Yep, you need a hardware state machine to monitor the power source. I don’t use batteries as I use supercaps which are just big enough to power the board during shutdown. When the power returns, I restart the board. There are a few corner cases that occur, such as when the power comes back on during the power down cycle, or the power fails during the power up cycle.
Regards, John > On Apr 17, 2016, at 7:18 PM, evilwulfie <[email protected]> wrote: > > Interesting. Too bad if you want the battery to act as a UPS it cant some > how notify the kernel that AC has been removed > and have a routine to just chill a while to see if power comes back. > > Be nice to have a variable that is user settable for the time between loss of > AC and shutdown. > > As it is now it sees the AC removed, shuts down and no easy way to restart on > power restored. Requiring some other IC to monitor power > and then press the pwr_but to restart the processor. > > > > On 4/17/2016 7:10 PM, John Syne wrote: >> Yep, it is in the BB kernel: >> >> https://github.com/RobertCNelson/bb-kernel/blob/am33x-v4.1/patches/beaglebone/dts/0006-tps65217-Enable-KEY_POWER-press-on-AC-loss-PWR_BUT.patch >> >> <https://github.com/RobertCNelson/bb-kernel/blob/am33x-v4.1/patches/beaglebone/dts/0006-tps65217-Enable-KEY_POWER-press-on-AC-loss-PWR_BUT.patch> >> >> So again, on line 164 is the Interrupt routing. It is this line: >> >> + input_report_key(tps->pwr_but, KEY_POWER, >> >> + ~status_reg & TPS65217_STATUS_ACPWR); >> that send a power button pressed as an input key when the AC 5V power is >> removed. >> >> Regards, >> John >> >> >> >> >>> On Apr 17, 2016, at 4:52 PM, William Hermans <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> The real reason why our source trees do not match up. My source tree is >>> based on 4.1.x, and yours seems to be 3.8.x. The patch you showed above >>> would probably botch up my source tree . . . >>> >>> On Sun, Apr 17, 2016 at 4:33 PM, William Hermans <[email protected] >>> <mailto:[email protected]>> wrote: >>> Yeah I recognize that code from source code not written by TI employees. >>> The file is called tps65217_charger.c, and is written by an employee of >>> another company. >>> >>> Anyway, I think we're going to blow this off. The idea was to wait around >>> without power for 5 minutes, to see if power comes back up. Before issuing >>> a shutdown. Then, on the power up end, using a simple R/C circuit to ramp >>> up voltage to 5v over a specific time period. >>> >>> > > > > <https://www.avast.com/en-us/lp-safe-emailing-2109?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=oa-2109-v2-a> > Virus-free. www.avast.com > <https://www.avast.com/en-us/lp-safe-emailing-2109?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=oa-2109-v2-a> > > -- > 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 [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/571443FC.6020505%40gmail.com > <https://groups.google.com/d/msgid/beagleboard/571443FC.6020505%40gmail.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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/B1D3922E-9D41-4222-AD11-407748DC7B0E%40gmail.com. For more options, visit https://groups.google.com/d/optout.
