BeagleBone RTC Battery

Hi

I recently picked up a BeagleBone Rev A3 and have not been able to
figure out how to maintain the RTC when power is absent. I have
reviewed both the BeagleBone SRM and AM3359 datasheet, but have not
been able to find how to power the RTC independent of an external
power availability.

Does anyone have experience with the BeagleBone RTC? Is it possible to
power it independently? Are there other/better solutions?

Thanks for your help!

The design does not support a RTC backup battery.

Gerald

Does anyone have experience with the BeagleBone RTC? Is it possible to
power it independently? Are there other/better solutions?

If there ist an TCP/IP cnnnection available in your application, you could synchronize the RTC time with the offical time by accessing a NTP server Network Time Protocol - Wikipedia.

Christian

Thank you for your help!

I'm bummed the beagle bone does not support a RTC backup battery, so I
may just move forward with Christian's solution. There should ideally
be an available internet connection when the device is in use, so it
may not be so large an issue.

Thanks again!

Hello,
I have the same problem and i resolved it by using the DS1307 RTC
circuit that work with I2C and has it's own battery (adafruit), so
time and date are backuped

Italo

@Italo

Could you share what was needed on the software side for this to work? once wired to one of the I2C busses what more needs done at the kernel level or otherwise to have the beagle find and make use of the 1307. (I did find there’s kernel drivers for this RTC)

Eric

Hi Eric,

In fact i used it with the PIC32 Ethernet Start Kit of microchip. The problem was the same, i mean that no battery could save the time. I have now to use the beaglebone because i think that it is a very good computer. I am a beginner with that board and i have to learn more about kernel to see how i can include that chip (DS1307) in and how to treat interrupt.

I wrote my own driver (C for PIC32) so that I can read the date and time and of course set them too for that board. But i have to rewrite the driver to use it with the beaglebone.

Do you know where i can found the kernel source (Angstrom 3.2.5+) ?
Do you have any idea about interrupt treatment ?
Where did you find those kernel drivers ?

So not the same problem solved due to it being on a pic vs beagle platform. Kernel sources for rtc1307 can be found in

https://github.com/ohporter/linux-am33x/blob/st7735fb/drivers/rtc/rtc-ds1307.c

that’s porters branch of the kernel, but I’d imaging that that paticular driver could be found in about any version of the kernel source in /drivers/rtc/rtc-ds-1307.c

Eric