Operation without battery (GTA02)

Andy Green andy at openmoko.com
Thu Jul 24 01:17:04 CEST 2008

Hash: SHA1

Somebody in the thread at some point said:
| On Wed, Jul 23, 2008 at 5:51 PM, Andy Green <andy at openmoko.com
| <mailto:andy at openmoko.com>> wrote:
|     That's right, to start Freerunner needs a battery in and the battery
|     needs some decent charge left in it, for the reason briefly during
|     startup it needs to eat more current that it is allowed via USB.  It
|     causes a "brownout" at that time since the USB current limit does its
|     job well, it chokes and restarts repeatedly.
| Does the latest u-boot

| contain the start-up current limiting code that keeps <100mA during
| boot?  If so, does that mean we should be able to boot from USB power

It looks like it does have those patches in, but this "brownout" problem
is coming before the CPU gets started even, so they don't help.

Those patches are aimed at even allowing us to run with 100mA USB
current limit.  Other problems we didn't solve yet will also conspire
against not having a battery in there in U-Boot and kernel, so I can
just say "you need a battery in Freerunner".

- -Andy
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