What all does the power management handle? Can it manage safely charging a lipo battery and supplying power to the board? Can it be used for projects that may have power intermittently? Like say a solar powered clock with a battery connected that charges the battery when there is sun and continues running from battery when there isn’t?
we use a BBB in a product and only use the battery to hold up the system
for a safe shutdown. I can imagine
if you had a large enough battery you can get days out of it. the
charger can seem to charge quite fast.
In short. Yes, and no.
Yes, the battery can hold the beaglebone up for a limited amount of time,
while there is an "ac power" outage.
No, the beaglebone will not be fully functional if you require USB
functionality at all. As USB requires 5v, and a typical lithium battery is
3.7-4.1v. So you lose USB on a power outage, and it will not come back
until after a reboot. Assuming "ac power" is back when the board comes back
up.
Without the debian package acpid installed, the battery functionality
varies. With some versions the board will stay up, other versions the board
will unceremoniously immediately shutoff( non clean power off ). Just as
if there were no battery.
Additionally, there is a PMIC register that can be toggled to keep the
board from shutting down while there is a battery connected correctly
through the board test points. I've tested this, and it works as expected.
As far as I can tell from my limited experimentation. You can not change
the charge aspects of the PMIC, it all seems to be hard coded in the
firmware. However, with that said, we've done extensive testing as far as
physically checking the battery voltage, and it seems that the voltage
rarely if ever goes above 4.0xx voltage. So it's pretty close to an 80%
charge, where many lithium people like to keep their batteries for the most
longevity.
Passed that, I probably can not talk much more about our design. However, I
can say that sometimes, the board will get put into a state, where it hangs
at reset. In these cases, one must disconnect the power, reconnect the
power, then toggle the reset pin on the board. Otherwise the board will
hang indefinitely. So, when I say disconnect power, I mean all power. DC
in, and battery alike. The only way to do this automatically, is design a
proper circuit, and use some form of micro-controller. That is, for
locations where physical interaction could be difficult.
All the technical information you need, is in the PMIC datasheet. The rest
will be learned through experimentation, and experience with using it.
Including knowing how I2C in Linux is used.