Werner Almesberger wrote:
Andy Green wrote:
| The root cause is the signal from VBUS rasies and drops rapidly when
| inserting a wall charger.
[...]
It sounds like you were already in Linux doing this, so I wonder what is
the excuse of the adapter now to drop dead briefly on insertion?
Is this VBUS coming out of the adapter (i.e., measured on the adapter's
cable) or VBUS obtained by the system,
I'm not sure of this. I measured it from USB1/USB2 which is connected to
PMU.
Do you think this elevator-style-signal is caused by system?
i.e., subject to contact bounce
and all that ?
Still, USB detection has a fairly generous debounce time of 62ms, which
should be sufficient.
Yes. But the USBx ping voltage raises/drops over 62ms, according to the
following pics.
http://people.openmoko.org/matt_hsu/defect_usbx_signal.jpg
http://people.openmoko.org/matt_hsu/usbx_signal.jpg
The time dimension is 500ms.
Matt
By the way, Matt, I didn't see your original mail. Could you perhaps
post it here with the pictures (or, if they're too big, put them on
sita aka people) ?
- Werner
