Op woensdag 13 november 2013 18:45:56 UTC+1 schreef Paulo Ferreira: > > > On 11/11/2013, at 19:44, hvn...@gmail.com <javascript:> wrote: > > > Hi, > > > > I connected a mechanical device to 1 of the USB A ports and this device > has a PID update rate of 1 kHz. Instead of make a nice movement as it did > on a pc, it started to oscillate. I searched for update rate info in the > board manual, but found nothing. Can anyone tell me what the USB A update > rate of the board is ? Or the turn around time ? > > > > Thanks. > > > To hvn052: > > You have not connected a mechanical device to an USB port.... > You have connected a device which has mechanical and electronic parts to > the USB port of the Beagle Bone. > And you have in the PID loop, software that runs on the Beagle Bone. >
Not the BeagleBone..the BeagleBoard-xM. All the USB timings are known from the USB specifications, but as you have > your software in the loop, asking someone on the Internet what is the > update rate of your software, seems very wishful thinking. > I agree with you on the USB specifications. However, my point is that I ran the same software on both a normal computer and the BeagleBoard. On the normal computer everything works fine while on the BeagleBoard-xM the device starts to oscillate. Back to the normal computer, it works fine again. Now assuming that all LS/FS/HS USB specifications are the same, how can this happen? Any suggestion on what I can be missing that is not the same ? > Please try an oscilloscope. > That's a good suggestion. Have to find one. hvn -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
