As I understand it, there is a hardware clock, but it is not backed up by battery. If the BBB always has access to a network, that’s not a big deal, it can grab time from NTP and reset the clock.
I’m planning to use the BBB in an underwater housing and power it off for days at a time to save battery, so I needed another solution for keeping time. The DS3231 suits this purpose well. After trying for a while with sleep modes, alarms, FETS, relays etc, I’ve decided I need a separate MCU to act as the timer to wake everything up when the BBB is powered down. I just received some new parts from Adafruit, we’ll see how that goes. -Steve > On Sep 11, 2020, at 8:51 AM, Chinmay Pendharkar <[email protected]> wrote: > > Thanks Steve! > > I have used external RTCs with BBB before. I was wondering if anything > changed with the new Beaglebone AI. I can see some mention in the AM5729 > datasheet, but not much on the BBAI System Reference documentation > https://github.com/beagleboard/beaglebone-ai/wiki/System-Reference-Manual > <https://github.com/beagleboard/beaglebone-ai/wiki/System-Reference-Manual> > > -Chinmay > > On Friday, September 11, 2020 at 8:14:24 PM UTC+8 [email protected] > <http://gmail.com/> wrote: > I just spent the last few weeks looking at the BBB RTC. > > If you want a battery backed RTC, you will need to add one. The Maxim DS3231 > is one example. Adafruit makes several breakout boards and modules so you > can pick your flavor of how you want to connect it. The clock will be > connected to the I2C - 2 bus. > > Then add this line to /boot/uEnv.txt: > > dtb_overlay=/lib/firmware/BB-I2C2-RTC-DS3231.dtbo > > > Restart, and that’s it. Your BBB now has a battery backed RTC. If it’s on a > network and can reach an NTP server, it will set the RTC automagically. > > The BBB still does not have a good low power sleep mode. The RTC will not > fix that, but it’s not the fault of the RTC, which otherwise works quite > nicely with the Linux drivers. > > -Steve > > > > >> On Sep 10, 2020, at 10:37 PM, Chinmay Pendharkar <[email protected] >> <applewebdata://74114A22-5D67-4016-8448-BA0C9EF0D305>> wrote: >> > >> Hello, >> >> Does the BeagleBone AI have an onboard RTC? If so is there any documentation >> about it and how it can work? If there is a mechanism to add >> battery/supercap to keep time. >> >> -Chinmay >> > >> -- >> 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] >> <applewebdata://74114A22-5D67-4016-8448-BA0C9EF0D305>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/0cae3f1d-2f95-4128-8a81-440c770c05ben%40googlegroups.com >> >> <https://groups.google.com/d/msgid/beagleboard/0cae3f1d-2f95-4128-8a81-440c770c05ben%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > 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/670727d8-acff-4b25-9ee5-231c5f8e05ecn%40googlegroups.com > > <https://groups.google.com/d/msgid/beagleboard/670727d8-acff-4b25-9ee5-231c5f8e05ecn%40googlegroups.com?utm_medium=email&utm_source=footer>. -- 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/71962CA2-88B9-4CB0-A88F-F4B866F3AD23%40gmail.com.
