>>>>> "Alan" == Alan Stern <[EMAIL PROTECTED]> writes:
Alan> On Sun, 13 Feb 2005, Uwe Bonnes wrote:
Alan> You seem to be saying that when connected through the external
Alan> hub, your device runs at 480 Mb/s (high speed). But it doesn't
Alan> according to your usbtree output above. Both Dev 15 on Bus 5 and
Alan> Dev 2 on Bus 1 are shown running at 12 Mb/s (full speed).
No,
I don't want to say that the device runs at 480 Mb/s . It is a Full Speed
device and behaves that way, running at 12 Mb/s. But what I am trying to say
is, that the frequency, at which pending control messages sent to the device is
different. These control messages make some port pins switch ( one single
change per usb control message per port pin). I can view and measure these
changes with an oscilloscope. Connected to the USB 2.0 Hub the frequency of
changes is 8 kHz, while connected directly to the PC this frequency is 1
kHz.
>From what I understand, for USB 2.0 devices on a 2.0 bus, these messages are
sent at 8 kHz (microframes), while 1.x devices only expect messages at 1 kHz
(full frames), and so do 2.0 devices on a 1.X bus.
Device hardware and bus are version 2.0, however the device is not high speed,
but only full speed, but also fully USB2.0 spec compatible.
Bye
--
Uwe Bonnes [EMAIL PROTECTED]
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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