Greg K-H wrote:
> On Wed, Jan 21, 2009 at 09:30:59PM +0100, Wim de Vries wrote:
> > OK. Thanks.
> > I have measured the voltage, with the device connected:
> > on my (Win) PC 5.10 V
> > on my (Linux) laptop: 5.12V
> > on the asus eee pc: 4.96V
> > Do you think that difference is a problem?
>
> Yes, that is on the lower bound of what the device is expecting, so it
> could cause problems.
4.96 V would appear to be well within the bounds of the specification.
USB2.0 paragraph 7.2.2 (page 175) says:
* The voltage supplied by high-powered hub ports is 4.75 V to 5.25 V.
* The voltage supplied by low-powered hub ports is 4.4 V to 5.25 V.
There is a diagram, Figure 7-47, on the same page, which details the
allowable voltages at various points in the USB power distribution
system.
Dave
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