Hi Jay, I think this was covered in my original post....
"I'm working on a project using the BBB. Supplying +5V (up to 3A) directly to the pins on P9 from a quality bench supply. I've found *that briefly switching the +5V supply OFF and then back on* can pretty reliably leave the BBB in an odd state characterized by... a) No LEDs on b) Very little current drawn from supply (10mA or less) c) +5 present on P9.5 and P9.6 d) 0.687V on P9.7 and P9.8 ( should be SYS_5V ). e) P9.9 = 3.57V f) P9.10 = 0V" The command line is not involved. I was using a lab supply and just switching it off for about 500ms then back on. I have also been able to cause the problem using an adjustable output supply by lowering the input voltage to around 2V then going back up to 5V. Regards, Jim On Fri, Apr 25, 2014 at 7:58 PM, <[email protected]> wrote: > I just foolishly posted pretty much the same question... > > I'm seeing very similar behavior, I also noticed that it can still be > powered from the USB when in this state but not VDD_5V. > > Can you please elaborate on the brownouts that you're seeing. You said > they're occurring when "the power is switched off", is this in software, > i.e. "shutdown -h now"? I haven't been able to see this on my scope but I > also can't reliably recreate the situation in which it occurs. > > I know the PMICs are the same on RevA and RevB, but I believe I've only > seen this on RevB boards. > > Thanks! > jay > > > On Monday, November 18, 2013 5:00:55 PM UTC-8, James Littlefield wrote: >> >> New to BBB but experienced with embedded systems. >> >> I'm working on a project using the BBB. Supplying +5V (up to 3A) >> directly to the pins on P9 from a quality bench supply. I've found that >> briefly switching the +5V supply OFF and then back on can pretty reliably >> leave the BBB in an odd state characterized by... >> a) No LEDs on >> b) Very little current drawn from supply (10mA or less) >> c) +5 present on P9.5 and P9.6 >> d) 0.687V on P9.7 and P9.8 ( should be SYS_5V ). >> e) P9.9 = 3.57V >> f) P9.10 = 0V >> >> I've found that once the system is in this mode no amount of >> pressing/holding the momentary BBB pushbuttons will get the system working >> again. Removing input power, waiting 10 sec or so, then restoring power >> will get things working again. >> >> Has anyone else seen this? It seems sort of like an issue with >> the TPS65217C chip but I've not found any reported errata on that part. >> >> Thanks >> Jim >> >> >> -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/p0CwsGzNYNw/unsubscribe. > To unsubscribe from this group and all its topics, 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.
