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Subject: USB On-The-Go (OTG) (was: Re: 2nd ATA Device on JB20 Recorder)
From: Francesco Grassi (frangras_at_tin.it)
Date: 2003-01-23


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.
>



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