My Gta02s wont charge
andy at openmoko.com
Sun Jun 22 22:49:39 CEST 2008
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Somebody in the thread at some point said:
| Am So 22. Juni 2008 schrieb Werner Almesberger:
|> Joerg Reisenweber wrote:
|>> I think battery charging *never* may be turned off.
|> That's my understanding so far as well. What bothers me is that I can't
|> the device to show the symptoms I would expect in the various states,
|> both good and bad symptoms.
| That's when I made a comment to the effect that we probably don't care
| our battery the way we should, some time ago.
| Charging of battery has to be autonomous by PCF506xx, and all we need
| about is to ENABLE it, and to *set the right currents and voltages*
| charger (and handle errors / monitor charging state). This has to be
| done/redone (as often and) as early in boot as possible, to guarantee
| never will be set a too high max voltage (would kill battery) or charging
| disabled (also by any error-condition [e.g. overvoltage] which has to be
| handled and reset) which would lead to the deadlock Steve faces now.
| It is utterly nonsense to intentionally disable battery charging in
In itself it's perfectly sane to tell the charger to standby if there is
no power coming in. What makes the trouble is the setting is sticky and
there is no always-on intelligence to reassess the situation when power
does come (and according to what Werner just wrote, we can't make the
CPU do that job either). Instead what we're left with is trying to find
a way through the maze of default fixed behaviours of the PMU and trying
to match them with what we need.
On the charging settings for the battery, it seems to use a constant
voltage mode for at least the latter part of the charging, because if
you hook up an ammeter you will see the current decreases visibly second
by second as the charger needs to push less and less current in to keep
the charging voltage up. So this is pretty adaptive. The temperature
of the cell never goes above 30 degrees here, you would expect to be
toasting marshmallows on the thing if there was problem?
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