Usb Device Driver for Bulk Data Transfer

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DESIGN OF USB DEVICE DRIVER FOR BULK DATA

TRANSFERABSTRACT

USB has become a popular interface for exchanging data between PCs and peripherals. Anincreasing number of portable peripherals are using the USB interface to communicate with the

PC. The design and implementation of a synthesizable model of the USB 1.1 protocol engine is

presented in this report The PHY is compatible with the USB 1.1 transceiver macrocell interface

(UTMI) specification and the simulation test confirmed the successful operation of circuits for

both full speed (12 Mbps) and low speed (1.5 Mbps) data transmission. The model is written

completely in behavioral HDL with a top down approach and the model was verified and

validated.This thesis describes the protocol used in USB 1.1 systems low-level interface. It also

describes the type of transactions and errors in USB transactions. The goal is to Designing of

Protocol Engine for the USB device. The design of SIE (Serial Interface Engine) is implemented

in a Verilog Hardware Description Language.

INTRODUCTION

Universal Serial Bus (USB) has emerged as a result of the difficulties associated with

thecost, configuration, and attachment of the peripheral devices in the personal computer

environment. In short, USB creates a method of attaching, and accessing peripheraldevices that

reduce overall cost, simplifies the attachment and configuration from theenduser perspective, and

attempt to solve several technical issues associated with the old style peripherals.

The motivation for the Universal Serial Bus (USB) comes from two interrelated considerations:

Ease of use: The lack of flexibility in reconfiguring the PC has been acknowledged as the

Achillesheel to its further deployment. The combination of user-friendly graphical interfaces

and the hardware and software mechanisms associated with new generation bus architectures

have made computers less confrontational and easier to reconfigure. However, from the end

users point of view, the I/O interfaces of PCs, such as serial/parallel ports,

keyboard/mouse/joystick interfaces, etc., do not have the attributes of plug-and-play. Other once

is Port Expansion: The addition of external peripherals continues to be constrained by port

availability. The lack of a bi-directional, low-cost, low-to-mid speed peripheral bus has held back

the creative proliferation of peripherals such as telephone/fax/modem adapters, answering


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machines, scanners, PDAs, keyboards, mice, etc. Existing interconnects are optimized to

connect products for one or two ports. As each new function or capability is added to the PC, a

new interface has been defined to address this need. The USB is the answer to connectivity for

the PC architecture. It is a fast, bidirectional, isochronous, low-cost, dynamically attachable

serial interface that is consistent with the requirements of the PC platform of today and

tomorrow.

BLOCK DIAGRAM:

Serial_out

Serial_in

Ack

Nack

ADVANTAGES:

Used to transfer large bursty data.

Error detection via CRC, with guarantee of delivery.

No guarantee of bandwidth or minimum latency.

Stream Pipe - Unidirectional

Full & high speed modes only.

TOOLS:

Language: Verilog HDL

Simulation: Modelsim

A Ack

Parallel_in

Nack

Serial_in

Tx Rx

State Machine

Host

Client


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USB 2.0 cables and peripherals were designed to be backward compatible with USB 1.1 devices.

Brief USB Overview and USB History

All Articles: USB Internals

USB Overview

In the past, connecting multiple peripheral devices to computer has been a real problem. There were too

many different port types (serial port, parallel port, PS/2 etc.) and their use imposes limitations such as no

hot-pluggability and automatic configuration. There are very limited number of ways to attach the peripheral

devices in the original IBM PC implementation due to the requirements in terms of non-shareable IRQ lines

and I/O address space. The main reason that Universal Serial Bus was implemented to provide a

replacement for those legacy ports on a computer to make the addition of the peripheral devices quick and

easy for end user.

USB is designed to allow many peripherals to be connected using a single standardized interface. It provides

an expandable, fast, bi-directional, low-cost, hot-pluggable Plug and Play serial hardware interface that

makes the life of the computer users easier allowing them to plug different peripheral devices into a USB

port and have them automatically configured and ready to use. Using a single connector type, USB allows

the user to connect a wide range of peripheral devices, such as keyboards, mice, printers, scanners, mass

storage devices, telephones, modems, digital still-image cameras, video cameras, audio devices to a

computer. USB devices do not directly consume system resources. They are not mapped into I/O address

space, nor do they use IRQ lines or DMA channels. The only system resources required by a USB system are

the memory buffers used by the USB system software. Due to its success and widespread acceptance, USB

became the 'de-facto' industry standard for connecting peripheral devices to PCs and laptops.

