On 2 Jun 2002, Dmitri wrote:
> On Sun, 2002-06-02 at 16:46, Vladimir Dergachev wrote:
>
> > I am not using any hubs, aside from the one in the card. Also the card
> > looks a quite similar to the one on VIA's website, but many capacitors are
> > missing (for example the ones near the ports).
>
> Smaller caps may be missing because this board passed EMI testing
> without them being installed.
Those looked like large ones.
>
> > I am suspecting this might
> > be a power issue of some sort - my device has about 11 microFarad before
> > voltage regulator.
>
> Most likely, this voltage regulator -requires- this cap for stability.
It does, the question is how much. If the capacitor takes too long to
charge this might be a reason for the error. (I.e. the device does not
have time to power on before the driver gives up on enumeration).
> Other regulators may not need it. Often a board is designed to
> accomodate several types of components, this allows for flexibility in
> supplies.
Right, but it looks like they replaced four electrolitic (or tantalum ?)
caps and four smaller capacitance ones with two ceramic ones. Which this
might be good enough for EMI, the board might not be able to handle the
initial plug-in current so well.
Vladimir Dergachev
>
> Dmitri
>
>
_______________________________________________________________
Don't miss the 2002 Sprint PCS Application Developer's Conference
August 25-28 in Las Vegas -- http://devcon.sprintpcs.com/adp/index.cfm
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
