> > *It also depends on the usb host/hub, on power up we get 100mA, and in* > * u-boot we request "1.3A" over usb... If we actually get that "1.3A" we* > * can do a lot, but most often then not we only get 500mA's..* > > * I don't have the exact numbers at my desk, but i thinking a booting* > * v3.8.x needs a peak around 350mA's for the core & mmc..* >
So that ust be some "special" USB power adapter, that is not plugged into a PC per se. I've been powering over USB 3.0 port to the RevC. Which is from a "high end" laptop, which should be able to give the board at least 800ma. I do not recall if I had problems with that setup using ethernet + CAN. But the one where we have the logic supply serial / can cape connected to. Used a 1A wall-wart to USB adapter. It worked fine for a little while, then start exhibiting strange behavior at system up. So on a hunch, wulf and I just replaced that power supply with a 1A barrel jack supply, and the problem went away . . . I'm still confused how you can get more than 500ma over USB2.0 though . . . as the spec says 500ma max. On Mon, Nov 9, 2015 at 2:29 PM, Robert Nelson <[email protected]> wrote: > On Mon, Nov 9, 2015 at 3:24 PM, William Hermans <[email protected]> wrote: > >> Powered by "usb" with a "usb" dongled plugged = no power left for the > >> cpu... > >> > >> Regards, > > > > > > I have found that you *can* power by USB and use ethernet, but that is > it. > > So when we tried powering by USB, and use ethernet + CAN . . . the board > > sometimes works, the board sometimes does not work. The take away from > this > > is that if you power by USB, you can maybe power one peripheral / IO > > interface, but when trying to power more than one peripheral / IO > interface. > > You should use the barrel jack, with a 1-2A *good* power supply. > > It also depends on the usb host/hub, on power up we get 100mA, and in > u-boot we request "1.3A" over usb... If we actually get that "1.3A" we > can do a lot, but most often then not we only get 500mA's.. > > I don't have the exact numbers at my desk, but i thinking a booting > v3.8.x needs a peak around 350mA's for the core & mmc.. > > Regards, > > -- > Robert Nelson > https://rcn-ee.com/ > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