The USB has the following key features:

Single connector type: USB replaces all the different legacy connectors with one well-defined,

standardized USB connector for all USB peripheral devices, eliminating the need for different cables

and connectors and thus simplifying the design of the USB devices. So all USB devices can be

connected directly to a standard USB port on a computer.

Hot-swappable: USB devices can be safely plugged and unplugged as needed while the computer is

running. So there is no need to reboot.

Plug and Play: Operating system software automatically identifies, configures, and loads the

appropriate device driver when a user connects a USB device.

High performance: USB offers low speed (1.5 Mbit/s), full speed (12 Mbit/s) and high speed (up to

480 Mbit/s) transfer rates that can support a variety of USB peripherals. USB 3.0 (SuperSpeed USB)

achieves the throughput up to 5.0 Gbit/s.
http://www.usblyzer.com/usb-internals.htmhttp://www.usblyzer.com/usb-internals.htm


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Expandability: Up to 127 different peripheral devices may theoretically be connected to a single bus

at one time.

Power supplied from the bus: USB distributes the power to all connected devices eliminating the

need for external power source for low-power devices. High-power devices can still require their

own local power supply. USB also supports power saving suspend/resume modes.

Easy to use for end user: A single standard connector type for all USB devices simplifies the end

user's task at figuring out which plugs go into which sockets. The operating system automatically

recognizes the USB device attachment and loads appropriate device drivers.

Low-cost implementation: Most of the complexity of the USB protocol is handled by the host, which

along with low-cost connection for peripherals makes the design simple and low cost.

A Brief USB History

The USB was developed and standardized by a group of leading companies from the computer and

electronics industries in 1995.

The Universal Serial Bus specification, which defines all aspects of the USB system from the physical layer

(mechanical and electrical) all the way up to the software layer, was developed by Compaq, Digital

Equipment Corporation (DEC),IBM, Intel, Microsoft andNEC, joined later by Hewlett-Packard,Lucent and

Philips. Compaq, which merged with Hewlett Packard, bought DEC and Lucent merged with Alcatel to form

Alcatel-Lucent.

These companies also formed the USB Implementers Forum, Inc. (USB-IF) as a non-profit corporation to

publish the specifications and provide a support organization and forum for the advancement and adoption

of USB technology.

USB Specification

The design of USB is standardized in Universal Serial Bus Specification that provides the technical details to

understand USB requirements. The specification describes the bus attributes, the protocol definition, types

of transactions, bus management, and the programming interface required to design USB compatible
http://www.compaq.com/http://www.digital.com/http://www.digital.com/http://www.ibm.com/http://www.ibm.com/http://www.intel.com/http://www.microsoft.com/http://www.nec.com/http://www.nec.com/http://www.hp.com/http://www.lucent.com/http://www.lucent.com/http://www.philips.com/http://www.philips.com/http://www.alcatel.com/http://www.alcatel-lucent.com/http://www.usb.org/http://www.usb.org/http://www.compaq.com/http://www.digital.com/http://www.digital.com/http://www.ibm.com/http://www.intel.com/http://www.microsoft.com/http://www.nec.com/http://www.hp.com/http://www.lucent.com/http://www.philips.com/http://www.alcatel.com/http://www.alcatel-lucent.com/http://www.usb.org/


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peripherals and software. USB Specifications and all related documents are freely downloadable from USB

Implementers Forum web site.

Versions of USB specification:

Revision 1.0 released on January 15, 1996, introduced a low-speed transfer rate of 1.5 Mbit/s and a

full-speed transfer rate of 12 Mbit/s.

Revision 1.1 released on September 23, 1998, introduced the improved specification and was the

first widely used version of USB.

Revision 2.0 released on April 27, 2000. The major feature of revision 2.0 was the addition of a

high-speed transfer rate of 480 Mbit/s.

Revision 3.0 released on November 17, 2008, brings significant performance enhancements to the

USB standard while offering backward compatibility with the peripheral devices currently in use.

