On Tue, 8 Jul 2014, Grant wrote: > >> You are right, the device will get 5 volts. However it is still part > >> of the spec that 2ms without a SOF will force the device into suspend > >> mode, so it will use less than 2ma. So depending on your definition of > >> function, there will be power, but no activity. If it uses more than > >> 2ma, from the bus, problems will ensue. > > > > What you're saying is true, so long as the spliced USB cable isn't > > plugged into a host. But of course, you wouldn't expect to get any > > activity on a device when it isn't plugged into a host -- even if you > > use a normal cable. > > > > If the spliced USB cable _is_ plugged into a host then the host will > > see it, issue a reset, and start sending SOF packets. In that > > situation your comment doesn't apply. > > > I should have been more specific then. I think I understand, but to > be sure, if I splice a USB cable, power VBUS with an external 5V power > supply, and connect a host and device, the device will work as if the > cable was connected to the host normally? Yes. But why do you want to do this? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
