release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Wiki > Main > SandiskE200BatteryMeasurements (compare)

Difference: SandiskE200BatteryMeasurements (r19 vs. r18)

Sansa Battery Measurements


This is about getting the battery level handling of the Sansa straight. Issues are tracked in FS:6860. Help needed, please provide battery_bench data to improve accuracy of the discharge curve on the SansaRuntime page.


Patching battery bench

  • The quick and dirty fix provided here is that no measurement buffering is being used but instead an instant file update is forced when voltage values are changing. A source code patch containing this fix is also available in the Flyspray entry FS#8070.

change line 232, add got_info

    do
    {
        if(!in_usb_mode && got_info && 
            (exit || timeflag || got_info || rb->ata_disk_is_active()) )

Limits - to be confirmed

  • Fully charged:
    • 4,20V ?
  • Low power shutdown (done by bootloader?): AS chip built into PP5024):
    • 3,3V ?

Charging

Battery charging is controlled by the integrated charger of the PP5024 SoC, which allows configureable charging current and voltage. The charge control register is currently not configured, resulting in a default maximum charging current of 50 mA and maximum charging voltage of 3.9V. This makes charging slow (and probably incomplete) compared to the original firmware. Furthermore, while USB is not supported yet by rockbox on the Sansa e200, the USB interface is allowed to draw only 100 mA instead of the possible maximum 500 mA.

In the meantime:

  • Use the Sansa original firmware for charging instead.
  • Charging with a dedicated charger with Rockbox will not work at full speed.

See also:


r20 - 18 Jul 2008 - 11:35:40 - BertrikSikken

Revision r19 - 08 Apr 2008 - 23:42 - MichaelGiacomelli
Revision r18 - 01 Feb 2008 - 04:32 - MarcGuay
Copyright by the contributing authors.