Legacy USB 1.1/2.0 devices continue to work while plugged into new USB 3.0 host and new USB

3.0 devices work at USB 2.0 speed while plugged into USB 2.0 host. Delivering data transfer rates

up to ten times faster (the raw throughput is up to 5.0 Gbit/s) than Hi-Speed USB (USB 2.0),

SuperSpeed USB is the next step in the continued evolution of USB technology.Data Transfer Rate Comparison

USB Revision USB1.0 USB2.0 USB3.0

Media (Data Size) Transfer Time

Song / Pic (4 MB) 5.3 sec 0.1 sec 0.01 sec

256 Flash (256 MB) 5.7 min 8.5 sec 0.8 sec

USB Flash (1 GB) 22 min 33 sec 3.3 sec

SD-Movie (6 GB) 2.2 hr 3.3 min 20 sec

USB Flash (16 GB) 5.9 hr 8.9 min 53.3 sec

HD-Movie (25GB) 9.3 hr 13.9 min 70 sec

Note, however, that all above mentioned are theoretical maximum data transfer rates that do not take into

consideration some USB protocol overhead and bus utilization, which makes a difference in actual maximum

throughput. The actual maximum throughput may vary depending on the transfer type, maximum packet

size, time reserved for control transfers, the overhead due to signaling imposed bit stuffing etc.

Each iteration of the specification is backward compatible with previous revisions. Since all USB devices use

the same cables, connectors and software interfaces, there is no change in the usage model for the end

user. USB 1.0, USB 1.1 and USB 2.0 compliant peripheral devices can operate on a computer at the same

time. It is possible for a high-speed USB 2.0 device to plug into a USB1.1 port and operate at the

appropriate transfer rate.

Using USBlyzer - Viewing the USB Specification Version

You can view USB Specification revision number for USB devices and external hubs.

To view USB Specification revision number a USB device compliant with

1. Open USBlyzer.
http://www.usb.org/developers/docs/http://www.usb.org/developers/docs/http://www.usb.org/developers/docs/http://www.usb.org/developers/docs/


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2. In the USB Device Tree panel select the device for which you want to see USB Specification revision

number.

3. In the USB Properties panel see the bcdUSB field value of the Device Descriptor.

Device Descriptor VOIP USB Phone

Offset Field Size Value Description0 bLength 1 12h1 bDescriptorType 1 01h Device2 bcdUSB 2 0101h Fails WHQL testing. Should be 0110h4 bDeviceClass 1 00h Class information in the Interface Descriptors5 bDeviceSubClass 1 00h6 bDeviceProtocol 1 00h7 bMaxPacketSize0 1 40h 64 bytes8 idVendor 2 6 99 3h Freshtel

10 idProduct 2 B 00 1h12 bcdDevice 2 0 00 0h 0.0014 iManufacturer 1 01h "Yealink Network Technology Ltd."15 iProduct 1 02h "VOIP USB Phone"16 iSerialNumber 1 00h

17 bNumConfigurations 1 01h

Note, that in the above example the U.S. Robotics USB Phone 9600 incorrectly reports its compliance with

the USB Specification 1.1 as 0101h.

bcdUSB field in the standard USB Device Descriptor may have the following values:

0100h - USB Specification 1.0



Since some devices incorrectly expose bcdUSB field as 0101h instead of 0110h, the operating system

accepts both as valid revision number. But failure to correctly report this value can prevent the driver from

passing the Windows Hardware Quality Labs (WHQL) testing and may also cause a device to fail tests in theUSB test tools.

USB Logo

To complement the USB specification in real products, the USB-IF maintains a Compliance Program that

provides reasonable measures of acceptability. Products that pass compliance testing have the right to

license the USB-IF certified USB Logo. Products that operate at either low-speed or full-speed can use only

the Basic-Speed version of the logo. Only products that support high-speed can use the Hi-Speed version of

the logo.

Certified Logo for USB Devices

USB Extensions
http://www.usb.org/developers/compliance/http://www.usb.org/developers/compliance/http://www.usb.org/developers/compliance/


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There are also the extensions to the original USB design. These are USB On-The-Go (OTG) and Certified

Wireless USB. USB On-The-Go allows connecting portable peripheral devices to each other directly without

having to connect to a PC. Certified Wireless USB is a wireless radio communication protocol that combines

the ease-of-use of USB with the convenience of wireless technology. Like standard USB, the USB-IF also

maintains the Compliance Program for OTG and Wireless USB devices.

Certified Logo for USB OTG and Wireless USB Devices

USB On-The-Go and Certified Wireless USB technologies are beyond the scope of this article series, the

details and specifications can be found on the USB-IF website.

Next Article:Basic Components of a USB System Architecture

The device (digital camera, card reader, scanner, hard drive, cable modem, etc.)

will work with the USB 2.0 ports even if the device only has a USB 1.0 or 1.1connection. The physical connectors are exactly the same for USB 1.1 and USB 2.0.However, the device will only work at USB 1.1 speeds (12 Mbps) and not USB 2.0speeds (480 Mbps).

