Neo Sound and USB Questions

danimanns at gmx.de danimanns at gmx.de
Fri Aug 17 20:25:58 CEST 2007


Thank you for that wonderful explanation!

BTW: Where is my own e-mail in the list? I still did not receive it,
but it seems you did?! Somethings strange in that list...

Am I right that I would need to solder some more things to make this
whole construction work? I mean, I have to spend these 5V to the Neo for 
charging,
and still need the other pins for transferring data from the USB drive 
to the Neo.
So I would have to split the cable, right?

Rusty Chris wrote:
> device (in theory the Neo can be host or client, though currently only
> client
> mode is functional).  
*But this feature will hopefully be added in GTA2?*
> If a device wants to draw more power it is required to
> "ask permission" from the host/hub.  Many simple [non-compliant] devices
> skip this step and
> just assume that they can draw as much power as they want, which leads to
> problems of overloading the host/hub.  The Neo will not draw more than 100ma
> until it has gotten "permission".  There is one exception - the neo can
> detect its
> own 'dumb' charger by the presence of 48kOhm resistance between USB pin 5
> and ground.  In this case the power mgmt unit will allow the full 500ma
> power
> draw.
>
> So if you have a decently noise-free 5V USB car charger, it would be fairly
> simple to solder in a 48k resistor (note that it should be low-tolerance
> - 1%)
> and have the neo pull 500mA for fast charging. 
>
> As for forcing the neo to ignore USB power negotiation, I don't know if this
> is a kernel driver issue (hackable) or a USB chipset issue (less
> hackable)...
>
> -Rust




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