K70 OTG

[hemanthkumarven]

All,

We are planning to use OTG functionality of the K70 microcontroller to connect an USB based cellular modem and PC to our device.

The reference manual of K70 mentions "The OTG implementation in this module provides limited host functionality as well as device solutions for implementing a USB 2.0 fullspeed/ low-speed compliant peripheral".

The definition of limited host functionality is not clear from the reference manual. Does anybody have an idea what the limited host functionality means?

Thanks

Hemanth

[hemanthkumarven]

Hi Mark and Carlos,

Thanks for the quick reply. Really appreciated..

Thanks

Hemanth

[CarlosCasillas]

Hi Hemanth,

The explanation from Mark is correct. As you have an embedded USB module on a MCU, the Host functionality will be limited to the pre-compiled functionality for specific kind of Devices that will be supported. You can also add the support for the HUB Class and connecting more than one device at the same time, but considering that it will require more memory and more robust software for managing all the USB transactions.

Hope this will be useful for you.
Best regards!
/Carlos

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[mjbcswitzerland · Accepted solution]

Hi

I think that the main understanding of "limited host" is that it allows connecting to a "single" USB device at one time and not a higher number via a USB hub since it doesn't support the hub protocol.

In addition, a full USB host would be able to load drivers for "any" USD device attached but a "limited host" would support just one or a limited number of pre-defined devices.

If you want to use OTG functionality between two pre-defined devices then there is nothing to worry about.

Regards

Mark