On Wednesday 26 January 2005 10:09 pm, Amit Choudhary wrote: > Hi, > > My system is an experimental board with an ARM processor running linux > 2.6. It is not a PC. It has got an OTG port. The device is a pen drive > (mass storage device). Normally, this device plugs directly into the > PC but since I have an OTG port, I use a cable that has mini-B on one
There's a standard for such cables, and it involves a Mini-A connector not a Mini-B connector. You might not be able to tell those apart; the simplest way is to try connecting it into a Mini-B socket. (For example, many recent hubs have those sockets.) Your board has an OTG socket (that is, Mini-AB), so it will accept both Mini-A and Mini-B connectors. A hub will never accept a Mini-A connector, only Mini-B ... So if your board implements OTG correctly -- even just for cable based role switching, not yet supporting HNP -- then your OTG driver will detect that the ID pin is grounded and kick in the host controller driver. When an OTG port is used in that Default-A mode, it will provide power on that OTG port. But NOT (!!) in the Default-B mode. > side and receptacle A (using a connector) on the other. The device > plugs into the 'A' end while the mini-B end plugs into the OTG port. > So, can I give power to the device from the board through mini-B end, > or do I need a mini-AB cable beacuse as far as I know only 'A' type > connectors/receptacles can supply power. I've never seen adapter cables converting Mini-B sockets to A-sockets. If your adapter cable is standard -- and I _have_ seen those -- it will just be converting a Mini-A socket to an A-socket. And that ought to behave just fine, even with a minimally capable OTG driver. - Dave ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
