When it fails to boot after connecting 5V, a short press of the power switch has no effect. The kernel has not booted, so the button press event is going nowhere.
>From this failure mode, pressing and holding the power switch until the power led goes off and then releasing it causes the device to boot - as does a short press of the reset switch. This is what has led me to the conclusion that the only way to guarantee the device boots after applying power is to control the reset signal with a watchdog circuit triggered off a transition of the heart-beat signal (or something similar). I'm wondering if it possibly is getting to u-boot under this failure mode. Do you know if any of the uarts available on P9 are configured by default for u-boot? Cheers, Andrew. On Friday, 25 October 2013 09:14:18 UTC+13, Gerald wrote: > > You must just press the power button once. Not hold it. If you do > it just power cycles. Pressing the button once let's the Linux kernel > shutdown after a 60 second time out. > > Try it again using the power button as it was intended. > > Gerald > > > > On Thu, Oct 24, 2013 at 3:05 PM, AndrewTaneGlen > <andrewt...@gmail.com<javascript:> > > wrote: > >> Hi Gerald, thank you for your response. >> >> I tried the following (Using a new BBB with no SD card inserted, and >> nothing else connected to it at all): >> >> Firstly, plug in 5V barrel connector (connected to regulated 5V, measured >> with good multimeter as 5.0001V), then: >> >> 1) Wait to see he heartbeat led (D2) come on. >> >> 2) Press and hold the power key until the power led (D1) goes off. >> >> 3) Release the power key >> >> Repeating this process (with 5V connected the entire time) the device >> failed to boot (the heartbeat led failed to come on) on the 14th try, and >> continues to do so about 1/20. >> >> I'm using the BBB in a location away from any regular user interaction >> and with a power supply that can come on and go off randomly (it functions >> as a wifi client I connect to and control/monitor with an ipad), so >> unfortunately I don't have the ability to manually press the power or reset >> buttons to ensure the device always comes on when power is applied (at >> least as I intend to use it). >> >> What I will do, as a kind of nuclear option, is reassign the heart-beat >> led to a spare gpio on P9, and implement a basic watchdog circuit that will >> pull the 'SYS_RESETn' low for a couple of hundred milliseconds if it >> doesn't see a change in state of the heart-beat signal within about 10 >> seconds. This should give a 100% guarantee that (as long as the hardware is >> ok) the kernel will eventually get booted whenever power is applied. >> >> There is a TI part, the TPS382x that is nearly perfect for this task, but >> has a non-configurable delay time of 1.6s - I'll try to find something like >> this. >> >> Cheers, >> Andrew. >> >> >> >> >> On Friday, 25 October 2013 02:01:51 UTC+13, Gerald wrote: >> >>> I don't see that fix as being the issue you are seeing. But, when they >>> are available, you can certainly give it a try. >>> >>> The reset button is a warm reset button. It is not the power on reset >>> for the board. >>> >>> I suggest that you use the power button as it is intended and use it to >>> power off the board and then power on the board. See what sort of results >>> you get in that use case. >>> >>> Gerald >>> >>> >>> On Wed, Oct 23, 2013 at 9:41 PM, AndrewTaneGlen <andrewt...@gmail.com>wrote: >>> >>>> Hello All, >>>> >>>> I am also having this problem - with a bench top power supply set to 5V >>>> and 5A, plugging into the barrel connector with no SD card inserted, so >>>> running the default Angstrom image from flash, the device will fail to >>>> boot >>>> at least 1 in 20 tries. A similar failure rate was observed on my two >>>> other >>>> boards. >>>> >>>> I noticed a new board revision has been a released - the A6. The list >>>> of revisions included a reference to fixing a random glitch in the >>>> SYS_RESETn signal. Could this possibly address the problem I have been >>>> seeing - I would be more than happy to buy more boards if this is the case. >>>> >>>> Regardless of the new release, I have tried various experiments to find >>>> a 100% reliable way of making the A5C board boot, as follows: >>>> >>>> 1) Hold reset button, connect power, release reset button after ~1 >>>> second. >>>> >>>> 2) Connect power, press and hold reset button, then release after ~1 >>>> second. >>>> >>>> 3) Hold Power button, connect power, wait till power led goes off, then >>>> release power button. >>>> >>>> All of these also failed at varying rates, but all showing at least one >>>> failure out of 40 tries - which is unfortunate as I am building a custom >>>> cape that will have access to the reset and power signals, so I there was >>>> some sure fire way of making it boot this would have been fairly easy to >>>> include in my design. >>>> >>>> Any further info would be greatly appreciated. >>>> >>>> >>>> Regards, >>>> Andrew. >>>> >>>> >>>> On Saturday, 28 September 2013 10:04:06 UTC+12, gmbe...@gmail.comwrote: >>>>> >>>>> Same problem here, its showing up in 2 ways. The Beagle Board Black >>>>> has a power control IC that is sensitive to 5 volt rise time and has >>>>> frozen >>>>> up under short brownout situations..in fact, I can freeze it up at will >>>>> by >>>>> dropping out 5 V for about 100mS, it will lock up with 3.3 volts turned >>>>> off >>>>> even though the 5 volt input is good. Removing the 5 volt input for more >>>>> than 1 second restores normal 3.3 Volt power and all is good. The other >>>>> way..I'm still investigating, it refuses to boot about 1 in 20 tries for >>>>> reasons that are so far unknown. In this instance I have power supply >>>>> monitoring instruments all over this board, and the power supply >>>>> controller >>>>> is working even when the lockup occurs. So I'm mainly interested in the >>>>> situation where the blue lights are on but the board is not booting. We >>>>> are >>>>> running a port of Debian Linux. >>>>> >>>>> >>>>> On Wednesday, July 31, 2013 5:48:54 PM UTC-4, duckhunt...@gmail.comwrote: >>>>>> >>>>>> Hi guys, >>>>>> >>>>>> we have a problem with our Beagle Bone Black (A5C). We are using >>>>>> Ubuntu Raring 13.04 armhf v3.8.13-bone21 (2013-06-14) on the eMMC (no SD >>>>>> Card). The Beagle Bone is placed in a case and we have connected it to a >>>>>> DC >>>>>> power supply. Sometimes (I would say every 5 to 10 times), when we are >>>>>> plugging in our power supply, the BeagleBone powers on (Power LED is >>>>>> on), >>>>>> but nothing more happens (none of the other four LEDs is on). If we are >>>>>> now >>>>>> removing the power supply and putting it in again, the BBB starts >>>>>> normally. >>>>>> I guess the power supply is strong enough: 5A@5V. >>>>>> >>>>>> Thanks for your help in advance. >>>>>> >>>>>> Regards, >>>>>> duckhunter >>>>>> >>>>> -- >>>> 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...@**googlegroups.com. >>>> >>>> For more options, visit >>>> https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> >>>> . >>>> >>> >>> -- >> 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...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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