Harald Welte writes: >On Sun, Jan 21, 2007 at 06:56:30AM -0700, Joe Pfeiffer wrote: >> Harald Welte writes: >> > >> >The main problem (with more powerful SoC) is not to provide a USB2.0 >> >host port in the device. The main problem is power. You need a pretty >> >powerful DC/DC step-up converter to provide the 5V power supply to the >> >USB bus. And you have to provide at least up to 100mA - but to support >> >all devices, 500mA. >> >> I don't see this is a real problem -- 1.1 is supposed to do that too. >> I'd have to look at the specs (USB and USBToGo) but I don't think >> unpowered USB is actually compliant under any of them. > >It's not a technical problem per se. > >It's just that you have to have one extra (powerful) DC/DC step-up >converter in the device, something that vendors of phones (and other >devices) usually don't put there for cost, battery life time and PCB >footprint reasons.
That wasn't my point: my point was that an unpowered USB 2.0 interface is no more noncompliant than the existing unpowered USB 1.1 interface. _______________________________________________ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community