USB unplug time for reset
werner at openmoko.org
Tue Mar 1 11:45:49 EST 2011
One way to reset the Ben is by removing the battery, disconnecting USB,
waiting a few seconds, and then connecting USB again.
There's been a bit of disagreement over how long "a few seconds" should
be. Based on experience but without actually measuring things, I
suggested something in the order of 20 seconds, while others found this
I now measured the reset time on three Bens. This was done by just
unplugging USB while watching time pass on a watch. The error margin
should be about +/- 1 second.
Ben "#3" 10 seconds
Ben "#4" highly variable, sometimes as little as 6 seconds did
work, at other times it needed 10 seconds.
Ben "#5" 11 seconds
This short experiment suggests that one can be reasonably sure a reset
does occur if unlugging USB for at least 12 seconds. If counting time
without the help of a watch, one should add 10-20%, because impatience
may shorten the subjective seconds a little.
What is also clear from this is that just unplugging and immediately
inserting USB will not work with the Ben.
More information about the discussion