asked anyone at TI if it is OK to use the PMU like this? Perhaps you
should post a question on E2E.
From http://e2e.ti.com/support/power_management/pmu/f/200/t/185514.aspx:
"The battery charger should work fine with a supercap. You'll need to
make sure the TS (battery temp sense) pin is at a proper voltage to
allow charging. If the supercap does not have a temperature sensor, you
can simply put a 10k resistor from TS to GND."
If you are charging at 440mA, it will take 50 Seconds to reach full
charge. What happens when the power fails before that 50 Seconds? I would
recommend that you monitor the supercap voltage and wait until it is fully
charged before opening any files.
That is why I use full data+metadata journaling on the filesystem.
If an unclean shutdown happens before the supercap is charged, the next
boot-up will be delayed for several seconds as the filesystem is
repaired using the full journal. That is annoying, but it is a minor
cost for robustness. Mostly, the supercap is there to eliminate the need
for the repair delay.
It is an interesting concept, but I'm still skeptical if this can really
work.
Well, I do use it, so that's one data point.
The other main alternative for bullet-proof power-fail robustness is to
rely on on something like unionfs to provide a mix of read-only and
read/write filesystems, but that's not so simple either. It's complex
and not very well supported in general.
Batteries have a fairly limited lifetime, so I don't consider that a
practical solution (for me).
I'm interested to hear how other people prevent corruption on power
loss, though.
- Mike
--
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].
For more options, visit https://groups.google.com/d/optout.
