February 10th 2010

Dehmani Feth-Allah

M2 ISTRe

Oral Presentation

Universal Serial Bus

II. How does it work ?

Summary

I. Presentation (Where, When, Why…)

III. ApplicationsHOW

DOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

Presentation

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

Purpose : Standardization of serial communication between a host and a device with a unique connexion and a unique communication protocol

Invented in 1996 by Microsoft, IBM, Intel, Compaq, Digital, NEC et Northern Telecom (USB 1.0)

Before invention of USB : Differents connexion port and protocol communication like RS-232, parallel, PS-2 or SCSI.

Generalities:

Presentation

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

HOSTDEVICE

Hardware connexions :

February 10th 2010

4. GND1. VDD 2 & 3. DATA

(D+ & D-)

Signal connexions :

How does it work ?

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

How does it work ?

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

NRZI diferential encryption between D+ and D-

LSB first transmit (Little Endian).

Speed

USB release 1.0 1.1 2.0 3.0

Year 1996 1998 2000 2010

Speed 1,5 Mbit/sLow Speed

12 Mbit/sFull Speed

480 Mbit/sHigh Speed

4,8 Gbit/sSuper Speed

USB Bus description

How does it work ?

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

« Host – Slave » system

Frame transmission (Token et Data)

8 bits 8 bits 7 bits 4 bits 5 bits

SYNC PID ADDRESS ENDP CRC

8 bits 8 bits 0 to 512 bits 16 bits

SYNC PID PAYLOAD CRC

Token frame

DATA frame

Communication protocol :

How does it work ?

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

Control : for command operation (enumeration, state of the device…)

Interrupt : for device with garanted time delay (mouse, keyboard…)

Isochrone : for device with garanted bit rate (garanted bandwidth : ex : printer, camera…)

Bulk : for big data transmissions (take maximum bandwidth as possible)

Transmission :

How does it work ?

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

Identification process of the device by the host

SPEED DETECTION

DEVICE IDENTIFICATION

Send descriptors

CONNEXION

High level in D+ ou D-

Enumeration:

Applications

HOWDOES IT WORK ?

APPLICATIONS

USBPRESENTATION

February 10th 2010

REAL TIME APPLICATIONS

DATA TRANSFER

OR CONTROL COMMAND

USB

BUS ENERGY

(only hardware, 500mA max)

Conclusion

February 10th 2010

Today, USB is one of the most serial protocole used

FireWire (Apple) is the alternative of USB (3 200 Mbits/s)

To sell USB device, you need to buy a Vendor ID (≈ 2000 $ US / year)

Thank You…