My Gta02s wont charge / chgena = 0 by default

Werner Almesberger werner at openmoko.org
Thu Jun 26 12:42:37 CEST 2008


Andy Green wrote:
> | thing that hints at a problem is that INT4.lowsys is set after
> | the sudden shutdown.
>
> Wouldn't this get set as a symptom of the shutdown, not a cause?

I'm kinda curious about that myself :-) My current understanding
is that Vsys shouldn't drop merely as a consequence of going into
Standby, and that power that is cut in Standby is cut at the
regulators. (Otherwise, STBYCTLx != 0 wouldn't be possible.)

> I wonder if what it is doing as part of the charging action is removing
> the load from the battery so it can assess the voltage on it.  This
> would "have consequences" if there was no external power.

That's a different scenario. The one that's causing these problems
is:

- charger disabled
- (sufficient) USB power
- no or weak battery (still have to determine what is "too weak")

The system can stay in this state indefinitely. But as soon as I
enable the charger, it dies quickly (within tens of milliseconds
if not faster).

So what I'll do is to look at Vsys directly (wish we had it on a
test pad), and to capture the timing with more accuracy (i.e.,
oscilloscope, not multimeter).

- Werner




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