If the BBB oscillator is not running, then I suspect the processor is bad. If you have two boards with the same issue, then I suspect the power supply you are using is bad. One of the big issues with the BBB is it doesn’t like to power down. Look at sheet 2 of the OSD335x schematics
http://octavosystems.com/octavosystems.com/wp-content/uploads/2016/05/OSD3358-SBC-Referece-Design.pdf <http://octavosystems.com/octavosystems.com/wp-content/uploads/2016/05/OSD3358-SBC-Referece-Design.pdf> You will see some protection circuitry at the bottom center of the sheet. This ensures the voltage difference between the 3v3 and 1v8 is never greater than 2V. The BBB does not have any such circuitry so when the 5V drops quickly, it is possible for the 1v8 to drop quicker than the 3v3 and hence killing the processor. This happened to me and I had to replace the processor. The Beagleboard-x15 does have the same protection circuitry (BeagleBoard-X15_RevA2.pdf sheet 4). Regards, John > On Oct 11, 2016, at 7:05 AM, Николай Курочкин <nkuroch...@gmail.com> wrote: > > Two BeagleBone black boards with 1GHZ processors do not make boot sequece > after some unsucceseful attemts to format eMMC. > It looks like they do not make PORz sequence. Both ocillators inacvtive. > NRESET_INOUT is low. PORZn input high. All power voltages are OK. > I use simple code wich make BBB to act as USB flash drive to monitor eMMC > with my PC. Code based on TI usb_dev_msc example in StarterWare. > It begin happens only with new boards. Old revision boards works OK. > Any body can help ? > I going to use JTAG to debug this processors but not shure that JTAG will > work in this case. > > -- > For more options, visit http://beagleboard.org/discuss > <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 > <mailto:beagleboard+unsubscr...@googlegroups.com>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/09fb54d2-3afa-4191-b10b-856ad52ae245%40googlegroups.com > > <https://groups.google.com/d/msgid/beagleboard/09fb54d2-3afa-4191-b10b-856ad52ae245%40googlegroups.com?utm_medium=email&utm_source=footer>. > For more options, visit https://groups.google.com/d/optout > <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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/F9487415-C5DE-4407-9EA8-14B272257589%40gmail.com. For more options, visit https://groups.google.com/d/optout.
