William Chops Westfield <billw@cisco.com> wrote:

> I've asked several microcontroller manufacturers about "host mode"
> USB support, specifically for the purpose of connecting the
> low-cost peripherals that are becoming available.  the answer has
> been uniformly "it's hard", with occasional elaborations into such
> areas as "well, a usb HOST-side controller is supposed to support
> the FULL USB spec, which means 127 devices, going through HUBs, and
> all that stuff..."

Bill:

The new "USB On-The-Go (OTG)" spec addresses this issue; it defines a
means of connecting exactly TWO USB peripherals directly together,
keeping the master/slave architecture of USB, but with a mechanism
for exchanging the master/slave role.

Because the operating conditions for OTG devices are so much simpler
than for a standard USB host controller, OTG chips are substantially
simpler to implement (and should be relatively simple to use, as
well).

The OTG spec is still unreleased, so no chips are currently
available... But I think you'll see chips VERY soon after the spec's
approved.

-Andy


=== Andrew Warren --- aiw@cypress.com
=== IPD Systems Engineering, CYSD
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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