[Bug 212] Charging seems completely broken

bugzilla-daemon at bugzilla.openmoko.org bugzilla-daemon at bugzilla.openmoko.org
Sat Mar 10 22:14:34 CET 2007


werner at openmoko.org changed:

           What    |Removed                     |Added
           Platform|PC                          |Other

------- Additional Comments From werner at openmoko.org  2007-03-10 22:14 -------
Here's how one can reproduce at least some of the symptoms on my bv2.
Be sure you know what you're doing. If you reverse the polarity,
all you're likely to get is a heap of smoking misery. All readings
are from the lab supply. I didn't measure what's going on on USB.

- remove the battery
- set the voltage of your lab power supply to 3.0V
- hook up your lab supply instead the the battery (careful !)
- set the current limit high (above 300 mA)
- connect USB
- your voltage readout on the lab supply should jump to about 4.1V
- turn your Neo on. You should now get, on the lab supply, up to
  250 mA and 3.0V
- while the system is running, limit the current to about 220 mA
- the system should reset, make it to the splash screen, reset
  again, etc.
- briefly press the power button to end this
- power on repeats the cycle
- you can reduce the time the splash screen is shown by limiting the
  current further. The minimum is about 150 mA.
- you'll notice that each cycle lasts about 1.25 seconds
- limit the current to about 90 mA
- all of a sudden, the cycles get quicker, about 0.6 seconds
- pressing the power button no longer has any effect now
- if I disconnect and reconnect USB, the machine happily enters the
  same cycle again
- further lowering the current accelerates the cycle to about 120 ms
- this goes on until I limit the current to nominally zero
- even at "zero", the cycle is restarted as soon as both USB and
  battery power are present (no matter in which order)

Note that my bv2 is "naked". In particular, it doesn't have a vibrator,
which may change some of the results.

- Werner

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