Very much agree with you - even though I don't want to use a battery, it seems more and more than a battery is a necessity for field use of the BBB, which would explain the existing connector.
On Monday, May 2, 2016 at 2:29:18 PM UTC-4, john3909 wrote: > > You cannot just use a supercap. You have to use a boost switching > regulator to keep the voltage on the processor constant while the supercap > discharges. > This is a lot more complicated than you suggest. You also have to deal > with the case of brown outs where the power is only off for fractions of a > seconds or cases where the power comes on and then off again before the > board has fully powered up. This requires a power monitor and a state > machine to only power the board on once the supercap is fully charged. > Also, if you don’t recycle the power after a power fail, the BBB has the > potential to lock and remains locked until the power is recycled. > > Regards, > John > > > > > On May 2, 2016, at 11:09 AM, William Hermans <[email protected] > <javascript:>> wrote: > > *Use a super capacitor.* >> > > Ok, a little abstract . . . > > Use a super capacitor, and if using a console image . . . sudo apt-get > install acpid > > Then the board will automatically shutdown when 5V input goes missing. I'd > make sure you pick a super cap that can sustain the beaglebone for ~30 > seconds, even if not needed. Just in case. Typically though, here, we see > that the board shuts down within 5 seconds or so. Maybe slightly longer. > > On Mon, May 2, 2016 at 10:47 AM, William Hermans <[email protected] > <javascript:>> wrote: > >> *I have been building embedded systems for a while now and I am >>> considering using the beaglebone (BBB) for an upcoming project, but I am >>> confused by everything I read regarding the shutdown requirements. As an >>> embedded system the only way to turn it off is to simply shutdown the power >>> with a switch, yet my preliminary research indicates that this is a no-no >>> as it may damage the BBB and/or corrupt the file system. I also read a lot >>> of comments regarding voltage on the pins after a shutdown; in my case, >>> very likely there will be a CAT5 cable with live activity connected even >>> after power down; assume the magnetics should protect the BBB, but just >>> checking.* >>> >> >> This is true of any system running an OS that is not red only. If you >> unceremoniously yank the power, you're asking for trouble. >> >> *I have used quite a few micro controllers and various self-standing >>> systems, but am fairly new to the BBB - still mostly reading about it. Am >>> I missing something? How can a device meant to be used in embedded systems >>> not be tolerant of power loss and be so finicky about power?* >>> >> >> It sounds like you're missing a lot. It sounds like you've had a lot of >> experience with small micros, that run bare metal, but have have no, or >> limited experience with using an embedded OS. >> >> Then if you stop and think of the cost of this board, and what the goal of >> beagleboard.org was when the board was created. Perhaps then it become >> clear as to how / why we're where we are in this context. You can fix all >> of this yourself, using external hardware, and custom software. >> >>> >>> *By the way, I can see there is a battery backup circuit but I do not >>> want to use a lithium battery for safety/temperature/cost reasons. Using a >>> large capacitor also seems tricky as the shutdown may take a few seconds so >>> I don't see how that will work.* >>> >>> *Any suggestions would be greatly appreciated.* >> >> >> Use a super capacitor. >> >> >> >> On Mon, May 2, 2016 at 8:39 AM, Gerald Coley <[email protected] >> <javascript:>> wrote: >> >>> >>> >>> On Mon, May 2, 2016 at 10:36 AM, Yiannis Papelis <[email protected] >>> <javascript:>> wrote: >>> >>>> I have been building embedded systems for a while now and I am >>>> considering using the beaglebone (BBB) for an upcoming project, but I am >>>> confused by everything I read regarding the shutdown requirements. As an >>>> embedded system the only way to turn it off is to simply shutdown the >>>> power >>>> with a switch, yet my preliminary research indicates that this is a no-no >>>> as it may damage the BBB and/or corrupt the file system. I also read a >>>> lot >>>> of comments regarding voltage on the pins after a shutdown; in my case, >>>> very likely there will be a CAT5 cable with live activity connected even >>>> after power down; assume the magnetics should protect the BBB, but just >>>> checking. >>>> >>>> I have used quite a few micro controllers and various self-standing >>>> systems, but am fairly new to the BBB - still mostly reading about it. Am >>>> I missing something? How can a device meant to be used in embedded >>>> systems >>>> not be tolerant of power loss and be so finicky about power? >>>> >>>> By the way, I can see there is a battery backup circuit but I do not >>>> want to use a lithium battery for safety/temperature/cost reasons. Using >>>> a >>>> large capacitor also seems tricky as the shutdown may take a few seconds >>>> so >>>> I don't see how that will work. >>>> >>>> Any suggestions would be greatly appreciated. >>>> >>>> -- >>>> 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] <javascript:>. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/beagleboard/4b2dc307-631d-405d-88d6-7537adb3ac29%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/beagleboard/4b2dc307-631d-405d-88d6-7537adb3ac29%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> >>> Main reason for the shutdown process is the corruption of the Linux file >>> system. >>> >>> If you have power on any signal when the processor is shutdown, then you >>> are asking for trouble. >>> >>> >>> http://www.elinux.org/Beagleboard:BeagleBoneBlack#Expansion_Header_Pin_Usage >>> >>> >>> Gerald >>> >>> [email protected] <javascript:> >>> http://beagleboard.org/ >>> [email protected] <javascript:> >>> >>> >>> -- >>> 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] <javascript:>. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/beagleboard/CAHK_S%2BergZ8%2BPd5zBdxsHqJDzQphgPXKXF0oayzjV1PVHPY8kw%40mail.gmail.com >>> >>> <https://groups.google.com/d/msgid/beagleboard/CAHK_S%2BergZ8%2BPd5zBdxsHqJDzQphgPXKXF0oayzjV1PVHPY8kw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >>> 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] <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CALHSORqqALRuwazqWtdLK4uzTKe8EJShCx60943s3%3DuvWBrroQ%40mail.gmail.com > > <https://groups.google.com/d/msgid/beagleboard/CALHSORqqALRuwazqWtdLK4uzTKe8EJShCx60943s3%3DuvWBrroQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/57667b70-5282-4806-aea0-2ab35d5ec1ef%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
