My Gta02s wont charge

Werner Almesberger werner at
Mon Jun 23 03:15:36 CEST 2008

Andy Green wrote:
> Well I'm just off to bed so I guess I have to study the datasheet vs the
> code tomorrow, but can't it be that the problems come from usbdevstat =
> 11?  It's that which kills USB -> SYS specifically which maybe is not
> what chgena = 0 does.

Setting MBCC7.usbdevstat to binary 11 would also kill all paths, yes.
However, MBCC7 resets to 500mA in Standby, so we should not have a
problem with this.

We could enable the USB->SYS path by setting MBCC8.usbenasus = 1. MBCC8
resets in NoPower, so it would be "sticky" as long as the backup battery
doesn't fail. But USB->SYS doesn't seem to be current-limited in this
case, so this mode is probably not a great idea.

A big problem with MBCC7 is that, if we were enabled the charger but
didn't do anything else (such was wake up when USB is plugged in), we'd
have the PMU charge in a 500mA configuration, violating the 100mA limit.

- Werner

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