Conversely, if your computer only has USB 1.0 or 1.1 ports and you would like touse a USB 2.0 device with it, the device will probablywork. Again, you will only beable to transfer data at the slower USB 1.1 transfer rate. Most USB 2.0 devices arebackwards compatible with USB 1.1, but for data-intensive devices (like a hard driveor iPod), the data transfer is so slow with USB 1.1, it may not even be worth using it.

Connecting

f lash memory cards, p en-like memory devices, d igital camera,

p rinter,

m ouse-device, P ocketPC,

v ideo games,

S canner

A crc field in a data packet permits error detection

USB Specification 1.1 was designed for low to medium speed applications

running at less then 12 Mbits/sec. As such it is not suited for high-end data

transfer such as high-speed back-ups to hard disks or CDs , high resolution

color printing and interactive gaming
http://www.usb.org/developers/onthego/http://www.usb.org/developers/wusb/http://www.usb.org/developers/wusb/http://www.usb.org/http://www.usblyzer.com/usb-system-architecture-components.htmhttp://www.usblyzer.com/usb-system-architecture-components.htmhttp://www.usb.org/developers/onthego/http://www.usb.org/developers/wusb/http://www.usb.org/developers/wusb/http://www.usb.org/http://www.usblyzer.com/usb-system-architecture-components.htm


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BUS COMPARISON

Type of BusBus

ClockSignal

Bus

Width

Theoretical Maximum

Transfer RateAdvantages Disadvantages

ISA 8 MHz 16-bit8 Mbytes/sec (64

Mbits/sec)low cost, compatibility,

widely usedlow speed, Jumpers & DIP

switches. becoming obsolete

Microchannel 10 MHz 32-bit40 Mbytes/sec (240

Mbits/sec)higher speed than ISA obsolete

PCI133MHz

64-bit 1 Gbytes/sec (8 Gbits/sec)very high speed, Plug

& Play, dominantboard-level bus

incompatible with older systems,can cost more

CompactPCI 33 MHz 64-bit132 Mbytes/sec (1

Gbit/sec)

designed for industrialuse, hot

swapping/Plug & Play,ideal for embedded

systems

lower speed than PCI, needadapter for PC use, incompatible

with older systems

PCMCIA 10 MHz 16-bit20 Mbytes/sec (160

Mbits/sec)

Ideal for portablesystems, hot

swappable, Plug &Play

lower speed , needs special drive

for use in desktop PCs

USB 1.1 n/a n/a1.5 Mbytes/sec (12

Mbits/sec)

low cost, ideal forportable systems, hotswapping/plug & play,

up to 127 devices via 1port

slower than PCI and other plug-inbusses (such as Firewire), not

compatible with older peripherals

USB 2.0 n/a n/a60 Mbytes/sec (480

Mbits/sec)

All the advantages ofUSB plus significantlyhigher speeds makingit compatible with high-

speed peripheralssuch as data drivesand video cameras.

Not compatible with older

peripherals, still slower than PCI

Ethernet 10Base T

n/a n/a1.25 Mbyte/sec (10

Mbits/sec)

Enables multiple PCsto remotely shareinformation and

peripheral devices,provides error

checking lacking instandard serialcommunication

Most peripheral devices cannotbe connected directly to ethernet,

adapter is required. Slow datacommunication by current

standards Possible securityissues.

Ethernet 100

Base T (FastEthernet) n/a n/a

12.5 MBytes/sec (100

Mbits/sec)

All advantages of10BaseT, with

significant speed

improvement.Backward compatiblewith 10Base Tinstallations.

Most peripheral devices cannotbe connected directly to ethernet,

adapter is required. Possiblesecurity issues.
http://www.quatech.com/support/comm-over-mca.phphttp://www.quatech.com/support/comm-over-pci.phphttp://www.quatech.com/support/comm-over-cpci.phphttp://www.quatech.com/support/comm-over-pcmcia.phphttp://www.quatech.com/support/comm-over-usb.phphttp://www.quatech.com/support/comm-over-mca.phphttp://www.quatech.com/support/comm-over-pci.phphttp://www.quatech.com/support/comm-over-cpci.phphttp://www.quatech.com/support/comm-over-pcmcia.phphttp://www.quatech.com/support/comm-over-usb.php

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Usb Device Driver for Bulk Data Transfer