From: Heikki Hannikainen <hessu_at_hes.iki.fi>
Date: Tue, 30 Jul 2002 16:05:30 +0300 (EEST)

  Hi,

  Here's my initial work on charging for the Recorders and long-term
battery voltage statistics for all models. The patch is against the
current CVS state. The players do not need this and can not make use of
this as they have the charging done in hardware. This recorder code runs
when rockbox runs, to get the Archos charging code reboot the device with
the charger connected.

  Please keep in mind that this is alpha quality code and comes with no
warranty - if it breaks, you get to keep both pieces. Probably the worst
it can do is burn out your batteries. But keep on eye on the box while it
charges. I've only tested it for a couple times now.

  The algorithm is roughly described in the beginning of
firmware/powermgmt.c, it was designed on #rockbox yesterday. The
implementation does vary a bit from the specification - it calculates an
average delta voltage instead of amount of negative samples, this seems to
be easier to tune.

  The code should probably cleaned up a bit, at least to provide a cleaner
API-sort of thing. And the 'battery full' condition detection parameters
(average length & limit values) must be tuned a little bit when we have
some experience on how the logic works out.

  Besides the charging logic, the patch adds a battery status viewer with
three views: an automatically scaled voltage graph, voltage/status/delta
display and a list of the last 7 1-minute deltas. Up/down keys switch
between these.

  This is work in progress, don't expect it to work properly yet. But this
should serve as a good starting point for experimenting.

  - Hessu


Received on 2002-07-30