16-bit)

FIFO

Data

Bus

RESET WAKEUP

Address

DMA Request

Interrupt, Ready

RD, WR

OE, PKTEND

IFCLK

24 MHzCrystal

EZ-USB Development Tools


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EZ USB Development Tools

Host PCUSB Cable and

RS-232C Interface cable

AN2131QC orCY7C64613-128NC

Peripheral

Function

EZ-USB

Also Included:

- EZ-USB Control Panel

- 8051 C Compiler, Assembler,Debugger/Monitor (Keil)

- USB Firmware Source Library

- General-Purpose Device Driver(Source Code)

- Firmware Example Code

Industry Recognized

Development Platform

Used by Intel and Most of the

Motherboard Manufacturers

EZ-USB xX2


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EZ USB xX2Development Kits

HARDWARE Development Board

Prototype Board

SOFTWARE Firmware Source Library

Firmware Frameworks Device Driver Source 8051 USB Examples EZ-USB Control Panel

DOCUMENTATION Technical ReferenceManual Datasheet Application Notes Getting Started Errata Sheets

High Speed (USB 2.0)


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High Speed (USB 2.0)Reference Designs

Mass Storage Reference Design/Eval Kit EZ-USB FX2 Based (CY7C68013-56PVC, SSOP)

Firmware source and object code

Custom drivers and support for Windows class drivers Design notes

Hardware files (schematics, bill of materials, Gerber files)

Support for up to UDMA-100 and All PIO Modes

Note: For Fixed Function solution, use ISD-300A1

USB 2.0 to ATA CY4615ATA-& compatibility for large capacity drive support

ATA IRQ support fo greater device compatibilityMultiple hardware design: vertical mount, horizontal mount, cable

Hardware adapter for 2.5 drivers included in kit

Documentation

RTOS support


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RTOS support

Opperating systems supported withdrivers for the host controllers: LINUX

VxWORKS

Windows (CE?)

Simple mini port drivers to support RTOSwithout a USB host stack

USB On The Go (OTG) Goals


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( )

Maintain spirit of USB Host-Peripheral, not Peer-to-Peer

Keyed connectors ensure correct topologies

No silent failures

Minimize deviations from core specification Mechanical, Electrical and Software

Address unique needs of portable devices Smaller connectors

Be both a host and a peripheral

Lower power output

Turn-off interface when not in use

Limited memory for drivers

Typical Applications


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yp ca pp cat o s

Mobile Applications

Cell Phones

PDAs

Video Cameras

Digital Still Cameras

MP3 Players

Mass Storage Devices

Documents

USB Fundamental