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Subject: Re: USB On-The-Go (OTG) (was: Re: 2nd ATA Device on JB20 Recorder)
From: Andrew Jamieson (andrew.jamieson_at_projectlab.net)
Date: 2003-01-23


USB OTG requires special controllers, and is not supported by either of the
USB chips Archos uses.

Andrew Jamieson
----- Original Message -----
From: "Francesco Grassi" <frangras_at_tin.it>
To: <rockbox_at_cool.haxx.se>
Sent: Thursday, January 23, 2003 10:25 AM
Subject: USB On-The-Go (OTG) (was: Re: 2nd ATA Device on JB20 Recorder)

> Hi guys,
> I found these links:
> http://www.semiconductors.philips.com/buses/usb/products/otg/
>
>
http://www.semiconductors.philips.com/buses/usb/products/otg/tutorial/index.
> html
> [...]
> Point-to-Point Connectivity The OTG Supplement extends the USB standard to
> enable point-to-point communication between two USB devices: one OTG
device
> and another OTG or traditional USB device. Because the two devices still
> maintain the roles of host and peripheral, OTG point-to-point
communication
> is not to be confused with peer-to-peer. Unlike traditional USB, OTG
allows
> only one peripheral at a time to be connected to the device acting as
host.
> OTG devices do support USB hubs, a traditional way of enabling multiple
USB
> peripherals to share a single USB host connection. However, some OTG
> functionality such as swapping host/peripheral roles and peripheral
session
> requests are not supported across today's USB hubs.
>
> USB OTG device types range from battery-powered handheld products to
> non-portable peripherals. While initial device roles (host/peripheral) are
> defined by how they are cabled together, some OTG devices can switch roles
> through the host negotiation protocol (HNP) without changing the cabling.
>
> Figure 3: OTG enables point-to-point connectivity between peripherals
> without a traditional PC host.
>
> To better understand how new OTG devices and features add to existing USB
> functionality, a quick review of USB device terminology follows.
>
> The A-device is the default host at the start of a session. It supplies
> power to VBUS.
> The B-device is the default peripheral at the start of a session.
> To these, the OTG Supplement adds the OTG device and defines two types: a
> dual-role device and a peripheralonly device.
> [...]
>
>
> http://www.usb.org/developers/onthego/
>
>
>
> Maybe it could be useful for our objective...
>
>
>
> FG
>
>
>
> -----Messaggio originale-----
> Da: owner-rockbox_at_cool.haxx.se [mailto:owner-rockbox_at_cool.haxx.se]Per
> conto di roland
> Inviato: mercoledý 22 gennaio 2003 23.35
> A: rockbox_at_cool.haxx.se
> Oggetto: Re: 2nd ATA Device on JB20 Recorder
>
>
> jep,
> otherwise CF2IDE Adapters like these:
>
http://www.flashmemory.com.au/shop/shopdisplayproducts.asp?id=3&cat=FlashMem
> ory+Disk+Drives
> would be a bit dangerous :)
>
> First I was unsure about this because I read contradictory comments - but
> at least
> http://www.compactflash.org/faqs/faq.htm#dvs approved that CF supports
BOTH
> voltages.
>
> Regards
> Roland
>
>
> ----- Original Message -----
> From: "Stuart Tedford" <stuart.tedford_at_piresearch.co.uk>
> To: <rockbox_at_cool.haxx.se>
> Sent: Wednesday, January 22, 2003 5:29 PM
> Subject: RE: 2nd ATA Device on JB20 Recorder
>
>
> > >-----Original Message-----
> > >From: Andrew Jamieson
> > >
> > >And dont forget that CF cards use 3.3V power, not 5V.
> >
> > No, CF cards allow for both 3.3 and 5V supply.
> >
> > Stu.
> >
>



Page was last modified "Jan 10 2012" The Rockbox Crew
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