October 10, 20001

2 USB OnTheGo Ed Beeman Hewlett Packard

October 10, OnTheGo Charter w Address the unique needs of portable devices – Connector size – Dual-role: u Sometimes peripheral (camera uploads pictures to PC) u Sometimes host (camera sends pictures to printer) w Maintain spirit of USB w Minimize deviations from core spec

October 10, Use Model Examples Exchange pictures Upload pictures to web Print pictures Camera Cell Phone PrinterCamera Exchange songs MP3 player Exchange Contact info Print call info Upload pictures to web Cell Phone PrinterCamera Synchronize phone list, meetings Upload pictures Download songs Cell Phone Camera MP3 player PCFunctionsSlaveMaster

October 10, Why USB? w Ubiquitous…Now w Cheap w Reliable w Good performance w Gates are cheap, easy to add light host controller w Wireless may play stronger role in future

October 10, Smaller Connectors w Now: – ECN to core spec – A to mini-B cable – Mini-B receptacle w Future: – Mini-A to mini-B and mini- A to B cables – Mini-AB receptacle – Not yet sanctioned – waiting for OTG spec

October 10, Mini-AB receptacles w Accepts either mini-A or mini-B plug – Mini-A plug => Master, Mini-B plug => Slave – 5 th pin is shorted to ground in mini-A plug (no 5 th wire) w Dual function allows small footprint, with no implied hub w Warning: don’t use mini-AB receptacle yet – Wait for OTG master capability – Breaks bus – cable inserted wrong and not reversible

October 10, Dual Role Devices w 100% compliant as a peripheral device w Additional limited host capability – 4mA Vbus – Supported device list u Hub support is optional – Primarily for single device to one other device u Can be extended to full host capability w Not peer-to-peer – Same USB protocol

October 10, Master Negotiation Protocol w Effectively turns cable around – Two dual-role devices – Mini-A to mini-B cable – Default slave (mini-B end) wants to start conversation w Operation – Master enables MNP in OTG slave with Set Feature – Slave disconnects – Master asserts pull-up – Slave issues reset and SOF – Slave enumerates and begins activity – On Suspend, Master drops pull-up and resumes Master role

October 10, Lots of work left w OTG Specification Schedule – V0.6 on Sept 26 – Spec not yet complete – V0.7 in Oct/Nov – all issues addressed in spec, final format, still some unresolved issues – V0.8 by Year end – finish prototypes – V1.0 by 2Q01 w Compliance definition just starting w Logo variant?

October 10, Issues raised by OnTheGo w Benefit to consuming < 4mA on Vbus w Multiple cables – A:B, A:mini-B, mini-A:mini-B, mini-A:B? w Masters that don’t support all devices – Targeted device list w Greater need for device class support – E.g., Printer page description