Reason for GPS problems found!
yair at mahalalel.com
Fri Jul 18 00:51:19 CEST 2008
Hi Andy, and thank you for your quick and focused efforts.
Do you know if the Antaris enters one of the sleep/backup modes
on system power loss? If it does, perhaps it mode switch is triggered by
external firmware. In backup mode it only consumes 8uA, and can
probably remain alive for a long time on with regular large capacitors,
such as the ones in the middle of the board.
If it was fitted with external flash, it might not need even that, of
course, but that may perhaps be messed with directly, perhaps by
changing expiration dates of cached data or such.
On Thu, Jul 17, 2008 at 08:58:32PM +0100, Andy Green wrote:
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> Somebody in the thread at some point said:
> | Russell Sears wrote:
> |> I did an opkg update on the factory image last night (~7-8 PM PST), and
> |> now GPS fix times are less than a minute. The update downloaded a new
> | False alarm; the satellites must have been aligned last night... Fix
> | times are multiple minutes again...
> Yes GPS chip is very "sticky", even when depowered for some time it
> seems to hold state and not act in a deterministic way. It makes it
> hard to know if the last thing you changed is responsible for the
> behaviour staying the same or changing, or if it was going to do that
> anyway. That makes debugging it very confused.
> - -Andy
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