October 10, 20001. 2 USB OnTheGo Ed Beeman Hewlett Packard.

October 10, 2000 1

October 10, 2000 2

USBOnTheGo

USBOnTheGo

Ed BeemanEd BeemanHewlett PackardHewlett Packard

October 10, 2000 3

OnTheGo CharterOnTheGo Charter

Address the unique needs of portable devicesAddress the unique needs of portable devices– Connector sizeConnector size– Dual-role:Dual-role:

Sometimes peripheral (camera uploads pictures to PC)Sometimes peripheral (camera uploads pictures to PC) Sometimes host (camera sends pictures to printer)Sometimes host (camera sends pictures to printer)

Maintain spirit of USBMaintain spirit of USB Minimize deviations from core specMinimize deviations from core spec

October 10, 2000 4

Use Model ExamplesUse Model Examples

Exchange picturesExchange pictures

Upload pictures to webUpload pictures to web

Print picturesPrint pictures

CameraCamera

Cell PhoneCell Phone

PrinterPrinter

CameraCamera

Exchange songsExchange songsMP3 playerMP3 playerMP3 playerMP3 player

Exchange Contact infoExchange Contact info

Print call infoPrint call info

Upload pictures to webUpload pictures to web

Cell PhoneCell Phone

PrinterPrinter

CameraCamera

Cell PhoneCell Phone

Synchronize phone list, meetingsSynchronize phone list, meetings

Upload picturesUpload pictures

Download songsDownload songs

Cell PhoneCell Phone

CameraCamera

MP3 playerMP3 player

PCPCFunctionsFunctionsSlaveSlaveMasterMaster

October 10, 2000 5

Why USB?Why USB?

Ubiquitous…NowUbiquitous…Now CheapCheap ReliableReliable Good performanceGood performance Gates are cheap, easy to add light host controllerGates are cheap, easy to add light host controller Wireless may play stronger role in futureWireless may play stronger role in future

October 10, 2000 6

Smaller ConnectorsSmaller Connectors

Now: Now: – ECN to core specECN to core spec– A to mini-B cableA to mini-B cable– Mini-B receptacleMini-B receptacle

Future: Future: – Mini-A to mini-B and mini-Mini-A to mini-B and mini-

A to B cablesA to B cables– Mini-AB receptacleMini-AB receptacle– Not yet sanctioned – Not yet sanctioned –

waiting for OTG specwaiting for OTG spec

October 10, 2000 7

Mini-AB receptaclesMini-AB receptacles

Accepts Accepts eithereither mini-A mini-A oror mini-B plug mini-B plug– Mini-A plug => Master, Mini-B plug => SlaveMini-A plug => Master, Mini-B plug => Slave– 55thth pin is shorted to ground in mini-A plug (no 5 pin is shorted to ground in mini-A plug (no 5thth wire) wire)

Dual function allows small footprint, with no Dual function allows small footprint, with no implied hubimplied hub

Warning: don’t use mini-AB receptacle yetWarning: don’t use mini-AB receptacle yet– Wait for OTG master capabilityWait for OTG master capability– Breaks bus – cable inserted wrong and not reversibleBreaks bus – cable inserted wrong and not reversible

October 10, 2000 8

Dual Role DevicesDual Role Devices

100% compliant as a peripheral device100% compliant as a peripheral device Additional limited host capabilityAdditional limited host capability

– 4mA Vbus4mA Vbus– Supported device listSupported device list

Hub support is optional Hub support is optional – Primarily for single device to one other devicePrimarily for single device to one other device

Can be extended to full host capabilityCan be extended to full host capability

Not peer-to-peerNot peer-to-peer– Same USB protocolSame USB protocol

October 10, 2000 9

Master Negotiation ProtocolMaster Negotiation Protocol

Effectively turns cable aroundEffectively turns cable around– Two dual-role devicesTwo dual-role devices– Mini-A to mini-B cableMini-A to mini-B cable– Default slave (mini-B end) wants to start conversationDefault slave (mini-B end) wants to start conversation

OperationOperation– Master enables MNP in OTG slave with Set FeatureMaster enables MNP in OTG slave with Set Feature– Slave disconnectsSlave disconnects– Master asserts pull-upMaster asserts pull-up– Slave issues reset and SOFSlave issues reset and SOF– Slave enumerates and begins activitySlave enumerates and begins activity– On Suspend, Master drops pull-up and resumes Master roleOn Suspend, Master drops pull-up and resumes Master role

October 10, 2000 10

Lots of work leftLots of work left

OTG Specification ScheduleOTG Specification Schedule– V0.6 on Sept 26 – Spec not yet completeV0.6 on Sept 26 – Spec not yet complete– V0.7 in Oct/Nov – all issues addressed in spec, final V0.7 in Oct/Nov – all issues addressed in spec, final

format, still some unresolved issuesformat, still some unresolved issues– V0.8 by Year end – finish prototypesV0.8 by Year end – finish prototypes– V1.0 by 2Q01V1.0 by 2Q01

Compliance definition just startingCompliance definition just starting Logo variant?Logo variant?

October 10, 2000 11

Issues raised by OnTheGoIssues raised by OnTheGo

Benefit to consuming < 4mA on VbusBenefit to consuming < 4mA on Vbus Multiple cablesMultiple cables

– A:B, A:mini-B, mini-A:mini-B, mini-A:B?A:B, A:mini-B, mini-A:mini-B, mini-A:B? Masters that don’t support all devicesMasters that don’t support all devices

– Targeted device listTargeted device list Greater need for device class support Greater need for device class support

– E.g., Printer page descriptionE.g., Printer page description