AM5746: USB ID GPIO Pin

Stuart Baker

Part Number: AM5746

I'm working with a customer to implement one USB interface in "dual-role" and one USB interface in "host" only.

We have found that for dual-role mode, the ID pin is expected to come in on a GPIO pin. However, it is not clear if there are any restrictions on which pin. Can it come into any GPIO pin on the device.

In host only mode, the TRM still mentions needing a GPIO for the ID pin (pulled down). Is this still really required, or can the USB interface be configured to be forced into host only mode? It seems rather silly to have to use an unconnected GPIO for the ID pin feature when we know the port will be in host mode no matter what.

Thanks,

Stuart

over 1 year ago

0 Josue Zamitiz-Ayala over 1 year ago

TI__Mastermind 32295 points

Hello Stuart,

Please allow us some time to look into this, I am currently out of office so I will get to your question next week.

-Josue

0 Josue Zamitiz-Ayala over 1 year ago in reply to Josue Zamitiz-Ayala

TI__Mastermind 32295 points

Hello Stuart,

For your first question it seems to me that the GPIO used is up to the designer of the system to pick a GPIO that is available and/or convenient.

For the second question I will have to defer to our USB expert.

Best,

-Josue

0 Stuart Baker over 1 year ago in reply to Josue Zamitiz-Ayala

TI__Genius 10630 points

Josue,

Any updates on the second question?

Thanks,

Stuart

0 Praveen Rao over 1 year ago in reply to Stuart Baker

TI__Mastermind 48263 points

Hello Stuart,

Stuart Baker said:
In host only mode, the TRM still mentions needing a GPIO for the ID pin (pulled down). Is this still really required, or can the USB interface be configured to be forced into host only mode? It seems rather silly to have to use an unconnected GPIO for the ID pin feature when we know the port will be in host mode no matter what.

Ideally if we want the USB interface to be only operate in host mode, then the ID pin is actually a don't care. But since the same USB software driver would be used for both the USB instance, it may have the software logic to check for the ID pin status to determine the mode switch. So we suggest to have the ID pin pulled down for this particular interface. Or else, suggest to make the required driver change.

Thanks.

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AM5746: USB ID GPIO Pin