General USB Ver 1.1

8/8/2019 General USB Ver 1.1

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2008 Microchip Technology Incorporated. All Rights Reserved. USB Solutions from Microchip Slide 1

USB Overview


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Topics Need for USB Benefits of USB

Speed comparisons USB Evolution USB Host / Peripheral / OTG Embedded Host USB Hub

Device Classes Data Transfer Mechanisms Application examples


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Need for USB Offering ease of use (Plug and Play)

Expandability (Port expansion)

Speed for the end user

Accommodate different applications simultaneously

Low cost

Self Powered

USB started as a standard for connecting peripherals (such as mice, keyboards)to PCs. Now its the standard for connecting personal devices (iPods, printers) to

PC and personal devices (PDA, scanner) to personal devices (printer, iPods)

Microchip offers USB products Peripherals, Embedded Hosts

and OTG in PIC18, PIC24 and PIC32 portfolio


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Benefits of USB

One interface for many applications

Auto configuration

No external supply required

Hot pluggable

No user settings

Microchip provides with a scalable choice of integrated USB

solutions across 8-, 16- and 32-bit PIC microcontrollers

Offering packages from 18 pin to 100 pins

Easy-to-use and upgradeable products for embedded designs

Ample code and data space for complex USB applications


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Buses and Speed

Comparison


6/17 2008 Microchip Technology Incorporated. All Rights Reserved. USB Solutions from Microchip Slide 6

USB EvolutionSpec Data Rate and

PerformanceApplications Notes

USB 1.1 Low-speed

USB 2.0 Low-speed

1.5Mbps Keyboard, mouse, joystick Low cost but limitedperformance; type andnumber of endpoints

limited

USB 1.1 Full-speed

USB 2.0 Full-speed

12Mbps Printers, audio derives,webcams

Moderate performance;guaranteed latency;guaranteed bandwidth

USB 2.0 High-speed 480Mbps Video, storage, imaging &more

Vast bandwidthimprovements. Adoptionin high-end consumersegment

USB 2.0 On-The-Go(OTG)

480Mbps or12Mbps PDAs, MP3 players, cameras Peripheral device cancommunicate directlywithout Host PC

Backward compatible

USB Wireless(WUSB) 480Mbps @ 3 meters110Mbps @ 10 metersRecently specified. Stillgoing through adoptionprocess



USB Host

Manages and controls the bus

Initiates all data packet activity on the bus

Manages data flow

Error checking

Enumerates inserted USB devices and matches device to a

particular class driver

Detects peripheral insertion / extraction

Provide Power

System typically consists of complex software applications with

an operating system and microprocessor

Class driver needed for each device or class of devices



USB Peripheral

Peripherals only respond to Hosts and have no capability toinitiate data transfers Focus on power consumption

Detects communication from Host

Exchange data with host

Respond to Standard Requests from Host

Checking for error data from Host

Power Management



USB OTG

Host and Peripheral both in one

Focus on power consumption

Transceiver driver to support new USB On-The-Go protocols

Host Negotiation Protocol

Session Request Protocol Full speed peripheral/host capability

One and only one Mini-AB receptacle, which can accept either aMini-A plug or a Mini-B plug

The ability to provide at least 8 mA of bus current whenfunctioning as the A-device



Embedded Host

Can support Limited resources

Supports a Target Peripheral List

Must be capable of supplying at least 8mA on VBUS

High, Full, Low-speed may be supported

Of the 4 USB transfer modes Mandatory to support Control and

could support Bulk, Interrupt and Isochronous based on target

peripheral list

Example Set Top box



On-The-Go Versus Embedded Host

OTG

Limited host capabilities

Possess dual role - host or peripheral

capability to switch between the two

Devices have Mini-AB receptacle

OTG devices must have Host

Negotiation Protocol (HNP) and

Session Request Protocol (SRP)

Embedded Host

Limited host capabilities

Posses single role host

Devices have only Mini-A receptacle

Does not require Host Negotiation

Protocol (HNP) and optionally

support Session Request Protocol

(SRP)

Do not operate either as hub or full

host as normal host does



USB Hub

Supports maximum of 5 Hubs chaining

Hubs to offer power to all the connected devices

USB 2.0 hub must support all three speeds

Cascade upto 127peripherals including the root hub

HubHub

HubHub

HubHub

HubHub

HubHub

HubHub

Speaker

Data Logger

LogicAnalyzer

Up to 126 peripherals...

Keyboard



Devices Classes Following classes have approved class specifications

Audio Chip/Smart CardInterface

Communication Class(CDC) Content Security

Device Firmware Upgrade Human Interface (HID)

IrDA Bridge Mass Storage (MSD)

Printer Still Image Capture

Test and Measurement Video

Microchip offers free source code for USB software stacks and class

driversClass drivers supported by Microchip are CDC, HID, MSD and custom



Data Transfer Mechanisms

Control

+

Interrupt

Control

+

Bulk

Control

+

Isochronous

GuaranteedLatency

GuaranteedData Integrity

GuaranteedLatency


GuaranteedLatency

http://images.google.co.in/imgres?imgurl=http://www.china-manufacturer-directory.com/picture/computer-speaker-system-6985.jpg&imgrefurl=http://www.china-manufacturer-directory.com/catalog-1-117170/speaker-horn-sound-box.html&h=300&w=300&sz=26&hl=en&start=5&um=1&tbnid=ocjWOLLw-QE9AM:&tbnh=116&tbnw=116&prev=/images%3Fq%3Dspeaker%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DGhttp://images.google.co.in/imgres?imgurl=http://www.ireviewelectronics.com/wp-content/uploads/2007/02/canon-photo-printer.jpg&imgrefurl=http://www.ireviewelectronics.com/canon-photo-printer.html&h=500&w=500&sz=35&hl=en&start=2&um=1&tbnid=DbZfQy5q3JOhDM:&tbnh=130&tbnw=130&prev=/images%3Fq%3Dprinter%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DGhttp://images.google.co.in/imgres?imgurl=http://www.germes-online.com/direct/dbimage/10332105/DS_2016_Mouse.jpg&imgrefurl=http://www.germes-online.com/catalog/96/97/520/20936/ds_2016_mouse.html&h=360&w=360&sz=27&hl=en&start=10&um=1&tbnid=pD-JLLCdL0qzxM:&tbnh=121&tbnw=121&prev=/images%3Fq%3Dmouse%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DG



USB Connectors

USB Type A receptacle

USB Type B receptacle

USB Type A Mini receptacle

USB Type AB Mini receptacle

Laptops

PCs

Printers

Scanners

Set Top Box

PDA



Application Examples

Host

Traditional

PCc

Peripheral

USB OTG

Host

Thumb driveinterface


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Thank You

General USB Ver 1.1

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